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CN-121993079-A - Method and system for prolonging service cycle of gas drilling rubber core

CN121993079ACN 121993079 ACN121993079 ACN 121993079ACN-121993079-A

Abstract

The invention relates to the technical field of oil and gas well drilling and completion, in particular to a method and a system for prolonging the service cycle of a rubber core of a gas drilling well, wherein the method comprises the following steps that after the rubber core of a rotary blowout preventer is installed, a wellhead continuously descends a drilling tool to the bottom of the well; the method comprises the steps of injecting gas into a hexagonal drill rod of a drilling tool, returning the gas from the drill bit of the drilling tool along the drilling tool, entering an annular space between the drilling tool and a borehole, moving upwards, detecting whether the rubber core is in sealing failure, if not, discharging the gas along an overflow pipeline at one side of the rotary blowout preventer, if not, injecting colloid liquid from a four-way part of the wellhead, entering the annular space, and filling the gap between the hexagonal drill rod of the wellhead and the rubber core of the rotary blowout preventer with liquid flow in the circumferential direction under the flushing of the gas in the annular space at the lower part until the sealing is completed, and continuously discharging the gas. By the method and the system, the possibility of failure of the seal of the shale oil water Ping Jingkou rubber core is reduced, and the overall drilling speed is ensured to be higher.

Inventors

  • GAO YONGWEI
  • SHI CHONGDONG
  • XU CHAOYANG
  • YANG XIAOFENG
  • LI YANZE
  • LI XIAOLI
  • CHEN CAIZHENG
  • ZHAO WENZHUANG
  • GUO BAILI
  • WANG PEIFENG

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
20241105

Claims (10)

  1. 1. A method for prolonging the service cycle of a gas drilling rubber core is characterized by comprising the following steps: S 1 , after the installation of the rubber core (6) of the rotary blowout preventer (7) is completed, continuously lowering a drilling tool to the bottom of the well by the wellhead; s 2 , injecting gas into the hexagonal drill rod (5) of the drilling tool, returning the gas from the drill bit (18) of the drilling tool along the drilling tool, entering the annulus of the drilling tool and the borehole, and moving upwards; S 3 , detecting whether the rubber core (6) is in sealing failure, if not, discharging the gas along an overflow pipeline (20) at one side of the rotary blowout preventer (7), if not, discharging the gas, injecting colloid liquid from a four-way (9) of a wellhead, enabling the colloid liquid to enter an annulus, and under the flushing of gas in the lower annulus, circumferentially filling the gap between a hexagonal drill rod (5) of the wellhead and the rubber core (6) of the rotary blowout preventer (7) by the liquid flow until the sealing is completed, and continuously discharging the gas.
  2. 2. The method for prolonging the service life of a gas drilling rubber core according to claim 1, wherein the viscosity of the colloid liquid is 500 cps-650 cps, and the film forming speed is 1 min-2 min.
  3. 3. A method for prolonging the service life of a gas drilling rubber core according to claim 2, wherein the installation of the rubber core (6) is specifically that lifting a hexagonal drill rod (5) of a drilling tool at a wellhead, enabling the end part of the hexagonal drill rod (5) to penetrate the rubber core (6) of a rotary blowout preventer (7), lifting the rubber core (6) of the rotary blowout preventer (7) at the wellhead, slowly lowering the rubber core (6) until the rubber core (6) is placed in the rotary blowout preventer (7) and the rubber core (6) is fixed, and buckling the hexagonal drill rod (5) together at the wellhead.
  4. 4. A method of extending the life of a gas drilling capsule as claimed in claim 2, wherein when a seal failure of the capsule (6) is detected, the gas is no longer vented and the gas acts as a power source to force the capsule fluid into the annulus.
  5. 5. A method of extending the life of a gas drilling gel according to claim 2, wherein the gas exiting through the overflow line (20) is combusted and then exhausted.
  6. 6. The method of claim 2, wherein the gas is carried during upward movement to carry the cutting movement.
  7. 7. The system for prolonging the service cycle of the gas drilling rubber core comprises drilling equipment, wherein the drilling equipment comprises a drilling tool, a rotary blowout preventer (7), an annular blowout preventer (25), a double flashboard (8) and a four-way valve (9) which are arranged from top to bottom, two sides of the four-way valve (9) are respectively connected with a blowout prevention pipeline (11) and a well control injection pipeline (12), the drilling tool comprises a hexagonal drill pipe (5), a drill pipe (16), a screw (17) and a drill bit (18) which are sequentially connected, the rotary blowout preventer (7) is internally provided with the rubber core (6), and the system is characterized by further comprising a gas injection device (4), a rubber liquid injection device (14) and an overflow pipeline (20), the gas injection device (4) is communicated with the hexagonal drill pipe (5) and is used for introducing gas into an annulus, the rubber liquid injection device (14) is communicated with the well control injection pipeline (12) and is used for injecting rubber liquid into the annulus of the four-way valve (9) when the rubber core (6) is in a sealing failure, the rubber liquid is filled in the annulus of the lower annulus under the flushing of the gas, the wellhead hexagonal drill pipe (5) is filled with the circumference, and the gap of the rubber core (6) is completely discharged from the rotary blowout preventer (20) until the gas injection device is completely arranged at one side of the rotary blowout preventer.
  8. 8. The system for prolonging the service life of a gas drilling rubber core according to claim 7, wherein the overflow pipeline (20) is provided with a valve (19), the overflow pipeline (20) between the rotary blowout preventer (7) and the valve (19) is further connected with the colloid liquid injection device (14) through a communicating pipe, and the communicating pipe is further provided with a control valve (26).
  9. 9. The system for extending the life of a gas drilling gel according to claim 7, further comprising a combustion pit (24), wherein the other end of the overflow line (20) is routed to the combustion pit (24).
  10. 10. The system for prolonging the service life of the gas drilling rubber core according to claim 8, wherein the overflow pipeline (20) is further provided with a gas-liquid separator (21), and an air outlet of the gas-liquid separator (21) is communicated with a combustion pit (24) through a discharge pipe (22).

