FR2540968A1 - APPARATUS FOR FORMING RADIALLY MULTIPLE DRILLS FROM A WELL AND METHOD FOR ITS IMPLEMENTATION - Google Patents

Abstract

THE INVENTION RELATES TO AN APPARATUS FOR FORMING A BOREHOLE IN AN UNDERGROUND FORMATION 22. IT INCLUDES A GUIDE TUBE 30, 32 HAVING A SEAL COUPLED TO A SOURCE OF PRESSURIZED FLUID, A TUBE 34, LOCATED IN THE GUIDE TUBE, BEING IN WATERPROOF CONTACT WITH THE JOINT AND ABLE TO MOVE INTO THE GUIDANCE TUBE AND TOWARDS THE EXTERIOR THROUGH THE OPPOSITE END OF THE GUIDANCE TUBE. ONE END OF TUBE 34 IS OPEN AND IS IN COMMUNICATION WITH THE GUIDE TUBE. FIELD OF APPLICATION: RECOVERY OF OIL FROM CONTAINER TRAINING.

Description

The present invention relates in the first place to a system allowing the

forming a borehole

  intended to be used for recovery or for

  improve the recovery of oil from a containment formation, or for the recovery of mineral deposits or the like, or for the drilling of an underground formation

  for any other purpose The system includes an

  seems to have a piston means in a guiding means

  The piston is constituted by a body formed by a drill pipe which is open at its rear end and has at its forward end a hydraulic jet type drill head which is provided with multiple fluid outlet orifices. guide is a tube or pipe in fluid communication with the interior of the drill pipe Sealing means are located between the drill pipe and the guide tube so that

  fluid under pressure flowing in the guide tube

  the drill pipe produces a force causing the piston to move in a forward direction by

  means of bending or bending of tube and in the underground formation.

  In a preferred embodiment, the

  tube bending means are in the form of a whistle -

  deflector which is attached to the guide tube for rotating the piston body or the drill pipe from the vertical direction to the generally horizontal direction under a short radius of about 15 24 to 30.48 cm for tubes steel drills which may for example have an outer diameter of 3.17 to 3.81 cm and a thickness

  wall thickness of 2.03 to 3.17 mm Such a metal piston body

  that normally rigid causes a plastic deformation of the metal at the passage of the elbow without collapse or rupture of the tube, because of the circumferential force caused by the high pressure internal drilling fluid and the bending force during the movement through the deflection whistle Then, straightening means allow

  the tubes to resume a substantially rectilinear position.

  The whistle of diversion can be fixed or

  retractable A retractable deflection whistle is con-

  staged by two connected sets which, when extended from a recessed position within the

  structure, form an arcuate tube bending guide

  when a hydraulic pressure is applied to the guide tube, it applies a force to the drill pipe so as to push it down through the guide tube and through the guide, causing the bending

  of the tube so as to project the lateral drilling head-

  Each of the sets of the deflection whistle has a series of rollers or pulleys transported so as to be rotatable by said assembly.

  to form a segment of the arched guide The means of cur-

  bage also include ways to straighten the

tube as it comes out of the guide.

  Two or more such assemblies can be provided in a well to thereby produce two or more holes extending laterally for injecting a hot fluid, such as steam, to heat the oil in the formation and cause its flow towards

  a production well nearby or to a pump of pro-

  ducting in the same well casing.

  The object of the invention is to provide a system and method for forming radially extending (radial) boreholes in a relatively short radius elbow and efficiently and economically in comparison with prior systems and methods. The invention also relates to training

  Multiple radials in a single well casing pre-

  existing. Another object of the present invention is a multiple radial system in a combined well.

injection and production.

  Yet another object of the present invention is a system of the foregoing type which is capable of drilling

  in an unconsolidated formation without the need for

read a rotating drill head.

  Other features and advantages of the present invention will become more clearly apparent in the

  following description of several forms of

  given by way of non-limiting example and in

  FIG. 1 is a side elevational view partially in section showing a drill string assembly with the conventional surface apparatus, and a

  well coating in partially expanded dilated view

  broken, as well as radial formed according to the present invention;

  FIG. 2 is a partial diagrammatic view

  In section of the assembly of the present invention moving horizontally by a deflection whistle and rotating in a vertical direction; Figures 3 and 4 are respectively side and end views of a drill head and a piston body;

* 254,096 B

  Fig. 5 is a sectional view showing the drill head and a single port, while Fig. 6 is a cross-sectional view taken along

  line 6-6 of the same orifice of FIG.

  tracing the oblique-oblique orientation of one of the multiple orifices of an embodiment of the drill head;

  FIG. 7 is a view in transverse section

  a casing comprising four radial and corresponding whistles and a central production column;

  FIG. 8 is a view in transverse section

  Fig. 9 shows a side elevational detail of another embodiment of the tube bending means; FIG. 10 is a view towards the exit end of the guide of the bending means and

straightening of Figure 9; -

  Figure 11 is an elevational view there-_

  a detail to show another form of

  bending and straightening means; Fig. 12 shows a detail towards the exit end of the guide of Fig. 11;

  Figure 13 is a side elevational view of

  and section of a detail to show means for establishing a tight connection to introduce steam into the drill pipe Figure 14 is similar to Figure 13 but shows a connection after it has been established for introduce steam;

  FIG. 15 is a diagrammatic view in

  side view showing the apparatus disposed within a terrestrial well, the drill pipe being extended by a lateral bore; Figure 16 is a side elevational view

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  a detail showing the tube bending means of Figure 14 and its mounting; Fig. 17 is an elevational view in section to show the side elevation bending means and in the extended position; Fig. 18 is a view towards the right side of Fig. 17; FIG. 19 is a sectional view of a

  detail showing another embodiment of the pre-

  this invention in side elevation; Fig. 20 is a view towards the right side of Fig. 19; FIG. 21 is a sectional view of a

  detail showing sealing means between the channeling

well and the drill pipe;

  Figure 22 is a side elevational view of

  partially in section showing another embodiment in which the guide means is in three sections; Fig. 23 is an elevation view to the right side of Fig. 21;

  Figure 24 is a side elevational view of

  similar to that of Figure 22 but showing the bending means in the extended position; and FIG. 25 is an enlarged sectional view of a detail showing adjustable means for

straighten the drill pipe.

