CN117703314A - Coal-bed gas well structure of coal mine area with near-end butt joint of well and hole and construction method - Google Patents
Coal-bed gas well structure of coal mine area with near-end butt joint of well and hole and construction method Download PDFInfo
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Abstract
The invention discloses a coal-bed gas well structure of a coal mine area with a well-hole near-end butt joint type, which comprises a ground horizontal well and a downhole drilling hole, wherein the ground horizontal well is of an L-shaped structure, and the lowest elevation point is a near end point; the downhole drilling is an upward inclined drilling, and the inclination angle is larger than 45 degrees and smaller than 90 degrees; the junction point of the ground horizontal well and the underground drilling is a near end point; the coal-bed gas well structure is provided with two inlets and outlets; according to the method, the underground drilling hole is communicated with the lowest elevation position of the ground horizontal shaft, the gravity of solid wastes such as water, sand, coal dust and bridge plug residues is utilized to be automatically discharged downwards and from an underground drilling roadway, the pressure and buoyancy of gas are fully utilized to be automatically discharged upwards from a wellhead, and the gas and water are automatically separated in the shaft.
Description
Technical Field
The invention relates to the technical field of coal bed gas exploitation, in particular to a construction method of a coal bed gas well structure of a coal mine area with a near-end butt joint type well-hole.
Background
Coalbed methane is primarily stored in the coal bed in an adsorbed form. The principle of coal bed gas development is that the reservoir pressure is reduced through drainage, the desorption of coal bed adsorption gas into free gas is promoted, and then the free gas is transported into a coal bed gas shaft through diffusion and seepage. The water is pumped and discharged to the ground by adopting a method of putting a submersible pump in a shaft, and the coalbed methane can be automatically discharged from a wellhead by utilizing the self pressure. According to different well types and different shaft numbers of coal-bed gas wells, drainage and gas production modes are different. The L-shaped horizontal well is provided with only one shaft, the drainage gas production is in the same shaft, and a gas-water separation device is arranged at the well mouth; the U-shaped horizontal well is provided with 2 wellheads, and is used for draining water by using the vertical well, and the horizontal well is used for gas production; the V-shaped horizontal well has 3 well heads, uses the middle vertical well to drain water, and uses the horizontal wells on two sides to produce gas.
The prior art of L-shaped horizontal wells has the defects that:
1. the use cost is high, including temporary land use, drainage pump, pump checking operation, electric charge, temporary generator, ground water treatment, labor charge and the like.
2. The temporary land time limit is limited by a policy, the drainage period of the coal bed methane horizontal well is generally 5-8 years, the temporary land time limit of the construction use of the energy project is not more than 4 years, and the forced pipe diameter can reduce the gas production and the outburst elimination effect.
3. Because the L-shaped well is large in well inclination, when a rod pump is adopted for drainage, the pump cannot go to the bottom of the well, so that the waste pressure of a reservoir is high, and the gas production and outburst elimination effects are reduced; (2) the eccentric wear of the pipe rod causes pipe leakage, torque increase, no liquid discharge or liquid discharge amount reduction and the like, so that the service life of the pump and the pump detection period are reduced, and discontinuous drainage and reservoir pollution are caused;
4. the electric submersible pump is adopted to replace a rod pump, so that the problems that the bottom of a well and a pipe rod are not worn off when the pump is lowered are solved, but the electric submersible pump is very sensitive to coal dust, so that the pump detection period is short, the service life of the pump is short, the electric submersible pump is not applicable to broken soft coal beds, and the price and the maintenance cost of the electric submersible pump are higher.
5. A certain sinking degree is needed for both the rod pump and the electric submersible pump, so that insufficient drainage and depressurization are caused, and the yield of coal bed gas and the outburst elimination effect of the coal bed are reduced.
6. The drainage effect of the drainage pump on large particles is poor, and bridge plug residues, sand, coal blocks and the like are hardened in a well bore deposition, so that the well bore is blocked. The prior sand fishing pump and the technical process of the horizontal well are still not mature, and frequent sand fishing has large damage to the reservoir and is irreversible.
