Abrasive jet casing windowing and sidetracking integrated system and method

Abstract

This invention belongs to the field of oil and gas field development and relates to an integrated system and method for abrasive jet casing window opening and sidetracking. The system includes a drill pipe, the top of which is connected to the drive unit of the drilling rig, and the bottom of which is connected to a window opening and sidetracking tool string. The window opening and sidetracking tool string is composed of an electro-hydraulic orienting device, a bend joint, a connecting sub, a shaping milling tap, and a hydraulic drill bit connected in sequence. Both the drill pipe and the window opening and sidetracking tool string have abrasive slurry passage chamber inside. The method utilizes abrasive jets to perform non-contact window opening in the casing section, and continuously enters the sidetracking stage during the same tool string operation. The orienting of the tool string is controlled by the electro-hydraulic orienting device, and the small-angle geometric offset provided by the bend joint ensures that the sidetracked wellbore extends along a predetermined direction. When necessary, the window is milled and shaped by the shaping milling tap, which reduces the frequency of process switching, reduces operational risks, and improves the controllability of the window opening position and wellbore trajectory. It is suitable for engineering applications in old well stimulation and complex well conditions.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development, and in particular to an integrated system and method for abrasive jet casing window drilling. Background Technology

[0002] In oil and gas field development, window-opening sidetracking technology is one of the important means to tap the remaining reserves of old wells and implement secondary or tertiary oil recovery. In existing projects, in-casing window-opening sidetracking usually adopts the operation method of "mechanical milling window opening + small-bore sidetracking". That is, after forming a window on the casing with mechanical milling tools, the sidetracking wellbore is extended using drill bits or screw drills. However, this type of mechanical window-opening sidetracking process is highly dependent on downhole conditions.

[0003] (1) Window opening operation is sensitive to the integrity of the casing, cementing quality and wellbore shape. In old wells or in cases of casing deformation or incomplete cementing, the shape of the window is difficult to control stably and may form steps or irregular breaks. If the window shape is not ideal, the drill bit, screw and other tools may be repeatedly blocked or milled twice at the window position during subsequent side drilling, affecting the continuity and stability of the wellbore trajectory.

[0004] (2) Mechanical milling and sidetracking processes are highly dependent on drilling pressure and torque. Under conditions of small boreholes and high friction, the large drilling pressure and torque requirements can easily induce complex downhole situations, such as drill bit skipping and stuck drill bit. At the same time, in the sidetracking section of long open holes and small boreholes, the overall stress conditions of the drill string are relatively harsh, with risks such as drill string fatigue, joint failure, and torsional overload of the screw drill string, which restricts the safety and reliability of the operation.

[0005] (3) In the renovation of old wells, when the original main wellbore is lost or a new production channel needs to be established outside the casing, it is usually necessary to carry out window side-drilling outside the casing. Unlike windowing inside the casing, window side-drilling outside the casing is carried out under positive curvature surface conditions, and the stress state of the mechanical milling tool is more unstable under this condition. When the milling cone is working on a positive curvature surface, it is more sensitive to external disturbances. Even slight uneven stress or changes in posture may cause the tool to deviate, thereby affecting the window position and the controllability of the subsequent wellbore trajectory.

[0006] In summary, whether it's the difficulty in controlling the window shape during inside-casing sidetracking, the complex stress conditions on the sidetracking tools, or the tendency for milling tools to deviate during outside-casing windowing operations, the common problem lies in the fact that existing technologies generally rely on mechanical contact methods, using drilling pressure and torque to achieve material removal and wellbore extension. This operational mechanism, under complex well conditions, small wellbore sizes, and high friction conditions, struggles to balance window quality, trajectory control, and operational safety, limiting the applicability of existing windowing sidetracking technologies in older wells and complex conditions. Summary of the Invention

[0007] The purpose of this invention is to address the problems of uncontrollable window morphology, high tool dependence on drill pressure and torque, and accumulated operational risks under complex well conditions in existing window-opening sidetracking operations. This invention provides an integrated system and method for abrasive jet casing window-opening sidetracking. This system and method utilize the erosive cutting action of the abrasive jet to achieve window opening in the casing section, and continuously enter the sidetracking stage during the same tool string operation to perform abrasive jet rock-breaking drilling on the target formation. Through the geometric offset of the downhole tool string and the wellbore constraint, the sidetracked wellbore extends continuously according to a predetermined trend, reducing the risk of repeated obstruction and secondary milling caused by steps, irregular breaks, etc., at the window, and mitigating complex situations such as drill bit skipping and stuck pipe caused by high drill pressure and high torque requirements under small wellbore and high friction conditions. Meanwhile, this invention completes key processes such as window opening, formation entry, and sidetracking continuously in a single running operation, which can reduce the number of tripping and running of tubing and the frequency of process switching, shorten the operation cycle, and reduce the accumulation of downhole risks. It is adaptable to different working conditions such as opening windows inside the casing and re-entering after opening windows outside the casing, which helps to improve the controllability of window position and wellbore trajectory and the stability of the operation process, thereby meeting the engineering needs of old well stimulation and complex well conditions.

