A device and method for drilling and transforming hot dry rock reservoir

Abstract

The present invention discloses a device and method for drilling and reforming hot dry rock reservoirs. The device includes a drill bit, a micro-hole drill, a power short joint, an upper joint, a connecting joint string and a continuous oil pipe connected in sequence; it can also include a bottom hole measurement while drilling tool, a direction finder and a downhole thruster; the drill bit has a front nozzle; the drill bit has a plugging column in the center, and a spring is sleeved on the plugging column; the micro-hole drill has a plurality of lateral nozzles on the side wall; the micro-hole drill has a control sleeve on the inner wall, and a flow channel is provided in the center of the control sleeve. The present invention can perform jet reformation on thermal reservoirs with developed natural fractures in the main wellbore and thermal reservoirs with a low number of fractures or poor connectivity in the main wellbore, respectively, can increase the reformation volume, reduce the risk of microseismicity, and can also be implemented in conjunction with chemical stimulation to improve the reformation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of hot dry rock drilling, and more particularly to a device and method for drilling and transforming hot dry rock reservoirs. Background Art

[0002] Hot dry rock is a green and clean energy source that is inexhaustible. During the development of hot dry rock, it is usually necessary to drill injection wells and transform the hot dry rock reservoir in order to increase the heat exchange volume and enhance the connectivity of the reservoir.

[0003] The commonly used methods at present are hydraulic fracturing, chemical and thermal stimulation. Hydraulic fracturing has a great impact on the formation, is prone to micro-earthquakes, and the single high-permeability fracture formed has a small heat exchange area, and it is difficult to control the direction. After the thermal stimulation ends, as the temperature rises, some fractures will close. Chemical stimulation reacts quickly with rock minerals in a high-temperature environment, making it difficult to penetrate deep into the thermal reservoir, and causing corrosive damage to the downhole casing.

[0004] Therefore, in order to change the existing technical defects and to be able to simultaneously deal with different situations of developed and undeveloped fractures in the main wellbore, how to provide a device and method that can effectively drill and transform hot dry rock reservoirs is an issue that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of this, the present invention provides a device for drilling and transforming hot dry rock reservoirs, aiming to solve the above technical problems.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A device for drilling and reforming a hot dry rock reservoir, comprising: a drill bit, a micro-hole drill, a power nipple, an upper joint, a connecting joint string and a coiled tubing connected in sequence;

[0008] A plurality of front-end nozzles are installed at the bottom of the drill bit; a sealing column is provided in the center of the drill bit, and a spring is sleeved on the sealing column; the micro-hole drill is a cylindrical structure with openings at both ends, and a plurality of lateral nozzles are evenly distributed circumferentially on the side wall close to the power short section, and the lateral nozzles are connected with the inside of the micro-hole drill; a control sleeve is slidably connected to the inner wall of the micro-hole drill, and a flow channel with both ends penetrating the control sleeve is opened at the axis of the control sleeve, and the flow channel corresponds to the sealing column; the continuous oil pipe is connected to the bottom drilling tool combination consisting of the upper joint, the power short section and the drill bit through the connecting joint string.

[0009] Through the above technical scheme, the present invention adopts a high-pressure hydraulic jet rock breaking device. After the main wellbore is completed, the continuous oil pipe, downhole micro-pore jet transformation tool and other equipment are lowered to the bottom of the well. The high-pressure abrasive jet mixed on the ground is pumped to the bottom of the well to jet and break the rock in the target layer. The movement of the control sleeve in the micro-pore driller is used to control the opening and closing of the lateral nozzle to deepen the cracks near the wellbore. At the same time, the wellbore is connected with the original cracks in the formation to form a crack-type grid. The device adjusts the position of the control sleeve by displacement to achieve switching injection of the front nozzle and the lateral nozzle, thereby completing the deepening of the cracks near the wellbore and improving the transformation effect.