The publication number is CN103967472B, the patent name is a prior patent technology of a coal bed methane staged fracturing horizontal well enhanced extraction method, and the prior patent technology discloses a U-shaped well type structure; the prior patent technology with publication number of CN106640018A and patent name of coal bed gas V-shaped well group exploitation method discloses a V-shaped well type structure; both patents are used for draining water by adding 1 vertical well, so that the problems of deep and shallow under the pump, eccentric wear of a pipe rod, high waste pressure, blockage of a shaft and the like are solved, but the problems of pump blockage, large particle retention, limited temporary land time and the like caused by coal dust cannot be avoided due to the arrangement; meanwhile, one vertical well and 1 ground well site are added, and engineering cost and use cost are increased. In addition, the adaptability to mountain land topography conditions is poor, and the application provides a construction method of a coal-bed gas well structure of a coal mine area with a near-end butt joint type well-hole, so that the defects are overcome.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: how to solve the problems of insufficient formation depressurization, shaft blockage, frequent pump detection, discontinuous drainage, limited temporary land time, high drainage cost and the like in the existing coal bed gas drainage.
In order to solve the technical problems, the invention provides the following technical scheme:
the coal-bed gas well structure comprises a ground horizontal well and underground drilling holes, wherein the ground horizontal well is of an L-shaped structure, and the lowest elevation point is a near end point; the downhole drilling is an upward inclined drilling, and the inclination angle is larger than 45 degrees and smaller than 90 degrees; the junction point of the ground horizontal well and the underground drilling is a near end point;
the coal-bed gas well structure has two inlets and outlets, one is a ground horizontal well and a wellhead for the reservoir fracturing reconstruction channel and the gas production channel, and the other is an orifice for underground drilling for discharging water or fracturing sand, coal dust and solid residues.
The application also discloses a construction method of the coal-bed gas well structure of the coal-mine area with the near-end butt joint of the well-hole, which comprises the following steps:
s1, determining a ground horizontal well and an underground drilling track according to coal seam spread of a mine target block, ground construction conditions and underground roadway positions;
s2, drilling, well cementation and fracturing of the ground horizontal well are completed;
s3, reinforcing a roadway connected with the position of the opening of the underground drilling hole;
s4, connecting a magnetic rotary emission short circuit at the front end of a drill rod of the underground directional drilling machine, arranging a data receiver in a drilling site, and putting a magnetic probe tube outside a butt joint of a horizontal well, wherein the magnetic probe tube is connected with a ground monitoring host computer through a cable, and the monitoring host computer is connected with the receiver through a mine industrial Ethernet ring;
s5, constructing underground drilling, collecting magnetic rotation data, analyzing the relative positions of the drill bit and the communication points, transmitting the data to an underground drilling field receiver in real time through an industrial Ethernet, and adjusting the directional drilling of an underground drilling tool face in real time according to the relative position data until the drill bit touches a ground horizontal well sleeve;
s6, drilling a hole in the well, running a sleeve, connecting a self-rotating whipstock at the front end of the sleeve, and cementing the sleeve after the whipstock is seated and hung with the sleeve of the ground horizontal well;
s7, a blind plug packer is put in from the ground horizontal well at the lower end of the butt joint point;
s8, installing a rotary blowout preventer at the orifice, and putting a milling cone into the orifice to finish windowing milling operation;
s9, supplementing water in the ground horizontal shaft, filling water in the shaft, unsealing the packer from the ground horizontal underground oil pipe, and realizing well-hole communication;
s10, automatic drainage is carried out from underground drilling, gas is automatically produced from a ground horizontal wellhead, and pump-free automatic drainage is realized.
As a further scheme of the invention: the ground horizontal well is located above the underground drilling hole, the bottom of the underground drilling hole is connected with the underground roadway, and the top of the underground drilling hole is communicated with the lowest part of the ground horizontal well.
As a further scheme of the invention: the elevation of the roadway is lower than the elevation of a communication point between the underground drilling hole and the ground horizontal well.
