CA1225926A - Method of procedure for construction of drilled well, principally water producing well and well outfit for carry out the procedure - Google Patents
Method of procedure for construction of drilled well, principally water producing well and well outfit for carry out the procedureInfo
- Publication number
- CA1225926A CA1225926A CA000472130A CA472130A CA1225926A CA 1225926 A CA1225926 A CA 1225926A CA 000472130 A CA000472130 A CA 000472130A CA 472130 A CA472130 A CA 472130A CA 1225926 A CA1225926 A CA 1225926A
- Authority
- CA
- Canada
- Prior art keywords
- casing string
- pressure
- open
- valve
- fluid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/02—Subsoil filtering
- E21B43/08—Screens or liners
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/02—Subsoil filtering
- E21B43/04—Gravelling of wells
Abstract
A B S T R A C T
Subject of the invention is method of procedure for construction of drilled well, principally water producing well and well outfit for carry out the procedure.
The main point of the procedure in conformity with the invention is that a casing string having essentially uniform diameter throughout is installed into the drilled hole intersecting one or more fluid-bearing strata, every single fluid-bearing stratum is sealed from each other by elastic open-hole packer, which can be pressurized and is fitted to the cylinder jacket of casing string, while caverns are developed around screen sections of casing string installed into the fluid-bearing strata, which are filled up with coarse grained sand and/or gravel if necessary. The well outfit in conformity with the invention consists at least of the followings: casing string fitted with one screen-section, of open-hole packer, of cement-ing valve and of sand-intake valve, which can be character-ized as follows: there are rows of holes /20, 47, 50/
running in circles on the cylinder jacket of the uniform diameter casing string /1/, positioned in various distances from each other, and to the proper rows of holes open-hole packer /4/, cementing valve /7/ or sand-intake valve /13/ is fitted, which are actuated by pressure transfer device /28, 53/, these units can be moved up and down inside the casing string /1/, the two closing de-vices made of two inner elastic pipes /32/ confine and close a given section of casing string /1/, the screen section /3/ of casing string /1/ consists of screen pipe /63/ having larger openings than the largest sand grain size of the fluid-bearing stratum /2/, of plate tube /64/, having longitudinal protruding slots, and between the two elements wire spiral /65/ is placed, and this screen section /3/ is confined by one protector ring /66/ on the top and one at the lower end.
/Figure 2/
Subject of the invention is method of procedure for construction of drilled well, principally water producing well and well outfit for carry out the procedure.
The main point of the procedure in conformity with the invention is that a casing string having essentially uniform diameter throughout is installed into the drilled hole intersecting one or more fluid-bearing strata, every single fluid-bearing stratum is sealed from each other by elastic open-hole packer, which can be pressurized and is fitted to the cylinder jacket of casing string, while caverns are developed around screen sections of casing string installed into the fluid-bearing strata, which are filled up with coarse grained sand and/or gravel if necessary. The well outfit in conformity with the invention consists at least of the followings: casing string fitted with one screen-section, of open-hole packer, of cement-ing valve and of sand-intake valve, which can be character-ized as follows: there are rows of holes /20, 47, 50/
running in circles on the cylinder jacket of the uniform diameter casing string /1/, positioned in various distances from each other, and to the proper rows of holes open-hole packer /4/, cementing valve /7/ or sand-intake valve /13/ is fitted, which are actuated by pressure transfer device /28, 53/, these units can be moved up and down inside the casing string /1/, the two closing de-vices made of two inner elastic pipes /32/ confine and close a given section of casing string /1/, the screen section /3/ of casing string /1/ consists of screen pipe /63/ having larger openings than the largest sand grain size of the fluid-bearing stratum /2/, of plate tube /64/, having longitudinal protruding slots, and between the two elements wire spiral /65/ is placed, and this screen section /3/ is confined by one protector ring /66/ on the top and one at the lower end.
/Figure 2/
Description
~L2~5~Z6 METHOD OF PROCEDUR3 FOR CONS~RUC~ION OF DRITT~D WE~, PRINCIPAL~Y WATER PRODUCING WE~ ~ND WE~ OUTFIT
~OR CARRY OU~ ~H~ PROCEDURE
Subject of the invention is method of procedure ~or construction of drilled well, principally water producing well and well out~it for carry out the procedure.
~ here are a number of known methods and a lot of equipment long since for putting down drilled wells e.gO water producing arte~ian wells, or petroleum and gas wells, which are improved continuous-ly. In general drilling rigs are used for constructio~
of drilled wells~ besides equipment like conductor pipes, casing strings, screen sets and stuffing boxe90 ~he screen sets consist of extensio~ pipe, screen pipe and ~ilt sump.
Since the drilled hole may intersect more fluid-bearing strata, in order to avoid co~mu~ication and mixing of ~luids of different aquiferY along the screen set, the slippage of silt layerY respectively7 casing-cementing or ca~ing-snoe~grouting is done.
~on~entionally a well could be completed as single~
production well, by tapping only one fluid-bearing ~tratum, or as multy~production well, tapping a group of layers, i~ more than one fluid-bearing stratum were of the same hydrostatic head approxi-, ~25~Z6
~OR CARRY OU~ ~H~ PROCEDURE
Subject of the invention is method of procedure ~or construction of drilled well, principally water producing well and well out~it for carry out the procedure.
~ here are a number of known methods and a lot of equipment long since for putting down drilled wells e.gO water producing arte~ian wells, or petroleum and gas wells, which are improved continuous-ly. In general drilling rigs are used for constructio~
of drilled wells~ besides equipment like conductor pipes, casing strings, screen sets and stuffing boxe90 ~he screen sets consist of extensio~ pipe, screen pipe and ~ilt sump.
Since the drilled hole may intersect more fluid-bearing strata, in order to avoid co~mu~ication and mixing of ~luids of different aquiferY along the screen set, the slippage of silt layerY respectively7 casing-cementing or ca~ing-snoe~grouting is done.
~on~entionally a well could be completed as single~
production well, by tapping only one fluid-bearing ~tratum, or as multy~production well, tapping a group of layers, i~ more than one fluid-bearing stratum were of the same hydrostatic head approxi-, ~25~Z6
- 2 -mately. ~asic disadvantage of the conventional practice is that the casing diameters are reduced telescopically downwards, so in case medium and deep wells, the upper part of the hole must be drilled with much bigger bit size than the required end diameter. Consequently the volume o~ cuttings to be w~ed out of the hole is enormous, drilling and transportation operations become difficult, the use of large capacity drilling rigs and the need o~ high power consumption arise in order to manipulate the big size equipment.
The mentioned operations need surplus material, machinery, power, working time in one respect; the total cost of the construction is increased by the use of expensive stuffing-boxes for sealing the annùlar space~ between telescopically positioned casing strings on the other hand; moreover, a big size casing costs much more than a smaller one, which is the determinant dimension of the well. ~his type o~ construction result~ in a relatively low-yield well e~en if geological conditions are favourable.
AdditionaIly if conditions are unfavourable, that is if dry well was drilled, the casing string can-not be recovered because it has been grouted already by necessity.
The mentioned operations need surplus material, machinery, power, working time in one respect; the total cost of the construction is increased by the use of expensive stuffing-boxes for sealing the annùlar space~ between telescopically positioned casing strings on the other hand; moreover, a big size casing costs much more than a smaller one, which is the determinant dimension of the well. ~his type o~ construction result~ in a relatively low-yield well e~en if geological conditions are favourable.
AdditionaIly if conditions are unfavourable, that is if dry well was drilled, the casing string can-not be recovered because it has been grouted already by necessity.
- 3~ 25926 An other basic problem of conventional wel~
drilling methods relate to the so called rule of gravel~packing, or in other words, the rule of screening, which prescribesthe granulation of form-ation material of the preselected fluid-bearing stratum compared to the size of screen opening along the length of the screen pipe. Should it prove necessary, the zone immediately surrounding the well screen was filled by sand, gravel or crushing, having adequate grain size, which again increased the hole size~
Attempts were made trying to overcome at least partly the mentioned problems by various solutions.
~he Hungarian patent specification No. 165 826 introduces a screen assembly for drilled wells, where there are protrusions outwards in predeter-mined distances in order to avoid clogging. ~his type of screen specified in this patent specifica-tion needs large capacity compressors and pressure rates to pump the aquifer's fine grained sand to the surface. Besides this, in case lf this procedure i9 applied, there is the danger that the developed cave, the so called cavern will get a ~hape dis-advantageous for water producing, so after a while it becomes silt-up and sand-up, /nich is certainly
drilling methods relate to the so called rule of gravel~packing, or in other words, the rule of screening, which prescribesthe granulation of form-ation material of the preselected fluid-bearing stratum compared to the size of screen opening along the length of the screen pipe. Should it prove necessary, the zone immediately surrounding the well screen was filled by sand, gravel or crushing, having adequate grain size, which again increased the hole size~
Attempts were made trying to overcome at least partly the mentioned problems by various solutions.
~he Hungarian patent specification No. 165 826 introduces a screen assembly for drilled wells, where there are protrusions outwards in predeter-mined distances in order to avoid clogging. ~his type of screen specified in this patent specifica-tion needs large capacity compressors and pressure rates to pump the aquifer's fine grained sand to the surface. Besides this, in case lf this procedure i9 applied, there is the danger that the developed cave, the so called cavern will get a ~hape dis-advantageous for water producing, so after a while it becomes silt-up and sand-up, /nich is certainly
4 ~ ~z~92~
disad~antageous for both the cleanliness of water and pump wear. This problem can be eliminated temporarily by applying additional procedures, but this will limit the production, in addition it is costly~
The Hungarian patent specification ~o. 162 569 descrlbes a solution, where the fluid-bearing stratum is reamed by a special drilling method; after the cavern i~ made 7 the screen set equipped with silt-p-ipe having reduced diameter is installed, then the cavern is filled up with coarse grained sand. Dis-advantage of thi-, solution is that the hydraulic friction losses of gravel~pack applied in the vicinity of screen silt-up, therefore in certain formations it is not applicable.
Mutual disadvantage of both described accomplish-ments is that even if conditions are favourable, their application results single-production well only, i.eO
merely one single fluid- bearing stratum can be put on production.
In contrast with this, it is known that in oil wells more productive zones are simultaneously in production; where' the porous formations are cased with casing string and/or with tubing, and are grouted, The procedure applies so called perforators to open layers in such a way that the wall of steel pipe and
disad~antageous for both the cleanliness of water and pump wear. This problem can be eliminated temporarily by applying additional procedures, but this will limit the production, in addition it is costly~
The Hungarian patent specification ~o. 162 569 descrlbes a solution, where the fluid-bearing stratum is reamed by a special drilling method; after the cavern i~ made 7 the screen set equipped with silt-p-ipe having reduced diameter is installed, then the cavern is filled up with coarse grained sand. Dis-advantage of thi-, solution is that the hydraulic friction losses of gravel~pack applied in the vicinity of screen silt-up, therefore in certain formations it is not applicable.