[0010] Preferably, in the above-mentioned device for drilling and reforming hot dry rock reservoirs, the flow channel is a two-stage stepped hole, the aperture of the flow channel toward the power short section is larger than the aperture toward the plugging column; the aperture of the flow channel toward the plugging column is smaller than the diameter of the plugging column, so as to meet the injection and plugging functions of the flow channel.

[0011] Preferably, in the above-mentioned device for drilling and reforming hot dry rock reservoirs, the end face of the plugging column is flush with the end face of the micro-hole drill facing the drill bit; the length of the control sleeve is less than the length from the end face of the micro-hole drill facing the drill bit to the lateral nozzle, so that the control sleeve can switch between the front nozzle and the lateral nozzle.

[0012] Preferably, in the above-mentioned device for drilling and reforming hot dry rock reservoirs, the injection end of the coiled tubing is connected to a jet mixing booster device and a mud pump that can switch the fluid source through a surface manifold, so as to meet the pressure supply requirements of mud injection.

[0013] Preferably, in the above-mentioned device for drilling and reforming hot dry rock reservoirs, the side wall of the micro-hole drill has an outer pin hole, and the outer pin hole is located between the lateral nozzle and the end face of the micro-hole drill facing the power short section; the side wall of the control sleeve has an inner pin hole corresponding to the outer pin hole. When drilling is completed, the drilling medium is switched from drilling fluid to high-pressure abrasive jet through the ground manifold, and the control sleeve is pushed downward by increasing the displacement. After the pin is cut off, the control sleeve moves downward to the bottom, blocking the front nozzle on the drill bit, and then the lateral nozzle on the micro-hole drill starts to work, which can continue to form micropores on the side wall of the micropore through the high-pressure jet, thereby improving the reformation effect. The pin can meet the stability of the control sleeve during drilling and prevent it from blocking the front nozzle during directional side drilling, resulting in the inability of the drilling fluid to flush the bottom hole cuttings.

[0014] The present invention also provides a method for drilling and transforming hot dry rock reservoirs based on the above-mentioned device for drilling and transforming hot dry rock reservoirs, and drilling and transforming hot dry rock reservoirs with natural fractures developed in the main wellbore, comprising the following steps:

[0015] S1. After the main wellbore is drilled, the above-mentioned device for drilling and reforming hot dry rock reservoirs is lowered to the layer to be reformed. The high-pressure abrasive jet is mixed and pressurized by the jet mixing and pressurizing equipment on the ground, and then sent to the micro-hole driller through the continuous pipe. The large-volume high-pressure abrasive jet drives the control sleeve to cut off the pin and move toward the drill bit, so that the plugging column blocks the flow channel, and the flow channel at the side nozzle is opened. The high-pressure abrasive jet is ejected through the side nozzle to break the rock in the target layer, forming and deepening the cracks;

[0016] S2. After step S1 is completed, the jetting is stopped or the jet displacement is reduced, the control sleeve is pushed back by the spring, the lateral nozzle is blocked, the front nozzle is opened, the coiled tubing is lifted up or lowered to allow the device for drilling and reforming the hot dry rock reservoir to reach the next layer to be reformed, and steps S1 and S2 are repeated to complete the multi-stage reformation of the hot dry rock reservoir one by one until the reformation requirements are met.

[0017] Through the above technical scheme, this method uses high-pressure hydraulic jetting to break rocks, mainly for drilling and transformation of thermal reservoirs with developed natural fractures in the main wellbore, and pumps the high-pressure abrasive jet mixed on the ground to the bottom of the well to break rocks in the target layer, deepen the fractures near the wellbore, and connect the wellbore with the original fractures in the formation to form a fracture-type grid. This method mainly utilizes the natural fractures in the formation, which can increase the transformation volume and reduce the risk of microseismicity. It can also be implemented in conjunction with chemical stimulation to improve the transformation effect.