[0008] The present invention discloses an integrated abrasive jet casing window-opening side-drilling system, comprising a drill rod and a guide vane. The top of the drill rod is connected to the drive device of the drilling rig, and the bottom of the drill rod is connected to a window-opening side-drilling tool string. The window-opening side-drilling tool string is composed of an electro-hydraulic directional device, a bend joint, a connecting short section, a shaping milling cone, and a hydraulic drill bit connected in sequence. Both the drill rod and the window-opening side-drilling tool string are provided with abrasive slurry passage cavities.

[0009] The drive unit is a top drive. Alternatively, in an optional configuration, the top drive can be replaced with a rotary swivel, and a square drill pipe and wellhead rotary table can be added. A weight gauge is installed on the drill pipe.

[0010] The aforementioned integrated abrasive jet casing window-opening side-drilling system also includes an abrasive slurry supply unit; the abrasive slurry supply unit includes a water tank, a sand box, a sand mixing truck, and a fracturing truck; wherein, the water tank and the sand box are respectively connected to the sand mixing truck through atmospheric pressure pipelines, and the sand mixing truck is connected to the fracturing truck through atmospheric pressure pipelines; the fracturing truck is connected to the drive device through a high-pressure pipeline; the water tank is connected to the annulus through a return pipeline.

[0011] The elbow joint consists of an upper elbow joint, an elbow joint housing, and a lower elbow joint. A fixed deflection angle α is formed between the central axis of the upper elbow joint and the central axes of the elbow joint housing and the lower elbow joint, wherein the deflection angle α is 1.5° to 1.75°. The elbow joint is used to provide a stable and controllable lateral pointing force to the tool tip under the condition of the electro-hydraulic orienting device locking the azimuth. This allows for continuous entry into the side-drilling section after the window is opened, with a determined azimuth and incident angle, reducing the risk of deviation and secondary milling at the window.

[0012] The shaping milling cone includes a shaping milling cone retainer, a shaping milling cone guide cone, and a shaping milling cone male connector connected sequentially from top to bottom; a shaping milling cone female connector is located inside the shaping milling cone retainer at the top; the shaping milling cone retainer and the shaping milling cone guide cone are covered with hard alloy particles. The shaping milling cone serves as a matching shaping component after the abrasive jet is opened, used to trim the window boundary and transition section, ensuring the window contour meets the requirements for smooth drill passage and trajectory continuity, thereby reducing repeated obstruction or secondary milling of the drill bit, screw, etc., at the window.

[0013] The hydraulic drill bit includes a hydraulic drill bit body, which is connected to a shaping milling cone; a nozzle is provided inside the hydraulic drill bit body, and the nozzle communicates with the inner cavity of the shaping milling cone; the nozzle and the hydraulic drill bit body are sealed by a sealing ring. The nozzle is composed of a nozzle inlet section, a nozzle constriction section and a nozzle straight column section, and a guide impeller is placed inside the nozzle inlet section; the nozzle constriction section is shaped like an inverted frustum.

[0014] The hydraulic drill bit of the present invention is provided with a jet modulation structure such as a guide impeller and a nozzle. The guide impeller is located in the nozzle inlet section, so that the high-pressure fluid is forced to rotate before entering the nozzle, forming a rotating jet from the source, and further forming a rotating abrasive jet together with the abrasive slurry.

[0015] The nozzle internal flow channel of this invention is clearly composed of a nozzle inlet section, a nozzle contraction section, and a nozzle straight section. The nozzle inlet section is used to accommodate the guide impeller, the nozzle contraction section is used for initial acceleration and rectification of the flow into the straight section, and the nozzle straight section is used for continuous acceleration and stabilizing the rotating jet shape. The nozzle of this invention is set inside the hydraulic drill bit body, and a sealing ring is used to achieve a sealed connection between the nozzle and the drill bit body. It belongs to the downhole tool end structure adapted to "window-opening-continuous side-drilling".

[0016] This invention also proposes an integrated method for abrasive jet casing window-opening side-drilling, which includes using the aforementioned integrated abrasive jet casing window-opening side-drilling system to perform window-opening side-drilling in a single wellbore or window-opening side-drilling connecting new and old wellbores.

[0017] The single-wellbore window-opening sidetracking method includes the following steps:

[0018] (1) After connecting the window-opening side-drilling tool string to the drill pipe, it is sent into the wellbore by the drilling rig. The electro-hydraulic directional device controls and maintains the spatial orientation of the window-opening side-drilling tool string in real time. The elbow joint provides a fixed small-angle geometric offset. The two work together to form a stable and controllable deflection trend during the abrasive jet window-opening side-drilling process, thereby ensuring that the side-drilled wellbore continues to extend in the predetermined orientation.