Mutual disadvantage of both described accomplish-ments is that even if conditions are favourable, their application results single-production well only, i.eO
merely one single fluid- bearing stratum can be put on production.
In contrast with this, it is known that in oil wells more productive zones are simultaneously in production; where' the porous formations are cased with casing string and/or with tubing, and are grouted, The procedure applies so called perforators to open layers in such a way that the wall of steel pipe and
- 5 ~ 12~926 the set cement behind is shot through, or it is slot-ted~ The opening created in this manner have small cross section area allowing limited flow-in-rates, by which the optimum yield can far not be achieved.
Moreover, if more than one zone were opened at the same time, only one hal~ of the casing can be put on production through opening made by oriented perforation.
Casing perforation is above all an expensive and time c~onsuming procedure.
~he purpose of the invention described in patent speciflcation No~ US 3 915 227 is to eliminate the need of perforation. The tool is highly sophisticated, complicated design, is made of metal7 the joining parts are machined with tight tolerances, it is very expen-sive. On the other hand, when this accomplishment is being applied, the productive zones can be put on production by the application of smaller size screen set than well casing diameter only. In case of a dry hole, the e~pen~ive equipment and casing column cannot be recovered.
In the oil well drilling technique, there are a number o~ various known accomplishments to close the full section of open-hole on the one hand, and annular ~space on the other hand between casing and drilled hole, an other part of these devices have been de-signed to overcome problems in drilling and production _ ~ 1225~26 derived from drill-stem testing~ Such accomplishments are described among others in the following patent specification~: GB-PS 1 441 131 and 1 455 955, DE-PS
2 443 094 and HU PS 156 561. These acoomplishments, however, are first of all for petroleum industry, so they are practically not applicable in water well drill ing practice9 because of their complicated designO
Summarizing the known accomplishments on the basi~ of the presentlevel of technique, it can be proved that all the water well3 nowadays are single-production well~, or w211s which produce water out of a group of strata: at the present time there is no such a known accomplishment by means o~ the water content of two or more strata having different hydro-static head could be brought to the surface throughone wellO Complicated and expensive constructions de~igned ~or oil wells are not practical and economic~
al for water wellsD Drilled well~ can be character-ized by telescopically arranged steel pipe~7 applying gradually decrea~ing diameter~ downwards, which in-volve drilling bigger hole diameter~ tha~ necessary.
An additional difficulty is developing a zone having ample permeability around the screen, e~g. gra~el-pack forming in the aquifer, which was a factor to increase the diameter of drilled hole~ at the same 2~;92Ç~
time the efficiency of water output could not be increased properly.
The aim of this invention is to terminate the listed disadvantageous features, to render a procedure for producing the fluid content of more than one fluid-bearing stratum simultaneously through one single well economically and with maximum yield.
Various aspects of the invention are as follows:
A method for construction of a drilled well comprising the not necessarily sequential steps of:
(a) drilling a bore hole through at least one fluid bearing strata' (b) sealing the upper loose formations by a retrievable conductor pipe;
lS (c) determining the various levels of intersected fluid bearing strata by geophysical logging;
(d) assembling, in conformity with the level and distance between said determined levels of intersected fluid bearing strata, a casing string such that open-hole packers correspond to said determined levels and location of said fluid bearing strata;
~e) installing and temporarily fixing said casing string in said bore hole;
~f) pumping fluid up through said bore hole until fluid is obtained;
(g) determining by test results the quality of fluid pumped through said casing string;
(h) if the test results are favorable, grouting of said casing string in said bore hole and placing said well into full production; or (i~ if the test results are unfavorable, filling up of said bore hole with concrete;
wherein, (i~ said casing string has a uniform diameter throughout its length;
(ii) said open-hole packers, made of elastic material, are fixed to the jacket of said casing string;
i326 - 7a -(iii) said open-hole packers close off said determined levels of intersected fluid bearing stratum by being expandable by applied pressure ~rom their insides;
S (iv) said open-hole packers provide fine grained formation material closely adjacent to said fluid bearing strata;
(v) a screen set assembly of said casing string is located proximal to said determined levels of fluid bearing strata;
(vi) said fine grained formation material is pumped to the surface through large openings of said screen set assembly by air pressure such that throughout the total thickness of said determined levels of fluid bearing strata an arch shaped cavern is developed;
(vii) said pumping of said fine gained formation material continues until clean fluid is pumped through said casing string;
(viii) if said test results are favorable, said cavern is filled up with coarse grained material comprising sand and/or gravel which composition is passed through said casing string by passing through openings radially located in the exterior of said casing string;
and (ix) if said test results are unfavorable, said casing string is hoisted to the surface and said bore hole is sealed, as mentioned.
An apparatus for construction of a drilled well comprising:
(a) a casing string fitted with a screen set section, at least one open-hole packer, a cementing valve and a sand-intake valve;
(b) a row of holes radially located on the cylinder jacket of said casing string is provided, said rows of holes being spaced apart from one another;
- 7b -~c) the diameter of said casing string, along its length, being uniform;
(d) said rows of holes corresponding to said open-hole packer, said cementing valve and said sand-intake valve;
(e) a pressure-transfer device for selectively activating said open-hole packer, said sand-intake valve and said cementing valve;
(f) said pressure-transfer device being selectively positionable within the inside of said casing string to positions proximal to said rows of holes;
(g) said pressure-transfer device having at least two closing devices made of two inner elastic lS pipes which confine and close off a given section of said casing string;
(h) said screen set section of said casing string consisting of a screen pipe having larger openings than the largest sand grain size of the determined fluid bearing strata of a bore hole through which said well mechanism is intended to be installed for well production;
(i) a plate tube is provided having longitudinally protruding slots and located between said slots is a spiral wire, said screen section being confined by a protector ring on both the top and the bottom;
(j) said pressure-transfer device further comprising: (i) a pressure pipe having a smaller diameter than said casing string;
(ii) said pressure pipe being closed at the bottom by closing means;
(k) said pressure-transfer device being connected to a source of pressure conveying means;
(1) said inner elastic pipes are secured to said pressure pipes by clamps, said closing devices being separated from each other and defining an inner cavity therebetween;
- 7c- ~2S;92~
(m) said inner elastic pipes being selectively expandable against the inner surface of said casing string;
(n) a plurality of pressure holes pass through said pressure pipe, said pressure holes being located below said inner elastic pipe; and (o) at least one hold is fitted with a check valve, at least one of said pressure holes being located between said closing devices.
The task of the invention is to develop such a procedure for construction of drilled well, principally water producing well and well outfit for carry out the described procedure, which allows the application of only one uniform size casing string throughout the total length, which permits the developing of-screen set vicinity having optimum permeability and maximum yield, which allows isolation of fluid-bearing strata from each other in a simple and efficient way, and which makes it possible to fix casing string temporarily and safely in order to permit its pulling out of the well if later on the necessity of pulling may arise.
The task set is being accomplished by the invention through a procedure, in which a casing string is in-stalled into the drilled hole having uniform diameter throughout, the casing string is fixed temporarily, the open-hole-packer made of elastic material is fixed ~3 ~2~5926 to the jacket o~ the casing string, the packer closes the given fluid-bearing stratum by being expanded by the applied pressure from inside, the fine grained part of formation material, or the full volume of it in close vicinity of the screen assembly of the casing 3trin~ placed into the fluid-bearing stratum, is pumped to the surface through the large openings of the screen assem31y by air lift, gradually, throughout the total thicknes~ of the fluid bearing stratum and by means o~ this, an arch shaped cavern is developed unt~ clean fluid is being pumped, after having analyzed the fluid of the tapped ~luid-bearing stratum, if conditions are favourableS the casing string positioned above the tapped fluid-bearing stratum is grouted through its proper side openings or through ejector pipe, then tubing is installed9 if necessary the developed cavern i~ filled up with coarse grained sand and/or gravel through the proper side openings of the casing string, a~ter that the tapped stratum is closed, then new strata located at a higher or lower level can be tapped, after tubing string and pump was installed the same way as described, and i~ conditions are unfavourable, the temporary fixation of casing string i9 releaged and hoisted to the sur~ace and the hole is sealed as u~ualO
~ 9- ~2~;i9~
According to the invention it i~ expedient, if formation ~trength is unfavourable, the formation material should be brought to the surface by flow of fluid or if there is not enough hydraulic pressure available, by pumping through the screen opening which are larger than the largest grain size of the formation material; in order to develop.cavern along the screen set of ca~ing string, the washed out cavern i~ ~illed up gradually with 1,5 to 3,0 mm size coarse grained sa~d and/or gravel through the proper side opening of ca3ing string.
The well outfit, suitable to carry out -the procedure in conformity with the invention consists at least of the followings: casing string with one screen-section, one open-hole-packer, one cementing valve and one san~intake va~e, which can be characterized as follows: there are rows of hole~ running in circles on the cylinder jacket of the uniform diameter casing string, positioned in variou~ distances from each other, and to the proper rows of holes open-hole-packer, cementing valve or sand-intake valve i9 ~itted, which are actuated by pressure transfer device, these units can be moved up and down inside the casing string, the two closing devices made o~ two inner elastic pipes confine and close a given section of casing string, the - 10~ 5~
screen section of the casing string consists of ~creen pipe having larger opening than the largest sand grain size of the fluid-bearing stratum, of plate tube, having longitudinal protruding slots, and between the two elements wire spiral i8 placed, and this screen section i~ confined by one protector ring on the top and one at the lower end.
One of the basic devices of the well outfit in eonformity with the invention is the open hole-packer, which is made of elastic pipe fixed to the casing string at both ends with clamps, consists and confines the firstvalve ring made of elastic material, which is being fitted to the proper row of holes of the casing string, this outer elastic pipe is reinforced on both ends by plate~ overlapping each other increasing the actuating pressure.
The first va~e ring of the advantageous open-hole-packer in conformity with the in~ention consists of closing elements vulcanized into the material of the ring, which protrude out of it and fit to the row of holes, the first valve ring is confined by protect-or ring3 on both ends: an other advantageou~ character-istic of the design i~ that the clamp~ of outer elastic pipe~ are rings prestressed before welding, ~hich are sealed off from the outer elastic pipe by steel plate 1 :L - 12zs~z6 and heat insulated b~J fibre thermal board below along the area of weld.
The characteristic feature of the cementing va~-e of the well outfit in conformity ~ith e invention is that it consists of a second elastic valve ring fitted to the row of holes of the casina strir~ positioned above the open-hole-pac~er tigntly surroundlng it, there are closing elements vulcanized into the material of it, which protrude out of the valve rin~ and fit to the row of holes, the second valve ring is confined by protector rings on both sides.
The sand-intake valve in conformitJ-l;rith the invention serves for filling up of caverns in case of necessity, it consists of a third valve ring made of elastic material, having smooth surface, it is fitted to a row of blg holes, machined into the casing string and is posltioned between the open-hole-packer and the screen-section, which surrounds the caslng tightly and is confined by protector rings on both sides.