[0018] The present invention also provides an improved device for drilling and transforming hot dry rock reservoirs based on the above-mentioned device for drilling and transforming hot dry rock reservoirs, including the above-mentioned device for drilling and transforming hot dry rock reservoirs; also including a downhole measurement while drilling tool, a direction finder and a downhole thruster connected in sequence between the upper joint and the connecting joint string, and using mud pulse transmission control; or also including a direction finder, a downhole measurement while drilling tool and a downhole thruster connected between the upper joint and the connecting joint string, and using cable transmission control.

[0019] Through the above technical scheme, the device drives the device for drilling and transforming hot dry rock reservoirs through the direction finder to rotate to the pre-adjusted tool face angle and then locks it, thereby adjusting the drilling direction; by pumping the high-pressure abrasive jet mixed on the ground to the bottom of the well, the target layer is jetted to break the rock, and the movement of the control sleeve in the micro-hole drill is controlled to control the opening and closing of the lateral nozzle to deepen the cracks near the wellbore, and at the same time, the wellbore is connected with the original cracks in the formation to form a fracture-type grid. The device adjusts the position of the control sleeve through the injection pressure to achieve switching injection of the front nozzle and the lateral nozzle, thereby completing the deepening of the cracks near the wellbore and improving the transformation effect.

[0020] Preferably, in the above-mentioned device for drilling and reforming hot dry rock reservoirs, a ground measurement and control device is also provided on the ground to decode the data uploaded by the downhole measurement tool and send the technician's instruction code to the direction finder and downhole thruster. The near-downhole measurement tool can measure the well inclination, azimuth, tool face angle, temperature and other data in real time, and transmit the measured parameters to the ground measurement and control device through mud pulse or downhole cable, and the ground technician will issue further instructions.

[0021] The present invention also provides a method for drilling and transforming hot dry rock reservoirs based on the above-mentioned improved device for drilling and transforming hot dry rock reservoirs, and drilling and transforming hot dry rock reservoirs with a low number of fractures or poor connectivity in the main wellbore, comprising the following steps:

[0022] S1. The improved device for drilling and reforming hot dry rock reservoirs is lowered into the section where natural fractures are developed as shown by logging to perform directional sidetracking. The power sub is driven by high-pressure drilling fluid to drive the drill bit to perform rotation or impact drilling to break the hot dry rock reservoir and drill a new micro-wellbore. During the drilling process, the borehole trajectory parameters measured by the downhole measurement tool are uploaded to the ground. After being solved by the ground measurement and control equipment, it is determined whether directional drilling is required. If continuous tubing directional drilling is required, the ground measurement and control equipment generates a drilling fluid pressure pulse or a cable signal to transmit the directional device downward. The directional device rotates the tool face angle to the planned position and then locks it to perform sliding directional drilling operations.

[0023] S2, during the drilling of the micro-branch wellbore in step S1, the mud pump pressurizes the drilling fluid and injects it into the coiled tubing, the mud enters the drill bit through the flow channel of the control sleeve, and is sprayed to the bottom of the well through the front nozzle to spray and break the rock at the bottom of the side drilling well;

[0024] S3, after the drilling of the micro-branch wellbore in step S1 is completed, the inflow fluid is switched from drilling fluid to high-pressure abrasive jet after mixing and pressurizing by the jet mixing and pressurizing equipment through the surface manifold, and the jet displacement is increased to drive the control sleeve to move toward the drill bit, so that the plugging column blocks the flow channel, and the outer wall of the control sleeve moves downward to open the flow channel at the lateral nozzle, and the high-pressure jet is sprayed toward the surrounding well walls through the lateral nozzle to deepen the cracks near the target layer;

[0025] S4. After step S3 is completed, the jetting is stopped or the jet displacement is reduced, the control sleeve is pushed back by the spring, the lateral nozzle is blocked, the front nozzle is opened, the coiled tubing is lifted up or lowered down so that the device for drilling and reforming the hot dry rock reservoir reaches the next layer to be reformed, and steps S1 and S2 are repeated to complete the multi-stage reformation of the hot dry rock reservoir one by one until the reformation requirements are met.

