CN220929356U - Coal-bed gas well structure of coal mine area with near-end butt joint of well-hole - Google Patents

Abstract

The utility model discloses a coal-bed gas well structure of a coal mine area with a near-end butt joint type well-hole, which comprises a ground horizontal well, an underground borehole and an underground roadway, wherein the underground borehole is arranged below the ground horizontal well and is communicated with the ground horizontal well, and the two communicating points are positioned at the bottommost part of the ground horizontal well; a casing is drilled in the underground borehole, the front end of the casing is connected with a self-rotating whipstock, and the self-rotating whipstock is communicated with a ground horizontal well; and a blind plug packer is arranged in the ground horizontal well. The underground drilling hole is communicated with the lowest elevation position of the ground horizontal shaft, and is automatically downwards discharged from the underground drilling tunnel by utilizing the gravity of solid wastes such as water, sand, coal dust, bridge plug residues and the like, and is automatically upwards discharged from a wellhead by fully utilizing the pressure and buoyancy of gas, so that the gas and water are automatically separated in the shaft.

Description

Coal-bed gas well structure of coal mine area with near-end butt joint of well-hole

Technical Field

The utility model relates to the technical field of coal bed gas exploitation, in particular to 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 the policy, the drainage period of the coal bed gas horizontal well is generally 5-8 years, and the temporary land time limit of the construction use of the energy project is not more than 4 years, which reduces the gas production and the outburst elimination effect.

3. Because the well inclination of the L-shaped well is larger, when a rod pump is adopted for drainage, the ① pump cannot go down to the bottom of the well, so that the waste pressure of the 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 the publication number of CN106640018A and the patent name of a 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 terrain conditions is poor, and the application provides a drainage and gas production method for the coal bed gas horizontal well in the coal mine area to solve the defects.

Disclosure of utility model

The technical problems to be solved by the utility model are as follows: how to solve the problems of the existing coal seam extraction device such as card pump, large particle retention, limited temporary land time and the like.

In order to solve the technical problems, the utility model provides the following technical scheme:

The utility model provides a coal seam gas well structure in well-hole near-end butt joint formula colliery district, includes ground horizontal well, borehole and underworkings, its characterized in that: the underground drilling hole is arranged below the ground horizontal well and is communicated with the ground horizontal well, and the underground drilling hole and the ground horizontal well are positioned at the bottommost position of the ground horizontal well;

The underground borehole is internally drilled with a sleeve, the front end of the sleeve is connected with a self-rotating whipstock, and the self-rotating whipstock is communicated with a ground horizontal well; and a blind packer is arranged in the ground horizontal well, wherein the blind packer is positioned between the communication point and the fracturing section of the ground horizontal well.

According to the application, the self-rotating whipstock is arranged, the self-rotating adjustment angle of the whipstock wraps the upper sleeve, 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.

As a further scheme of the utility model: the magnetic detection pipe is arranged in the ground horizontal well, the magnetic detection pipe is positioned at the front end of the blind packer, the magnetic rotary emission short circuit is arranged in the underground drilling hole, the magnetic rotary emission short circuit is connected with the magnetic detection pipe in a magnetic mode.

As a further scheme of the utility model: the downhole drilling is inclined, wherein the inclination angle of the downhole drilling is greater than 45 ° and less than 90 °.

As a further scheme of the utility model: 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 in the mine industry.

As a further scheme of the utility model: the self-rotating whipstock comprises an inner ring and an outer ring, balls are arranged between the inner ring and the outer ring through a retainer, a groove is formed in one side of the outer ring facing the ground horizontal well, and a coupling head is arranged on one side of the inner ring facing away from the ground horizontal well.

As a further scheme of the utility model: the coupling head at one end of the self-rotating whipstock is connected with a fixed hole sleeve of the underground drilling, a groove at the other end of the self-rotating whipstock wraps the sleeve of the horizontal well, and the radian of the groove is designed according to the butt joint angle of the underground drilling and the horizontal well.

As a further scheme of the utility model: the edges of the grooves are provided with saw-tooth heads.