[0019] (2) The high-pressure abrasive slurry enters the window-opening side-drilling tool string, forming a rotating abrasive jet, which erodes and cuts the casing and cementing sheath to form a window. The abrasive and debris generated by the window are returned upward through the annulus.

[0020] Specifically, the water tank and sand box are connected to the sand mixing truck via atmospheric pressure pipelines. After the water and sand are evenly mixed in the sand mixing truck, they enter the fracturing truck through another atmospheric pressure pipeline. The fracturing truck pressurizes the mixture and then delivers the high-pressure abrasive slurry to the top drive via a high-pressure pipeline. It is then guided into the window-opening side-drilling tool string through the drill pipe. The hydraulic drill bit inside the window-opening side-drilling tool string modulates a rotating abrasive jet to erode and damage the casing and cementing sheath. During this process, the window-opening side-drilling tool string is continuously lowered, and the changes in the weight gauge must be constantly monitored to determine if the lowering speed is too fast. During the lowering process, the guide guide continuously guides the drill pipe. During the window opening process, abrasive, metal shavings, etc., return through the annulus between the window-opening side-drilling tool string and the casing. After passing through the wellhead tee, they are guided into the water tank through the return pipeline, where they are settled and recycled.

[0021] (3) After the window is formed, continue to lower the window opening side-drilling tool string or mill and shape the window and continue to lower the window opening side-drilling tool string to enter the reservoir side-drilling process. The rotating abrasive jet continuously breaks the rock to form a long horizontal section of the reservoir wellbore in the reservoir. After the reservoir wellbore reaches the predetermined length, the downhole tools are pulled out and the construction is completed.

[0022] If the window-opening side-drilling tool string continues to be lowered without encountering significant resistance, the process proceeds to the reservoir side-drilling process; if there is significant resistance, the top drive is activated to rotate the drill pipe and the window-opening side-drilling tool string, and the window is milled and shaped using a shaping milling cone before proceeding to the reservoir side-drilling process.

[0023] Optionally, the top drive can be replaced with a rotary faucet, and a square drill rod and a wellhead rotary table can be added. The wellhead rotary table drives the square drill rod to rotate, and the square drill rod drives the drill rod and the window-opening side-drilling tool string to rotate. The opening window is milled and shaped by the shaping milling cone in the window-opening side-drilling tool string.

[0024] During the sidetracking process, the electro-hydraulic directional device and the elbow continue to work together to guide the window-opening sidetracking tool string toward the predetermined azimuth. The rotating abrasive jet continuously breaks the rock to form a long horizontal section of the reservoir wellbore. Once the reservoir wellbore reaches the predetermined length, the downhole tools are retrieved and the operation ends. The rock cuttings and abrasive generated during this process return along the annulus between the window-opening sidetracking tool string and the reservoir wellbore, as well as the annulus between the drill pipe and the casing. After passing through the wellhead tee, they are guided into the water tank by the return pipeline, where they are settled and recycled.

[0025] The method for connecting old and new wellbores by opening a window and side-drilling includes the following steps:

[0026] (1) After connecting the window-opening side-drilling tool string to the drill pipe, it is sent into the wellbore by the drilling rig. The electro-hydraulic directional device controls and maintains the spatial orientation of the window-opening side-drilling tool string in real time, and the elbow joint provides a fixed small-angle geometric offset.

[0027] (2) The high-pressure abrasive slurry enters the window-opening side-drilling tool string, forming a rotating abrasive jet, which erodes and cuts the casing and cementing sheath to form a window. The abrasive and debris generated by the window are returned upward through the annulus.

[0028] (3) After the window is formed, continue to lower the window opening side drilling tool string or mill and shape the window and continue to lower the window opening side drilling tool string to enter the reservoir side drilling process. The rotating abrasive jet continues to break the rock and form a connecting channel in the reservoir.

[0029] The process of steps (1)-(3) is as described above and will not be repeated here.

[0030] (4) When the connecting channel touches the cement sheath of the old well, slow down the lowering speed of the window-opening side drilling tool string, and the rotating abrasive jet erodes the cement sheath and casing of the old well to form a window.

[0031] During this process, after the rotating abrasive jet erodes and forms a window on the cement sheath and casing of the old well, the surface sand box needs to be closed and sand addition stopped to prevent the abrasive jet from damaging the casing on the opposite side of the old well window. At this time, the pump pressure of the surface fracturing truck remains unchanged, and the window-opening side-drilling tool string is continuously lowered to verify whether it can successfully enter the old well. If the subsequent lowering process of the window-opening side-drilling tool string does not encounter significant resistance, all downhole tools are retrieved and the surface equipment is removed to end the operation. If there is significant resistance during the lowering process, the top drive can be activated, and the drill pipe can be used to drive the window-opening side-drilling tool string to rotate. The shaping milling tap in the window-opening side-drilling tool string is then used to mill and shape the old well window.