~he pressure transfer device of the well outfit in conformity with the invention "/hich ~ctuates the open-hole-packer, the cemènting lraIve anl sand-intake val~-e can be characterized by a pressur^ pipe, having smaller diameter than casing string, wh ch is closed at the bottom or fitled with foc -valve, is connec ed to the source of pre__ure conveJ~ e ~r, this :,~
pressure pipe is fitted with closing devices made of inner elastic pipes clamped to the pressure pipe on both ends in proper distance from each other, which can be expanded against the inner surface of casing string, and below the inner elastic pipe there are holes running into the pressure pipe and between the two closing devices there is at least one single hole on the pressure pipe fitted with check valveO
Pressure transfer device applied to open-hole-; 10 packer is fitted with two-way needle ~alve, serves as check valve, but in case of the pressure pipe of pressure~transfer device:applied to cementing valve and sa~intake valve is surrounded by an intermediate pipe, havlng an open end at the bottom, holes of which are connected to holes of pressure pipe by threaded stubs, and a fourth elastic valve ring confined by retainer rings serves as check valve, the inner elas-tic pipes of closing devices are fixed to the inter-mediate pipe, the holes of intermediate pipe covered by inner elastic pipes are connected to pressure pipe holes by pipe stubs~
The advantage of the accomplishment in conformity with the invention is the application of smaller diam-eter casing string than known well structures, the temporarily operated packers used before permanent application are of simple designs, materials used eOgO
-''' .
- 1 3 ~ 5926 rubber or plastic, do not need high precision in machlnlng, material costs are reasonable, besides cost of manufacture and fitting i3 cheaper than the complicat-ed equipments of the past, Packer3 in conformity with the invention can be assembled at the drill site, on the spot.
The open hole packers and valve rings of well outfit can be easily selected and manufactured for given pipe diameters.
; 10 : Among the most important advantages of the in-vention there are two significant characteristics, one of them i9, that more than one fluid-bearing stra-: :tum can be put on:production simultarLsously through : one~drilled well, secondly, that resistance of flow ~15 around screen set:can be reduced. By this means the : speclflc yisld of wells completed in conformity with the invention's procedure can be increased three to four times compared to conventional wells having the same scrssn dlameter, mo~ver, even in unfavourable formation and hydrological conditions, the yield of , well oan be doubled at least by applying gravel pack.
The~devices of well structure in cor,formity with : the invention can be handled more easily, and are ~; suitable for higher productivity, 'he for~ation pack-: ~25 ers can be loaded by high pressures, too, The screen .
22592~
assembly in conformity with the invention is of simple design, easy to fit, replaceable, has longer life time and.while in operation there is no need of cleaningO
At last, it is a big advantage of accomplishment in conformity with the invention, that in case of a dry hole the casing string having a high value is re-coverable and can be reused.
~he invention will be introduced in details through the drawings:
Figure 1: Scheme of well construction in conform-ity with the invention for single pro-duction well, side-view, partly section;
Figure 2: Side-view scheme of well construction for double production well, partly section;
Figure ~: ~ongitudinal section scheme of double production well construction, partly in producing phase;
Figure 4: Schematic diagram of open-hole packer in conformity with the invention applied with temporary casing string;
- Figure 5: ~ongitudinal section of open-hole packer and actuating pres~ure-transfer device in conformity with the invention;
: 25 Figure 6: Detail "a" of Figu~e 5, ~howing the ~`
, 259~6 enlargement of first valve ring of open-hole packer;
Figure 7: Detail "b" of Figure 5, showing the enlargement of clamp arrangement of open hole packer;
Figure 8: Detail "c" of Figure 5, showing the enlargement of clamp arrangement of pressure-transfer device's inner elastic pipe;
Figure 9: Detail-"d~i of Figure 5, showing the . enlargement of needle valve of pressure-transfer device;
Pigure 10: Cross section of outer elastic pipe of open-hole packer near its fixed end;
Figure 11: Cross section of the fixed~end of elastic pipes i~ the vicinity of clamp weld, before welding;
Figure 12: Shows a section of casing string, with rows of holes having different object3 ~0 and valve rings of those;
Figure 13: "A-A" cross section of Figure 12, through a cementing valve in conformity with the invention;
Figure 14: "B-B~ cross section of Figure 12, through a sand-intake valve in conform-~: ity with the invention;
`
.
16- ~1L2~59Z~i :
: Figure 15: View o~ sand-intake valve and the pressure-transfer device and actuat-ing device belonging to the former, in addition a part of screen-section, .
: partly section;
Figure 16: Detail "e" of Figure 15, showing the enlargement of clamp arrangement o~
inner elastic pipe;
, ~igure 17: :Section -through "C-C" of Figure 15;
.
lO~: Figure 18~: Deta~ af Figure 17.
Flgure~l: shows well con~truction for one fluid- :
bearing stratum /2/~l,e;. a single production well in ~ :
oonformity~with`:the~ i~vention,:~It indicates that the :: casing~string~ low~red into:the~drilled well~has 15 ~uniform diameter:throughout,~ even ~the ~oreen set /3/ :
has the:~same ~diameter~which i: located ln the fluid~
~bearing stratum~ 2/. Above:the fluid-bearing stratum /2/ :~
`: an opèn-hole packer /41 is located, fixed at: both end to the.~ca~ing ~tring tl/ py clamps /5/; the packer `:
: 20`: ` will be .~pe~ci~ied later. Above the open-hole packer /4/ there lg oementing valve 171 confined by protector ring~:/6/, the~ first:annular ~pace /9/ between the wall :of~the~hole /8/ and the casing string tl/ can be grouted when permanent fixing becomes due, which means that 25~ `:casing cementing 19 carried out by the cementing valve ~ , , . ~ : -: ~ ' , /7t. The bottom of well outfit is closed by a plug /10/, the top of the hole is protected by conductor pipe !11/, which is retractable~
Figure 2 illustrates well construction for two fluid-bearing strata /2/, iOe. double-production well, where there is one open-hole packer and one cementing valve above both fluid-bearing strata /2/~ Compared to the arrangement shown in Figure 1, here 7 there are caverns~/12/ developed in the ~luid-bearing strata j2/
around the screen section, in order to fill up these caverns with sand and/or gravel, there are sand-intake valves /13/ located on casing strirg/l,/ above both fluid~bearing strata~/2/. ~he aim of developing cavern~
/12j ia to develop surroundings havlng good permeability, at the same time good ~iltering ~eatures, which does nQt have~sIimlng~tendency, but assures optimum yleld in tha vicinity os screen ~ection. ~he developed cav-ern~ are not necessarily filled up if formation strength and ~tructure allow. In loose formations it is practical to fill up caverns /12/ through sand-lntake valve jl3/
with 1,5 to 3,0 mm grain size coarse sa~d and/or gravel. Detailed specification of caverns will follow.
Figure 3 illustrates well construction for two fluid-bearing strata /2/ too, in that case the figure shows well outfit for two water-bearing strata being al-` ~ .
~.~
r ~ - `
- 18 - ~22~92~
' :
ready in producing phase. Compared to ~igure 2, the difference i9 that within the casing string /lj already grouted, a tubing string /14/ is positioned, which extends below the upper fluid-bearing stratum /2/ and it is plugged by closing head /15/. ~he pump /16/
pumps water from the lower fluid-bearing stratum /2/
through tubing string /14/~ pump /17/ located out of tubing ~tring /14/ deliver~ water from the upper ,, fluid-bearing stratum.
Figure 4 illu~trates a special case, when badly swelling formations, or loose clastic zones causing lost circulation are being drilled through~ In order to overcome such difficulties, it is practical to lower a~;temporary casing strlng /laj ~ fitted wlth a left~hand thread coupling /19/ and with an open-hole packer at the bottom. ~he critical zone~ of the hole : .
will be sealed off from the lower part by putting the open-hole packer j4/~under pressure, so the los~oP
valuable drilling mud of big quantities is eliminated.
After the drilling is completed, the temporary casing string /18/ is retracted together with the open-hole packer~/4/, in case it became stuck because o~ caving or ~ettling~, it can be unscrewed by turning the coupling /l9/ to~the right and hoisted, ensuring it can be replaced by a permanent casing string, or the temporary .
: : :
1~59~6 casing string /18/ is hoisted after installing the permanent casing string.
~ igure 5 shows the detailed arrangement of the open-hole packer and the actuating pressure-trans~er device in conformity with the invention. ~he open-hole packer /4/ itself is made of elastic pipe /22/
fixed to the ca~ing string ~1/ at both ends with clamps /5/,~consists and encloses the ~irst valve ring /21/ made of elastic material, which is being fitted tightly to the proper row of holes /20/ of the casing string In ~igure 6 it is shown that the valve ring /21/
is confined by protector rings 123/ on both ends and that a row :of balls~/24/ is vulcanized into the valve ring /21/, which fit to the~row of~holea /20/. The :Figure:7 shows the clamping of the outer elastic pipe-: end~/22/, it is visible that the elastic pipe /22/ i9 : reinforced by~plates /25/ on both end near to the clamp overlapping each other, as illustrated in ~igure 10 which are vulcanized into the material of èlastic plpe /22/ and the clamp /5/ is covered by retainer ring /26/. Moreover, Figure 7 shows that the backing-rlng /54/ placed between casing /1/ and elastic pipe /22/ is grooved on the surface which contacts elastic Pipe end /22/ and is pressed by clamp /5/ to ~ ' - 20 - ~2~5926 ensure firm fastening, additionally the backing ring /54/ is recessed according to the shape of the clamp /5/. ~he outer elastic pipe /22/ put ~mder pressure, forms a second annular space /27/, which is located in the ~irst annular space /91 existing between casing string /1/ and the wall of drilled hole /8/.
~he task of the pressure-transfer device /2~/ :
is to actuate open-hole packer /4/, in other words, to put outer elastic pipe /22/ under pressure, which .
consists of~a pressure pipe /3y having smaller diameter than caslng string /1/,~whic~h is closed at the bottom and fitted~with foot-valve /29/,:it is connected to the source of pressure conveying medium, which pressure :
i . 15 ~ pipe iæ~fitted with:two closing devices arranged in 1 . ~ . : :
proper di9tance from each other, the closing devices can be expandcd against the inner surface o~ casing string /l/:~and axe in ~act designed as inner elastic :
pipes /32l closed by clamps 131/ o~ both ends. ~igure 8~shows ;thab inner elastic pipe ends are fixed the same way ~s the~outer~elastic pipe ends /22/, but here the ~ use oP embedded plates /25/ i~ not necessary. Clamps : /31/ are surrounded by backing rings /3310 In ~igure 8 Lt is vi~slble, that the inner elastic pipe j32/ is fixed .
to the end of enlarged section /34/ of pressure pipe ; /30/. Figure S shows again that in the middle of enlarged r;
:
- 21- ~L2~S926 section /34/ there is at least one machined hole /35/, which connects the inner space of pressure-pipe /30/
with inner space confined by elast1c pipe /32/. T~a two upper described closing devices expand again~ the inner surface of casing string /l/ if put~under pressure, establish1ng a t~ird annular space /~6/ between the outer surface of pressure pipe /30/ and the inner surface of casing string /l/ confined axially by the closing de-vIces. In this annular spacs /36/ there is at least one hole between the two closing devices on the pressure pipe /30/, which hole can;be closed by check valve.