  In an important use of the present invention, there is provided a system for forming one or more radial tubes or pipes in radial holes extending

  from a pre-existing cask well The primary use

  of such a radial tube consists of injecting a fluid

  such as steam or solvents in the forma-

  Adjacent formation to make the highly viscous oil of the underground formation more fluid An important application is to heat the oil left in the ground by a system of production wells which has ceased

to produce economically.

  In FIG. 1, the level of the ground 20 is seen above a mineralized subterranean formation 22, a production installation is arranged on the right of the figure and a rolled tube installation 26

  on the left of the figure The function of an installation

  Production unit 24 is to screw together sections of one or more tubes or pipes 30 and 32 in situ in the usual manner. The piston body or drill pipe 34 is formed of a solid wall type metal tube which may for example have an outer diameter of about 3.17 cm and which is wound on the coil 26 and down into the guide tube When a sufficient length of the piston body or the drill pipe 34 is in the tube of guidance to be able to reach

  the final radial length sought, the drill pipe-

  is cut and lowered into the guide tube.

  The lower part of FIG. 1 shows a cemented pre-existing well casing 28 which is contained

  two different guide tubes arranged axially, comprising

  wherein tubes or guide tubes axially disposed and 32 terminating in deflection whistles 30a and 32a, respectively, each whistle having bent guides or bodies Piston means are disposed in each guide tube, each piston means having an elongated piston body in the form of a

  drilling tube, this tube ending in a drill head.

  The piston body is formed of a relatively rigid metallic material such as steel, and therefore has the advantage of being able to move in a substantially rectilinear path through the formation. In the figure, only the body is visible. piston or drill pipe 34 moving in a guide tube 30, with a drill head 36 at its anterior end A suitable guide tube is constituted by sections of about 9 m having a

  outer diameter of about 5 cm.

  The piston body or drill pipe 34 can be turned by bending and after turning through

  the diversion whistle 30a and after drilling in the drill

  mation, it becomes a radial or lateral tube or pipe suitable for injection into the formation of a hot fluid such as steam for the purpose of

  heat the viscous oil so that it can be extracted.

  In a variant, the heat of the hot fluid causes the oil to flow back towards a casing containing a production pump and towards the radial, as is shown in more detail in FIGS. 7 and 8 which are described.

below.

  In the illustrated embodiment, a fluid weir 38 (eg 3.17 cm OD) protrudes in the center of the guide tubes 30 and 32 and is intended for the injection of a soft or healthy fluid. foam or a high viscosity fluid for

  assist in the recovery of debris formed during the

  This debris flows along the tube 34 and is lifted by the foam so as to rise through axial spaces within the well casing. The tube 38 can also be used to drive and deposit cement in a chamber 40 to fix the position of the radial and deflection whistles.

  after completion of the drilling of the vertical borehole.

  In a typical operation, the casing of

  Well 28 may result from a pre-established injection well.

  A typical size in some areas of the United States of such casing involves an outer diameter of 13.97 cm

  although larger casings can be used.

  Normally, the casing was milled and the training was

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  In an alternative embodiment, an abrasive such as silica may be added to the drilling fluid supplied to the drill bit 36 or to a recess whitened in a conventional manner. a separate drilling device, and directed to a well casing wall or formation

  cement that already exists to pierce an opening through

  to the tubing or formation so that the drill pipe 34 and the head 36 can move through the

  wall or formation to form a radial.

  The general principle of forming a radial according to the present invention will now be described although the detailed structure of the parts is described more fully below with reference to the drawings. The piston body or tube 34 is generally intended to move to inside the guide tube and has an internal fluid passage with an external posterior end

  open and a drill head at its anterior end.

  One or more fluid outlet ports are provided in the drill head to allow drilling fluid passage from the piston body fluid conduit into the adjacent formation.

  guide tube is in fluid communication with U Vex-

  Posterior tremity of the internal passage of the piston body.

  The sealing means constitutes a seal between the piston and the guide tube High fluid under pressure S 'flowing through the fluid passage of the piston body applies pressure against the back of the drill bit to cause movement towards the front of the piston When the piston body or tube reaches the deflection whistle,

  combined stresses including circumferential stress

  tiel (or radial stress) caused by: the fluid under high pressure inside the piston body, as well as the bending force in the deflection whip make the piston body or tube which is

254 0960

  normally made of rigid metal is constrained and plastically deformed in the metallurgical physical sense and curves and rotates in a radial direction preferably

  horizontal to be able to move in formation.

  The high pressure fluid exiting the drill head enters the formation and forms debris therein which is muddled and pushed back along the outer periphery of the piston body, into the cavity 40 or the foam or other upflow fluid that passes down through the weir 38 may be added to raise the sludge to the formation surface by the axial space within the casing which

  is not otherwise occupied by the guide tubes.

  In a variant, not shown, there is no need for any

  fluid and the fluid is directed to the adjacent formation with sufficient force for the formation to break causing cracks in which the formed sludge may flow, so that no debris may be displaced to the slurry. back along the radial

  and that the recovery of debris is no longer necessary.