[0032] Optionally, the top drive can be replaced with a rotary faucet, and a square drill pipe and a wellhead rotary table can be added. The wellhead rotary table drives the square drill pipe to rotate, and then the square drill pipe drives the drill pipe and the window-opening side-drilling tool string to rotate. The old well window is milled and shaped by the shaping milling cone in the window-opening side-drilling tool string.

[0033] After reshaping, the window-opening side-drilling tool string was lowered down. Once the tool string successfully entered the old well, all downhole tools were retrieved, and the surface equipment was removed, thus ending the operation.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] (1) Reduce load dependence and complex risks.

[0036] Using abrasive jets for casing windowing and formation side-drilling reduces the dependence of traditional mechanical milling on drill pressure and torque. In small wellbore, high friction and complex well conditions, it helps to reduce load requirements and reduce the risk of complex downhole situations such as drill bit skipping and stuck drill.

[0037] (2) Improve the stability of window forming.

[0038] Non-contact cutting with abrasive jets can achieve casing windowing, which can reduce stress fluctuations caused by casing deformation, uneven cementing quality, or abnormal wellbore morphology. This helps improve the consistency of window forming and reduces the risk of repeated obstruction or secondary milling at the window due to defects such as steps and irregular breaks.

[0039] (3) Achieve process integration and efficiency improvement.

[0040] Integrating key processes such as window opening, formation entry, and side-drilling wellbore extension into the same tool string or continuous operation can reduce the complexity of procedures and the accumulation of downhole risks caused by staged construction and multiple tripping of tubing strings, shorten the operation cycle, and improve the efficiency and stability of single-well construction.

[0041] (4) Enhance trajectory controllability and formation adaptability.

[0042] In this invention, a bent joint is set in the window-opening sidetracking tool string to form a predetermined small-angle offset, so that the tool tip generates a lateral pointing force relative to the casing axis pointing to the target direction; at the same time, the electro-hydraulic directional device locks the offset direction in the predetermined direction, so that the offset does not drift with tool rotation. The tool contacts the well wall / casing wall inside the casing (or window transition section) to form a constraint support point. The reaction force of the well wall on the outer wall of the tool and the offset generated by the bent joint work together to make the tool tip stably fit against and point towards the window / sidetracking entrance. Thus, after the window is opened, it can continuously enter the sidetracking section with a controlled incident angle and azimuth and maintain a stable trajectory direction. Moreover, the abrasive jet has a stronger cutting and rock-breaking ability than the water jet, which is beneficial to improve the controllability and repeatability of wellbore trajectory extension and enhance the adaptability to complex formation conditions such as tight sandstone and high-strength cementation. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the integrated window-opening and side-drilling system of the present invention.

[0044] Figure 2 This is a schematic diagram of the optional combination methods of the window opening and side drilling integrated system of the present invention;

[0045] Figure 3 This is a schematic diagram of the window-opening side-drilling tool string structure of the present invention;

[0046] Figure 4 This is a schematic diagram of the bent joint structure of the present invention;

[0047] Figure 5 This is a schematic diagram of the milling cone structure of the present invention;

[0048] Figure 6 This is a schematic diagram of the hydraulic drill bit structure of the present invention;

[0049] Figure 7 This is a schematic diagram of the nozzle structure of the present invention;

[0050] Figure 8 This is a schematic diagram of the process for the hydraulic window opening starting section of the present invention;

[0051] Figure 9 This is a schematic diagram of the process after the hydraulic window opening of the present invention is completed;

[0052] Figure 10 This is a schematic diagram of the hydraulic rock-breaking side-drilling process of the present invention;

[0053] Figure 11 This is a schematic diagram of the process after hydraulic rock-breaking side drilling of the present invention is completed;

[0054] Figure 12 This is a schematic diagram of the window and wellbore after hydraulic window opening side drilling according to the present invention;

[0055] Figure 13 This is a schematic diagram of the combined configuration of the new and old wellbore connection and window-opening side-drilling integrated system of the present invention;

[0056] Figure 14 This is a schematic diagram of the process for the hydraulic window opening section connecting the old and new wellbores in this invention.

[0057] Figure 15 This is a schematic diagram of the process after hydraulic window opening of the new wellbore of the present invention is completed;

[0058] Figure 16 This is a schematic diagram of the process after hydraulic window opening of an old wellbore according to the present invention.

[0059] Figure 17 This is a schematic diagram showing the establishment of the new and old wellbore channels according to the present invention.

[0060] In the diagram: 1 is a water tank, 2 is a sand box, 3 is a sand mixing truck, 4 is a fracturing truck, 5 is an instrument truck, 6 is a drilling rig, 7 is a top drive, 8 is a weight gauge, 9 is a drill pipe, 10 is a wellhead tee, 11 is a window-opening side-drilling tool string, 12 is a guide vane, 13 is a rotary swivel, 14 is a square drill pipe, and 15 is a wellhead rotary table.