[0026] Through the above technical scheme, this method is mainly used for drilling and transformation of thermal reservoirs with low number of fractures or poor connectivity in the main wellbore. The device for drilling and transforming hot dry rock reservoirs is driven by the direction finder to rotate to the pre-adjusted tool face angle and then locked, so as to control the drilling trajectory toward the section with natural fracture development. This method can avoid the section with undeveloped fractures in the main wellbore, increase the transformation volume, reduce the risk of microseismicity, and can also be implemented in conjunction with the chemical stimulation method to improve the transformation effect.

[0027] Preferably, in the above-mentioned method for drilling and reforming hot dry rock reservoirs, the distribution of fractures in the thermal reservoir is evaluated by the logging results of imaging logging, dual lateral resistivity logging, and acoustic remote detection. The above-mentioned two devices for drilling and reforming hot dry rock reservoirs are essentially adopted according to the distribution of fractures in the thermal reservoir, and the use is more targeted and the effect is better.

[0028] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a device and method for drilling and transforming hot dry rock reservoirs, which has the following beneficial effects:

[0029] 1. The two devices for drilling and transforming hot dry rock reservoirs and the corresponding methods designed in the present invention are specifically adopted according to the distribution of fractures in the thermal reservoir. They can respectively perform drilling and transformation on thermal reservoirs with developed natural fractures in the main wellbore and thermal reservoirs with a low number of fractures or poor connectivity in the main wellbore, which can increase the transformation volume and reduce the risk of microseismicity. They can also be implemented in conjunction with the chemical stimulation method to improve the transformation effect.

[0030] 2. This device uses high-pressure abrasive jet to implement lateral injection to break rocks, connect the original cracks in the formation, form a volume fracture network, and transform the hot dry rock reservoir; it can also use the power of the drilling fluid to drive the device to rotate or impact, driving the drill bit for directional drilling. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0032] Figure 1 The accompanying drawing is a schematic structural diagram of a device for drilling and reforming a hot dry rock reservoir according to Example 1 provided by the present invention.

[0033] Figure 2 The accompanying drawing is a schematic structural diagram of a device for drilling and reforming hot dry rock reservoirs using mud pulse transmission control according to Example 2 provided by the present invention.

[0034] Figure 3The accompanying drawing is a schematic structural diagram of a device for drilling and reforming hot dry rock reservoirs using cable transmission control according to Example 3 provided by the present invention.

[0035] Figure 4 The accompanying drawings are schematic diagrams of the working states and external control structures of embodiments 1-3 provided by the present invention.

[0036] Figure 5 The accompanying drawing is a schematic structural diagram of the power sub driving drilling working state of embodiments 1-3 provided by the present invention.

[0037] Figure 6 The accompanying drawing is a schematic structural diagram of the side injection working state of embodiments 1-3 provided by the present invention.

[0038] Figure 7 The accompanying drawing is a schematic structural diagram of the lower injection working state of embodiments 1-3 provided by the present invention.

[0039] in:

[0040] 1-drill bit; 2-micro-hole drill; 3-power short joint; 4-upper joint; 5-connecting joint string; 6-coiled tubing; 7-front nozzle; 8-blocking column; 9-spring; 10-lateral nozzle; 11-control sleeve; 12-flow channel; 13-jet mixing and boosting equipment; 14-mud pump; 15-bottomhole measurement while drilling tool; 16-director; 17-downhole thruster; 18-ground measurement and control equipment. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Embodiment 1:

[0043] See attached Figure 1 The embodiment of the present invention discloses a device for drilling and reforming a hot dry rock reservoir, comprising: a drill bit 1, a micro-hole drill 2, a power short joint 3, an upper joint 4, a connecting joint string 5 and a coiled tubing 6 connected in sequence;