  An important advantage of this system is that it can drill radial holes with a non-rotating drill bit and that

  drilling is cased during drilling.

  In Fig. 2, a system for vertical hydraulic jet drilling is shown. It uses the guide and piston tube assembly of Fig. 1, in which the piston tube rotates from a horizontal direction to the surface of the piston. This allows the guide tube to extend along the ground rather than being supported vertically. The subterranean formation 42 includes an upper cavity 44 to facilitate drilling. tube or guide pipe 46 is supported, at ground level by conventional means The end

254 0968

  rear of the guide tube 46 is shown as protruding inwardly of a casing 48 which comprises

  a source of high-pressure drilling fluid, not illus-

  and a means for introducing the piston comprising the piston or drill pipe 50 terminating in a drill head 52. There is provided a drilling fluid seal 54 which may be of the chevron type as shown in FIG. front or front of the guide tube 46 forms a curved deflection whistle 46 d connected by a

  Coupling 46c to the main body of the guide tube.

  Whip whip 46 d has a bent barrel capable of bending or rotating the piston body 9 Q O from a generally horizontal direction to a

  generally vertical direction -

  In operation, the piston or drill pipe 50 is pushed forward away from the high-pressure pump.

  casement 48 to the left of the figure,

  beyond the seal 54, by the pressure of the drilling fluid which applies a force against the fluid pressure application zone on the posterior side of the drill head When the piston tube is pushed through the whipstock 46 d, bending forces are applied so that the tube substantially follows the curve of the deflection whistle, so that the tube rotates downwards in the formation.

  provided at the front end of the diversion whistle 46 d.

  It is inclined towards the vertical direction (for example

  to 5 or 10) in the same general direction as the movement

  In this way, the contact of the tube with the tube straightener at point A

  the tube is upright in a generally vertical direction

  hold rather than continue its curve and curl backward into a spiral path

  drilling is directed to the outside by one or more

  Figs. 52a of the drilling head 52 inwardly of the formation to provide a sludge through which the drill head is easily moved by force

  applied by the fluid under pressure.

  The piston body or tube may be formed of steel or other metal of sufficient rigidity to allow it to move in a straight line through the formation but it must be able to deform plastically as indicated above. Suitable wall thickness for this purpose is 2.03 to 3.17 mm in steel having a yield strength of 248 to 482 M Pa or greater for tubes ranging from 3.17 to 3.81 cm in outer diameter. The principle of operation of the guide tube and piston assembly is illustrated more clearly in the embodiment of FIG. 2 there is provided a fluid seal 54 between the fixed guide tube and the movable piston so that high pressure fluid exiting the housing 48 (e.g. 6.89 68.9 M Pa or greater) applies a high pressure force against the drill head 52 to move it forward at a speed relatively high The pressurized drilling fluid pushes against the seal 54 and the portion of the guide tube which is upstream of this seal which is in fluid communication with the entire length of the tube 50 to ensure that the maximum force is directed against the rear side of the drill head to advance it While a minimum part of the pressure is lost because the drilling fluid exits the orifice or orifices 52, the maximum part of this force causes the head of fo rage and the drill pipe

forward.

  Downstream of the seal 54, a significant internal radial pressure (circumferential pressure) causes

  high stress of the normal piston body tube-

  rigid (for example formed with a wall thickness-

  from 2.03 to 3.17 mm for a steel tubing ranging from 3.17 to 3.81 cm in outer diameter) This constraint associated with the bending stresses produced when the piston tube passes through the whipstock, makes that the tube is plastically deformed and turns

  or is curved into a relatively small radius of a di-

  horizontal rection in a vertical direction.

  With the system of FIG. 2, a vertical drilling is produced without formation of radials As the pressure behind the seal 54 must be maintained to allow the propulsion mode described above, and simultaneously the jet cutting (hereinafter referred to as the effect of piston) - it is apparent that the length of the piston body downstream of the joint can not be greater than the

  initial length of the guide tube upstream of the joint.

  One of the primary advantages of the illustrated system is that no pre-existing casing is needed and there is no need to drill a preliminary hole for the guide tube.

  Figures 3 and 4 show a form of reali-

  The drill head 56 is mounted on the front end of the piston body tube 58, suitably by welding. As illustrated, the leading end of the head

  is generally rounded, hemispherical in shape

  In general, generally spaced apart orifices 56a are shown in the Figure. In addition, elliptical orifices 56b may be provided to direct drilling fluid in a generally backward direction to assist fluidization of debris. surrounding the piston body as it passes through the formation, to lubricate debris and prevent

  liaison with training as well as to assist in -

  movement towards: the rear debris formed Alter-

  natively, all orifices or a single orifice can

25409 ô 6

  be directed forward to maximize cutting. Figures 5 and 6 show the nose of the drill head of Figures 3 and 4; there is one or more orifices 56a in an oblique-oblique direction. In other words, such an orifice is arranged in one direction

  which is oblique in two different planes with respect to-

  In this way, the jets cut the groove walls or slot which would be formed otherwise in front of the drill head by orifices which would be oblique only in one direction and could create possible resistances. at the advancement of the drill head By arranging the orifices obliquely at least 1030 with respect to the axis in at least two directions, the jet of fluid tears the formation so that the drill head functions progressively to cut the bleeding from the cut-to-measure formation

that the drill head passes.

  FIGS. 7 and 8 show a combination of an injection well and a production well. In this case, there already exists a well casing 90 and four guide tubes 92, 94, 96 and 98, ending deflection whistles 92a, 94a, 96a and 98a, respectively, are circumferentially positioned within the guide tube Whistles 92a and 96a extend parallel to each other in directions Similarly, the whistles 94a and 98a extend in parallel with each other in opposite directions and perpendicular to the directions of the whistles 92a and 96a. Piston bodies 100, 102, 104 and 106 are headed down in,

  passing through guide tubes 92, 94, 96 and 98

  respectively and rotate through their respective whistles to form a horizontal or radial portion 100a, 102a, 104a and 106a respectively. Radials extend 90 apart from each other in a horizontal direction in

Training.