As a further scheme of the invention: the roadway is located outside the influence range of fracturing cracks of the ground horizontal well, and the periphery of the roadway is free of structures.
As a further scheme of the invention: in the step S6, after the underground drilling is used for casing cementing, a water injection and compaction test is carried out, whether the roadway is subjected to water spraying and deformation is observed, and if so, supplementary reinforcement operation is carried out;
the test pressure is larger than the sum of the horizontal wellhead pressure and the hydrostatic pressure of water column after fracturing, and the test time is not less than 48 hours.
As a further scheme of the invention: the track of the underground drilling section is kept smooth, the hole inclination is gradually increased, and the hole inclination is more than 45 degrees and less than 90 degrees.
As a further scheme of the invention: in the step S7, when the power of the drilling machine is suddenly reduced and the pressure at the bottom of the hole is suddenly increased, the well-hole communication is indicated, the drilling is stopped, and the drill rod is lifted up and down for multiple times to polish the hole; and opening the pressure release valve to timely discharge drill cuttings in the hole.
As a further scheme of the invention: the coupling head at one end of the self-rotating whipstock is connected with the fixed-hole sleeve, the groove at the other end wraps the horizontal well sleeve, and the radian of the groove is designed according to the butt joint angle of the underground drilling and the horizontal well; the ball bearing can realize automatic rotation of the groove; the edges of the grooves are saw-tooth-shaped.
As a further scheme of the invention: the blind plug packer is positioned at the inner side of the butt joint in the horizontal well and temporarily isolates the fracturing reconstruction section from the underground drilling.
As a further scheme of the invention: the underground roadway is internally provided with a data receiver, wherein the data receiver is connected to a monitoring host arranged on the well through an Ethernet ring network of the mine industry, the monitoring host can analyze and generate a three-dimensional model of the relative positions of a drill bit and a cave, and the data receiver is transmitted to the underground data receiver through a system platform of the Ethernet ring network of the mine industry to guide underground directional drilling.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the self-rotating whipstock, the whipstock automatically rotates to adjust the angle to wrap the upper sleeve, so that the windowing direction is guided, and the drill bit is prevented from shifting during windowing; the edge of the connecting hole sleeve is serrated, and has a certain impact rock breaking function;
2. according to the method, relative position data of the drill bit and the butt joint point are transmitted in real time from the ground to the underground through the mine industrial Ethernet ring, so that underground directional drilling is accurately guided;
3. according to the method, the blind packer is arranged in the ground horizontal well, and can isolate the fracturing section of the horizontal well from the underground borehole, so that formation excitation or sand and powder are prevented from being caused when the horizontal well is in first butt joint communication; the drillable bridge plug can be used for replacing the blind plug packer, so that a worker can select correspondingly during operation;
4. the zero-power automatic drainage is realized, the ground submerged pump drainage is canceled, the working procedures of pump clamping, pipe leakage, pump detection, temporary power generation and the like and the drainage interruption accidents caused by the working procedures are stopped, and the continuous drainage of coal bed gas is realized; the water carrying sand powder is discharged from the lower orifice by utilizing the self gravity, so that the automatic cleaning function of a shaft is realized, the cleanness of the shaft is kept, the phenomenon of shaft blockage caused by sand powder deposition is improved, the poor ground sand-bailing effect and the safety risk are avoided, and the damage of a reservoir is reduced; the formation pressure can be reduced to the theoretical minimum value, the production period is long, and the maximization of gas production and outburst elimination effect is realized;
5. the ground of the application cancels the land used for drainage pipeline laying, water sump, pipe pole stacking, crane, temporary power generation cabinet, well site road and the like, only one well mouth and one gas transmission pipeline are reserved, and the temporary drainage ground is greatly reduced and basically canceled;
6. the method and the device cancel the cost of the submersible pump, pump replacement operation of the pump, water transportation, water treatment, well site road, temporary generator and the like, and can greatly reduce the drainage and production cost.