[0044] A plurality of front-end nozzles 7 are installed at the bottom of the drill bit 1; a plugging column 8 is provided in the center of the drill bit 1, and a spring 9 is sleeved on the plugging column 8; the micro-hole drill 2 is a cylindrical structure with openings at both ends, and a plurality of lateral nozzles 10 are evenly distributed circumferentially on the side wall close to the power short section 3, and the lateral nozzles 10 are connected to the inside of the micro-hole drill 2; a control sleeve 11 is slidably connected to the inner wall of the micro-hole drill 2, and a flow channel 12 with both ends penetrating the control sleeve 11 is opened at the axis of the control sleeve 11, and the flow channel 12 corresponds to the plugging column 8; the continuous oil pipe 6 is connected to the bottom drilling tool assembly consisting of the upper joint 4, the power short section 3, the micro-hole drill 2 and the drill bit 1 through the connecting joint string 5.

[0045] In order to further optimize the above technical solution, the flow channel 12 is a two-level stepped hole, and the aperture of the flow channel 12 toward the power short section 3 is larger than the aperture toward the blocking column 8; the aperture of the flow channel 12 toward the blocking column 8 is smaller than the diameter of the blocking column 8.

[0046] In order to further optimize the above technical solution, the end face of the blocking column 8 is flush with the end face of the micro-hole drill 2 facing the drill bit 1; the length of the control sleeve 11 is less than the length from the end face of the micro-hole drill 2 facing the drill bit 1 to the lateral nozzle 10.

[0047] In order to further optimize the above technical solution, the injection end of the coiled tubing 6 is connected to a jet mixing booster 13 and a mud pump 14 that can switch the fluid source through a ground manifold.

[0048] In order to further optimize the above technical solution, the side wall of the micro-hole drill 2 has an external pin hole, which is located between the lateral nozzle 10 and the end surface of the micro-hole drill 2 facing the power short section 3; the side wall of the control sleeve 11 has an internal pin hole corresponding to the external pin hole.

[0049] The method for drilling and reforming a hot dry rock reservoir in this embodiment is to perform drilling and reforming a hot dry rock reservoir with developed natural fractures in a main wellbore, and includes the following steps:

[0050] S1. After the main wellbore is drilled, the above-mentioned device for drilling and reforming the hot dry rock reservoir is lowered to the layer to be reformed. The high-pressure abrasive jet is mixed and pressurized on the ground through the jet mixing and pressurizing device 13, and then sent to the micro-hole driller 2 through the continuous pipe 6. The large-volume high-pressure abrasive jet drives the control sleeve 11 to cut off the pin and move toward the drill bit 1, so that the plugging column 8 blocks the flow channel 12, and the flow channel at the lateral nozzle 10 is opened. The high-pressure abrasive jet is sprayed through the lateral nozzle 10 to break the rock on the wellbore wall of the target layer, forming and deepening the cracks;

[0051] S2. After step S1 is completed, the jetting is stopped or the jet displacement is reduced, the control sleeve 11 is pushed to reset by the spring 9, the lateral nozzle 10 is blocked, the front nozzle 7 is opened, the coiled tubing is lifted up or lowered to allow the device for drilling and reforming the hot dry rock reservoir to reach the next layer to be reformed, and steps S1 and S2 are repeated to complete the multi-stage reform of the hot dry rock reservoir one by one until the reformation requirements are met.

[0052] The device for drilling and reforming hot dry rock reservoirs uses a high-pressure abrasive jet to implement lateral injection to break rocks, connect the original cracks in the formation, form a volume fracture network, and reform the hot dry rock reservoir; the power of the drilling fluid can also be used to drive the device for drilling and reforming hot dry rock reservoirs to rotate or impact, driving the drill bit 1 carried by the front end of the device for drilling and reforming hot dry rock reservoirs to perform directional sidetracking drilling. The structure changes in the tool under different working conditions are as follows: Figure 5-7 shown.

