RU2494214C1 - Method for well construction - Google Patents

Abstract

FIELD: mining.SUBSTANCE: in process of production well drilling before drilling-out of the horizon with cavings, well tightness is inspected. A boring bit is lowered onto drill pipes, a clay mud containing inert long-fibre fillers is injected into the well. The first clay mud in the well is replaced with the clay mud without long-fibre filler during stroking of a drilling string. The inclined well bore is drilled with a zenith angle of 74-77° in cavings of the Kynovian horizon. The flushing fluid is a gel-emulsion solution "MULTIBUR". As pressure of flushing fluid injection increases, the drilling assembly is unloaded, flushing is carried out with gradual increase of flushing fluid flow and with tool stroking. The assembly is again loaded to repeat the operation until the pressure of the flushing fluid injection reaches 10-11 MPa. Prior to every adding of a drill pipe length to the drilling string, the well is flushed. After reaching the previously drilled bottomhole, deepening is continued until coarse sludge is no longer available on lattices. A wiper trip of the well hole is carried out with raising of the tool above the Kynovian horizon and lowering to the bottomhole with subsequent removal of the drilling tool. The capital string is lowered, the casing string annulus is cemented.EFFECT: possibility to build wells stretching via caving zones at a large zenith angle.1 dwg, 2 tbl

Description

The invention relates to the oil industry and may find application in well construction.

A known method of sinking unstable clay rocks during the drilling of oil and gas wells, for example shale, comprising deepening the hole with a bit in the interval of the formation with unstable clay rocks using a viscoplastic washing fluid in a laminar flow regime in the annular channel of the wellbore. To ensure a guaranteed laminar flow regime in the annular channel of the borehole, consequently, and penetration by a bit of the aforementioned interval without cavern formation, the flow rate of the flushing fluid is chosen 20-30% less than the critical flow rate at which the laminar regime changes to turbulent, while the visco-plastic flushing fluid is chosen with the lowest possible filter return (RF patent No. 2256762, publ. 20.07.2005).

The disadvantage of this method is the difficulty of determining the critical flow rate and maintaining the laminar flow regime in the annular channel of the wellbore. All this leads to the irreproducibility of the laminar regime, turbulization of the flow of flushing fluid, the appearance of cavern formation and sticking of the drilling tool while drilling the well. In addition, the use of the laminar regime leads to a significant slowdown in the drilling speed of the well.

Closest to the proposed invention in technical essence is a method of constructing a well, comprising drilling and securing a direction, a conductor and an intermediate or production string. When drilling an intermediate or production string, technical water is used as the drilling fluid, the shedding zone is drilled and the underlying zone with non-shedding rocks is drilled, the drill assembly is lifted from the well and the drill pipe string is lowered into the well with an open end, clay mud is pumped through the well, displaced clay drilling mud to the surface with industrial water, rotate the drill pipe string and pump cement into the drill pipe string when entering cement mortar into the annulus stop rotation and pace the drill pipe string for a length of 10-14 m, push the cement mortar with technical water of the same density that is in the well into the annulus until the same level in the drill pipe string and annulus is established, raise drill pipe string from the well, carry out technological exposure until cement sets, drill the cement bridge with the same drill layout that was used earlier, and continue to build stvo well to the design level (RF patent №2439274, publ. 01/10/2012 - prototype).

The disadvantage of this method is the unresolved issue of building a well passing through the zone of shedding rocks at a large zenith angle of about 75 °.

The proposed invention solves the problem of constructing a well passing through the zone of shedding rocks at a large zenith angle.