Compared with the prior art, the utility model has the beneficial effects that:

1. According to the application, the self-rotating whipstock is arranged, the self-rotating adjustment angle of the whipstock wraps the upper sleeve, 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 application, the relative position data of the drill bit and the butt joint point are transmitted from the ground to the underground in real time through the Ethernet ring network in the mine industry, so that the underground directional drilling is accurately guided;

3. According to the application, 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 generated when the horizontal well is in first butt joint communication; the application can also use drillable bridge plugs to replace blind plugs, so that the drillable bridge plugs can be used for corresponding selection by staff during operation;

4. The application realizes zero-power automatic drainage, eliminates the drainage of the ground submerged pump, eliminates 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, and realizes continuous drainage of coal bed gas; 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 application omits the land used for drainage pipeline laying, water sump, pipe pole stacking, crane, temporary power generation cabinet, well site road and the like, only reserves one well mouth and one gas transmission pipeline, and greatly reduces the temporary land used for drainage and production;

6. The application eliminates the cost of submersible pump, pump detection and replacement operation, 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 drainage and gas production method for a coal bed methane horizontal well in a coal mine area according to 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 utility model more apparent, the technical solutions in the embodiments of the present utility model will be clearly and completely described in the following in conjunction with the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1, 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 1, a downhole drilling hole 12 and a downhole roadway 6, wherein the downhole drilling hole 12 is arranged below the ground horizontal well 1 and is communicated with the ground horizontal well 1, and the two communicating points are positioned at the bottommost part of the ground horizontal well 1; a casing is drilled in the underground borehole 12, the front end of the casing is connected with a self-rotating whipstock 18, and the self-rotating whipstock 18 is communicated with the ground horizontal well 1; the inside of the ground horizontal well 1 is provided with a blind packer 7, wherein the blind packer 7 is positioned between the communication point and the fracturing section of the ground horizontal well 1.

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 monitoring host computer 16 through a mine industry ethernet ring 15, and the ground monitoring host 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. 2 and 3, 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 groove 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. 3 and 4, 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.

The specific operation principle of the application is as follows: the method 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.

Because the application is butted at the near end, the butted communication is needed after the completion of the well cementation and hydraulic fracturing construction of the horizontal well casing on the ground, namely the simultaneous butted communication of the well-hole and the well-hole inner casing is needed. 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 utility model, and are not limiting; although the utility model 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 utility model.

Claims (7)

1. The utility model provides a coal seam gas well structure in well-hole near-end butt joint formula colliery district, includes ground horizontal well (1), borehole (12) and underworkings (6), its characterized in that: the underground drilling hole (12) is arranged below the ground horizontal well (1) and is communicated with the ground horizontal well (1), and the underground drilling hole and the ground horizontal well are positioned at the bottommost position of the ground horizontal well (1);

The underground drilling hole (12) is internally drilled into a sleeve, the front end of the sleeve is connected with a self-rotating whipstock (18), and the self-rotating whipstock (18) is communicated with the ground horizontal well (1); the inside of ground horizontal well (1) is equipped with blind packer (7), and wherein blind packer (7) are located between the fracturing section of communication point and ground horizontal well (1).

2. A coal seam gas well structure in a well-to-well proximal docking coal mine area as claimed in claim 1, wherein: the magnetic detection pipe (10) is arranged in the ground horizontal well (1), the magnetic detection pipe (10) is positioned at the front end of the blind packer (7), the magnetic rotary emission short circuit (11) is arranged in the underground drilling hole (12), the magnetic rotary emission short circuit (11) is connected with the magnetic detection pipe (10), and the magnetic rotary emission short circuit (11) is magnetically connected with the magnetic detection pipe (10).

3. A coal seam gas well structure in a well-to-well proximal docking coal mine area as claimed in claim 1, wherein: the downhole drilling (12) is arranged at an inclination, wherein the inclination angle of the downhole drilling (12) is more than 45 DEG and less than 90 deg.

4. A coal seam gas well structure in a well-to-well proximal docking coal mine area as claimed in claim 1, wherein: the underground roadway (6) is internally provided with a data receiver (17), wherein the data receiver (17) is connected to a monitoring host (16) arranged on the well through a mine industrial Ethernet ring network (15).

5. A coal seam gas well structure in a well-to-well proximal docking coal mine area as claimed in claim 1, wherein: the self-rotating whipstock (18) comprises an inner ring (184) and an outer ring (183), balls (181) are arranged between the inner ring (184) and the outer ring (183) through a retainer (188), a groove (186) is formed in one side, facing the ground horizontal well (1), of the outer ring (183), and a coupling head (187) is arranged on one side, facing away from the ground horizontal well (1), of the inner ring (184).

6. A well-bore near end docking coal mine area coalbed methane well structure as claimed in claim 5, wherein: the coupling head (187) at one end of the self-rotating whipstock (18) is connected with a fixed-hole sleeve of the underground drilling, the groove (186) at the other end wraps the sleeve of the horizontal well, and the radian of the groove (186) is designed according to the butt joint angle of the underground drilling and the horizontal well.

7. A well-bore near end docking coal mine area coalbed methane well structure as claimed in claim 5, wherein: the edges of the grooves (186) are provided with saw-tooth heads (185).