Drawings
FIG. 1 is a schematic diagram of a construction method of a coal-bed gas well structure in a coal mine area with a near-end butt joint of a well-hole in an embodiment of the invention;
FIG. 2 is a schematic view of a self-rotating joint of a whipstock according to an embodiment of the invention;
FIG. 3 is a plan view of a self-rotating whipstock according to an embodiment of the invention;
FIG. 4 is a diagram illustrating the connection of a self-rotating whipstock to a surface horizontal well and downhole drilling in accordance with an embodiment of the present invention;
reference numerals illustrate: 1. a ground horizontal well; 2. a first drill hole; 3. drilling holes at two times; 4. three-hole drilling; 5. fracturing a fracture; 6. a downhole tunnel; 7. blind plugging a packer; 8. a butt joint point; 9. a cable; 10. a magnetic probe tube; 11. magnetic rotation emission short circuit; 12. drilling holes in the well; 13. drilling and opening; 14. a drill rod; 15. mine industry Ethernet ring network; 16. monitoring a host; 17. a data receiver; 18. a self-rotating whipstock; 181. a ball; 182. a centralizer; 183. an outer ring; 184. an inner ring; 185. a saw tooth head; 186. a groove; 187. a coupling head; 188. a retainer; 19. rotating the blowout preventer; 20. a horizontal well casing; 21. downhole drilling casing.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, 2, 3 and 4, a coal-bed gas well structure of a coal mine area with a near-end butt joint type well-hole comprises a ground horizontal well and a downhole drilling hole, wherein the ground horizontal well is of an L-shaped structure, and the lowest elevation point is a near end point; the underground drilling is an upward inclined drilling, and the inclination angle is larger than 45 degrees and smaller than 90 degrees; the junction point of the ground horizontal well and the underground drilling is a near end point;
the coal-bed gas well structure has two inlets and outlets, one is a ground horizontal well and a wellhead for the reservoir fracturing reconstruction channel and the gas production channel, and the other is an orifice for underground drilling for discharging water or fracturing sand, coal dust and solid residues.
Referring to fig. 1, 2 and 4, a construction method of a coal-bed gas well structure of a coal-mine area with a near-end butt joint type well-hole comprises the following steps:
s1, determining the track of a ground horizontal well 1 and a downhole drilling 12 according to the coal seam spread of a mine target block, ground construction conditions and the position of a downhole roadway;
s2, drilling, well cementation and fracturing of the ground horizontal well 1 are completed;
it should be noted that the ground horizontal well is arranged in an L-shaped structure, the ground horizontal well is positioned at a high position of a construction of a target layer, the underground drilling is positioned at a low position of the construction, the underground drilling is communicated with the lowest elevation position of the L-shaped horizontal well, the ground horizontal well adopts three-way cementing, and is sequentially provided with a first way 2, a second way 3 and a third way 4, and the ground horizontal well 1 (shown in figure 1) is formed by adopting three ways of cementing; the coal seam gas well in the coal mining area is provided with two inlets and outlets, the ground wellhead is a reservoir fracturing transformation channel and a gas production channel, and the underground orifice is a discharge channel for water, fracturing sand, coal dust, solid residues and the like.
Furthermore, the underground drilling track should be kept smooth, the hole inclination gradually increases, and steps are avoided, preferably more than 45 degrees and less than 90 degrees; the larger the inclination angle is, the more favorable is for drainage and deslagging, and when the well inclination is 90 degrees, the deslagging effect is optimal.
S3, reinforcing a roadway connected with the position of the opening of the underground borehole 12;
it should be noted that, further, the roadway is located outside the influence range of the fracturing fracture of the ground horizontal well 1, and there is no structure around the roadway 6, the reinforcement range of the roadway 6 is not less than 20m, and the reinforcement method includes, but is not limited to, anchor rod reinforcement, anchor cable reinforcement, bracket reinforcement, U-shaped steel reinforcement, grouting reinforcement, and the like.