: ~he check valve of the open hole packer's /4/ pressure .
transfer device /28/ is a two-way needle valve /38/, the design o~f whlch is shown in Figure 9. The ~igure show~ that the needle valve consists of valve needle~
.
/39/, spiral springs /401 and prestres~er~ 141/. ~he ta~k of thi3 needle valve /38/ is to control the flow of pres~ure medium from pressure pipe to the third an-nular space /36/.
One of the possible arrangement~ of welding the clamps of ela~tic pipes, exposed to pressure stress, is shown in Figure ll, through the example of ela~tic pipe's /32/ clamp 13l/. Namely one of the important features of the~invention is that the clamp should ha~e minimum space requirement, in view of the limited size of drilled hole or the inner ~pace of casing string , .
1~25926 /1/, and con~idering that if space requirement is reduced, smaller, consequently cheaper pipes can be applied. As it is shown in Figure 11, there are two lugs /42/ welded on the two ends of clamp /31/ having cylindrical shape, and these lugs are tied by adjusting bolt /43/ and nut /44/. A fibre thermal board /45/ and a ~teel protector plate /46/ is placed on the inner elastic pipe /32/ below the clamp /31/ in the vicinity of welding. In such a way the welding of clamp ends can be done, after that t~e lugs are removed, e.g.
cut by saw. ~he same procedure can be applied when clamps /S/ o~ outer elastic pipe /22t are fitted.
Figure 12 shows a section of casing string /1/ with cementing valve~/7/ on the top and sand-intake valve /131 below, without actuating device. ~he Figure shows clearly~, that the cementing valve /7/ consists of row of~holes /47/ positioned on casing string /1/, and of second valve ring /48/ which surrounds and cover~ the hole~, there are balls j49j vulcanized into the ring ~0 fitting to row of holes /47/, ju~t like in case of valve ring /21/o This is well illustrated in ~igure 13 which show~ that cementing valve /7/ is very similar to pressure-intake valve of open-hole packer' 9 /4/ outer elastic pipe /22/, moreover in given case it can be the same design. ~he cementing valve's /7/ valve ring /48/
.
3 ~l225926 is fixed by protector rings /6/ on both 3Ida3.
~ he 3and-intake valve /13/ has bigger diameter hole3 /50/ than the former cementing valve /7/, which are clo~ed bg a third valve ring i51/ having no balls, as ahown clearLy in ~igure 14. The valve ring /51/ is fi~ed by protector rlnga /52/.
~ igure L5 shows sand-intake valve ~13/ with pressure-transfer device /53/, as well as a part of screan /3/ section below. The design of sand-intake valve /13/ of the~pressure-tranafer device /53/ dif~ers somewhat ~rom the pressure-transfer device /28/ of open-hole packer /4/, however, Its prlnciple of operation i9 - essentislLy the same. The pressure pipe /30/ and the two closlng;de~rlc~es can be found here~tco, both are essentialLy~c;omposed of one inner elastic pipe /32/, ~which are flxed by clamp /31/, retainer ring /33/ and backing ring /54/ on both 9lde~ gure 16 shows this arrangement. The presaure plpe /30/ is surrounded by an open end intermediate pipe /55/ and the inner ela~tic pipe9 /32i are fastened to the latter; this ia not the same design as the former. The inner spaco of elastic pipes /32/ is connected to the innar space of pres~ure ~; pipe /30/ through pipe stubs /56/, 90 the closing devices put under pressure confine a fourth annular space /57 together with the inbermediate pipe /55/ and caaing .
, , .
~25926 string /l/, then again between the pressure pipe /30/
and intermediate pipe /55/ there is a fifth annular space /58¦. The threaded pipe stubs /59/ and /60/
fitted to the hole /37/ o~ the pressure pipe /30/
transfers pressure from pressure pipe /30/ into fourth annular space /57/, as the details are shown in Figure 17 and ~igure 18.
: At the bottom of Figure 15, the screen section /3/
of casing string /l/ located into the fluid-bearing stratum /2/ is illustrated, where the screen section /3/ consist~of screen pipe /63/, having larger size openings /62/ than the coarse grains of fluid-bearing stratum /2/, moreover of plate~tube /64/ having longi-tudinal /brldge-type/ protruding slots, and between lS the two elements a wire spiral /65l is placed, the described screen-section /3/ is confined by protector rings /66/ on both ends.
The procedure and method of operation of well out-fit in conformity with the invention are as follows:
~he well is drilled at the location marked out with a bit adequate in size to accomodate the largest size device fitted to the outer jacket of the uniform O~Do :
of casing string /1/. The conductor pipe /ll/ is used to case through loose overburden having caving materials, which will be hoisted before grouting is carried out.
:~ .
i~2~92 lhe drilling is done until the target fluid bearing strata /2/ are reached. The position o~ the intersected -fluid-bearing strata /2/ is defined by geophysical logging, and the casing string /l/ is installed into the hole assembled according to the position of the aqu~ers. In order to separate fluid-bearing strata /2/ from èach other there are open-hole packers /4/
fitted into the casing string /l/ in proper intervals and in proper number as per fluid-bearing strata /2/ intersected. Operation of these i9 done by in-stalling pressure-transfer device /28/ through casing stri~ /l/ into a position illustrated in .
Figure 5, then the pressure pipe /301 is connected to a pressure medium source, e.g. to a drilling rig flush pump,~or to a hand operated hydraulic pump, By this means the inner space of inner elastic pipe /~2/ is being pressurized through holes /35/, so the olosing devices of pressureotransfer device /28/
confine the third annular space /36/, which can be pressurized through row of holes /37/ and needle valve .
/38l. Thls pressure opens the first valve ring /21/
of open-hole packer /4/ by lifting row of balls /24/ and the pressure medium enters the second annu-lar space /27/ through row of holes /20/, where the pressure coming into being presses the outer elastic pipe /22/ against the wall of drilled hole /8/.
- 2~ - ~2~59~
In such a way the open-hole packer /4/ seals the annular space /9/ at a proper spot and prevents the communication, i.e. mixing and flow together of fluids of certain fluid-bearing strata between casing string /1/ and wall of drilled hole /8/.
After thi9 the pressure-transfer device /28/ is hoi9ted, following a pressure pipe /30/ is lnstalled~
equipped with a mixing head having openings, this lat-ter consi~ts~of a tubular closing~element suitable for closing the screen section, through thîs mixing head compressed air i pressed into the well by compressor. This results in the decrease of hydrostatic pre9sure above the mixing head and as a consequence of :
the pressure of fluld located in the fluid-bearing atratum, the flow of-~uid e.g. water starts into the well through the upper or lower section of the screen pipe /63/, namely together with flow of sand, which will be 9ettled into a tank on the surface.
After a quantity of sand which is equal with the ~0 predetermined volume of cavern /12/ has been pumped out, the pressure pipe and mlxing head together with closing device is lowered or pulIed upward, according to the position of cavern to ~e developed, and the pumping of sand is continued in conformity with the length of screen section /3/, i.e. until the lower or .
,_.
- , ~
27 - ~ 2259Z6 upper level of fluid-b~aring stratum /2/ is reached.
So a cavern is being developed along the screen sec-tion, which assure~ the free flow of fluid of aquifer into the wel1 construction and eliminates the occa~ional clogging of s~creen pipe as well as the si~ing up of fluid-bearing stratum.
lhe developments of cavern~ /12/ are done in each fluid-bearing stratum /2/, then the pressure pipe /30/
equipped with closing elements i3 hoisted. If the quant1tative and quality tests of the pumped fluid show good results, the annular space j9/ may be grouted, i.e. the installing of permanent well outfit may be done.
This procedure is carr1ed out by~lowering the pressure-transfer device /53/ down to the row o holes l47/ of cementing~valve /7/ and grout is pumped with adequate ; pressure~into the annular space /9f through valve ring /48l by lifting its row of balls /49/.
..
In case the quantitative and quality testsof pumped fluid shov disadvantageou~ results, so grouting i3 not carried out, the casing string /l/ can be hoi~ted with-out more ado, by chance after having demolished of the open-hole packers, 90 considerable value can be saved.
`~ The drilled hole is filled up by grout after the casing ~ string wa~ pulled out.
.
.
~- 28 - 1225926 When the hydrostatic pressure of fluid-bearing strata /2/, the grain size distribution of formation materials and tne strength of upper layers are known, decision is made whether the caverns .developed remain 5 open or will be filled up by 1,5 to 3,0 mm grain size sand or gravel. ~he sand-intake valve 113/ is practi-cally always the part of the well outfit, so there is the possibility that any time dur~ng the operation of-the well, if necessity may arise, the caverns can be filled up.
~ he operation of sand-intake:valve /13/ is done through the pressure-transfer device /53/, as shown ; in Figure 15. The pressure-transfer device /53/ is lowered to the level of row of holes /50/ of casing string /1/, see Figure 15 and the water-sand mixture is : being pumped in through pressure pipe /30/. ~he applied pressure will pressurize first the inner elastic pipes /321expanding those against the wall of casing string, so between the two closing elements a closed annular space /57/ is established. After this, the water-sand mixture will enter into this annular space /57/ through ; row of~holes j37/ and through valve ring /61/, in which adequate pressure will be generated too, this pressure will open the valve ring /51/ of 3and-intake valve /13/, through which the flow of the mixture will fill up the .
, ~
- 29- 122592~
cavern /12/. ~he fluid, i.e water to be produced will be air lifted to the surface through screen section /3/ and through the inner space o~ intermediate pipe /55/, i.e. through annular space /5~/0 After having completely fllled up caverns /12/, the pressure-transfer device /531 is pulled out of well construction and tubing s-tring~jl4/ is installed with pumps /16/ and /17/ and permanent production of well starts, see ; Figure 3~
~ecause~of the demand of room for pumps /16/ and 117i it may happen, that the upper section of the hole mu~st be constructed with bigger diameter up to the anticipated~pumplng level, in order to accomodate pumps, below this the casing string has uniform diameter ;
throughout.
.
:
:
. ~
.
;`` ~
Moreover, if more than one zone were opened at the same time, only one hal~ of the casing can be put on production through opening made by oriented perforation.
Casing perforation is above all an expensive and time c~onsuming procedure.
~he purpose of the invention described in patent speciflcation No~ US 3 915 227 is to eliminate the need of perforation. The tool is highly sophisticated, complicated design, is made of metal7 the joining parts are machined with tight tolerances, it is very expen-sive. On the other hand, when this accomplishment is being applied, the productive zones can be put on production by the application of smaller size screen set than well casing diameter only. In case of a dry hole, the e~pen~ive equipment and casing column cannot be recovered.
