CN-116263079-B - Coiled tubing operation grading well cementation system and well cementation method

CN116263079BCN 116263079 BCN116263079 BCN 116263079BCN-116263079-B

Abstract

The invention belongs to the technical field of oil and gas field well cementation, and particularly relates to a coiled tubing operation grading well cementation system and a well cementation method. A coiled tubing operation graded well cementation system comprises a wellhead injection device, a graded hoop, a windowing tool, a first-stage rubber plug and a second-stage rubber plug, wherein the coiled tubing operation graded well cementation comprises the steps of lowering the graded hoop, installing the wellhead injection device, first-stage well cementation, opening the graded hoop by the lower windowing tool, second-stage well cementation and pulling out the windowing tool. According to the invention, the coiled tubing is adopted to realize well cementation operation, after the cementing operation is completed, the secondary rubber plug is lifted out of the wellhead along with the coiled tubing, the secondary rubber plug does not need to be poked down to the bottom of the well through the tubular column, the operation cost is low, the efficiency is high, the drilling-free graded well cementation of the full-bore well bore of the coiled tubing operation is realized, the integrity of the well bore is effectively improved, and the well cementation quality is improved.

Inventors

LIU KEQIANG
CHEN CAIZHENG
HAN CHAOHUI
JIANG SHENGHUI
WANG CHANGNING
WEI HAIFANG
LI XIN
WANG PEIFENG
LIANG HONGWEI
LIU ZHIXIONG
YANG BIN
GAO YONGWEI

Assignees

中国石油天然气集团有限公司
中国石油集团川庆钻探工程有限公司

Dates

Publication Date: 20260508
Application Date: 20211213

Claims (6)

