CN106481326A - The no chock pressure difference fracturing strings of self controllable supercharging - Google Patents

Abstract

The invention discloses a non-throttle differential pressure segmental fracturing pipe string capable of self-control boosting. A fracturing packer, the pressurized setting controller is also connected to the high-pressure fracturing packer through a pressure transmission pipeline. At least one set of high-pressure fracturing packers is provided. When fracturing multiple stages, multiple sets of high-pressure fracturing packers need to be arranged sequentially. Between two sets of high-pressure fracturing packers The non-throttle ball fracturing sleeve is set, and all the high-pressure fracturing packers are connected in series through the pressure transmission pipeline. The string body is also provided with a safety joint and a guide head, the safety joint is located above the anchor, and the guide head is located at the lowest end of the pipe string body, that is, below the last high-pressure fracturing packer. The invention realizes setting by arranging a pressurized setting controller to generate a setting pressure difference inside and outside the packer, thereby achieving the purpose of effectively sealing off the oil layer and performing staged fracturing.

Description

Non-restricted differential pressure staged fracturing string with self-controlled pressurization

technical field

The invention relates to an oil well fracturing technology, in particular to an unthrottled pressure difference staged fracturing pipe column capable of self-controlling pressurization.

Background technique

The staged fracturing technology of the packer in the casing is one of the important means to realize the effective production of low-permeability and thin interlayer reservoirs. It has the advantages of highly targeted fracturing intervals, continuous fracturing process, increased drainage area after fracturing, It has technical advantages such as improving oil displacement efficiency, timely flowback, and effectively protecting reservoirs.

At present, the domestic and foreign casing packer staged fracturing technologies that can be retrieved mainly include the staged fracturing technology of the lifting string packer (such as the single lifting fracturing string of the horizontal well with the patent number ZL 200720169453.2) and Staged fracturing technology without moving string packer. In these two technologies, the use of hydraulically driven setting packers is mainly realized in two ways. One is to reduce the flow area of the sandblasting port of the fracturing sand blaster to generate choke pressure inside and outside the fracturing string. Poorly set packers isolate the oil layer in sections. The disadvantage of this design is that the fracturing fluid wears the sandblasting port during the fracturing process, which increases the flow area of the entire sandblasting port and saves energy. If the flow pressure difference decreases or disappears, the setting of the packer will fail, and even the entire fracturing string will break, resulting in construction accidents. The other is to connect a setting ball seat or other similar tools at the bottom of the pipe string to form a closed cavity in the pipe string and pressurize the set packer. This design requires pitching, and the process is cumbersome, and the packer generally needs to be lifted and unsealed, and the lifting force is relatively large. At present, many domestic research institutes and companies are researching new in-pipe segmented fracturing strings, which can not only overcome the shortcomings of existing fracturing strings, but also meet the development needs of low-permeability and thin interbedded reservoirs.

Contents of the invention

The purpose of the present invention is to provide self-controlling pressurization of non-throttle differential pressure staged fracturing string, by installing a pressurization setting controller to generate a setting pressure difference inside and outside the packer to achieve setting, so as to achieve effective sealing Reservoir, for the purpose of staged fracturing.

In order to achieve the above-mentioned purpose, the present invention adopts the following technical solution, the non-throttle pressure difference staged fracturing string that can be self-controlled and pressurized includes a string body, and the string body is sequentially provided with anchors, A booster setting controller and a high pressure fracturing packer, the booster setting controller is also connected to the high pressure fracturing packer through a pressure transmission pipeline.

At least one set of high-pressure fracturing packers is provided. When fracturing multiple stages, multiple sets of high-pressure fracturing packers need to be arranged sequentially. Between two sets of high-pressure fracturing packers The non-throttle ball fracturing sleeve is set, and all the high-pressure fracturing packers are connected in series through the pressure transmission pipeline.

The string body is also provided with a safety joint and a guide head, the safety joint is located above the anchor, and the guide head is located at the lowest end of the pipe string body, that is, below the last high-pressure fracturing packer.

The pressurized setting controller includes a central pipe and a cylinder sleeve. The cylinder sleeve forms an annular space outside the central pipe and between the central pipe, and a piston is installed in the annular space. The upper end of the central pipe is distributed radially and symmetrically in two A radial pressure transmission hole is used to communicate with the inner cavity of the central tube and the above-mentioned annular space. The hole is connected to the pressure transmission pipeline through a quick joint, and the piston is connected to the central pipe through four starting shear pins evenly distributed in the axial direction, and is located in the channel between the radial pressure transmission hole and the axial pressure transmission hole.

The surface areas of the upper and lower ends of the axial direction of the piston are different, and the area of the upper end surface is larger than that of the lower end surface.

The upper end of the cylinder liner is connected to the upper joint, and the inside of the upper joint is sealed with the central pipe by a sealing rubber ring, and the lower end of the pressure transmission joint is connected to the lower joint.