  Central to the well casing is a production tubing or tubing 110 having conventional dimensions and shape, and including a conventional pump and pump rod assembly with a pump rod 112 and a schematically illustrated piston valve. by the reference numeral 114 in FIG. 8 At the bottom of the tube 110, a conventional slotted cylindrical portion 110 aqui is permeable to the flow of oil but which filters the particulate material in the manner of a sand filter with a sieve surrounded by The embodiment of FIGS. 7 and 8 essentially comprises a combined injection and production system, that is to say that after the radials 100a, 102a, 104a, and 106a are in place and that the bottom of; production tubing 110 is disposed in a sludge basin at the bottom of the tubing 90, a hot fluid such that steam can flow through the radials and out of the drill head to heat the adjacent oil-containing formation for allow the oil to flow downward and laterally and into the sludge basin, generally designated by reference numeral 116. At this location, the oil is pumped to the surface in the usual manner by a pump and rod assembly Pumping Thermal energy is used effectively since some of the heat from the descending vapor is used to keep the oil rising to a temperature such that the oil is kept fluid when it reaches the

top of the well.

  In FIG. 8, it can be seen that the system can be used in the following manner for "steam stimulation". After forming the radials 102a, 104a and 106a, they can be cut off from their corresponding deflection whistles, and the latter removed to the surface of the water for possible reuse. Next, the steam is lowered into the well casing 90 to penetrate the formation. A pump is placed in the mud basin as illustrated and the oil which has been heated by the steam to flow into the basin is pumped to

the surface.

  It is possible that the force applied to the drill head is sufficient to cause the piston body to move at a greater speed than could the jets to effectively fluidize the formation that the drill head contacts. means in the form of a constraint channel for controlling the maximum speed of movement of the piston body This channel can also be used to monitor the speed of progression

  of the drill head in the formation.

  A system of the foregoing type can be used for injecting a hot fluid or steam through the radials that are formed in the system to heat the subterranean formation to produce a production either in the same well as that of the radial ones,

in a remote well.

  When the drilling is complete, the system is sealed as shown in Figures 13 and 14 below or by other means. For example, the system can be sealed by passing cement into the area surrounding the piston body by the fluid weir or the guide tube If the holes in the drill head are of insufficient size to pass the necessary volumes of vapor or other fluids,

  an abrasive can be added to the drilling fluid to

  erode the orifices to the size necessary for the fluid injection, or the orifices can be enlarged by the effect of a suitable solvent O The drill head can be cut completely using a

explosive charge.

  Two additional embodiments of

  Tube bending means are shown in Figures 9-12.

  In both cases, the dimensions and configurations are such that the well must be of sufficient diameter to permit their introduction. In FIG. 9, a body 151 surrounds a portion of the tube bending means 152. The bending means is constituted by a

  body which is rigid and which is formed by the side plates

  spaced ribs 154 which are secured together by connecting walls Two series of pulleys 156 and 157 are mounted between the side walls 154 and are placed to form the curved passageway 158 This passage has a dimension compatible

  with the movement of the drill pipe through it, the

  position such that when the drill head and the tube are pushed through the passage by the hydraulic pressure, the tube is at all times in contact with a

  set of pulleys and be curved according to the desired radius.

  Tube straightening means 159 is disposed at the end.

  mity of the exit of the guide passage; it is constituted by a body 161 of the cross-shaped type which is attached to the side plates 154 This body carries four

  pulleys, namely the upper and lower pulleys.

  162 and the opposite side pulleys 163 These pulleys are

  formed so that their peripheral surfaces embrace

  are substantially the entire circumference of the drill pipe.

  It should be noted that when the drill pipe is forced through the guide 158, the curvature is accompanied by a change in its cross-sectional configuration.

  that the tube reaches the end of the guide, it has a

  It is found that the straightening of such a tube is sometimes more effective if it involves the circular reshaping of the tube. To accomplish this reshaping, the pulleys 163 are such that they apply a force on the outgoing drill pipe so as to give it a somewhat circular configuration while simultaneously applying a stripping force In this straightening effect, the pulleys 162 and 163 cooperate

  also with adjacent pulleys 156 and 157.

  In another embodiment, one does not

  do not read the cruciform type of straightening means shown in Figures 9 and 10 Thus, as shown by

  FIGS. 11 and 12, the rectifying means can in this case

  tuality use only the two upper pulleys

and lower 162.

  Figs. 13 and 14 show means for introducing drilling fluids such as steam into the drill head after formation of the borehole. This may be necessary if the sliding seal suitable for the effect of the control piston is not waterproof enough to fully contain the steam injection

  in the piston body to heat the subterranean formation

  This is the purpose of the vapor seal described below.

  The figures show a guide tube 166 and a threaded coupling 167 between sections of the guide tube The drill pipe 168 is shown as passing through the seal 164 The upper end of the drill pipe 168 is provided with the threaded portion 171 The lower end

  of the upper section of the guide tube 166 is also

  The threads of the coupling 167 are the same as the threads of the collar 171 and of the portion 172. More particularly, the threads intended to couple the two sections of the guide tube may be on the left and the threads of coins 171 and

  172 can also be left Assuming that the pres-

  Hydraulic pressure has been applied to the guide tube, to force the drill pipe 168 and the drill head connected thereto to penetrate laterally into the mineralized formation and it is desired to maintain the introduction of steam or other treatment fluid. in the drill pipe, the coupling 167 is uncoupled by turning the upper portion of the guide tube 166 to the right, after which it is raised and turned to the left for

  contact threaded portions 171 and 172.