The problem is solved in that in the method of constructing a well, including drilling and securing the direction, the conductor and the production string, according to the invention, before drilling the Kynov horizon with crumbling rocks, the cutter crown on the drill pipes is lowered, a solution with a density of 1250-1350 kg / m ^{3 is} pumped into the well containing inert long-fiber fillers at the rate of 1-1.5 m ³ per 10 m ^{3 of the} solution until pressure is created at the mouth of 2.8-3.0 MPa with a pump capacity of less than 15 m ³ / h, the pressure in the well is increased, at zero the acceptivity and a pressure of at least 2.3 MPa, the well is considered leakproof, a clay solution with a long fiber filler is replaced in the well with a clay solution without a long fiber filler when the drill string is paced, an inclined wellbore is drilled with an zenith angle of 74-77 ° in the crumbling rocks of the Kynov horizon with a layout without a telemetry system and an over-bit gamma-ray logging module with a flushing fluid flow rate of 30-35 l / s and a bit load of 7-9 tons, a gel emulsion is used as flushing fluid MULTIBUR ionic solution with a density of 1250-1350 kg / m ³ , with tool landings and an increase in flushing fluid pumping pressure up to 14-15 MPa, the drilling assembly is unloaded by 2-3 tons, flushing is carried out with a gradual increase in flushing fluid flow rate from 15 to 30 l / s with an intense reciprocation and rotation of the tool on the downhill, on the grids shaker for filtering the washing liquid note the presence of a large size greater than 1 cm ³ kynovskogo slurry horizon without signs of swelling, re-load force arrangement of 7-9 m and repeated operations pa before reaching the drilling fluid pumping pressure of 10–11 MPa, before each build-up of the drill string, the well is flushed for 45–60 minutes, after reaching the previously drilled bottom, drilling is continued at a mechanical speed of up to 20 m / h with washing before building until there is no coarse sludge grids, perform wellbore gauging with raising the tool above the Kynovsky horizon and descending to the bottom with the subsequent removal of the drilling tool, lowering the production casing, cement dissolved annulus in one step from forcing the cement slurry at a reduced flow rate mode with 5-6 l / sec at a pressure of 11-13 MPa before entering the mouth of the cement slurry.

SUMMARY OF THE INVENTION

When drilling complicated by shedding horizons, various technical solutions are used to drill a relatively vertical well. However, these solutions are not suitable for drilling shallow wells with zenith angles of the order of 75 °. The proposed invention solves the problem of constructing a well passing through the zone of shedding rocks at a large zenith angle. The problem is solved as follows.

Build a well. Perform drilling and fastening of the direction, conductor and production casing.

When drilling a production string before drilling the Kynovsky horizon with crumbling rocks, the tightness of the well is checked. The crown is lowered (the crown is pointed incisors along the diameter of the end part of the bottom of the drill string) on the drill pipes, a clay solution with a density of 1250-1350 kg / m ³ containing inert long-fiber fillers at the rate of 1-1.5 m ³ per 10 m ^{3 is} pumped into the well solution to create a pressure at the mouth of 2.8 0 3.0 MPa with a pump capacity of less than 15 m ³ / h As long-fiber fillers, they use uluk, cordofiber, sawdust, etc. In the well increase the pressure. At zero injectivity and a pressure of at least 2.3 MPa, the well is considered leakproof. When a well is leaking, the fillers used can eliminate leaks. A clay solution with a long fiber filler is replaced in the well with a clay solution without a long fiber filler when pacing the drill string (pacing the drill tool along the length of the lead pipe with a speed of 3-4 meters per minute, with an interval of 1.5-2 m ^{3 of the} volume of pumping drilling fluid) . Walking is necessary to avoid jamming of the drill tool. An inclined wellbore is drilled with a zenith angle of 74-77 ° in the crumbling rocks of the Kynov horizon with a layout without a telemetry system and a gamma-ray over-bit module with a flow rate of 30-35 l / s flushing fluid and a load on the bit of 7-9 tons. As a washing liquid use the gel-emulsion solution "MULTIBUR" with a density of 1250-1350 kg / m ³ .

The multibur corresponds to the patent of the Russian Federation No. 2369625 and contains, wt.%: High molecular weight polymer reagent 0.07-0.2, low molecular weight polymer reagent 0.2-0.5, sodium hydroxide 0.02-0.05, formate sodium 0.5-0.7, xanthan biopolymer 0.1-0.2, bactericide 0.02-0.1, lubricant 0.2-0.5, water - the rest. Moreover, a high molecular weight polymer reagent is selected from a number of high viscosity polyanionic celluloses, and a low molecular weight polymer reagent is selected from a number of low viscosity polyanionic celluloses or a high molecular weight polymer reagent is selected from a number of hydrolyzed high molecular weight acrylic copolymers, and a low molecular weight polymer reagent is selected from acrylic copolymers of medium molecular weight.