Compared with the prior art, the present invention has the following beneficial effects:

The self-controllable pressurized non-throttle pressure differential staged fracturing string is suitable for horizontal wells, deviated wells and vertical wells. The pressure system sets the packer, and the packer setting is not affected by the size of the sandblasting port and other supporting tools, so the oil layer is more reliable to be sealed. In addition, the sandblasting port of the sand blaster has a large flow area and no throttling pressure difference, which greatly reduces the wear on the sandblasting port during the fracturing process, improves the safety and reliability of the string, and eliminates The flow area is small and the construction displacement is limited.

Description of drawings

Fig. 1 is a schematic structural view of the non-throttling differential pressure staged fracturing string capable of self-controlling pressurization of the present invention;

Fig. 2 is a structural schematic diagram of a pressurized setting controller.

In the figure: safety joint 1, anchor 2, pressurized setting controller 3, pressure transmission pipeline 4, unthrottled ball fracturing sleeve 5, high pressure fracturing packer 6, guide head 7;

Upper joint 3-1, center pipe 3-2, starting shear nail 3-3, piston 3-4, cylinder liner 3-5, pressure transmission joint 3-6, lower joint 3-7.

detailed description

The detailed description and technical content of the present invention are described below with the accompanying drawings, but the accompanying drawings are only provided for reference and description, and are not intended to limit the present invention.

According to Fig. 1-2, embodiment 1: the unrestricted differential pressure staged fracturing string with self-control boosting, including the string body, the anchor 2, boost A setting controller 3 and a high-pressure fracturing-resistant packer 6 , and the pressurized setting controller is also connected to the high-pressure fracturing-resistant packer through a pressure transmission pipeline 4 . At least one set of high-pressure fracturing packers is provided. When fracturing multiple stages, multiple sets of high-pressure fracturing packers need to be arranged sequentially. Between two sets of high-pressure fracturing packers The unthrottled ball fracturing sleeve 5 is set, and all the high-pressure fracturing packers are connected in series through the pressure transmission pipelines. The pressurized setting controller includes a central pipe 3-2 and a cylinder liner 3-5. The cylinder liner forms an annular space outside the central pipe and between the central pipe, and a piston 3-4 is installed in the annular space. The upper end of the central tube is radially symmetrically distributed with two radial pressure transmission holes, which are used to communicate with the inner cavity of the central tube and the above-mentioned annular space. An axial pressure transmission hole connected to the annular space, the pressure transmission hole is connected to the pressure transmission pipeline through a quick joint, the piston is connected to the center pipe through four starting shear pins 3-3 evenly distributed in the axial direction, and is located in the radial pressure transmission The channel between the hole and the axial pressure transmission hole. The surface areas of the upper and lower ends of the axial direction of the piston are different, and the area of the upper end surface is larger than that of the lower end surface.

Embodiment 2: On the basis of Embodiment 1, a safety joint 1 and a guide head 7 are also arranged on the pipe string body. Below the high pressure fracturing packer. The upper end of the cylinder liner is connected to the upper joint 3-1, and the inside of the upper joint is sealed with the central pipe by a sealing rubber ring, and the lower end of the pressure transmission joint is connected to the lower joint 3-7.

In general, at least one set of high-pressure fracturing packers 6 should be installed in the string. When fracturing multiple stages, multiple sets of high-pressure fracturing packers 6 should be installed in the string. The flow ball fracturing sleeve 5 and the high-pressure fracturing packer 6 can be connected with oil pipes or short-circuited. The high-pressure fracturing packer 6 is used to seal off the oil layer to realize effective staged fracturing. The lower end of the pressurized setting controller 3 and the upper and lower ends of the high-pressure fracturing packer 6 are designed with pressure transmission joints, which are controlled by transmission. The pressure pipeline 4 is connected to the pressure transmission joint, and the pressurization setting controller 3 and the high pressure fracturing packer 6 in the pipe string of the present invention are connected in series, through the independent pressurization system in the 3 pressurization setting control assembly Increase the pressure of the pressure system in the pressurized setting controller 3, and transmit the high pressure to the inside of the high-pressure fracturing packer 6 rubber barrel through the pressure transmission pipeline 4, so that the inside and outside of the high-pressure fracturing packer 6 rubber barrel Create the differential pressure required to set the cartridge. An unrestricted ball-dropping fracturing sleeve 5 is arranged between every two high-pressure fracturing packers 6, and each unrestricted ball-dropping fracturing sleeve 5 is designed with multiple sandblasting ports. The flow area is larger than the inner diameter of the connecting tubing in the tubing string, so there is no throttling pressure difference between the inside of the tubing string and the annulus of the oil jacket, and the damage to the tubing string and its casing caused by fracturing sand can be reduced during the fracturing process degree. The lower end of the upper joint 3-1 of the pressurized setting controller is externally connected to the upper end of the cylinder liner 3-5, and the inner part is sealed with the central pipe 3-2 by a sealing rubber ring, and the upper end of the central pipe 3-2 is axially symmetrically distributed with two The pressure transmission hole, the piston 3-4 is connected to the central tube through four starting shear pins 3-3 evenly distributed in the axial direction, after the starting shear pins 3-3 are cut off, they can slide along the outer wall of the central tube 3-2, the pressure transmission joint The upper end of 3-6 is connected with the cylinder liner 3-5 through thread, and the lower end is connected with the lower joint 3-7 through thread. There is a pressure transmission hole on the pressure transmission joint 3-6, which can be connected with the pressure transmission pipeline through the quick joint.