[0061] 11-1 is an electro-hydraulic orienter, 11-2 is a bent joint, 11-3 is a connecting short section, 11-4 is a shaping milling tap, and 11-5 is a hydraulic drill bit;

[0062] 11-2-1 is the upper coupling of the elbow joint; 11-2-2 is the elbow joint housing; 11-2-3 is the lower coupling of the elbow joint; 11-4-1 is the female connector of the shaping milling cone; 11-4-2 is the diameter retainer of the shaping milling cone; 11-4-3 is the guide cone surface of the shaping milling cone; 11-4-4 is the male connector of the shaping milling cone; 11-4-5 is the carbide particle; 11-5-1 is the body of the hydraulic drill bit; 11-5-2 is the sealing ring; 11-5-3 is the guide impeller; 11-5-4 is the nozzle.

[0063] 11-5-4-1 is the nozzle inlet section, 11-5-4-2 is the nozzle contraction section, and 11-5-4-3 is the nozzle straight section;

[0064] A is the atmospheric pressure pipeline, B is the high pressure pipeline, C is the return pipeline, D is the casing, E is the cement sheath, F is the reservoir, S is the rotating abrasive jet, W is the window, T is the reservoir wellbore, H is the old well casing, K is the old well cement sheath, and L is the connecting passage. Detailed Implementation

[0065] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0066] Example 1

[0067] Reference Figures 1-3 An integrated abrasive jet casing window-opening side-drilling system includes a drill rod 9 and a guide vane 12. The top of the drill rod 9 is connected to the drive device of the drilling rig 6, and the bottom of the drill rod 9 is connected to a window-opening side-drilling tool string 11. The window-opening side-drilling tool string 11 is composed of an electro-hydraulic orienter 11-1, a bend joint 11-2, a connecting short section 11-3, a shaping milling tap 11-4, and a hydraulic drill bit 11-5 connected in sequence, with each pair connected by API standard threads. Both the drill rod 9 and the window-opening side-drilling tool string 11 have abrasive slurry passage cavities inside. The drive device is a top drive 7.

[0068] It also includes an abrasive slurry supply unit; the abrasive slurry supply unit includes a water tank 1, a sand box 2, a sand mixing truck 3, and a fracturing truck 4; wherein, the water tank 1 and the sand box 2 are respectively connected to the sand mixing truck 3 through an atmospheric pressure pipeline A, and the sand mixing truck 3 is connected to the fracturing truck 4 through an atmospheric pressure pipeline A; the fracturing truck 4 is connected to the top drive 7 through a high pressure pipeline B; the water tank 1 is connected to the annulus through a return pipeline C. A weight gauge 8 is installed on the drill pipe 9.

[0069] Optionally, the top drive 7 can be replaced with a rotary swivel 13, and a square drill pipe 14 and a wellhead rotary table 15 can be added.

[0070] Reference Figure 4 The elbow joint 11-2 is composed of an upper elbow joint 11-2-1, an elbow joint housing 11-2-2, and a lower elbow joint 11-2-3, which are integrally formed. The central axis of the upper elbow joint 11-2-1 forms a fixed deflection angle α with the central axes of the elbow joint housing 11-2-2 and the lower elbow joint 11-2-3, wherein the deflection angle α is 1.5° to 1.75°.

[0071] Reference Figure 5The shaping milling cone 11-4 includes a shaping milling cone retainer body 11-4-2, a shaping milling cone guide cone surface 11-4-3, and a shaping milling cone male connector 11-4-4 connected sequentially from top to bottom; a shaping milling cone female connector 11-4-1 is provided inside the upper part of the shaping milling cone retainer body 11-4-2; and hard alloy particles 11-4-5 are provided on the outside of the shaping milling cone retainer body 11-4-2 and the shaping milling cone guide cone surface 11-4-3.

[0072] Reference Figure 6 The hydraulic drill bit 11-5 includes a hydraulic drill bit body 11-5-1, which is connected to the shaping milling cone 11-4 via an API standard thread. A nozzle 11-5-4 is provided inside the hydraulic drill bit body 11-5-1. The nozzle 11-5-4 communicates with the inner cavity of the shaping milling cone 11-4. The nozzle 11-5-4 and the hydraulic drill bit body 11-5-1 are sealed by a sealing ring 11-5-2.

[0073] Reference Figure 7 The nozzle 11-5-4 has an internal flow channel consisting of a nozzle inlet section 11-5-4-1, a nozzle contraction section 11-5-4-2, and a nozzle straight section 11-5-4-3. A guide impeller 11-5-3 is placed inside the nozzle inlet section 11-5-4-1. The nozzle contraction section 11-5-4-2 is shaped like an inverted frustum and is used to initially accelerate the high-pressure fluid and guide it into the nozzle straight section 11-5-4-3. The nozzle straight section 11-5-4-3 then continuously accelerates the initially accelerated high-pressure fluid, ultimately modulating it to form a rotating jet.