  This provides a metal-to-metal waterproof coupling.

  The pieces are then in the condition shown in FIG. 14. Steam or other process fluid may now be introduced through the guide tube and through the drill pipe 168 and thence into the mineralized formation. Figs. 13 and 14 also show an annular portion 173 at the inlet of portion 1711 which is shaped to provide a converging inward port

  This improves the flow characteristics

  The portion of the system 173 is sized to provide a transition from the larger inner diameter of the tube 166 to the smaller inner diameter of the tube 168. The portion 173 is sized to form a stop when the threaded portions

171 and 172 are in contact.

  FIG. 15 schematically shows a terrestrial well 210 which extends towards the mineralized formation 211. In this case, the well is shown to be provided with a casing 212 which can extend downwards towards a cavity 213 which is close to the formation 211 The tubing which extends in the well is constituted in this

  case by a tubular column 214 inside the-

  which a drill pipe 215 is normally disposed.

  As shown in FIG. 21, a seal 216 is mounted inside the tubular column 214 and forms a seal

  between the tubular column and the drill pipe 215

  upper open end of the drill pipe 215 is above the joint 216 when the drill pipe is fully extended as shown in FIG. 15 Before the drill pipe is in extension, it is inside the column tubular 214, the drill head 217 being located below the seal 216 The structure 221 serves to transport the tube bending means 222 Although the seal 216 can be incorporated in a coupling between sections of the tubular column 214, it is

  preferably incorporated in the close coupling of the former

  upper trough of the bending means 222 The tube 249

is a fluid weir -

  FIG. 15 also schematically shows a mobile type production facility 224 and a truck 225 carrying a spool capable of carrying a reserve of the drill pipe 215. An embodiment of the deflection whip or the expandable bending means is shown in FIGS. 16 to 18 It consists of a structure 221 which carries the bending assemblies 226 and 227 The structure 221 may be in the form of a tubular section having a

  cut side as indicated by reference number 228.

  The assembly 226 is constituted by a rigid assembly made of rigid side plates 229 attached to a plate

  rear (not shown) and to an upper plate 231.

  This assembly is attached to the structure-221 as indicated by the reference number 232 The assembly 227 likewise comprises a rigid assembly formed by the side plates

  connected 233 which have a pivotal connection 234 with the end

  The upper assembly 226 carries two sets of rollers or pulleys 236 and 237. They are arranged to form a guide path 228 sized to receive the drill pipe 215. The lower assembly 227 is provided with even two

  series of rollers or pulleys 239 and 240. They are

  The above-described bending means are extended to the position shown in FIG. 17 by pivoting the lower assembly outwardly and upwardly. The guide formed by each set becomes

  segment of the overall guidance path formed when the

  appears to be less than rotated to the position of Figure 17.

  A suitable driving force element is provided to move the lower assembly 227 to the extended position of FIG. 17.

* of driving force can be constituted by an element of action-

  hydraulic element 244 of the cylinder and piston type having its working rod pivotally connected to

  246 to the side walls 233 of the assembly 227

  that the pressurized hydraulic fluid is applied to the actuator 244, it moves the lower assembly 227 from the position of FIG. 15 to that shown in FIG. 16 The prolonged application of hydraulic pressure on the actuating element 244 , or hydraulic load is used to hold the assembly in the position of Figure 17 during the passage through it of a drill pipe

  and during subsequent drilling operations

  Since the actuator is of the single-acting type, the control valve admitting or allowing the hydraulic fluid to escape can be closed after actuation so as to lock the assembly 226 in the extended position. FIG. 14 shows a tube 247 extending up the well to allow operation

Hydraulic Actuator 244.

  When it is desired to recover the bending means by applying steam or other process fluid through the radially extending boring tube, the tubular column 214 and the housing 221 may be pulled up to cause removal of the set 227 and crushing and breaking the

  position in extension of the drill pipe In case the action

  neur 244 is of the double-acting type, it can be used

  as a motor means for removing the assembly 227 while crushing or deforming the drill pipe The manifold 215 may be cut off by explosion or otherwise before

  sagging of the diversion whistle.

  As shown in FIG. 17, the series of rolls or pulleys carried by the assemblies 226 and 227 provide a continuous guide curve through which the drill pipe passes for the application of the desired curve. The pulleys of each set can enter. in contact with either the inner wall or the outer wall of the curved tube. It is assumed that the curve of the tube is usually of the order of 90, although

  may vary according to the particular needs.

  By way of example according to the present invention, it is possible to use radii of curvature of the order of 15 to 30 cm, for a steel tube of 3.17 to 3.81 cm of external diameter.

  and a wall thickness of the order of 2.03 to 3.17 mm.

  The metal of the tubing can for example have a limit

  elastic ranging from 248 to 482 M Pa.

  The tube would normally be expected to deform or break after bending along such relatively short radii. However, the fact that the tube does not deform or break does not, in part, be attributed to the presence of a A liquid having a relatively high pressure inside the tube as it moves through the bending means This imposes a circumferential stress in the walls of the metal in conjunction with stresses applied during bending. Referring again to FIG. 17, pulleys 239a, 239b, 239c, and 239d are noted, and opposing pulleys 240a, 240b, and 240d are arranged to form a straight guide path. purpose of these pulleys is to form rectifying means so that the drill pipe leaving the pulleys is relatively straight The pulleys 239 d and 240 d have a large diameter

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  and have peripheral grooves as they

  encompass substantially the entire circumference of the tube.