In the oil well drilling technique, there are a number o~ various known accomplishments to close the full section of open-hole on the one hand, and annular ~space on the other hand between casing and drilled hole, an other part of these devices have been de-signed to overcome problems in drilling and production _ ~ 1225~26 derived from drill-stem testing~ Such accomplishments are described among others in the following patent specification~: GB-PS 1 441 131 and 1 455 955, DE-PS
2 443 094 and HU PS 156 561. These acoomplishments, however, are first of all for petroleum industry, so they are practically not applicable in water well drill ing practice9 because of their complicated designO
Summarizing the known accomplishments on the basi~ of the presentlevel of technique, it can be proved that all the water well3 nowadays are single-production well~, or w211s which produce water out of a group of strata: at the present time there is no such a known accomplishment by means o~ the water content of two or more strata having different hydro-static head could be brought to the surface throughone wellO Complicated and expensive constructions de~igned ~or oil wells are not practical and economic~
al for water wellsD Drilled well~ can be character-ized by telescopically arranged steel pipe~7 applying gradually decrea~ing diameter~ downwards, which in-volve drilling bigger hole diameter~ tha~ necessary.
An additional difficulty is developing a zone having ample permeability around the screen, e~g. gra~el-pack forming in the aquifer, which was a factor to increase the diameter of drilled hole~ at the same 2~;92Ç~
time the efficiency of water output could not be increased properly.
The aim of this invention is to terminate the listed disadvantageous features, to render a procedure for producing the fluid content of more than one fluid-bearing stratum simultaneously through one single well economically and with maximum yield.
Various aspects of the invention are as follows:
A method for construction of a drilled well comprising the not necessarily sequential steps of:
(a) drilling a bore hole through at least one fluid bearing strata' (b) sealing the upper loose formations by a retrievable conductor pipe;
lS (c) determining the various levels of intersected fluid bearing strata by geophysical logging;
(d) assembling, in conformity with the level and distance between said determined levels of intersected fluid bearing strata, a casing string such that open-hole packers correspond to said determined levels and location of said fluid bearing strata;
~e) installing and temporarily fixing said casing string in said bore hole;
~f) pumping fluid up through said bore hole until fluid is obtained;
(g) determining by test results the quality of fluid pumped through said casing string;
(h) if the test results are favorable, grouting of said casing string in said bore hole and placing said well into full production; or (i~ if the test results are unfavorable, filling up of said bore hole with concrete;
wherein, (i~ said casing string has a uniform diameter throughout its length;
(ii) said open-hole packers, made of elastic material, are fixed to the jacket of said casing string;
i326 - 7a -(iii) said open-hole packers close off said determined levels of intersected fluid bearing stratum by being expandable by applied pressure ~rom their insides;
S (iv) said open-hole packers provide fine grained formation material closely adjacent to said fluid bearing strata;
(v) a screen set assembly of said casing string is located proximal to said determined levels of fluid bearing strata;
(vi) said fine grained formation material is pumped to the surface through large openings of said screen set assembly by air pressure such that throughout the total thickness of said determined levels of fluid bearing strata an arch shaped cavern is developed;
(vii) said pumping of said fine gained formation material continues until clean fluid is pumped through said casing string;
(viii) if said test results are favorable, said cavern is filled up with coarse grained material comprising sand and/or gravel which composition is passed through said casing string by passing through openings radially located in the exterior of said casing string;
and (ix) if said test results are unfavorable, said casing string is hoisted to the surface and said bore hole is sealed, as mentioned.
An apparatus for construction of a drilled well comprising:
(a) a casing string fitted with a screen set section, at least one open-hole packer, a cementing valve and a sand-intake valve;
(b) a row of holes radially located on the cylinder jacket of said casing string is provided, said rows of holes being spaced apart from one another;
- 7b -~c) the diameter of said casing string, along its length, being uniform;
(d) said rows of holes corresponding to said open-hole packer, said cementing valve and said sand-intake valve;
(e) a pressure-transfer device for selectively activating said open-hole packer, said sand-intake valve and said cementing valve;
(f) said pressure-transfer device being selectively positionable within the inside of said casing string to positions proximal to said rows of holes;
(g) said pressure-transfer device having at least two closing devices made of two inner elastic lS pipes which confine and close off a given section of said casing string;
(h) said screen set section of said casing string consisting of a screen pipe having larger openings than the largest sand grain size of the determined fluid bearing strata of a bore hole through which said well mechanism is intended to be installed for well production;
(i) a plate tube is provided having longitudinally protruding slots and located between said slots is a spiral wire, said screen section being confined by a protector ring on both the top and the bottom;
(j) said pressure-transfer device further comprising: (i) a pressure pipe having a smaller diameter than said casing string;
(ii) said pressure pipe being closed at the bottom by closing means;
(k) said pressure-transfer device being connected to a source of pressure conveying means;
(1) said inner elastic pipes are secured to said pressure pipes by clamps, said closing devices being separated from each other and defining an inner cavity therebetween;
- 7c- ~2S;92~
(m) said inner elastic pipes being selectively expandable against the inner surface of said casing string;
(n) a plurality of pressure holes pass through said pressure pipe, said pressure holes being located below said inner elastic pipe; and (o) at least one hold is fitted with a check valve, at least one of said pressure holes being located between said closing devices.
The task of the invention is to develop such a procedure for construction of drilled well, principally water producing well and well outfit for carry out the described procedure, which allows the application of only one uniform size casing string throughout the total length, which permits the developing of-screen set vicinity having optimum permeability and maximum yield, which allows isolation of fluid-bearing strata from each other in a simple and efficient way, and which makes it possible to fix casing string temporarily and safely in order to permit its pulling out of the well if later on the necessity of pulling may arise.
The task set is being accomplished by the invention through a procedure, in which a casing string is in-stalled into the drilled hole having uniform diameter throughout, the casing string is fixed temporarily, the open-hole-packer made of elastic material is fixed ~3 ~2~5926 to the jacket o~ the casing string, the packer closes the given fluid-bearing stratum by being expanded by the applied pressure from inside, the fine grained part of formation material, or the full volume of it in close vicinity of the screen assembly of the casing 3trin~ placed into the fluid-bearing stratum, is pumped to the surface through the large openings of the screen assem31y by air lift, gradually, throughout the total thicknes~ of the fluid bearing stratum and by means o~ this, an arch shaped cavern is developed unt~ clean fluid is being pumped, after having analyzed the fluid of the tapped ~luid-bearing stratum, if conditions are favourableS the casing string positioned above the tapped fluid-bearing stratum is grouted through its proper side openings or through ejector pipe, then tubing is installed9 if necessary the developed cavern i~ filled up with coarse grained sand and/or gravel through the proper side openings of the casing string, a~ter that the tapped stratum is closed, then new strata located at a higher or lower level can be tapped, after tubing string and pump was installed the same way as described, and i~ conditions are unfavourable, the temporary fixation of casing string i9 releaged and hoisted to the sur~ace and the hole is sealed as u~ualO
~ 9- ~2~;i9~
According to the invention it i~ expedient, if formation ~trength is unfavourable, the formation material should be brought to the surface by flow of fluid or if there is not enough hydraulic pressure available, by pumping through the screen opening which are larger than the largest grain size of the formation material; in order to develop.cavern along the screen set of ca~ing string, the washed out cavern i~ ~illed up gradually with 1,5 to 3,0 mm size coarse grained sa~d and/or gravel through the proper side opening of ca3ing string.
The well outfit, suitable to carry out -the procedure in conformity with the invention consists at least of the followings: casing string with one screen-section, one open-hole-packer, one cementing valve and one san~intake va~e, which can be characterized as follows: there are rows of hole~ running in circles on the cylinder jacket of the uniform diameter casing string, positioned in variou~ distances from each other, and to the proper rows of holes open-hole-packer, cementing valve or sand-intake valve i9 ~itted, which are actuated by pressure transfer device, these units can be moved up and down inside the casing string, the two closing devices made o~ two inner elastic pipes confine and close a given section of casing string, the - 10~ 5~
screen section of the casing string consists of ~creen pipe having larger opening than the largest sand grain size of the fluid-bearing stratum, of plate tube, having longitudinal protruding slots, and between the two elements wire spiral i8 placed, and this screen section i~ confined by one protector ring on the top and one at the lower end.
One of the basic devices of the well outfit in eonformity with the invention is the open hole-packer, which is made of elastic pipe fixed to the casing string at both ends with clamps, consists and confines the firstvalve ring made of elastic material, which is being fitted to the proper row of holes of the casing string, this outer elastic pipe is reinforced on both ends by plate~ overlapping each other increasing the actuating pressure.
The first va~e ring of the advantageous open-hole-packer in conformity with the in~ention consists of closing elements vulcanized into the material of the ring, which protrude out of it and fit to the row of holes, the first valve ring is confined by protect-or ring3 on both ends: an other advantageou~ character-istic of the design i~ that the clamp~ of outer elastic pipe~ are rings prestressed before welding, ~hich are sealed off from the outer elastic pipe by steel plate 1 :L - 12zs~z6 and heat insulated b~J fibre thermal board below along the area of weld.
The characteristic feature of the cementing va~-e of the well outfit in conformity ~ith e invention is that it consists of a second elastic valve ring fitted to the row of holes of the casina strir~ positioned above the open-hole-pac~er tigntly surroundlng it, there are closing elements vulcanized into the material of it, which protrude out of the valve rin~ and fit to the row of holes, the second valve ring is confined by protector rings on both sides.
The sand-intake valve in conformitJ-l;rith the invention serves for filling up of caverns in case of necessity, it consists of a third valve ring made of elastic material, having smooth surface, it is fitted to a row of blg holes, machined into the casing string and is posltioned between the open-hole-packer and the screen-section, which surrounds the caslng tightly and is confined by protector rings on both sides.
~he pressure transfer device of the well outfit in conformity with the invention "/hich ~ctuates the open-hole-packer, the cemènting lraIve anl sand-intake val~-e can be characterized by a pressur^ pipe, having smaller diameter than casing string, wh ch is closed at the bottom or fitled with foc -valve, is connec ed to the source of pre__ure conveJ~ e ~r, this :,~
pressure pipe is fitted with closing devices made of inner elastic pipes clamped to the pressure pipe on both ends in proper distance from each other, which can be expanded against the inner surface of casing string, and below the inner elastic pipe there are holes running into the pressure pipe and between the two closing devices there is at least one single hole on the pressure pipe fitted with check valveO
Pressure transfer device applied to open-hole-; 10 packer is fitted with two-way needle ~alve, serves as check valve, but in case of the pressure pipe of pressure~transfer device:applied to cementing valve and sa~intake valve is surrounded by an intermediate pipe, havlng an open end at the bottom, holes of which are connected to holes of pressure pipe by threaded stubs, and a fourth elastic valve ring confined by retainer rings serves as check valve, the inner elas-tic pipes of closing devices are fixed to the inter-mediate pipe, the holes of intermediate pipe covered by inner elastic pipes are connected to pressure pipe holes by pipe stubs~
The advantage of the accomplishment in conformity with the invention is the application of smaller diam-eter casing string than known well structures, the temporarily operated packers used before permanent application are of simple designs, materials used eOgO
-''' .