[0074] Example 2: Single-wellbore window opening and sidetracking implementation method

[0075] Reference Figures 1-12 The single-wellbore window-opening sidetracking method includes the following steps:

[0076] (1) After connecting the window-opening side-drilling tool string 11 to the drill pipe 9, it is sent to the wellbore by the drilling rig 6. The electro-hydraulic directional device 11-1 controls and maintains the spatial orientation of the window-opening side-drilling tool string 11 in real time, and the elbow joint 11-2 provides a fixed small-angle geometric offset.

[0077] The window-opening sidetracking tool string 11 is equipped with an electro-hydraulic orienting device 11-1 and a bend joint 11-2 in sequence. The electro-hydraulic orienting device 11-1 is used to control and maintain the spatial orientation of the window-opening sidetracking tool string 11 in real time downhole, while the bend joint 11-2 provides a fixed small-angle geometric offset for the window-opening sidetracking tool string 11. During the running and operation process, the electro-hydraulic orienting device 11-1 and the bend joint 11-2 work together to ensure that the window-opening sidetracking tool string 11 maintains the predetermined orientation downhole and forms a stable and controllable deflection trend during subsequent abrasive jet window opening and sidetracking, providing an azimuth basis for the extension of the sidetracked wellbore along the target direction.

[0078] (2) The high-pressure abrasive slurry enters the window-opening side-drilling tool string 11, forming a rotating abrasive jet S, which erodes and cuts the casing D and cementing annulus E to form a window W. The abrasive and debris generated by the window opening return upward through the annulus.

[0079] During construction, water tank 1 and sand box 2 are connected to sand mixing truck 3 via atmospheric pressure pipeline A. Water and abrasive are thoroughly mixed in sand mixing truck 3 to form a uniform abrasive slurry. The mixed abrasive slurry is then transported to fracturing truck 4 via another atmospheric pressure pipeline A. After being pressurized by fracturing truck 4, the high-pressure abrasive slurry is transported to top drive 7 via high-pressure pipeline B, and then guided into the window-opening side-drilling tool string 11 via drill pipe 9. The high-pressure abrasive slurry is modulated by hydraulic drill bit 11-5 in the window-opening side-drilling tool string 11 to form a rotating abrasive jet S, which erodes and destroys the casing D and the cementing annulus E on its outer side. During the window opening process, the window-opening side-drilling tool string 11 is continuously lowered under the control of drilling rig 6, and the change in suspended weight is monitored in real time by suspended weight gauge 8 to determine whether the lowering speed is appropriate and to avoid abnormal stress caused by excessively fast lowering. During the lowering process, guide vane 12 continuously guides drill pipe 9. Abrasives, metal shavings, and cement debris generated during the window opening process are returned through the annulus between the window opening side drilling tool string 11 and the casing D, and then enter the return pipeline C through the wellhead tee 10, eventually flowing back to the water tank 1, where they are recycled after sedimentation.

[0080] (3) After the window W is formed, continue to lower the window opening side-drilling tool string 11 or mill and shape the window W and continue to lower the window opening side-drilling tool string 11 to enter the reservoir F side-drilling process. The rotating abrasive jet S continuously breaks the rock and gradually forms a long horizontal section of reservoir wellbore T in reservoir F. After the reservoir wellbore T reaches the predetermined length, the downhole tools are pulled out and the construction is completed.

[0081] After the rotating abrasive jet S erodes and forms a window W on the casing D and cement sheath E, different operating methods are selected according to the resistance encountered during the subsequent descent: if the window-opening sidetracking tool string 11 does not encounter significant resistance during the continued descent, the sidetracking operation on the reservoir F can proceed directly without window trimming; if there is significant resistance during the descent, the top drive 7 is activated, and the window-opening sidetracking tool string 11 is rotated as a whole through the drill pipe 9. The shaping milling cone 11-4 set on the window-opening sidetracking tool string 11 is then used to mill and shape the formed window W to improve the window shape and provide access conditions for subsequent sidetracking operations.

[0082] As an alternative implementation, when window reshaping is required, the top drive 7 can be replaced with a rotary faucet 13, and a square drill pipe 14 and a wellhead rotary table 15 can be added to the wellhead. The wellhead rotary table 15 drives the square drill pipe 14 to rotate, which in turn drives the drill pipe 9 and the window-opening side-drilling tool string 11 to rotate as a whole, thereby allowing the reshaping milling cone 11-4 to perform milling and reshaping on the window W. This method can complete the window reshaping operation without using the top drive 7.

[0083] During sidetracking of reservoir F, the electro-hydraulic directional tool 11-1 and the elbow joint 11-2 continue to work together to ensure that the sidetracking tool string 11 always faces the predetermined orientation downhole. At this time, the rotating abrasive jet S continuously breaks up the rock in reservoir F, gradually extending the wellbore and forming a long horizontal section of the reservoir well T within reservoir F. Rock cuttings and abrasive materials generated during sidetracking return along the annulus between the sidetracking tool string 11 and the reservoir wellbore T, as well as the annulus between the drill pipe 9 and the casing D, and flow back through the wellhead tee 10 into the return line C, then back to the water tank 1 for sedimentation and recycling. Once the horizontal section of the reservoir wellbore T reaches the predetermined length, the abrasive jet operation is stopped, all downhole tools are retrieved, and surface equipment is removed, completing the construction.