Take horizontal well construction as an example. During on-site construction, when the pipe string is lowered to the design position, the well is cleaned, and the ball matching the first-stage unrestricted ball fracturing sleeve 5 is put in to replace the preflush. When the ball reaches the pressure of the first-stage unrestricted ball, After cracking the ball seat position of the sliding sleeve 5, increase the displacement, increase the pressure, cut off the starting shear pin 3-3 in the booster setting controller 3, and start the booster system. At this time, the piston 3 under the action of hydraulic pressure -4 goes down along the outer wall of the central tube 3-2, because the upper and lower areas of the piston 3-4 are different, when the force on the piston 3-4 reaches balance, the pressure of the independent pressure system connected to the pressure transmission line 4 is higher than the pressure in the oil pipe , and the high pressure is transmitted to the inside of the high-pressure fracturing packer 6 rubber cylinder by the pressure transmission pipeline 4, and the pressure difference required for the setting rubber cylinder is generated, so that the high-pressure fracturing packer 6 of each level is set, and the continuation Increase the pressure to open the sliding sleeve of the first-stage no-throttle ball fracturing sleeve 5, and expose the sand blasting port for fracturing. The matching ball is used as the preflush. When the ball reaches the ball seat position of the second-stage unrestricted ball fracturing sleeve 5, increase the pressure to open the second-stage unrestricted ball fracturing sleeve 5. Exposed the sandblasting port for fracturing, and so on to complete the fracturing of the remaining sections. After the fracturing is completed, the pressure is released, the spray is released, and the pressure in the tubing decreases, so the piston 3-4 moves upward under the action of hydraulic pressure. The internal pressure of the pressure transmission pipeline 4 and the high-pressure fracturing packer 6 at all levels decreases, the rubber tube is automatically unsealed, and the string is lifted up to complete the entire staged fracturing without throttling differential pressure with self-controllable pressurization crafting process.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Other equivalent changes using the patent spirit of the present invention all belong to the patent scope of the present invention.

Claims (6)

1. The non-throttling differential pressure staged fracturing string with self-controlled pressurization, including the string body, is characterized in that the string body is provided with anchors, pressurization setting controllers, For a high-pressure fracturing packer, the pressurized setting controller is also connected to the high-pressure fracturing packer through a pressure transmission pipeline. 2. The self-controllable pressurized non-throttle differential pressure staged fracturing string according to claim 1, characterized in that at least one set of high-pressure resistant fracturing packers is provided, when fracturing multiple stages In this case, multiple sets of high-pressure fracturing packers need to be configured sequentially, and no-throttle ball fracturing sleeves are set between two sets of high-pressure fracturing packers. All high-pressure fracturing packers are also Connect in series through the pressure transmission pipeline. 3. The self-controllable pressurized non-throttle pressure differential staged fracturing string according to claim 2, characterized in that, the string body is also provided with a safety joint and a guide head, and the safety joint is located at the anchor Above the setter, the steering head is located at the lowermost end of the string body, that is, below the last high-pressure fracturing packer. 4. The self-controllable pressurized non-throttle pressure differential staged fracturing string according to claim 1, characterized in that the pressurized setting controller includes a center pipe and a cylinder liner, and the cylinder liner is set in An annular space is formed outside the central tube and between the central tube, and a piston is installed in the annular space. The upper end of the central tube is radially symmetrically distributed with two radial pressure transmission holes, which are used to communicate with the inner cavity of the central tube and the above-mentioned annular space. The lower end of the cylinder liner is connected to the pressure transmission joint. The pressure transmission joint is axially provided with an axial pressure transmission hole communicating with the above-mentioned annular space. The pressure transmission hole is connected to the pressure transmission pipeline through a quick joint. A starting shear pin is connected to the central pipe and is located in the channel between the radial pressure transmission hole and the axial pressure transmission hole. 5 . The self-controllable pressurized non-restricted differential pressure staged fracturing string according to claim 4, characterized in that the upper and lower axial ends of the piston have different surface areas, and the upper end surface area is larger than the lower end surface area. 6. The self-controllable pressurized non-throttle pressure difference staged fracturing string according to claim 4, characterized in that the upper end of the cylinder liner is connected to the upper joint, and the inside of the upper joint and the center pipe pass through a sealing rubber ring Sealing, the lower end of the pressure transmission joint is connected with the lower joint.