- 1 3 ~ 5926 rubber or plastic, do not need high precision in machlnlng, material costs are reasonable, besides cost of manufacture and fitting i3 cheaper than the complicat-ed equipments of the past, Packer3 in conformity with the invention can be assembled at the drill site, on the spot.
The open hole packers and valve rings of well outfit can be easily selected and manufactured for given pipe diameters.
; 10 : Among the most important advantages of the in-vention there are two significant characteristics, one of them i9, that more than one fluid-bearing stra-: :tum can be put on:production simultarLsously through : one~drilled well, secondly, that resistance of flow ~15 around screen set:can be reduced. By this means the : speclflc yisld of wells completed in conformity with the invention's procedure can be increased three to four times compared to conventional wells having the same scrssn dlameter, mo~ver, even in unfavourable formation and hydrological conditions, the yield of , well oan be doubled at least by applying gravel pack.
The~devices of well structure in cor,formity with : the invention can be handled more easily, and are ~; suitable for higher productivity, 'he for~ation pack-: ~25 ers can be loaded by high pressures, too, The screen .
22592~
assembly in conformity with the invention is of simple design, easy to fit, replaceable, has longer life time and.while in operation there is no need of cleaningO
At last, it is a big advantage of accomplishment in conformity with the invention, that in case of a dry hole the casing string having a high value is re-coverable and can be reused.
~he invention will be introduced in details through the drawings:
Figure 1: Scheme of well construction in conform-ity with the invention for single pro-duction well, side-view, partly section;
Figure 2: Side-view scheme of well construction for double production well, partly section;
Figure ~: ~ongitudinal section scheme of double production well construction, partly in producing phase;
Figure 4: Schematic diagram of open-hole packer in conformity with the invention applied with temporary casing string;
- Figure 5: ~ongitudinal section of open-hole packer and actuating pres~ure-transfer device in conformity with the invention;
: 25 Figure 6: Detail "a" of Figu~e 5, ~howing the ~`
, 259~6 enlargement of first valve ring of open-hole packer;
Figure 7: Detail "b" of Figure 5, showing the enlargement of clamp arrangement of open hole packer;
Figure 8: Detail "c" of Figure 5, showing the enlargement of clamp arrangement of pressure-transfer device's inner elastic pipe;
Figure 9: Detail-"d~i of Figure 5, showing the . enlargement of needle valve of pressure-transfer device;
Pigure 10: Cross section of outer elastic pipe of open-hole packer near its fixed end;
Figure 11: Cross section of the fixed~end of elastic pipes i~ the vicinity of clamp weld, before welding;
Figure 12: Shows a section of casing string, with rows of holes having different object3 ~0 and valve rings of those;
Figure 13: "A-A" cross section of Figure 12, through a cementing valve in conformity with the invention;
Figure 14: "B-B~ cross section of Figure 12, through a sand-intake valve in conform-~: ity with the invention;
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16- ~1L2~59Z~i :
: Figure 15: View o~ sand-intake valve and the pressure-transfer device and actuat-ing device belonging to the former, in addition a part of screen-section, .
: partly section;
Figure 16: Detail "e" of Figure 15, showing the enlargement of clamp arrangement o~
inner elastic pipe;
, ~igure 17: :Section -through "C-C" of Figure 15;
.
lO~: Figure 18~: Deta~ af Figure 17.
Flgure~l: shows well con~truction for one fluid- :
bearing stratum /2/~l,e;. a single production well in ~ :
oonformity~with`:the~ i~vention,:~It indicates that the :: casing~string~ low~red into:the~drilled well~has 15 ~uniform diameter:throughout,~ even ~the ~oreen set /3/ :
has the:~same ~diameter~which i: located ln the fluid~
~bearing stratum~ 2/. Above:the fluid-bearing stratum /2/ :~
`: an opèn-hole packer /41 is located, fixed at: both end to the.~ca~ing ~tring tl/ py clamps /5/; the packer `:
: 20`: ` will be .~pe~ci~ied later. Above the open-hole packer /4/ there lg oementing valve 171 confined by protector ring~:/6/, the~ first:annular ~pace /9/ between the wall :of~the~hole /8/ and the casing string tl/ can be grouted when permanent fixing becomes due, which means that 25~ `:casing cementing 19 carried out by the cementing valve ~ , , . ~ : -: ~ ' , /7t. The bottom of well outfit is closed by a plug /10/, the top of the hole is protected by conductor pipe !11/, which is retractable~
Figure 2 illustrates well construction for two fluid-bearing strata /2/, iOe. double-production well, where there is one open-hole packer and one cementing valve above both fluid-bearing strata /2/~ Compared to the arrangement shown in Figure 1, here 7 there are caverns~/12/ developed in the ~luid-bearing strata j2/
around the screen section, in order to fill up these caverns with sand and/or gravel, there are sand-intake valves /13/ located on casing strirg/l,/ above both fluid~bearing strata~/2/. ~he aim of developing cavern~
/12j ia to develop surroundings havlng good permeability, at the same time good ~iltering ~eatures, which does nQt have~sIimlng~tendency, but assures optimum yleld in tha vicinity os screen ~ection. ~he developed cav-ern~ are not necessarily filled up if formation strength and ~tructure allow. In loose formations it is practical to fill up caverns /12/ through sand-lntake valve jl3/
with 1,5 to 3,0 mm grain size coarse sa~d and/or gravel. Detailed specification of caverns will follow.
Figure 3 illustrates well construction for two fluid-bearing strata /2/ too, in that case the figure shows well outfit for two water-bearing strata being al-` ~ .
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r ~ - `
- 18 - ~22~92~
' :
ready in producing phase. Compared to ~igure 2, the difference i9 that within the casing string /lj already grouted, a tubing string /14/ is positioned, which extends below the upper fluid-bearing stratum /2/ and it is plugged by closing head /15/. ~he pump /16/
pumps water from the lower fluid-bearing stratum /2/
through tubing string /14/~ pump /17/ located out of tubing ~tring /14/ deliver~ water from the upper ,, fluid-bearing stratum.
Figure 4 illu~trates a special case, when badly swelling formations, or loose clastic zones causing lost circulation are being drilled through~ In order to overcome such difficulties, it is practical to lower a~;temporary casing strlng /laj ~ fitted wlth a left~hand thread coupling /19/ and with an open-hole packer at the bottom. ~he critical zone~ of the hole : .
will be sealed off from the lower part by putting the open-hole packer j4/~under pressure, so the los~oP
valuable drilling mud of big quantities is eliminated.
After the drilling is completed, the temporary casing string /18/ is retracted together with the open-hole packer~/4/, in case it became stuck because o~ caving or ~ettling~, it can be unscrewed by turning the coupling /l9/ to~the right and hoisted, ensuring it can be replaced by a permanent casing string, or the temporary .
: : :
1~59~6 casing string /18/ is hoisted after installing the permanent casing string.
~ igure 5 shows the detailed arrangement of the open-hole packer and the actuating pressure-trans~er device in conformity with the invention. ~he open-hole packer /4/ itself is made of elastic pipe /22/
fixed to the ca~ing string ~1/ at both ends with clamps /5/,~consists and encloses the ~irst valve ring /21/ made of elastic material, which is being fitted tightly to the proper row of holes /20/ of the casing string In ~igure 6 it is shown that the valve ring /21/
is confined by protector rings 123/ on both ends and that a row :of balls~/24/ is vulcanized into the valve ring /21/, which fit to the~row of~holea /20/. The :Figure:7 shows the clamping of the outer elastic pipe-: end~/22/, it is visible that the elastic pipe /22/ i9 : reinforced by~plates /25/ on both end near to the clamp overlapping each other, as illustrated in ~igure 10 which are vulcanized into the material of èlastic plpe /22/ and the clamp /5/ is covered by retainer ring /26/. Moreover, Figure 7 shows that the backing-rlng /54/ placed between casing /1/ and elastic pipe /22/ is grooved on the surface which contacts elastic Pipe end /22/ and is pressed by clamp /5/ to ~ ' - 20 - ~2~5926 ensure firm fastening, additionally the backing ring /54/ is recessed according to the shape of the clamp /5/. ~he outer elastic pipe /22/ put ~mder pressure, forms a second annular space /27/, which is located in the ~irst annular space /91 existing between casing string /1/ and the wall of drilled hole /8/.
~he task of the pressure-transfer device /2~/ :
is to actuate open-hole packer /4/, in other words, to put outer elastic pipe /22/ under pressure, which .
consists of~a pressure pipe /3y having smaller diameter than caslng string /1/,~whic~h is closed at the bottom and fitted~with foot-valve /29/,:it is connected to the source of pressure conveying medium, which pressure :
i . 15 ~ pipe iæ~fitted with:two closing devices arranged in 1 . ~ . : :
proper di9tance from each other, the closing devices can be expandcd against the inner surface o~ casing string /l/:~and axe in ~act designed as inner elastic :
pipes /32l closed by clamps 131/ o~ both ends. ~igure 8~shows ;thab inner elastic pipe ends are fixed the same way ~s the~outer~elastic pipe ends /22/, but here the ~ use oP embedded plates /25/ i~ not necessary. Clamps : /31/ are surrounded by backing rings /3310 In ~igure 8 Lt is vi~slble, that the inner elastic pipe j32/ is fixed .
to the end of enlarged section /34/ of pressure pipe ; /30/. Figure S shows again that in the middle of enlarged r;
:
- 21- ~L2~S926 section /34/ there is at least one machined hole /35/, which connects the inner space of pressure-pipe /30/
with inner space confined by elast1c pipe /32/. T~a two upper described closing devices expand again~ the inner surface of casing string /l/ if put~under pressure, establish1ng a t~ird annular space /~6/ between the outer surface of pressure pipe /30/ and the inner surface of casing string /l/ confined axially by the closing de-vIces. In this annular spacs /36/ there is at least one hole between the two closing devices on the pressure pipe /30/, which hole can;be closed by check valve.
: ~he check valve of the open hole packer's /4/ pressure .
transfer device /28/ is a two-way needle valve /38/, the design o~f whlch is shown in Figure 9. The ~igure show~ that the needle valve consists of valve needle~
.
/39/, spiral springs /401 and prestres~er~ 141/. ~he ta~k of thi3 needle valve /38/ is to control the flow of pres~ure medium from pressure pipe to the third an-nular space /36/.
One of the possible arrangement~ of welding the clamps of ela~tic pipes, exposed to pressure stress, is shown in Figure ll, through the example of ela~tic pipe's /32/ clamp 13l/. Namely one of the important features of the~invention is that the clamp should ha~e minimum space requirement, in view of the limited size of drilled hole or the inner ~pace of casing string , .