[0053] Embodiment 2:

[0054] See attached Figure 2 This embodiment is improved on the basis of embodiment 1, and also includes a bottom hole measurement while drilling tool 15, a direction finder 16 and a downhole thruster 17 which are sequentially connected between the upper joint 4 and the connecting joint string 5, and adopts mud pulse transmission control.

[0055] In order to further optimize the above technical solution, a ground measurement and control device 18 is also provided on the ground to decode the data uploaded by the downhole measurement while drilling tool 15 and send the technician's instruction code to the orienter 16 and the downhole thruster 17.

[0056] The method for drilling and reforming a hot dry rock reservoir in this embodiment is to perform drilling and reforming a hot dry rock reservoir with a low number of fractures or poor connectivity in a main wellbore, and includes the following steps:

[0057] S1. The improved device for drilling and reforming hot dry rock reservoirs is lowered into the section where natural fractures are developed as shown by logging for directional sidetracking. The power sub 3 is driven by high-pressure drilling fluid to drive the drill bit 1 to perform rotary or impact drilling to break the hot dry rock reservoir and drill a new micro-wellbore. During the drilling process, the downhole measurement tool 15 uploads the measured wellbore trajectory parameters to the ground. After being solved by the ground measurement and control equipment 18, it is determined whether directional drilling is required. If continuous tubing directional drilling is required, the ground measurement and control equipment 18 generates a drilling fluid pressure pulse or a cable signal to transmit it to the directional device 15. The directional device 15 rotates the tool face angle to the planned position and then locks it to perform sliding directional drilling operations.

[0058] S2, during the drilling of the micro-branch wellbore in step S1, the mud pump 14 pressurizes the drilling fluid and injects it into the coiled tubing 6, the mud enters the drill bit 1 through the flow channel of the control sleeve 11, and is sprayed toward the bottom of the well through the front nozzle 7 to spray and break the rock at the bottom of the side drilling well;

[0059] S3, after the drilling of the micro-branch wellbore in step S1 is completed, the inflow fluid is switched from drilling fluid to high-pressure abrasive jet after mixing and pressurizing by the jet mixing and pressurizing device 13 through the surface manifold, and the jet displacement is increased to drive the control sleeve 11 to move toward the drill bit 1, so that the plugging column 8 blocks the flow channel 12, and the outer wall of the control sleeve 11 moves downward to open the flow channel at the lateral nozzle 10, and the high-pressure jet is sprayed toward the surrounding well walls through the lateral nozzle 10 to deepen the cracks near the target layer section;

[0060] S4. After step S3 is completed, the jetting is stopped or the jet displacement is reduced, the control sleeve 11 is pushed to reset by the spring 9, the lateral nozzle 10 is blocked, the front nozzle 7 is opened, the coiled tubing 6 is lifted up or lowered to allow the device for drilling and reforming the hot dry rock reservoir to reach the next layer to be reformed, and steps S1 and S2 are repeated to complete the multi-stage reform of the hot dry rock reservoir one by one until the reformation requirements are met.

[0061] In order to further optimize the above technical solutions, the distribution of thermal reservoir fractures was evaluated through the logging results of imaging logging, dual lateral resistivity logging, and acoustic remote detection.

[0062] The ground measurement and control equipment 18 can decode the mud pulse signal or electrical signal uploaded by the downhole measurement tool 15 and provide it to the technicians. The technicians transmit the signal to the orientator 16 through cables or mud pulses according to the directional requirements. The orientator 16 drives the device for drilling and transforming hot dry rock reservoirs to rotate to the pre-adjusted tool face angle and then locks it, thereby adjusting the drilling direction.

[0063] The jet mixing and pressurizing device 13 first mixes the jet medium and the abrasive evenly, then pressurizes it to above 30 MPa, pumps it into the well through the continuous oil pipe 6, and flows through the lateral nozzle of the device for drilling and transforming hot dry rock reservoirs to form an abrasive jet to impact the well wall rock, forming a hole with a certain depth.