[0084] During the above implementation process, the construction parameters can be selected according to the project requirements, including an abrasive volume ratio of 8% to 12%, a fracturing truck displacement of 600 to 1200 L / min, and a pressure drop of 40 to 70 MPa for the hydraulic drill bit 11-5.

[0085] Example 3: Implementation of Side-Drilling with Window Opening for Connecting New and Old Wellbores

[0086] Reference Figures 3-7 , Figures 13-17 After completing the drilling operation of drilling a new well alongside the old well, the window-opening side-drilling tool string 11 is connected to the drill pipe 9, and the drilling rig 6 lowers it into the new well. The process of steps (1)-(3) is the same as steps (1)-(3) in Example 2. The rotating abrasive jet S continuously breaks the rock and gradually forms a connecting channel L in the reservoir F.

[0087] (4) When the connecting channel L touches the old well cement sheath K, slow down the lowering speed of the window-opening side drilling tool string 11, and the rotating abrasive jet S erodes the old well cement sheath K and the old well casing H to form a window W.

[0088] After the rotating abrasive jet S erodes and forms a window W on the old well cement sheath K and the old well casing H, the surface sand box 2 is closed and sand addition is stopped to prevent the abrasive jet from damaging the casing on the opposite side of the old well window.

[0089] (5) After stopping sand addition, keep the pump pressure of the surface fracturing truck 4 unchanged, and continue to lower the window side drilling tool string 11 or mill and shape the window W and continue to lower the window side drilling tool string 11 to verify whether it can enter the old well smoothly. If the window side drilling tool string 11 can enter the old well smoothly, then take out the downhole tools and end the construction.

[0090] If no significant resistance is encountered during the lowering process, it indicates that the window-opening side-drilling tool string 11 can smoothly enter the old well. In this case, all downhole tools are retrieved, and the surface equipment is removed to end the construction. If significant resistance is encountered during the lowering process, the top drive 7 is activated, and the window-opening side-drilling tool string 11 is rotated through the drill pipe 9. The shaping milling cone 11-4 in the window-opening side-drilling tool string 11 is used to mill and shape the window W of the old well.

[0091] As an alternative implementation, when shaping the old well window W, the top drive 7 can be replaced with a rotary swivel 13, and a square drill pipe 14 and a wellhead rotary table 15 can be added. The wellhead rotary table 15 drives the square drill pipe 14 to rotate, which in turn drives the drill pipe 9 and the window-opening side-drilling tool string 11 to rotate as a whole, so that the shaping milling cone 11-4 can perform milling and shaping on the old well window W. After the shaping is completed, the window-opening side-drilling tool string 11 is lowered down. If it can successfully enter the old well, all downhole tools are retrieved, and the surface equipment is removed, ending the construction.

[0092] During the above implementation process, the construction parameters can be selected according to the project requirements, including an abrasive volume ratio of 8% to 12%, a fracturing truck displacement of 600 to 1200 L / min, and a pressure drop of 40 to 70 MPa for the hydraulic drill bit 11-5.

[0093] Any person skilled in the art can modify the above-described technical solutions or modify them into equivalent technical solutions. Therefore, any simple modifications or equivalent transformations made based on the technical solutions of this invention are within the scope of protection claimed by this invention.

Claims

1. An integrated abrasive jet casing window-opening side-drilling system, comprising a drill rod (9) and a guide vane (12), characterized in that, The top of the drill rod (9) is connected to the drive device of the drilling machine (6), and the bottom of the drill rod (9) is connected to the window-opening side-drilling tool string (11). The window-opening side-drilling tool string (11) is composed of an electro-hydraulic orienter (11-1), a bent joint (11-2), a connecting short section (11-3), a shaping milling cone (11-4), and a hydraulic drill bit (11-5) connected in sequence. Both the drill rod (9) and the window-opening side-drilling tool string (11) are provided with abrasive slurry passage cavities.

2. The integrated abrasive jet casing window-opening side-drilling system according to claim 1, characterized in that, It also includes an abrasive slurry supply unit; the abrasive slurry supply unit includes a water tank (1), a sand box (2), a sand mixing truck (3) and a fracturing truck (4); wherein, the water tank (1) and the sand box (2) are respectively connected to the sand mixing truck (3) through an atmospheric pressure pipeline (A), and the sand mixing truck (3) is connected to the fracturing truck (4) through an atmospheric pressure pipeline (A); the fracturing truck (4) is connected to the drive device through a high pressure pipeline (B); the water tank (1) is connected to the annulus through a return pipeline (C).