1. The coiled tubing operation grading well cementation system is characterized by comprising a wellhead injection device, a grading hoop, a windowing tool, a primary rubber plug and a secondary rubber plug, wherein: the wellhead injection device comprises a displacement fluid injection flat gate valve (1), a three-ram blowout preventer (2) and a cement slurry injection flat gate valve (3) which are connected in sequence from top to bottom; The classifying hoop comprises an upper joint (4), a sliding sleeve (5), a spring (10) and a lower joint (12), wherein the outer wall of the lower part of the upper joint (4) is fixedly connected with the inner wall of the upper part of the lower joint (12), an annular step (11) is arranged on the inner wall of the lower part of the lower joint (12), the spring (10) is arranged on the annular step (11), the sliding sleeve (5) is arranged above the spring (10), the upper end face of the sliding sleeve (5) is in contact with the lower end face of the upper joint (4), a diameter-changing groove (9) is formed in the inner wall of the sliding sleeve (5), a plurality of radial through holes (8) are formed in the middle shell of the lower joint (12), the centers of the radial through holes (8) are located on the same plane, the shell of the sliding sleeve (5) is provided with a plurality of flow-dividing holes (6) with the same quantity and size as those of the radial through holes (8), and the diameter-changing groove (9) is formed in the inner wall below the flow-dividing holes (6). The window opening tool comprises a continuous oil pipe joint (13), a cone (15), a central rod (17), a window opening tool body (18), a connector (19) and a spring claw (20) which are sequentially connected from top to bottom, wherein a rubber sleeve (16) is arranged on the outer side of the central rod (17), steel wire shafts (22) are respectively arranged on two sides of the lower end of the spring claw (20), steel wires (21) are arranged on the steel wire shafts (22), the steel wires (21) are rotatably connected with the spring claw (20) through the steel wire shafts (22), the window opening tool body (18) penetrates through the spring claw (20) to be fixedly connected with the connector (19), the continuous oil pipe joint (13) is connected with the cone (15) through threads, and the central rod (17) is connected with the cone (15) through a shear pin (14); The primary rubber plug comprises a primary rubber plug body (23) and a primary rubber plug skirt wing (24) positioned on the side surface of the primary rubber plug body (23), and the primary rubber plug body (23) is solid; The secondary rubber plug comprises a secondary rubber plug body (25) and a secondary rubber plug skirt wing (26) arranged on the side face of the secondary rubber plug body (25), a through hole (27) is formed in the secondary rubber plug body (25), and the diameter of the through hole (27) is the same as the outer diameter of a continuous oil pipe for operation.
2. The coiled tubing operation grading well cementation system according to claim 1, wherein a plurality of sealing rings (7) are arranged between the sliding sleeve (5) and the inner wall of the lower joint (12).
3. A coiled tubing operation graded well cementation system according to claim 1, wherein the inner diameter of the upper joint (4) is the same as the inner diameter of the sliding sleeve (5).
4. The coiled tubing operation grading well cementation system according to claim 1, wherein bosses (201) are arranged on two sides of the lower end of the spring claw (20), clamping grooves (202) are longitudinally formed in the middle of the bosses (201), the steel wire shaft (22) penetrates through the clamping grooves (202) to be connected with the spring claw (20), a lap joint right angle (211) is formed in the middle of the steel wire (21), one end of the steel wire (21) is rotatably connected with the steel wire shaft (22) on one side of the lower end of the spring claw (20), and the other end of the steel wire shaft (22) is overlapped with the steel wire shaft (22) on the other side of the lower end of the spring claw (20) through the lap joint right angle (211) and then extends out of the clamping grooves (202).
5. The coiled tubing operation grading well cementation system according to claim 1, wherein the primary rubber plug is made of wear-resistant rubber, the outer diameter of the primary rubber plug skirt wing (24) is larger than the inner diameter of an operating casing, the primary rubber plug skirt wing (24) can retract radially in a shaft, the secondary rubber plug is made of wear-resistant rubber, the outer diameter of the secondary rubber plug skirt wing (26) is larger than the inner diameter of the operating casing, and the secondary rubber plug skirt wing (26) can retract radially in the shaft.
6. A coiled tubing operation staged cementing method, using a coiled tubing operation staged cementing system as defined in any of claims 1-5, characterized in that: the method comprises the following steps: s1, putting a grading hoop; after the grading hoops are connected to the designed positions of the casing, the casing is put into an open hole well; s2, installing a wellhead injection device; S3, primary well cementation, which comprises the following specific processes: Closing a three-ram blowout preventer (2), injecting a first-stage rubber plug between a displacement fluid injection flat gate valve (1) of a wellhead injection device and the three-ram blowout preventer (2), opening a cement slurry injection flat gate valve (3) to start cement slurry injection, closing the cement slurry injection flat gate valve (3), opening the three-ram blowout preventer (2), opening the displacement fluid injection flat gate valve (1) to start water injection displacement fluid, and allowing the first-stage rubber plug to enter a sleeve along with the clear water displacement fluid until the first-stage well cementation is completed at the bottom of a well manually; s4, opening the classifying hoop by a lower window opening tool, wherein the concrete process is as follows: S41, enabling an operation coiled tubing to pass through a secondary rubber plug and a windowing tool, adopting rolling connection with a coiled tubing joint (13), then integrally putting the operation coiled tubing and the wellhead injection device into a wellhead injection device, adopting packing to seal the operation coiled tubing and the wellhead injection device, and after the windowing tool passes through a three-gate blowout preventer (2), enabling the secondary rubber plug to be placed between the three-gate blowout preventer (2) and a displacement fluid injection flat gate valve (1) of the wellhead injection device, wherein cement slurry is injected into the flat gate valve (3) and the displacement fluid is injected into the flat gate valve (1) to be closed; S42, the operation coiled tubing sends a windowing tool to a position below the classifying hoop, the operation coiled tubing is lifted up, two steel wires (21) in a reducing groove (9) of the sliding sleeve (5) are mutually crossed and overlapped to be released, a spring claw (20) is released to be in a free state capable of radially shrinking, the operation coiled tubing is lowered again, the spring claw (20) is clamped in the reducing groove (9) of the sliding sleeve (5), the sliding sleeve (5) compresses a spring (10) and moves downwards along with the operation coiled tubing to enable a shunt hole (6) of the sliding sleeve (5) to be communicated with a radial through hole (8) of a lower joint (12) to realize a windowing process, in the process, a coiled tubing joint (13), a cone (15), a rubber cylinder (16), a central rod (17), a windowing tool body (18) and a connector (19) move downwards relative to the spring claw (20), the connector (19) supports the spring claw (20) and enables the rubber cylinder (20) not to deform radially, and a shear pin (14) is sheared off, and the cone (15) enables the rubber cylinder (16) to be sealed with the sliding sleeve (5) radially; s5, secondary well cementation, which comprises the following specific processes: When the cement slurry injection amount is calculated, the cement slurry injection flat gate valve (3) is closed, the three-ram blowout preventer (2) is fully opened, the replacement liquid injection flat gate valve (1) is opened to start water injection replacement liquid, and the secondary rubber plug passes through the operation coiled tubing along with the replacement liquid to enter the casing pipe in a full range until the secondary well cementation is completed at the position of the classification hoop; s6, a windowing tool is started to finish the graded well cementation operation, and the concrete process is as follows: After the cement paste of the secondary well cementation is solidified, lifting the operation coiled tubing, separating the cone (15) from the rubber cylinder (16), radially retracting the rubber cylinder (16), meanwhile, staggering the split hole (6) of the sliding sleeve (5) and the radial through hole (8) of the lower joint (12) by the spring 10 after the cone (15) and the rubber cylinder (16) are separated from each other, sealing the shaft by the classification hoop, and sealing the shaft.