1~25926 /1/, and con~idering that if space requirement is reduced, smaller, consequently cheaper pipes can be applied. As it is shown in Figure 11, there are two lugs /42/ welded on the two ends of clamp /31/ having cylindrical shape, and these lugs are tied by adjusting bolt /43/ and nut /44/. A fibre thermal board /45/ and a ~teel protector plate /46/ is placed on the inner elastic pipe /32/ below the clamp /31/ in the vicinity of welding. In such a way the welding of clamp ends can be done, after that t~e lugs are removed, e.g.
cut by saw. ~he same procedure can be applied when clamps /S/ o~ outer elastic pipe /22t are fitted.
Figure 12 shows a section of casing string /1/ with cementing valve~/7/ on the top and sand-intake valve /131 below, without actuating device. ~he Figure shows clearly~, that the cementing valve /7/ consists of row of~holes /47/ positioned on casing string /1/, and of second valve ring /48/ which surrounds and cover~ the hole~, there are balls j49j vulcanized into the ring ~0 fitting to row of holes /47/, ju~t like in case of valve ring /21/o This is well illustrated in ~igure 13 which show~ that cementing valve /7/ is very similar to pressure-intake valve of open-hole packer' 9 /4/ outer elastic pipe /22/, moreover in given case it can be the same design. ~he cementing valve's /7/ valve ring /48/
.
3 ~l225926 is fixed by protector rings /6/ on both 3Ida3.
~ he 3and-intake valve /13/ has bigger diameter hole3 /50/ than the former cementing valve /7/, which are clo~ed bg a third valve ring i51/ having no balls, as ahown clearLy in ~igure 14. The valve ring /51/ is fi~ed by protector rlnga /52/.
~ igure L5 shows sand-intake valve ~13/ with pressure-transfer device /53/, as well as a part of screan /3/ section below. The design of sand-intake valve /13/ of the~pressure-tranafer device /53/ dif~ers somewhat ~rom the pressure-transfer device /28/ of open-hole packer /4/, however, Its prlnciple of operation i9 - essentislLy the same. The pressure pipe /30/ and the two closlng;de~rlc~es can be found here~tco, both are essentialLy~c;omposed of one inner elastic pipe /32/, ~which are flxed by clamp /31/, retainer ring /33/ and backing ring /54/ on both 9lde~ gure 16 shows this arrangement. The presaure plpe /30/ is surrounded by an open end intermediate pipe /55/ and the inner ela~tic pipe9 /32i are fastened to the latter; this ia not the same design as the former. The inner spaco of elastic pipes /32/ is connected to the innar space of pres~ure ~; pipe /30/ through pipe stubs /56/, 90 the closing devices put under pressure confine a fourth annular space /57 together with the inbermediate pipe /55/ and caaing .
, , .
~25926 string /l/, then again between the pressure pipe /30/
and intermediate pipe /55/ there is a fifth annular space /58¦. The threaded pipe stubs /59/ and /60/
fitted to the hole /37/ o~ the pressure pipe /30/
transfers pressure from pressure pipe /30/ into fourth annular space /57/, as the details are shown in Figure 17 and ~igure 18.
: At the bottom of Figure 15, the screen section /3/
of casing string /l/ located into the fluid-bearing stratum /2/ is illustrated, where the screen section /3/ consist~of screen pipe /63/, having larger size openings /62/ than the coarse grains of fluid-bearing stratum /2/, moreover of plate~tube /64/ having longi-tudinal /brldge-type/ protruding slots, and between lS the two elements a wire spiral /65l is placed, the described screen-section /3/ is confined by protector rings /66/ on both ends.
The procedure and method of operation of well out-fit in conformity with the invention are as follows:
~he well is drilled at the location marked out with a bit adequate in size to accomodate the largest size device fitted to the outer jacket of the uniform O~Do :
of casing string /1/. The conductor pipe /ll/ is used to case through loose overburden having caving materials, which will be hoisted before grouting is carried out.
:~ .
i~2~92 lhe drilling is done until the target fluid bearing strata /2/ are reached. The position o~ the intersected -fluid-bearing strata /2/ is defined by geophysical logging, and the casing string /l/ is installed into the hole assembled according to the position of the aqu~ers. In order to separate fluid-bearing strata /2/ from èach other there are open-hole packers /4/
fitted into the casing string /l/ in proper intervals and in proper number as per fluid-bearing strata /2/ intersected. Operation of these i9 done by in-stalling pressure-transfer device /28/ through casing stri~ /l/ into a position illustrated in .
Figure 5, then the pressure pipe /301 is connected to a pressure medium source, e.g. to a drilling rig flush pump,~or to a hand operated hydraulic pump, By this means the inner space of inner elastic pipe /~2/ is being pressurized through holes /35/, so the olosing devices of pressureotransfer device /28/
confine the third annular space /36/, which can be pressurized through row of holes /37/ and needle valve .
/38l. Thls pressure opens the first valve ring /21/
of open-hole packer /4/ by lifting row of balls /24/ and the pressure medium enters the second annu-lar space /27/ through row of holes /20/, where the pressure coming into being presses the outer elastic pipe /22/ against the wall of drilled hole /8/.
- 2~ - ~2~59~
In such a way the open-hole packer /4/ seals the annular space /9/ at a proper spot and prevents the communication, i.e. mixing and flow together of fluids of certain fluid-bearing strata between casing string /1/ and wall of drilled hole /8/.
After thi9 the pressure-transfer device /28/ is hoi9ted, following a pressure pipe /30/ is lnstalled~
equipped with a mixing head having openings, this lat-ter consi~ts~of a tubular closing~element suitable for closing the screen section, through thîs mixing head compressed air i pressed into the well by compressor. This results in the decrease of hydrostatic pre9sure above the mixing head and as a consequence of :
the pressure of fluld located in the fluid-bearing atratum, the flow of-~uid e.g. water starts into the well through the upper or lower section of the screen pipe /63/, namely together with flow of sand, which will be 9ettled into a tank on the surface.
After a quantity of sand which is equal with the ~0 predetermined volume of cavern /12/ has been pumped out, the pressure pipe and mlxing head together with closing device is lowered or pulIed upward, according to the position of cavern to ~e developed, and the pumping of sand is continued in conformity with the length of screen section /3/, i.e. until the lower or .
,_.
- , ~
27 - ~ 2259Z6 upper level of fluid-b~aring stratum /2/ is reached.
So a cavern is being developed along the screen sec-tion, which assure~ the free flow of fluid of aquifer into the wel1 construction and eliminates the occa~ional clogging of s~creen pipe as well as the si~ing up of fluid-bearing stratum.
lhe developments of cavern~ /12/ are done in each fluid-bearing stratum /2/, then the pressure pipe /30/
equipped with closing elements i3 hoisted. If the quant1tative and quality tests of the pumped fluid show good results, the annular space j9/ may be grouted, i.e. the installing of permanent well outfit may be done.
This procedure is carr1ed out by~lowering the pressure-transfer device /53/ down to the row o holes l47/ of cementing~valve /7/ and grout is pumped with adequate ; pressure~into the annular space /9f through valve ring /48l by lifting its row of balls /49/.
..
In case the quantitative and quality testsof pumped fluid shov disadvantageou~ results, so grouting i3 not carried out, the casing string /l/ can be hoi~ted with-out more ado, by chance after having demolished of the open-hole packers, 90 considerable value can be saved.
`~ The drilled hole is filled up by grout after the casing ~ string wa~ pulled out.
.
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~- 28 - 1225926 When the hydrostatic pressure of fluid-bearing strata /2/, the grain size distribution of formation materials and tne strength of upper layers are known, decision is made whether the caverns .developed remain 5 open or will be filled up by 1,5 to 3,0 mm grain size sand or gravel. ~he sand-intake valve 113/ is practi-cally always the part of the well outfit, so there is the possibility that any time dur~ng the operation of-the well, if necessity may arise, the caverns can be filled up.
~ he operation of sand-intake:valve /13/ is done through the pressure-transfer device /53/, as shown ; in Figure 15. The pressure-transfer device /53/ is lowered to the level of row of holes /50/ of casing string /1/, see Figure 15 and the water-sand mixture is : being pumped in through pressure pipe /30/. ~he applied pressure will pressurize first the inner elastic pipes /321expanding those against the wall of casing string, so between the two closing elements a closed annular space /57/ is established. After this, the water-sand mixture will enter into this annular space /57/ through ; row of~holes j37/ and through valve ring /61/, in which adequate pressure will be generated too, this pressure will open the valve ring /51/ of 3and-intake valve /13/, through which the flow of the mixture will fill up the .
, ~
- 29- 122592~
cavern /12/. ~he fluid, i.e water to be produced will be air lifted to the surface through screen section /3/ and through the inner space o~ intermediate pipe /55/, i.e. through annular space /5~/0 After having completely fllled up caverns /12/, the pressure-transfer device /531 is pulled out of well construction and tubing s-tring~jl4/ is installed with pumps /16/ and /17/ and permanent production of well starts, see ; Figure 3~
~ecause~of the demand of room for pumps /16/ and 117i it may happen, that the upper section of the hole mu~st be constructed with bigger diameter up to the anticipated~pumplng level, in order to accomodate pumps, below this the casing string has uniform diameter ;
throughout.
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:
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Claims (13)
1. A method for construction of a drilled well comprising the not necessarily sequential steps of:
(a) drilling a bore hole through at least one fluid bearing strata;
(b) sealing the upper loose formations by a retrievable conductor pipe;
(c) determining the various levels of intersected fluid bearing strata by geophysical logging;
(d) assembling, in conformity with the level and distance between said determined levels of intersected fluid bearing strata, a casing string such that open-hole packers correspond to said determined levels and location of said fluid bearing strata;
(e) installing and temporarily fixing said casing string in said bore hole;
(f) pumping fluid up through said bore hole until fluid is obtained;
(g) determining by test results the quality of fluid pumped through said casing string;
(h) if the test results are favorable, grouting of said casing string in said bore hole and placing said well into full production; or (i) if the test results are unfavorable, filling up of said bore hole with concrete;
wherein, (i) said casing string has a uniform diameter throughout its length;
(ii) said open-hole packers, made of elastic material, are fixed to the jacket of said casing string;
(iii) said open-hole packers close off said determined levels of intersected fluid bearing stratum by being expandable by applied pressure from their insides;
(iv) said open-hole packers provide fine grained forfnation material closely adjacent to said fluid bearing strata;
(v) a screen set assembly of said casing string is located proximal to said determined levels of fluid bearing strata;
(vi) said fine grained formation material is pumped to the surface through large openings of said screen set assembly by air pressure such that throughout the total thickness of said determined levels of fluid bearing strata an arch shaped cavern is developed;
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(vii) said pumping of said fine grained formation material continues until clean fluid is pumped through said casing string;
(viii) if said test results are favorable, said cavern is filled up with coarse grained material comprising sand and/or gravel which composition is passed through said casing string by passing through openings radially located in the exterior of said casing string; and (ix) if said test results are unfavorable, said casing string is hoisted to the surface and said bore hole is sealed, as mentioned.