As the polymer reagent of high molecular weight can be used various hydrolyzed acrylic copolymers of high molecular weight with a molecular weight of from 6,000,000 to 1,500,000 (for example, Cydril 4000 ("Cytec"), Acrylamide polymer AK-631 (Gel-Service LLC), Poly -Kem D ("Kem-Tron Technologies, inc.") And others) or high viscosity polyanionic celluloses, which are purified sodium carboxymethyl celluloses having an effective viscosity of at least 70 MPa · s, corresponding to API RP 13I (for example, Aquapac R (“Aqualon "), Staflo Regular (" Aczo Nobel ") and others).

As a polymer reagent of low molecular weight, you can use low viscosity polyanionic cellulose having an effective viscosity of not more than 40 MPa · s, corresponding to API RP 13I (for example, Aquapac LV ("Aqualon"), Staflo Exio ("Aczo Nobel" and others), and it is also possible to use medium molecular weight acrylamides polymerized with sodium acrylate, with a significant anionic charge distribution, having a molecular weight of less than 5,000,000 (for example, Cypan ("Cytec"), Haihua PAN ("United Haihua Company Limited" and others).

Sodium hydroxide, produced according to TU 2132-185-00203312-99, performs the function of a pH regulator.

As a xanthan biopolymer, which plays the role of a regulator of the rheological properties of the solution, various grades of xanthan gum, obtained as a result of exposure of bacteria to carbohydrates having a molecular weight of approximately 5,000,000 and plastic viscosity of a 1% solution in a 1% KCI 1300-1600 cPz solution, in particular Xanthan Gum HV ("United Haihua Company Limited"), Kem-X (("Kem-Tron Technologies, inc.").

As a lubricating additive, you can use a lubricating additive based on vegetable oils, or a lubricating additive based on modified fatty acids, or a lubricating additive based on natural oils, for example FC-2000 (TU 2458-002-49472578-03), Lubriol (TU 2458- 001-74138808-06) and others.

Sodium formate (TU 2432-008-50685486-2004) acts as an inhibitor of shale swelling.

To prevent the biological degradation of xanthan biopolymer, a bactericide is used that prevents the growth of sulfate-reducing bacteria, anaerobic bacteria, blue-green algae and microscopic fungi, for example Bactericide LPE-32 (TU 2458-039-00209295-02), M-I CIDE ("M-I SWACO").

When planting (stopping the drill string while lowering under the influence of its own weight) and increasing the pumping pressure of the flushing fluid to 14-15 MPa, the drilling assembly is unloaded (by holding the tool on the weight, the load on the bit is increased) by 2-3 tons, flushing is carried out with a gradual increase flushing fluid flow rate from 15 to 30 l / s with intensive pacing (round-trip operations on the length of the lead pipe at a speed of 5-6 meters per minute) and rotation of the tool (rotor 60 rpm). On the screens of vibrating screens for filtering the washing liquid, the presence of coarse sludge with a size of more than 1 cm ^{3 of the} Kynov horizon without signs of swelling is noted. The assembly is again loaded with a force of 7–9 tons and the operations are repeated until the pumping pressure of the washing liquid reaches 10–11 MPa. Before each extension of the drill string, the well is flushed for 45-60 minutes. After reaching the previously drilled face, deepening is continued with a mechanical speed of up to 20 m / h (mechanical speed - deepening of the face for a certain period of time) with leaching before building up until there is no coarse slurry on the grids. The wellbore is patterned with the tool rising above the Kynovsky horizon and running before bottoming followed by removal of the drilling tool. The production casing is lowered, the annular space is cemented in one step with the cement mortar pushed in a reduced mode (flow rate of 5-6 l / s) at a pressure of 11-13 MPa until the cement mortar reaches the mouth. Then drill a small diameter horizontal wellbore along the reservoir. The well is mastered and put into operation.

The complex of technical, technological and organizational solutions used during well construction ensures trouble-free well drilling through Kyn mudstones in compliance with geometric parameters without the use of navigation equipment and additional geophysical surveys in a relatively short time.