Description

Coiled tubing operation grading well cementation system and well cementation method Technical Field The invention belongs to the technical field of oil and gas field well cementation, and particularly relates to a coiled tubing operation grading well cementation system and a well cementation method. Background The staged cementing process is to install one special staged cementing device on casing string, and the staged cementing device and the plugs to complete the cementing operation of one well in two, three or more stages. When the conventional primary return well cementation process cannot meet the protection requirement of a shaft sealing sleeve, a graded well cementation process is often adopted, wherein the primary cement injection amount is too large, the stratum cannot bear excessive liquid column pressure, a special layer is sealed, annular gas channeling after well cementation is prevented, the upper and lower temperature difference of a sealing section is large, the cement slurry performance is not easy to adjust and the like. At present, the grading well cementation device is mainly divided into two major categories, namely conventional type well cementation device and drilling-free type well cementation device, and the drilling-free grading device is popularized and applied on site because the internal sliding sleeve, the rubber plug seat and the like of the small drilling tool drilling device are not needed to be put in. The drilling-free graded well cementation device can be divided into a mechanical type well cementation device and a hydraulic type well cementation device from the aspect of opening the circulating holes. Mechanical classification well cementation devices are usually put into an open plug after primary cementing is bumped and pressed, and the open plug automatically falls to a rubber plug seat to open a circulation hole, but the mode is difficult to realize the automatic well falling of a tool accessory in the design drift diameter of a classification device body. The hydraulic classification well cementation device adopts hydraulic pressure to open the circulation hole, and the structural form is simplified, but the design difficulty is high. After cementing operation is completed, the rubber plug and the rubber plug seat in the drilling-free graded well cementing device also have two falling modes, namely, a well completion oil production string is adopted in the early stage to pass through a well, and the rubber plug seat are poked to the bottom of the well. The second mode is that the closing Kong Chongli plug, the upper rubber plug and the rubber plug seat fall to the bottom of the well together. In the first way, completion electrical testing operations cannot be performed before the string is run. In the second way, the success rate of the rubber plug and the rubber plug seat falling to the bottom of the well needs to be further improved. Disclosure of Invention Aiming at the problems, the invention aims to provide a coiled tubing operation staged well cementation system and a well cementation method, which adopt a coiled tubing to realize well cementation operation, and after the cementing operation is finished, a secondary rubber plug is lifted out of a wellhead along with the coiled tubing, and is not required to be poked down to the bottom of a well through a tubular column, so that the operation cost is low, the efficiency is high, the drilling-free staged well cementation of a full-drift diameter shaft of the coiled tubing operation is realized, the integrity of the shaft is effectively improved, and the well cementation quality is improved. The technical scheme of the invention is that the coiled tubing operation grading well cementation system comprises a wellhead injection device, a grading hoop, a windowing tool, a primary rubber plug and a secondary rubber plug, wherein: The wellhead injection device comprises a displacement fluid injection flat gate valve, a three-ram blowout preventer and a cement slurry injection flat gate valve which are sequentially connected from top to bottom; the classifying hoop comprises an upper joint, a sliding sleeve, a spring and a lower joint, wherein the outer wall of the lower part of the upper joint is fixedly connected with the inner wall of the upper part of the lower joint, an annular step is arranged on the inner wall of the lower part of the lower joint, the spring is arranged on the annular step, the sliding sleeve is arranged above the spring, the upper end face of the sliding sleeve is in contact with the lower end face of the upper joint, and a reducing groove is formed in the inner wall of the sliding sleeve; The windowing tool comprises a continuous oil pipe joint, a cone, a central rod, a windowing tool body, a connector and spring claws which are sequentially connected from top to bottom, wherein a rubber cylinder is arranged on the outer side of the central rod, steel wire shafts are respectively arranged on