[0064] The near-bottomhole measurement while drilling tool 15 can measure the well inclination, azimuth, tool face angle, temperature and other data in real time, and transmit the measured parameters to the ground measurement and control equipment 18 through mud pulse or downhole cable, and further instructions are issued by ground technicians.

[0065] Embodiment 3:

[0066] See attached Figure 3 This embodiment is improved on the basis of embodiment 1, and further includes a direction finder 16 connected between the upper joint 4 and the connecting joint string 5, a bottom hole measurement while drilling tool 15 and a downhole thruster 17, and adopts cable transmission control.

[0067] The other structures and methods of this embodiment are the same as those of Embodiment 2 and will not be described in detail here.

[0068] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0069] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for drilling and transforming hot dry rock reservoirs, characterized in that: include: A drill bit (1), a micro-hole drill (2), a power short joint (3), an upper joint (4), a connecting joint string (5) and a coiled tubing (6) connected in sequence; A plurality of front nozzles (7) are annularly mounted at the bottom of the drill bit (1); a plugging column (8) is provided in the center of the drill bit (1), and a spring (9) is sleeved on the plugging column (8); the micro-hole drill (2) is a cylindrical structure with openings at both ends, and a plurality of lateral nozzles (10) are evenly distributed circumferentially on the side wall close to the power short section (3), and the lateral nozzles (10) are connected to the inside of the micro-hole drill (2); a control sleeve (11) is slidably connected to the inner wall of the micro-hole drill (2), and a flow channel (12) is opened at the axis of the control sleeve (11) with both ends penetrating the control sleeve (11), and the flow channel (12) corresponds to the plugging column (8); the continuous oil pipe (6) is connected to the bottom drilling tool assembly consisting of the upper joint (4), the power short section (3), the micro-hole drill (2) and the drill bit (1) through the connecting joint string (5); The flow channel (12) is a two-stage stepped hole, the hole diameter of the flow channel (12) at one end facing the power short joint (3) is larger than the hole diameter at one end facing the blocking column (8); the hole diameter of the flow channel (12) at one end facing the blocking column (8) is smaller than the diameter of the blocking column (8); The end surface of the blocking column (8) is flush with the end surface of the micro-hole drill (2) facing the drill bit (1); the length of the control sleeve (11) is less than the length from the end surface of the micro-hole drill (2) facing the drill bit (1) to the lateral nozzle (10); The side wall of the micro-hole drill (2) has an outer pin hole, and the outer pin hole is located between the lateral nozzle (10) and the end surface of the micro-hole drill (2) facing the power short joint (3); the side wall of the control sleeve (11) has an inner pin hole corresponding to the outer pin hole.

2. The device for drilling and transforming hot dry rock reservoirs according to claim 1, characterized in that: The injection end of the coiled tubing (6) is connected to a jet mixing and pressurizing device (13) and a mud pump (14) that can switch the fluid source through a surface manifold.

3. A method for drilling and transforming a hot dry rock reservoir, characterized in that: The drilling transformation of the thermal reservoir with natural fractures in the main wellbore includes the following steps: S1. After the main wellbore is drilled, the device for drilling and reforming hot dry rock reservoirs according to any one of claims 1 to 2 is lowered into the layer to be reformed, and the high-pressure abrasive jet is mixed and pressurized on the ground through a jet mixing and pressurizing device (13), and then sent to the micro-hole driller (2) through a continuous oil pipe (6). The high-pressure abrasive jet drives the control sleeve (11) to cut off the pin and move toward the drill bit (1), so that the plugging column (8) blocks the flow channel (12), and the flow channel at the side nozzle (10) is opened. The high-pressure abrasive jet is sprayed through the side nozzle (10) to break the rock on the wellbore wall of the target layer, forming cracks and deepening them; S2. After step S1 is completed, the jetting is stopped or the jet displacement is reduced, the spring (9) pushes the control sleeve (11) to reset, the lateral nozzle (10) is blocked, the front nozzle (7) is opened, and the coiled tubing (6) is lifted or lowered so that the device for drilling and reforming the hot dry rock reservoir reaches the next layer to be reformed, and steps S1 and S2 are repeated to successively complete the reformation of multiple sections of the hot dry rock reservoir until the reformation requirements are met.