Concrete example

Table 1 Build a well design according to table 1 No pp Column name Diameter mm Interval of descent, m Cement lifting height, m chisels the columns vertically along the trunk one 2 3 four 5 6 7 one Mine 490 426 0-10 0-10 0-10 2 Direction 393.7 323.9 0-100 0-100 0-100 3 Conductor 295.3 244.5 0-330 0-330 0-330 four Operational 215.9 168.3 0-1735 0-1946 0-1946 5 Shank Filter 144 114.3 1710-1739 1846-2224 1846-1946

Figure 1 presents the profile of the well.

The well has a vertical section 1, a section of initial curvature with a set of zenith angle according to project 2, a section of a set of zenith angle with access to horizontal 3 and a section of horizontal trunk 4.

The first two sections are standard and are used in directional drilling to direct the wellbore to the point of the reservoir specified by the project.

Drilling of directional wells is determined by the surface topography and is used in cases where there is an offset from the drilling point on the surface (wellhead) to the roof of the productive horizon. When drilling directional wells, systematic monitoring of the zenith angle and the direction of curvature of its trunk along the entire depth is carried out. The curvature parameters are adjusted promptly during the drilling process according to the results of control inclinometric measurements, intermediate and georeferenced well logging logs.

When drilling a well, there are complications identified by the results of drilling neighboring wells and are presented in table 2.

Drilling a vertical 1 section, under a casing with a diameter of 168 mm, from under the conductor produce:

- in the depth interval 330-860 m, 3-cone bit with a diameter of 215.9 mm, turbine method (downhole motor TSSh-195), with a flow rate of flushing fluid (natural water suspension EMU) 30-32 l / s.

- in the depth range of 860–934 m, in Verey, Bashkir and Protvinsky deposits (the zone of complications due to the presence of unstable clay layers and reservoir layers with the presence of water-saturated layers in the geological section) drilling with a clay solution with unregulated parameters (used) specific weight 1120-1300 kg / cm ³ , 3-cone bit with a diameter of 215.9 mm with a calibrator 215.9 mm, in a rotary way, with a flow rate of washing fluid 15-16 l / s.

- in the range of depths 934-1220 m with a 3-cone bit with a diameter of 215.9 mm, in a turbine way (downhole motor TSSh-195), with a flow rate of flushing fluid (natural water suspension EMU) 30-32 l / s.

Drilling vertical 2 sections produce:

- in the depth interval 1220-1406 m with a set of zenith angle up to 15 degrees. and its stabilization, with a 3-cone chisel with a diameter of 215.9 mm, screw method (downhole motor DR-178.6 / 7.68), with a flow rate of flushing fluid (natural water suspension of EMU) 30-32 l / s.

- in the depth interval 1406-1510 m, in the Lower Famennian and Upper Fransk deposits (the zone of complications due to the presence of cavernous and fractured carbonate rocks in the geological section with the presence of water-saturated intervals) drilling on a mud with unregulated parameters (used) specific gravity 1080-1350 kg / cm ³ , with stabilization of the zenith angle of 15 degrees, 3-cone bit with a diameter of 215.9 mm with a calibrator of 215.9 mm, in a rotary manner, with a flow rate of flushing fluid of 15-16 l / s.

Drilling 3 sections produce:

- in the depth interval 1510-1790 m with a set of zenith angle up to 75 °, 3-cone bit with a diameter of 215.9 mm, screw method (downhole motor DR-178.6 / 7.68), with a flow rate of flushing liquid (natural water suspension ЕВС) 30- 32 l / s. The layout of the bottom of the drill string includes the ZTS-42EM-M navigation system, with the aim of supplying a continuous signal to the surface of the parameters of the drilling path (zenith angle and azimuth data).

Drilling 4 horizontal sections are as follows.

The crown is lowered on the drill pipes to a depth of 1790 m (before the bottomhole drill).