S4, connecting a magnetic rotary emission short circuit 11 (the magnetic rotary emission short circuit is linked between the drill rod and the drill bit, and a magnetic field is generated when the drill rod rotates) at the front end of the drill rod of the underground directional drilling machine, wherein the magnetic carbon tube receives the magnetic field, so that the relative position can be judged, a data receiver 17 is arranged in the drill field, a magnetic probe 10 is arranged outside a butt joint point of a horizontal well, the magnetic probe is connected with a ground monitoring host computer 16 through a cable 9, and the monitoring host computer is connected with the receiver through a mine industry Ethernet ring 15.
S5, constructing underground drilling, collecting magnetic rotation data, analyzing the relative positions of the drill bit and the communication points, transmitting the data to an underground drilling field receiver in real time through an industrial Ethernet, and adjusting the directional drilling of an underground drilling tool face in real time according to the relative position data until the drill bit touches a ground horizontal well sleeve;
s6, the underground borehole 12 is sleeved, the front end of the sleeve is connected with a self-rotating whipstock 18, and the whipstock is well cementation is carried out after the whipstock is seated and hung with the sleeve of the ground horizontal well;
further, after the well is fixed under the casing of the underground borehole 12, a water injection and compaction test is carried out to observe whether the roadway 6 is subjected to water spraying, deformation and the like, otherwise, supplementary reinforcement operation is carried out; the test pressure is greater than the sum of the pressure of the surface wellhead after fracturing and the hydrostatic pressure between the surface wellhead and the downhole drilling hole, and the test time is not less than 48 hours.
S7, a blind packer 7 is put into the ground horizontal well from the lower end of the butt joint point, and the blind packer 7 has the functions of isolating a fracturing section in the horizontal well from a downhole drilling 12 and preventing formation excitation and sand and powder discharge during butt joint communication;
other than the above, the invention herein may use drillable bridge plugs instead of blind packers 7, but drilling the post-bridge plug cuttings increases wellbore complexity;
s8, installing a rotary blowout preventer at the orifice, and putting a milling cone into the orifice to finish windowing milling operation;
it should be noted that in the working process, when the power of the drilling machine suddenly decreases and the pressure at the bottom of the hole suddenly increases, the communication between the well (the ground horizontal well) and the hole (the underground drilling) is indicated, and the drilling is immediately stopped at the moment, so that the upper wall of the horizontal section sleeve in the ground horizontal well is prevented from being damaged, and the drill rod is lifted up and down for multiple times to polish the hole; and opening the pressure release valve to timely discharge drill cuttings in the hole.
In the step S8, besides the selection of installing the blowout preventer in the hole and putting down the milling cone, the invention can also put down the water jet protective material in the horizontal well shaft to the butt joint point, then put down the angle-adjustable high-pressure water jet nozzle from the underground drilling hole, and finish the cutting and windowing operation; the water jet protective material can prevent water jet from cutting the upper wall of the horizontal section sleeve.
S9, supplementing water in the ground horizontal shaft, filling water in the shaft, unsealing the packer from the ground horizontal underground oil pipe, and realizing well-hole communication;
it should be noted that the blind packer 7 needs to supplement water to the well bore of the ground horizontal well before unsealing, so that rapid pressure relief of the stratum at the fracturing section caused by large pressure difference during unsealing is prevented, and sand and powder are discharged.
S10, automatic drainage is carried out from underground drilling, gas is automatically produced from a ground horizontal wellhead, and pump-free automatic drainage is realized.
Referring to fig. 1, a data receiver 17 is arranged in a down-hole roadway 6, the data receiver 17 is connected to a ground data acquisition and analysis computer 16 through a mine industry ethernet ring 15, and the ground data acquisition and analysis computer 16 is connected with a magnetic probe 10 through a cable; when the underground drilling is performed, the magnetic rotary emission short circuit 11 arranged on the drill rod generates a magnetic field, the magnetic probe 10 positioned in the ground horizontal well is excited by the influence of the magnetic field to generate an electric signal, the electric signal is transmitted to the ground computer 16 through a cable, the computer 16 generates relative position data of a drill bit and a butt joint point through analysis and analysis, the data is transmitted to the underground drilling field data receiver 17 in real time through the mine industrial Ethernet 15, and a driller adjusts underground to perform underground directional drilling according to the position data in real time, so that intelligent drilling processing is realized.