(a) drilling a bore hole through at least one fluid bearing strata;
(b) sealing the upper loose formations by a retrievable conductor pipe;
(c) determining the various levels of intersected fluid bearing strata by geophysical logging;
(d) assembling, in conformity with the level and distance between said determined levels of intersected fluid bearing strata, a casing string such that open-hole packers correspond to said determined levels and location of said fluid bearing strata;
(e) installing and temporarily fixing said casing string in said bore hole;
(f) pumping fluid up through said bore hole until fluid is obtained;
(g) determining by test results the quality of fluid pumped through said casing string;
(h) if the test results are favorable, grouting of said casing string in said bore hole and placing said well into full production; or (i) if the test results are unfavorable, filling up of said bore hole with concrete;
wherein, (i) said casing string has a uniform diameter throughout its length;
(ii) said open-hole packers, made of elastic material, are fixed to the jacket of said casing string;
(iii) said open-hole packers close off said determined levels of intersected fluid bearing stratum by being expandable by applied pressure from their insides;
(iv) said open-hole packers provide fine grained forfnation material closely adjacent to said fluid bearing strata;
(v) a screen set assembly of said casing string is located proximal to said determined levels of fluid bearing strata;
(vi) said fine grained formation material is pumped to the surface through large openings of said screen set assembly by air pressure such that throughout the total thickness of said determined levels of fluid bearing strata an arch shaped cavern is developed;
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(vii) said pumping of said fine grained formation material continues until clean fluid is pumped through said casing string;
(viii) if said test results are favorable, said cavern is filled up with coarse grained material comprising sand and/or gravel which composition is passed through said casing string by passing through openings radially located in the exterior of said casing string; and (ix) if said test results are unfavorable, said casing string is hoisted to the surface and said bore hole is sealed, as mentioned.
2. A method for construction of a drilled well, according to claim 1, further including the steps of:
(a) exhausting the fluid from a first of said determined levels of said fluid bearing strata by pumping said fluid to the surface; and (b) a second cavern is created throughout the total thickness of a second determined level of fluid bearing strata while said: exhausted determined level of said first fluid bearing strata is closed.
(a) exhausting the fluid from a first of said determined levels of said fluid bearing strata by pumping said fluid to the surface; and (b) a second cavern is created throughout the total thickness of a second determined level of fluid bearing strata while said: exhausted determined level of said first fluid bearing strata is closed.
3. A method as claimed in claim 1, further comprising the steps of:
(a) if said test results are unfavorable, said caverns are filled up with grained sand and/or gravel through the holes of said casing string, said grained sand and/or gravel having a size within the range of about 1.5 to 3.0 mm.
(a) if said test results are unfavorable, said caverns are filled up with grained sand and/or gravel through the holes of said casing string, said grained sand and/or gravel having a size within the range of about 1.5 to 3.0 mm.
4. A method as claimed in claim 1, wherein said determined level of fluid bearing strata are, after being exhausted, closed off by the closing head of a tubing string of side casing string, while another cavern is being developed of a different fluid determined level of fluid bearing strata.
5. A method as claimed in claim l, further comprising:
(a) A temporary cacsing string is fitted with a left-hand thread coupling and an elastic expanding open-hole packer at the bottom;
(b) pressure is placed on said open-hole packer such that critical layers are sealed off from the lower part of said bore hole;
(c) after drilling operations are completed, said temporary casing string can be unscrewed by turning said left-hand thread coupling to the right;
(d) said temporary casing string is removed; and (e) a permanent casing string is installed into said bore hole.
(a) A temporary cacsing string is fitted with a left-hand thread coupling and an elastic expanding open-hole packer at the bottom;
(b) pressure is placed on said open-hole packer such that critical layers are sealed off from the lower part of said bore hole;
(c) after drilling operations are completed, said temporary casing string can be unscrewed by turning said left-hand thread coupling to the right;
(d) said temporary casing string is removed; and (e) a permanent casing string is installed into said bore hole.
6. An apparatus for construction of a drilled well comprising:
(a) a casing string fitted with a screen set section, at least one open-hole packer, a cementing valve and a sand-intake valve;
(b) a row of holes radially located on the cylinder jacket of said casing string is provided, said rows of holes being spaced apart from one another;
(c) the diameter of said casing string, along its length, being uniform;
(d) said rows of holes corresponding to said open-hole packer, said cementing valve and said sand-intake valve;
(e) a pressure-transfer device for selectively activating said open-hole packer, said sand-intake valve and said cementing valve;
(f) said pressure-transfer device being selectively positionable within the inside of said casing string to positions proximal to said rows of holes;
(g) said pressure-transfer device having at least two closing devices made of two inner elastic pipes which confine and close off a given section of said casing string;
(h) said screen set section of said casing string consisting of a screen pipe having larger openings than the largest sand grain size of the determined fluid bearing strata of a bore hole through which said well mechanism is intended to be installed for well production;
(i) a plate tube is provided having longitudinally protruding slots and located between said slots is 4 spiral wire, said screen section being confined by a protector ring on both the top and the bottom;
(j) said pressure-transfer device further comprising:
(i) a pressure pipe having a smaller diameter than said casing string;
(ii) said pressure pipe being closed at the bottom by closing means;
(k) said pressure-transfer device being connected to a source of pressure conveying means;
(l) said inner elastic pipes are secured to said pressure pipes by clamps, said closing devices being separated from each other and defining an inner cavity therebetween;
(m) said inner elastic pipes being selectively expandable against the inner surface of said casing string;
(n) a plurality of pressure holes pass through said pressure pipe, said pressure holes being located below said inner elastic pipe; and (o) at least one hold is fitted with a check valve, at least one of said pressure holes being located between said closing devices.
(a) a casing string fitted with a screen set section, at least one open-hole packer, a cementing valve and a sand-intake valve;
(b) a row of holes radially located on the cylinder jacket of said casing string is provided, said rows of holes being spaced apart from one another;
(c) the diameter of said casing string, along its length, being uniform;
(d) said rows of holes corresponding to said open-hole packer, said cementing valve and said sand-intake valve;
(e) a pressure-transfer device for selectively activating said open-hole packer, said sand-intake valve and said cementing valve;
(f) said pressure-transfer device being selectively positionable within the inside of said casing string to positions proximal to said rows of holes;
(g) said pressure-transfer device having at least two closing devices made of two inner elastic pipes which confine and close off a given section of said casing string;
(h) said screen set section of said casing string consisting of a screen pipe having larger openings than the largest sand grain size of the determined fluid bearing strata of a bore hole through which said well mechanism is intended to be installed for well production;
(i) a plate tube is provided having longitudinally protruding slots and located between said slots is 4 spiral wire, said screen section being confined by a protector ring on both the top and the bottom;
(j) said pressure-transfer device further comprising:
(i) a pressure pipe having a smaller diameter than said casing string;
(ii) said pressure pipe being closed at the bottom by closing means;
(k) said pressure-transfer device being connected to a source of pressure conveying means;
(l) said inner elastic pipes are secured to said pressure pipes by clamps, said closing devices being separated from each other and defining an inner cavity therebetween;
(m) said inner elastic pipes being selectively expandable against the inner surface of said casing string;
(n) a plurality of pressure holes pass through said pressure pipe, said pressure holes being located below said inner elastic pipe; and (o) at least one hold is fitted with a check valve, at least one of said pressure holes being located between said closing devices.
7. A mechanism as claimed in claim 6, wherein said closing means is a foot valve.
8. A mechanism as claimed in claim 6, wherein said open-hole packer is made of elastic pipe fixed to said casing string by valve rings made of elastic material, said valve rings being fitted to said row of holes of said casing string, the outer elastic pipe of said open-hole packer being reinforced on both ends by plates overlapping each other.
9. A mechanism as claimed in claim 6, wherein said open-hole packer's closing elements are balls vulcanized into the material of a first valve ring, said ban protruding out of said first valve ring fitted being fitted to said row of holes, said first valve ring being confined by protector rings on both ends.
10. A mechanism as claimed in claim 6, wherein said open-hole packer's clamps of said outer elastic pipes are rings prestressed before welding, which are sealed off from said outer elastic pipe by a steel plate and heat insulated by fiber-thermal board along the area of weld.
11. A mechanism as claimed in claim 6, wherein said cementing valve comprises a second elastic valve ring fitted to the row of holes of said casing string positioned above said open-hole packer and tightly surrounding it, said cementing valve further comprising closing elements in the form o- balls vulcanized into and protruding out of the material and being fitted to the row of holes, said secondvalve ring being confined by protector rings on both sides.
12. A mechanism as claimed in claim 6, wherein said sand-intake valve consists of a third valve ring made of elastic material, having a smooth surface and is fitted to a row of big holes machined into said casing string and is positioned between said open-hole packer and said screen section, said third valve ring surrounding said casing tightly and being confined by protector rings on both sides.
13. A mechanism as claimed in claim 6, wherein said pressure pipe 30 is surrounded by an intermediate pipe, having an open end at the bottom, holes of which are connected to holes of said pressure pipe by threaded stubs and a fourth elastic valve ring confined by retainer rings serves as a check valve, said inner elastic pipes of said closing devices are fixed to said intermediate pipe, the holes of said intermediate pipe being covered by inner elastic pipes and connected to pressure pipe holes by said pipe stubs.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000472130A CA1225926A (en) | 1985-01-15 | 1985-01-15 | Method of procedure for construction of drilled well, principally water producing well and well outfit for carry out the procedure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000472130A CA1225926A (en) | 1985-01-15 | 1985-01-15 | Method of procedure for construction of drilled well, principally water producing well and well outfit for carry out the procedure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1225926A true CA1225926A (en) | 1987-08-25 |
Family
ID=4129580
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000472130A Expired CA1225926A (en) | 1985-01-15 | 1985-01-15 | Method of procedure for construction of drilled well, principally water producing well and well outfit for carry out the procedure |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1225926A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102561998A (en) * | 2010-12-10 | 2012-07-11 | 淮南矿业(集团)有限责任公司 | Gas extraction bored well and forming method |
| CN107939328A (en) * | 2017-11-29 | 2018-04-20 | 重庆前卫海洋石油工程设备有限责任公司 | Underwater production tree cup running tool |
| CN113047294A (en) * | 2021-05-17 | 2021-06-29 | 白求力 | Duplex-pipe type multifunctional grouting device and construction method thereof |
-
1985
- 1985-01-15 CA CA000472130A patent/CA1225926A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102561998A (en) * | 2010-12-10 | 2012-07-11 | 淮南矿业(集团)有限责任公司 | Gas extraction bored well and forming method |
| CN107939328A (en) * | 2017-11-29 | 2018-04-20 | 重庆前卫海洋石油工程设备有限责任公司 | Underwater production tree cup running tool |
| CN107939328B (en) * | 2017-11-29 | 2019-11-29 | 重庆前卫科技集团有限公司 | Underwater production tree cup running tool |
| CN113047294A (en) * | 2021-05-17 | 2021-06-29 | 白求力 | Duplex-pipe type multifunctional grouting device and construction method thereof |
| CN113047294B (en) * | 2021-05-17 | 2022-03-04 | 白求力 | Duplex-pipe type multifunctional grouting device and construction method thereof |
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