Description

Method and system for prolonging service cycle of gas drilling rubber core Technical Field The invention relates to the technical field of oil and gas well drilling and completion, in particular to a method and a system for prolonging the service cycle of a gas drilling rubber core. Background A large number of examples prove that in the gas drilling and completion process, because annular space is gas and solid-phase rock cutting, the rubber core in the wellhead rotary blowout preventer is easy to cause abnormal sealing failure and can not seal well mouth pressure timely due to dry grinding or burr scraping of a drill rod coupling, so that the rubber core of the rotary blowout preventer needs to be replaced frequently in the gas drilling process, the drilling cost of the drilling speed is reduced, the drilling cost is greatly increased, wherein 12 rubber cores are used for N1 single wells, the drilling speed is 2.6 m/h, and the drilling period is obviously prolonged. Aiming at the problem of sealing failure of a wellhead rubber core in a drilling site, a sealing rubber core suitable for a large-caliber annular blowout preventer is designed. Based on the virtual work principle and combined with constitutive equations of Blatz and Ko material super-elastic models, a spherical rubber core sealing finite element model is established, deformation-sealing processes (initial deformation, large deformation stage and sealing contact) of the rubber core under the pushing of a piston are simulated, and rubber core sealing performance researches under different shear moduli and piston strokes are carried out. Meanwhile, the rubber core is tested and verified by combining the technical requirements of national standards GB/T20174, 2009 and API 16A. The research result shows that the sealing performance of the spherical rubber core is greatly influenced by the shear modulus of the material, the contact pressure is firstly increased and then decreased along with the increase of the shear modulus, the deformation is decreased along with the increase of the shear modulus, and the larger the piston pushing stroke is, the larger the contact pressure and the deformation of the rubber core are. The sealing part has no leakage in the test process, and the developed rubber core has the sealing performance meeting the requirement. Secondly, determining the erosion model parameters of the nitrile rubber through inversion analysis based on an LM optimization algorithm according to an erosion test of a rubber test piece, embedding the determined erosion model into Fluent software through UDF, calculating the erosion performance of a sealing rubber core by a numerical model of a flow field near a semi-seal flashboard of the blowout preventer in the well construction process, and researching the change of the rubber core material removal amount in the process Guan Jingquan along with the well closing duration. As a result, improved Finnie erosion model parameters of the nitrile rubber material are obtained, and the maximum relative error between the relation of the erosion rate of the test piece predicted by the erosion model along with the change of the impact angle and the test data is only 5.77%, so that the erosion model parameters can be used for simulating the erosion performance of the nitrile rubber member. In the valve closing process of the blowout preventer, the erosion of the rubber core by the rock carrying drilling fluid mainly occurs in a rock debris high-speed collision area at the edge of the end face. The erosion rate of the rubber core is in linear positive correlation with the sand content of the drilling fluid and in nonlinear positive correlation with the flow rate of the drilling fluid. As the shutter opening degree decreases, the erosion rate increases exponentially. When the opening of the gate plate is 104mm, 26mm and 6mm respectively, the material removal rate of the rubber core is 1.52mm 3/s、5.22mm3/s and 28.3mm 3/s respectively, which shows that the rubber core is most severely eroded in the later period of well closing and immediately before the gate plate is closed. The material removal amount of the rubber core in the Guan Jingquan process is increased along with the increase of the well closing time length, and the corresponding rubber core volume removal amounts of the 3s and 8s of the well closing time length are 5.04mm 3 and 13.43mm 3 respectively. Thirdly, through the phenomena of annular circulation pressure consumption, pumping pressure, high exciting pressure and the like of the high-density oil-based drilling fluid in the slim hole well drilling, the pressure sensitive stratum well drilling is caused to overflow and leak frequently, and the operation safety is seriously influenced. In the prior art, the drilling of a 149.2mm well volcanic stratum of a TF2 well is taken as an example, and the engineering technical risk caused by sudden change of bottom hole pressure under different working condi