Referring to fig. 4, the self-rotating whipstock 18 is connected to the downhole borehole casing 21 by a rear coupling head 187, wrapping the horizontal well casing 20 by a front recess 186; the self-rotating whipstock has the function of accurately guiding the milling windowing operation and preventing the drill bit direction from deviating during windowing.
Referring to fig. 2 and 3, at the intermediate position of the self-rotating whipstock 18 is a ball bearing including an inner race 184 and an outer race 183, with balls 181 provided between the inner race 184 and the outer race 183, the balls 181 being mounted between the inner and outer races by a cage 188; the ball bearing outer ring 183 is fixedly connected to the groove 186, and the ball bearing inner ring 184 is fixedly connected to the coupling head 187.
Referring to fig. 4, the curvature of the recess 186 is designed to maximize the contact area based on the angle of intersection of the borehole and the horizontal well; the groove 186 can automatically adjust the posture of the groove through a ball bearing when being in butt joint with the horizontal well casing 20, so that the groove is ensured to tightly wrap the horizontal well casing.
Referring to fig. 3, the outside of the recess 186 is provided in a zigzag shape so as to have a certain impact breaking function, and the set cement outside the horizontal well casing is peeled off.
Because the connection is performed at the near end, the connection is performed after the completion of the well cementation and hydraulic fracturing construction of the horizontal well casing on the ground, namely the connection is performed by simultaneously connecting the well-hole casing and the well-hole casing. To this end, the present patent invented a docking whipstock and a docking method. Firstly realizing well-hole butt joint, then realizing casing pipe butt joint, and the specific method is as follows: after well-hole butt joint is good, the casing is put into the underground drilling, the front section of the casing is connected with the whipstock, after the whipstock touches the horizontal well casing, the groove part can automatically rotate, the butt joint gesture is adjusted, so that the groove wraps the upper horizontal well casing, then the hole is fixedly grouted, then a milling cone is put into the drilling, milling and windowing operation is carried out, and the butt joint communication of the casing is realized. The traditional remote end butt joint mode at present can realize communication only by drilling butt joint, and the two butt joint difficulties are different.
The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The coal-bed gas well structure of the coal-mine area with the near-end butt joint type well-hole is characterized by comprising a ground horizontal well and a downhole drilling hole, wherein the ground horizontal well is of an L-shaped structure, and the lowest elevation point is a near-end point; the downhole drilling is an upward inclined drilling, and the inclination angle is larger than 45 degrees and smaller than 90 degrees; the junction point of the ground horizontal well and the underground drilling is a near end point;
the coal-bed gas well structure has two inlets and outlets, one is a ground horizontal well and a wellhead for the reservoir fracturing reconstruction channel and the gas production channel, and the other is an orifice for underground drilling for discharging water or fracturing sand, coal dust and solid residues.
2. A method of constructing a coal-bed gas well structure in a coal mine area employing a well-bore proximal end butt joint as claimed in claim 1, comprising the steps of:
s1, determining a ground horizontal well and an underground drilling track according to coal seam spread of a mine target block, ground construction conditions and underground roadway positions;
s2, drilling, well cementation and fracturing of the ground horizontal well are completed;
s3, reinforcing a roadway connected with the position of the opening of the underground drilling hole;
s4, connecting a magnetic rotary emission short circuit at the front end of a drill rod of the underground directional drilling machine, arranging a data receiver in a drilling site, and putting a magnetic probe tube outside a butt joint of a horizontal well, wherein the magnetic probe tube is connected with a ground monitoring host computer through a cable, and the monitoring host computer is connected with the receiver through a mine industrial Ethernet ring;
s5, constructing underground drilling, collecting magnetic rotation data, analyzing the relative positions of the drill bit and the communication points, transmitting the data to an underground drilling field receiver in real time through an industrial Ethernet, and adjusting the directional drilling of an underground drilling tool face in real time according to the relative position data until the drill bit touches a ground horizontal well sleeve;
s6, drilling a hole in the well, running a sleeve, connecting a self-rotating whipstock at the front end of the sleeve, and cementing the sleeve after the whipstock is seated and hung with the sleeve of the ground horizontal well;
s7, a blind plug packer is put in from the ground horizontal well at the lower end of the butt joint point;
s8, installing a rotary blowout preventer at the orifice, and putting a milling cone into the orifice to finish windowing milling operation;
s9, supplementing water in the ground horizontal shaft, filling water in the shaft, unsealing the packer from the ground horizontal underground oil pipe, and realizing well-hole communication;
s10, automatic drainage is carried out from underground drilling, gas is automatically produced from a ground horizontal wellhead, and pump-free automatic drainage is realized.