  Thus, this system makes it possible to apply

  to the tube as it exits the guide path.

  In addition to straightening the tube by applying stripping forces thereto, the pulleys 239 d and 240 d may have reforming forces to reform the tube of a

  oval configuration to a more circular configuration.

  In order to straighten the structure 221 against a lateral thrust, its upper end is shown as being connected to the template extension 221a which may be a section of pipe which extends a substantial distance in the tubing from

well 212.

  The practice of using the extensible whipstock in practice is as follows: Assuming that the well has been drilled by conventional means and a cavity 213 has been formed near the mineralized formation

  211, sections of the drill string 214 are

  with the lowest coupling connected to the tube bending means member 251 A suitable length of the boring tube is provided with the boring head 217

  hydraulic jet type connected to one of its ends.

  It can then be assembled inside the drill string, the drill head being at the seal 216 or slightly below it. An adequate length of drill pipe must be sufficient to extend laterally of the required distance, plus one extra length sufficient to ensure that the open top end of the tube is well above seal 216 when the tube is extended as shown in FIG. 15 The entire drill string 214, with casing 221 connected thereto and the bending means 222 is now lowered into the well, the bending means then being in its retracted position When the bending means has reached a level corresponding to the mineralized formation, the upper end of the tube 214 is connected to a source of liquid

  hydraulic (ie water) pressure at a pressure

  relatively high, which may range, for example, from 6.89 to 68.9 M Pa or more. According to a modified and preferred method, the drill string including the deflection whistle but not the drill head and the drill pipe is first lowered to the desired final location Next, the drill bit and the drill pipe are lowered. Now assuming that it is desired to make a lateral hole in the mineralized formation, the bending means 222 is placed in extension as the FIG. 15 shows, applying a hydraulic pressure to the actuator 244 and then a hydraulic fluid under high pressure is

  introduced into the upper end of the tubular column

  The hydraulic fluid flows into and through the drill pipe 215 and due to the fluid pressure zones provided by the drill pipe and the drill head 217, the pipe is driven to the

  by the seal 216, the bending means 222 and then laterally

  The jet drill head 217 penetrates the formation in such a way as to produce a laterally extending hole as shown, for example, in FIG. 15 at the end of this operation, and in FIG. Assuming that the mineralized formation is to be treated with steam or other fluids, the application of hydraulic pressure to the tubular column 214 is interrupted, a vapor seal is formed and this column is connected to the Well surface, to a source of process fluid Thus, the device can then serve for a long time as a

  means for introducing deep processing fluid

  insane in the mineralized formation.

  The embodiment shown in FIGS. 19 and 20 shows another form of tube rectifying means. Instead of the tube rectifying rollers or pulleys 239 d and 240 d, it is a cruciform type of rectifying means 251. It is constituted by a body 252 which serves to mount the opposite pulleys 253 and 254 and pulleys 256 and 257 arranged laterally. The grooves formed in the peripheries of these pulleys are proportional so as to encompass substantially the entire circumference of the tube. Although the drill pipe does not sag during bending, there is plastic deformation of the metal walls, which causes the tube to exit the guide path, its cross-sectional configuration is slightly oval rather than circular. 256 and 257 rollers can be adjusted so that when the tube passes between them, a lateral pressure is applied to the side walls of the tube for establish the cross-sectional configuration somewhat so that it is close to the circle This has been found to help

  straightening of the tube in combination with the action of the

  239a-239c and 240a, 240b, so that this portion of the tube S extending from the straightening means to the formation is sufficiently rectilinear to transmit the desired thrust of the drill head to the formation, without

additional adjustment.

  The embodiment of Figs. 22-25 is also provided with a plurality of pulleys which form the arcuate guide path of the bending means. However, the bending means is formed by three sets instead of two sets according to Figs. 16 and 17. Adjustable rectifying means 261 may be similar to housing 221 of FIG. 16 The tube bending means is constituted by the three assemblies 262, 263 and 264 each of which forms a segment of the arcuate guide path. is constituted by the rigid side walls 266 which are fixed rigidly to one another at a certain spacing and are also fixed to the upper part of the casing 261 The edges of the side walls are shown as being connected by closure plates or covers 266 a and 266 b The assembly 263 is also constituted by -espaced and connected walls 267 whose upper ends have a pivotal connection 268 with the side walls 266 of the assembly 262 are also connected walls 267

  by closing plates or covers 267a and 267b.

  The assembly 264 also consists of spaced-apart connected walls 269 which have a pivotal connection 271 with the lower ends of the walls 267 and which possess

  closure plates or covers 269a and 269b.

  Figures 22 and 23 show the assemblies 263 and 264 retracted inside the housing structure 261 The motor means: to move forward

  the sets to the position shown in Figure 22 can

  may be constituted by a hydraulic actuator 272 which is pivotally anchored at 273 to the housing 261 and which has its working rod 274 connected in a

  pivoting at 276 to the side walls of the assembly 264.

  The side walls of the assemblies 262 and 263 have their adjacent ends 276 and 277 formed to come into abutting contact when the bending means are fully extended. The opposite ends 278 and 279 of the side walls of the assemblies 263 and 264 are formed of in the same way The assembly 264 can be connected to a traction cable extending upwards from the well,

  rather than the motor-drive actuator.

  When the actuator 272 is actuated by the hydraulic pressure, the assemblies 262, 263 and 264 are in extension at the limit position shown in FIG. 22, the ends 276 and 277 and 278 and 279 being in contact with each other.

stop.