2. A solution with a density of 1300 kg / m ³ treated with inert fillers (uluk, cordofibre, sawdust) is pumped into the well, at the rate of 1-1.5 m ³ per 10 m ^{3 of the} solution until pressure is created at the mouth of Ru = 2.9 MPa with two valves mud pump (BRN-1) with a capacity of Q <15 m ³ / h. Pressure is created in the barrel and if the pressure at which there is no injectivity is at least 2.3 MPa, the clay solution is completely cleaned of the filler through a cleaning system with the drill string pacing.

3. The first stage of horizontal drilling in the interval 1794-1958 m is conducted with stabilization of the trajectory of the trunk at an antiaircraft angle of 75-77 ° through unstable rocks of the Kynov horizon.

The layout used: PDC 215.9 MSRE516M bit - 0.45 meter shaft extension - DSHOTR-178 engine with nipple centralizer ⌀ 214 mm at a flow rate of 30-35 l / s and a load of 7-9 tons. Telemetry systems and the above-bit gamma-ray logging module were excluded from the layout due to the selected drilling mode, resulting in significant vibrations of the drill string generated from bottomhole vibrations during the operation of the bit, which in turn negatively affects the readings of downhole tools.

Washing is carried out with the MULTIBUR solution

Solution Parameters:

- density - 1300 kg / m ³ ;

- conditional viscosity - 55 seconds;

- filtration - 1.8-2.0 ml / 30 min.

The content of the hydrocarbon phase (multi oil) is 10%.

table 2 No pp Stratigraphy The depth of the roof along the trunk, m Possible complications Elimination of complications one 2 3 four 6 one Quaternary 0 2 Kazan tier one 3 Ufa tier 141 four Artinsky 271 Partial absorption (when drilling under a conductor) Inert filler washing (followed by cement casting of a 9 '' conductor) 5 Upper carbon 421 6 Myachkovsky 573 7 Podolsky 682 8 Kashirsky 762 9 Vereisky 827 Well wall shedding Cement bridge installation 10 Bashkir tier 839 eleven Protvinsky 881 Partial absorption (a.o. - 592-663 m) Clay drilling followed by cement pouring in the range of 863-934 12 Serpuokhsky 923 13 Tula 1154 fourteen Bobrikovsky 1178 Well wall shedding Cement bridge installation fifteen Tournaisian 1194 16 at. Famensky 1330 17 n Famennian 1403 Partial absorption (a.o. - 1131-1231 m) Drilling on polymer-clay mud followed by cement pouring in the range of 1406-1510 m eighteen Verkhnefransky substage 1491 Clay drilling followed by cement pouring in the range of 1406-1510 m 19 Buregsky 1648 twenty Semiluksky 1701 21 Sargaevsky 1790 22 Kynovsky 1830 Well wall shedding polymer clay drilling. 23 Pashi 1958 24 Bottom hole 2222

The mechanical speed is:

- in the interval 1794-1832 m 5 meters per hour (marls, limestone);

- in the interval 1832-1953 m 20 meters per hour (Kyn mudstones);

- in the range of 1953-1958 m 3 meters per hour (limestone)

At the bottom of 1884 meters, the drilling tool was raised and geophysical work was performed: an inclinometer and radioactive logging. According to the GIS data, the roof of the Kyn mudstones of 1832 m, the zenith angle of 1880 - 74.9 degrees.

When the tool was lowered at the entrance to the Kynovsky horizon (1824 - 1842 m), the tool landed and pressure increased with a safety diaphragm rupturing on the manifold (14.4 MPa). Drilling tools with puffs are raised to a depth of 1822 m. Flushing is carried out with a gradual increase in flow rate from 15 to 30 l / s with intensive pacing and rotation of the tool. On the grids of vibrosieve, the presence of large (more than 1 cm ³ ) sludge of the Kynov horizon without signs of hydration (swelling) is noted. Subsequently, during the passage of the roof of the Kynov horizon, insignificant landings and an increase in pressure up to 10.5 MPa were also noted (working pressure is 9.0-9.5 MPa). The study of the interval 1832-1884 m is carried out when unloading the tool for 2-3 tons with washing at a flow rate of 30 l / s, at a speed of 40 m / h. Before each build-up, intensive washing is performed for 45 ÷ 60 minutes. After reaching the previously drilled face (1884 m), deepening is continued with a mechanical speed of up to 20 m / h with leaching before building up until there is no coarse slurry on the grids.