3. The integrated abrasive jet casing window-opening side-drilling system according to claim 1, characterized in that, The elbow joint (11-2) is composed of an upper elbow joint clamp (11-2-1), an elbow joint housing (11-2-2), and a lower elbow joint clamp (11-2-3). The central axis of the upper elbow joint clamp (11-2-1) forms a fixed deflection angle α with the central axes of the elbow joint housing (11-2-2) and the lower elbow joint clamp (11-2-3), wherein the deflection angle α is 1.5° to 1.75°.

4. The integrated abrasive jet casing window-opening side-drilling system according to claim 1, characterized in that: The shaping milling cone (11-4) includes a shaping milling cone retainer (11-4-2), a shaping milling cone guide cone (11-4-3), and a shaping milling cone male connector (11-4-4) connected from top to bottom; a shaping milling cone female connector (11-4-1) is provided inside the shaping milling cone retainer (11-4-2) at the top; and hard alloy particles (11-4-5) are provided outside the shaping milling cone retainer (11-4-2) and the shaping milling cone guide cone (11-4-3).

5. The integrated abrasive jet casing window-opening side-drilling system according to claim 1, characterized in that: The hydraulic drill bit (11-5) includes a hydraulic drill bit body (11-5-1), which is connected to a shaping milling cone (11-4); a nozzle (11-5-4) is provided inside the hydraulic drill bit body (11-5-1), and the nozzle (11-5-4) communicates with the inner cavity of the shaping milling cone (11-4); the nozzle (11-5-4) and the hydraulic drill bit body (11-5-1) are sealed by a sealing ring (11-5-2).

6. The integrated abrasive jet casing window-opening side-drilling system according to claim 4, characterized in that: The nozzle (11-5-4) consists of a nozzle inlet section (11-5-4-1), a nozzle converging section (11-5-4-2), and a nozzle straight section (11-5-4-3). A guide impeller (11-5-3) is placed inside the nozzle inlet section (11-5-4-1). The nozzle converging section (11-5-4-2) is in the shape of an inverted frustum.

7. An integrated method for abrasive jet casing with window opening and side drilling, characterized in that, The abrasive jet casing window-opening side-drilling integrated system as described in any one of claims 1-6 is used to implement a single wellbore window-opening side-drilling method or a new and old wellbore interconnection window-opening side-drilling method.

8. The integrated method for abrasive jet casing window opening and side drilling according to claim 7, characterized in that, The single-wellbore window-opening side-drilling method includes the following steps: (1) After connecting the window-opening side-drilling tool string (11) to the drill pipe (9), it is sent into the wellbore by the drilling rig (6). The electro-hydraulic directional device (11-1) controls and maintains the spatial orientation of the window-opening side-drilling tool string (11) in real time, and the elbow joint (11-2) provides a fixed small-angle geometric offset. (2) The high-pressure abrasive slurry enters the window-opening side-drilling tool string (11) to form a rotating abrasive jet (S), which erodes and cuts the casing (D) and cementing sheath (E) to form a window (W). The abrasive and debris generated by the window opening return through the annulus. (3) After the window (W) is formed, continue to lower the window opening side-drilling tool string (11) or after milling and shaping the window (W), continue to lower the window opening side-drilling tool string (11) to enter the reservoir (F) side-drilling process. The rotating abrasive jet (S) continuously breaks the rock and gradually forms a long horizontal section of reservoir wellbore (T) in the reservoir (F). After the reservoir wellbore (T) reaches the predetermined length, the downhole tools are pulled out and the construction is completed.

9. The integrated method for abrasive jet casing window opening and side drilling according to claim 7, characterized in that, The method for connecting old and new wellbore via window drilling includes the following steps: (1) After connecting the window-opening side-drilling tool string (11) to the drill pipe (9), it is sent into the wellbore by the drilling rig (6). The electro-hydraulic directional device (11-1) controls and maintains the spatial orientation of the window-opening side-drilling tool string (11) in real time, and the elbow joint (11-2) provides a fixed small-angle geometric offset. (2) The high-pressure abrasive slurry enters the window-opening side-drilling tool string (11) to form a rotating abrasive jet (S), which erodes and cuts the casing (D) and cementing sheath (E) to form a window (W). The abrasive and debris generated by the window opening return through the annulus. (3) After the window (W) is formed, continue to lower the window opening side drilling tool string (11) or after milling and shaping the window (W), continue to lower the window opening side drilling tool string (11) to enter the reservoir (F) side drilling process. The rotating abrasive jet (S) continuously breaks the rock and gradually forms a connecting channel (L) in the reservoir (F). (4) When the connecting channel (L) touches the old well cement sheath (K), slow down the lowering speed of the window-opening side drilling tool string (11), and the rotating abrasive jet (S) erodes the old well cement sheath (K) and the old well casing (H) to form a window (W). (5) Continue to lower the window-opening side-drilling tool string (11) or after milling and shaping the window (W), continue to lower the window-opening side-drilling tool string (11). After the window-opening side-drilling tool string (11) successfully enters the old well, the downhole tools are pulled out and the construction is completed.

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