254096 &

  Each of the assemblies 262, 263 and 264 comprises a plurality of pulleys which are arranged so as to form when the assemblies are in extension.

  continuous tube bending guide which curves progressively

  The complete guide is arched, the assemblies 262, 263 and 264 forming the segments of the arc. The pulleys

  of the set 2.62 are designated by the reference numbers

  281 and 282, those of the set 263 are designated 283 and 284 and those of the set 264 are designated 286 and 287 The pulleys 286a, 286b, 286c, 286d and 286e and 287a, 287c and 287e cooperate to straighten the drill pipe before it exits the assembly 264 Preferably, the pulley 287c is adjustable to vary the straightening force it applies. Thus, in FIG. the watch rotatably carried by the structure 288 which, in turn, is pivotally connected to the spindle or shaft 289 which is supported by the sidewalls of the assembly 264 '. pulley 287 c can be adjusted to pulleys 286 b, 286 c and 286 d by adjusting the

  291 To strengthen the recovery action, the

  lie 286b, 286c and 286d are shown to be arranged with their lines of centers arched upwards (FIGS. 23 and 24). The pulley 287e is not essential for

  the recovery effect and can be omitted.

  The pulley adjustment knob 287 c is also applicable

  to the embodiments of Figures 9, 11 and 16.

  As in FIGS. 16 and 17, the pulleys 286 e and 287 e have dimensions and grooves such that they encompass substantially the entire circumference of the drill pipe. They can reform somewhat the tube.

  so that it has a roughly circular shape.

  The embodiment of Figures 22-25,

  when it is in extension, works about the same-

254 0968

  as the embodiments of Figures 16-20.

  However, in retreat, it is more compact because

  assemblies 262, 263 and 264 have a rectilinear configuration.

  In addition, when the actuator 272 receives a driving force to put the assemblies in extension, the assembly 264

  is the first to swing outwards because of

  placements of pivotal links 271 and 272 and it is

followed by the whole 263.

  When the drill pipe is driven through the bending means, and into the neighboring formation, it is desirable to introduce water into the assemblies 262, 263 and 264. Thus, a small pipe 293 is shown in FIG. 24 to deflect water from the top of the seal 292 to the assembly 262 It can be discharged into the assembly 262 or it can be -connected to the pipes 294, 295 and 296 of the side walls of the sets These last-pipes are located

  so that they are in communication when

  sebles are in extension Line 296 can unload

  water sprays through the nozzles 297 The introduction of

  Draining water tends to flush and prevent clogging of the guide or jamming of the pulleys due to the ingress of foreign matter (eg

sand or rock fragments).

  The cover plates or the closures of the

  assemblies 262, 263 and 264 can be used to pre-

  come fall rocks or other debris In some

  case, they can be perforated.

Claims (33)