4. A device for drilling and transforming hot dry rock reservoirs, characterized in that: The device for drilling and reforming hot dry rock reservoirs comprises the device according to any one of claims 1 to 2; further comprising a downhole measurement while drilling tool (15), a direction finder (16) and a downhole thruster (17) connected in sequence between the upper joint (4) and the connecting joint string (5), and adopting mud pulse transmission control; or further comprising a direction finder (16), a downhole measurement while drilling tool (15) and a downhole thruster (17) connected between the upper joint (4) and the connecting joint string (5), and adopting cable transmission control.

5. The device for drilling and transforming hot dry rock reservoirs according to claim 4, characterized in that: A ground measurement and control device (18) is also provided on the ground to decode the data uploaded by the downhole measurement while drilling tool (15) and to send the technical personnel's instruction code to the direction finder (16) and the downhole thruster (17).

6. A method for drilling and transforming a hot dry rock reservoir, characterized in that: Drilling stimulation for thermal reservoirs with low fracture count or poor connectivity in the main wellbore includes the following steps: S1. The device for drilling and reforming hot dry rock reservoirs as claimed in claim 4 or 5 is lowered into the section where natural fractures are developed as shown by logging to perform directional side drilling. The power short section (3) is driven by high-pressure drilling fluid to drive the drill bit (1) to rotate or impact the hot dry rock reservoir to drill a new micro-wellbore. During the drilling process, the downhole measurement tool (15) uploads the measured wellbore trajectory parameters to the ground. After being solved by the ground measurement and control equipment (18), it is determined whether directional drilling is required. If continuous tubing (6) directional drilling is required, the ground measurement and control equipment (18) generates a drilling fluid pressure pulse or a cable signal to transmit it to the directional device (16). The directional device (16) rotates the tool face angle to the planned position and then locks it to perform sliding directional drilling operations. S2, during the drilling process of the micro-branch wellbore in step S1, the mud pump (14) pressurizes the drilling fluid and injects it into the coiled tubing (6), and the drilling fluid enters the drill bit (1) through the flow channel of the control sleeve (11), and is sprayed toward the bottom of the well through the front nozzle (7), thereby spraying and breaking the rock at the bottom of the wellbore; S3, after the drilling of the micro-branch wellbore in step S1 is completed, the fluid entering the well is switched from drilling fluid to a high-pressure abrasive jet that has been mixed and pressurized by a jet mixing and pressurizing device (13) through a surface manifold, and the jet displacement is increased to drive the control sleeve (11) to move toward the drill bit (1), so that the plugging column (8) blocks the flow channel (12), and the outer wall of the control sleeve (11) moves downward to open the flow channel at the lateral nozzle (10), and the high-pressure jet is ejected through the lateral nozzle (10) to deepen the fractures near the target layer section; S4. After step S3 is completed, the jetting is stopped or the jet displacement is reduced, the control sleeve (11) is pushed back by the spring (9), the lateral nozzle (10) is blocked, the front nozzle (7) is opened, and the coiled tubing (6) is lifted or lowered so that the device for drilling and reforming the hot dry rock reservoir reaches the next layer to be reformed, and steps S1 and S2 are repeated to successively complete the reformation of multiple sections of the hot dry rock reservoir until the reformation requirements are met.

7. A method for drilling and transforming hot dry rock reservoirs according to claim 6, characterized in that: The distribution of thermal reservoir fractures is evaluated through imaging logging, dual lateral resistivity logging, and acoustic wave remote detection logging results.

Images