3. The method for constructing the coal-bed gas well structure of the coal-mine area with the near-end butt joint of the well-hole is characterized in that: the ground horizontal well is located above the underground drilling hole, the bottom of the underground drilling hole is connected with the underground roadway, and the top of the underground drilling hole is communicated with the lowest part of the ground horizontal well.
4. A method for constructing a coal-bed gas well structure in a coal mine area by near-end well-to-well docking according to claim 3, wherein: the elevation of the roadway is lower than the elevation of a communication point between the underground drilling hole and the ground horizontal well.
5. The method for constructing the coal-bed gas well structure of the coal-mine area with the near-end butt joint of the well-hole is characterized in that: the roadway is located outside the influence range of fracturing cracks of the ground horizontal well, and the periphery of the roadway is free of structures.
6. The method for constructing the coal-bed gas well structure of the coal-mine area with the near-end butt joint of the well-hole is characterized in that: in the step S6, after the underground drilling is used for casing cementing, a water injection and compaction test is carried out, whether the roadway is subjected to water spraying and deformation is observed, and if so, supplementary reinforcement operation is carried out;
the test pressure is larger than the sum of the horizontal wellhead pressure and the hydrostatic pressure of water column after fracturing, and the test time is not less than 48 hours.
7. The method for constructing the coal-bed gas well structure of the coal-mine area with the near-end butt joint of the well-hole is characterized in that: in the step S7, when the power of the drilling machine is suddenly reduced and the pressure at the bottom of the hole is suddenly increased, the well-hole communication is indicated, the drilling is stopped, and the drill rod is lifted up and down for multiple times to polish the hole; and opening the pressure release valve to timely discharge drill cuttings in the hole.
8. The method for constructing the coal-bed gas well structure of the coal-mine area with the near-end butt joint of the well-hole is characterized in that: the coupling head at one end of the self-rotating whipstock is connected with the fixed-hole sleeve, the groove at the other end wraps the horizontal well sleeve, and the radian of the groove is designed according to the butt joint angle of the underground drilling and the horizontal well; the ball bearing can realize automatic rotation of the groove; the edges of the grooves are saw-tooth-shaped.
9. The method for constructing the coal-bed gas well structure of the coal-mine area with the near-end butt joint of the well-hole is characterized in that: the blind plug packer is positioned at the inner side of the butt joint in the horizontal well and temporarily isolates the fracturing reconstruction section from the underground drilling.
10. The method for constructing the coal-bed gas well structure of the coal-mine area with the near-end butt joint of the well-hole is characterized in that: the underground roadway is internally provided with a data receiver, wherein the data receiver is connected to a monitoring host arranged on the well through an Ethernet ring network of the mine industry, the monitoring host can analyze and generate a three-dimensional model of the relative positions of a drill bit and a cave, and the data receiver is transmitted to the underground data receiver through a system platform of the Ethernet ring network of the mine industry to guide underground directional drilling.
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| CN202311495754.4A CN117703314A (en) | 2023-11-08 | 2023-11-08 | Coal-bed gas well structure of coal mine area with near-end butt joint of well and hole and construction method |
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|---|---|---|---|
| CN202311495754.4A CN117703314A (en) | 2023-11-08 | 2023-11-08 | Coal-bed gas well structure of coal mine area with near-end butt joint of well and hole and construction method |
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