At the bottom of 1953 m there was a sharp decrease in mechanical speed to 3 m / h. Limestone is noted in samples of sludge. Upon reaching the bottom of 1958, the recess is stopped due to obvious signs of the opening of the upper limestone benchmark. Make a decision to launch a technical column without logging.

The wellbore is patterned with the tool rising above the Kynovsky horizon and descending to the bottom with the subsequent ejection of the drilling tool.

A column is lowered with a diameter of 168 mm in the range of 1830-1958 m with gradually increasing landings due to the trajectory of the barrel and the rigidity of the layout.

Column fastening is carried out in one step. After injection of 15 m ^{3 of} squeezing liquid with an estimated volume of 37.8 m ³ , an increase in pressure is noted up to 18 MPa. The pushing of the cement slurry was continued at a reduced mode at a pressure of 12 MPa until the moment “stop” was obtained and an outlet of 7 m ^{3 of} cement slurry reached the mouth.

The total time from the beginning of the opening of the Kynovsky horizon to the end of the filling of the technical column was 116.5 hours.

At the end of cement hardening, after 48 hours, a cement cup was drilled in the shoe of the column and a complex of hydrodynamic studies of the well was completed. According to the inclinometer, the zenith angle at a depth of 1958 m is 76.8 degrees. The roof of the benchmark “Upper Limestone” is 1953 m. According to ACC (acoustic cementing logging), SGDT (spectral gamma defectometer-thickness gauge) cement quality behind the technical column in the interval 1832-1951 is continuous contact. Above and below opposite the “Upper Limestone” (solid carbonate rock located under the Kyn clay) and “Ajax” (solid carbonate rock located above the Kynov clay) is partial. A possible reason for such a mismatch in the result of cementing (when opening clay polymer to the polymer is partial or poor) is the “dry” state of the well wall in the Kyn horizon.

Application of the proposed method will allow to solve the problem of constructing a well passing through the zone of shedding rocks at a large zenith angle.

Claims (1)

A method of constructing a well, including drilling and securing a direction, a conductor and a production string, characterized in that before drilling the Kynov horizon with crumbling rocks, a crown on drill pipes is lowered, a solution with a density of 1250-1350 kg / m ³ containing inert long-fiber fillers from calculation of 1-1.5 m ³ per 10 m ^{3 of the} solution to create a pressure at the mouth of 2.8-3.0 MPa with a pump capacity of less than 15 m ³ / h, increase the pressure in the well, at zero injectivity and a pressure of at least 2, 3 MPa the well is considered airtight, clay is replaced in the well with a long-fiber filler for a clay without a long-fiber filler when the drill string is paced, an inclined wellbore is drilled with a zenith angle of 74-77 ° in the crumbling rocks of the Kynov horizon with a layout without a telemetry system and over-gamma module logging at a flow rate of flushing fluid 30-35 l / s and a load on the bit 7-9 tons, as a flushing fluid use a gel-emulsion solution "MULTIBUR" density w 1250-1350 kg / m ^3, when landing tool and increase the washing liquid pumping pressure up to 14-15 MPa drilling assembly is unloaded by 2-3 tons, washing is carried out with a gradual increase in the washing liquid flow rate from 15 to 30 l / s with intense reciprocation and rotation of the tool descent on grids shaker for filtering the washing liquid note the presence of a large size greater than 1 cm ³ kynovskogo slurry horizon without signs of swelling, re-load force arrangement of 7-9 m and the operation is repeated until the pumping pressure washing 10-11 MPa of liquid, before each build-up of the drill string, the well is flushed for 45-60 minutes, after reaching the previously drilled face, deepening is continued at a mechanical speed of up to 20 m / h with rinses before building until there is no coarse slurry on the grids, borehole patterning with the tool rising above the Kynovsky horizon and descending to the bottom with subsequent removal of the drilling tool, the production string is lowered, the annulus is cemented in one step with the sale pouring the cement mortar in a reduced mode with a flow rate of 5-6 l / s at a pressure of 11-13 MPa until reaching the mouth of the cement mortar.

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