_REVENDICATIONS   1 Apparatus for forming a hole   drilling in an underground formation (22), characterized   characterized in that it comprises a guide tube (30, 32) containing a fluid-tight seal and coupled at one end to a source of pressurized fluid, a tube (34) in the guide tube ( 30, 32) being in sealing contact with the seal, and being able to   move in the guide tube (30, 32) and out   therebetween by the opposite end of the guide tube, one end of the tube (34) being open and in fluid communication with the guide tube, and means at the opposite end of the tube (34). to form a surface against which pressurized fluid can be directed to cause a fluid force to be exerted on the tube (34) to move it relative to   to the guide tube (30, 32) and through the seal.   Apparatus according to claim 1, characterized   characterized in that the surface forming means comprises a drill head (36) having at least one fluid outlet port.   Apparatus according to claim 1, characterized   in that the drilling head (36) does not comprise   means applying a rotary motion to it.   Apparatus according to claim 2, characterized   in that at least the boring head (36) and the front part of the boring tube (34) protrude from the guide tube (30) in the subterranean formation (22) in such a way that the front part is surrounded by by this training.   Apparatus according to claim 1, characterized in that it comprises means (48) for supplying a pressurized drilling fluid to the fluid passage drilling tube (34). 0968   Apparatus according to claim 1, characterized   in that the sealing device is mounted on the inner surface of the guide tube (30, 32) and is in fluid-tight contact with the drill pipe (34).   Apparatus according to claim 1, characterized   in that it includes means for forming a link between   communication sound between the guide tube (30) and letube (34).   Apparatus according to claim 1, characterized   in that it is placed inside a well casing (28) projecting into the formation region underground (22).   Apparatus according to claim 8, characterized   in that it comprises a weir tube (38) aligned with the assembly and mounted in the well casing (28).   Apparatus according to claim 1, characterized   characterized in that it comprises constraint means operably associated with the piston-containing tube (34) for the purpose of controlling the maximum speed of movement   of it with respect to the guide means.   11, Apparatus according to claim 2, characterized   in that at least one (56a) of the orifices of the drill head (56) extends in an oblique direction in two different planes with respect to the axis of the tube (34) containing a piston.   Apparatus according to claim 2, characterized   in that the drill head (56) has orifices (56b) directed to the rear.   Apparatus according to claim 1, characterized   in that it includes deflection whistles (30a, 32a) adjacent to the leading end of the guide tube (30, 32) for rotating the drill pipe (34) at a substantial angle to to the axis of the guide tube   when drilling is moved into it.   Apparatus according to claim 13, characterized in that the tube (34) has walls   rigid metal which can be plastically deformed.   Apparatus according to claim 13, characterized in that the deflection whistles (30a, 32a) comprise a plurality of connected assemblies (226, 227) which, in the extended position with respect to a position -introduced from of a structure (221) form an arcuate guide passage (238, 242) for bending the tube, the arrangement being such that when hydraulic pressure is applied to the guide tube, the drill pipe (215) is pushed downwards in the guide tube and in the guide passage, causing the bending   of the tube so as to push the lateral drilling head-   to the formation, each of the assemblies comprising a series of pulleys (236, 237, 239, 240) rotatably supported by said assembly and forming   a segment of the arcuate guide passage (238, 242) when that they are in extension.   Apparatus according to claim 13, characterized   characterized in that the series of pulleys (236, 237, 239, 240) supported by each assembly (226, 227) are arranged to contact the walls of the tube on the outer sides of the curve thereof to effect a curvature continuous incremental of the tube.   Apparatus according to claim 13, characterized   characterized in that the first upper assembly (226) of the bending means is attached to the structure (221) and in that its lower end is pivotally connected to one end of the next lower assembly (227), drive means (244) being provided to move the assembly (227) from a recessed position within the structure to an extended position in which it forms in conjunction with the first 254 0968   together (226) the arcuate guideway.   Apparatus according to claim 13, characterized in that it comprises means for rectifying the tube (239 a-d, 240 a-d) carried by the outlet end of the lower assembly.   Apparatus according to claim 18, characterized   in that the straightening means of the tube comprise pulleys arranged so as to apply forces   bending on the upper and lower sides   the tube to straighten it, said pulleys being   supported by the lower assembly (227).   Apparatus according to claim 18, characterized   in that the straightening means of the tube comprise opposed pulleys arranged so as to contact and push against the side walls of the outgoing tube.   in order to reform the configuration into trans section   versale of it to make it pass from an oval shape to a roughly circular shape   Apparatus according to claim 19, characterized   in that the straightening means of the tube are constituted by a set (161) of the cruciform type which   includes upper and lower rollers (162) which-   are arranged to contact the upper and lower sides of the tube and side rollers (163) which contact and push against the side walls of the tube.   Apparatus according to claim 20, characterized   in that the two side rollers (163) are spaced apart so that the tube passing between them is reformed from an oval shape to an approximately circular in cross section.   Apparatus according to claim 13, characterized   in that three connected assemblies (262, 263, 264) are used, the first (262) being pivotally connected at its lower end to the second assembly (263).   and the second is pivotally connected to its end.   lower than the third assembly (264), the first assembly being attached to the structure (-261), motor means (272) being connected to the third assembly (264) for extending the second and third assemblies relative to each other; to the first so as to form the passage arched guide.   Apparatus according to claim 18, characterized   characterized in that the tube straightening means comprises a pulley (286 ae) for applying a force to the tube on the outer side of the tube curve, and adjustable means for rotatably mounting the pulley, thereby it can be advanced or retracted relative to the tube.   Apparatus according to claim 13, characterized   in that it comprises means for introducing water into the bending means during application   to the hydraulic fluid tube under pressure.   Apparatus according to claim 13, characterized   characterized in that the deflection whistles (30a, 32a) comprise means constituting a curved guiding passage in which the tube (34) is pushed when pressurized hydraulic fluid is applied to the pressure tube.   guide (30, 32), the whistle guide passage includes   both rollers or rotary pulleys arranged to contact the drill pipe and apply thereto forces to bend it.   Apparatus for injecting a process fluid from a downwardly directed borehole in the radial direction into a subterranean formation, characterized in that it is in place in said formation and comprises an assembly comprising a guide tube ( 30, 32) lying downwardly, having a sealing means mounted therein and terminating at its forward end in a deflection whistle (30a, 32a), 254 0965   a tube (34) having a head at its front end and open at its posterior end, the head having   at least one outlet port of the fluid, the   upper portion of the tube (34) being retained in fluid-tight contact with the sealing means within the guide tube (30, 32) to define a fluid passage extending from the posterior end of the guide tube through said tube to said head (36), said tube comprising a radially protruding front portion of the deflection whistle (30a, 32a) in the formation,   such that treatment fluid supplied at the end   the posterior tube of the guide tube can flow   through the orifice of the head in the formation.   Apparatus according to claim 27, characterized   characterized in that it comprises at least a second assembly disposed within a well casing, the guide tube of the second set being aligned with the first   together on one side of it, and the deviation whistles   the two sets being close to one another.   A method of forming a borehole in a mineralized subterranean formation, using a drilling system comprising a guide tube and a drill pipe within the guide tube, the tube   having a hydraulic jet type drilling head   having at least one orifice at its front end and extending its other open end, characterized in that it comprises the steps of disposing the drill pipe inside the guide tube with   the posterior open end of the drill pipe in   the guide tube, a seal between the drill pipe and the guide tube, and directing hydraulic fluid under pressure into the guide tube and from there into the drill pipe to ensure that the fluid applies a force against the drill head for   move it along with the drill pipe into the formation.   Process according to claim 29, characterized   rised in that the drill head does not rotate so   sensitive when the drilling fluid passes through the orifice.   The method of claim 30, characterized   in that the drilling fluid is directed through at least one orifice of the drill head in an oblique direction in two different planes with respect to the axis of the drill. drilling tube containing a piston.   The method of claim 30, characterized   rised in that it includes the step of bending   the drill pipe in a whip whip for the steering   laterally to the neighboring formation.   The method of claim 32, characterized   in that the drill pipe has walls   solid in a normally rigid metal which is deformed plastically   only when it changes direction.   The method of claim 32, characterized   in that the guide tube is disposed within a well casing, and that a pressurized abrasive fluid exits the drill head as it rotates in the deflection whistle to form by erosion a opening in the well casing.   Method according to claim 32, characterized   in that the guide tube is placed in an existing well casing prior to the step of directing a fluid under pressure in the guide tube.   The method of claim 32, characterized   in that it involves interrupting the flow of drilling fluid into the drill pipe after completion of the drilling operation, and then applying a fluid   of treatment by the tube in the formation.   37. The method of claim 32, characterized   rised in that the tube during the bending is in contact with   rotating pulleys and is straightened after bending.