CN-121993087-A - Borehole wall stabilizing method based on formation water outflow prevention

CN121993087ACN 121993087 ACN121993087 ACN 121993087ACN-121993087-A

Abstract

The invention discloses a well wall stabilizing method based on preventing stratum from yielding water, which relates to the technical field of petroleum drilling and comprises the steps of firstly connecting a spraying tool on a drilling tool, drilling and expanding the inner diameter of a well wall of an area to be solidified, secondly, putting in a put-in type coating loading cylinder, thirdly, controlling the put-in type coating loading cylinder to be connected with the spraying tool, fourthly, controlling a resin coating to enter the spraying tool and spray towards the well wall, fifth, standing the drilling tool to solidify solidified resin, sixth, repeating the fourth step to continuously spray catalytic coating onto the resin coating, seventh, lifting the drilling tool, enabling the resin coating and the catalytic coating to enter a microcrack and forming an anti-yielding water isolation layer, eighth, continuing to drill downwards, and repeating the first step to seventh, and finishing the stabilization of the well wall of the other area to be solidified. The method can form a compact isolation layer on the well wall by utilizing sprayed solidified resin in the drilling process, thereby playing a role in effectively preventing the well wall from yielding water and providing effective technical support for on-site rapid drilling construction.

Inventors

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

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. A well wall stabilization method based on preventing stratum from yielding water is realized by spraying resin paint on a well wall in a gas drilling process, and is characterized by comprising the following steps: In the gas drilling process, when the drilling tool finishes drilling in a region to be solidified, the inner diameter of a well wall of the region to be solidified is enlarged through short-lift drilling and reaming, and the spraying tool is positioned at a spraying starting point above the region to be solidified after reaming is finished; Stopping injecting high-pressure gas, unloading the square drill rod at the wellhead, and using the drill rod to put into an input type paint loading cylinder, wherein the input type paint loading cylinder is internally provided with resin paint and catalytic paint, and the outer diameter of the input type paint loading cylinder and the inner diameter of the drill rod form dynamic seal; Step three, controlling the input type paint loading cylinder to descend along the inner hole of the drill rod, reach the upper part of the spraying tool and be connected with the spraying tool; Controlling a side hole on a spraying tool shell to be opened, controlling a nozzle to extend out of the side hole, increasing the pressure above an input type paint loading cylinder, enabling resin paint in the input type paint loading cylinder to enter the spraying tool and be sprayed to a well wall through the spraying tool; controlling the nozzle and the side hole to reset, and standing the drilling tool to solidify the solidified resin; Controlling the spraying tool to reset to the spraying starting point above the area to be cured, and repeating the fourth step to continuously spray the catalytic paint in the input paint loading cylinder onto the resin paint; Step seven, lifting the drilling tool, and under the action of the extrusion of the drilling tool bit, the resin coating and the catalytic coating enter into micro cracks of the well wall and form a compact water-proof isolation layer, so that the stabilization of the well wall in the area to be solidified is completed; and step eight, continuing downwards drilling, and repeating the step one-step seven to finish the stabilization of the well wall of the rest area to be solidified.
2. The method of claim 1, wherein in the first step, the drilling tool comprises an eccentric tricone bit, an MWD, a drill collar and a drill rod which are fixedly connected in sequence, and the spraying tool is fixed between the MWD and the drill collar through the shell.
3. The method of claim 1, wherein in the second step, the input type paint loading cylinder comprises a cylinder body which is used for being connected with a shell of the spraying tool in a sealing way, an annular piston which is communicated with the outside is arranged at the upper part of the cylinder body, an end rupture disc is arranged at the lower part of the cylinder body, and the catalytic paint and the resin paint are arranged between the annular piston and the end rupture disc in an up-and-down layering way.
4. The method of claim 1, wherein in the third step, an air circulation is formed in the drill pipe by starting a slurry pump, and the input type paint loading cylinder is controlled to move downwards by using the pressure of the air circulation.
5. The method for stabilizing a well wall based on preventing water from flowing out of a stratum according to claim 1, wherein in the fourth step, after the nozzle extends out of the side hole, the distance between the nozzle and the well wall is 5-6mm.
6. The method of claim 1, wherein in the fourth step, the spraying device is rotated at a speed of 50-55 rpm while descending at a speed of 3-4 m/min.
7. The borehole wall stabilization method based on preventing formation water from exiting as recited in claim 1, wherein: and fifthly, the rest time of the drilling tool is 5-10 minutes.
8. The method for stabilizing a well wall based on preventing water from flowing out of a stratum according to claim 1, wherein in the seventh step, the thickness of the water-flowing-out preventing isolation layer is 2-3mm.
9. The method for stabilizing a well wall based on preventing water from flowing out of a stratum according to claim 1, wherein the length of the areas to be solidified is 200-300mm, and the interval between the areas to be solidified is 200-300mm.
10. The method for stabilizing a well wall based on preventing water from flowing out of a stratum according to claim 1, wherein the automatic opening and closing of the side hole and the automatic extension and contraction of the nozzle in the spraying tool are controlled by a ground system.

Description

Borehole wall stabilizing method based on formation water outflow prevention Technical Field The invention relates to the technical field of petroleum drilling, in particular to a well wall stabilizing method based on formation water outflow prevention. Background The under-balanced pressure drilling technology is a drilling mode that the pressure of drilling fluid applied to the bottom of a well is smaller than the pore pressure of a stratum, the stratum fluid is effectively controlled to flow into a well shaft and is controlled to be treated, and the under-balanced pressure drilling technology is suitable for low-pressure low-permeability reservoirs, fractured reservoirs, failure, marginal reservoirs or areas where drilling fluid leakage, differential pressure stuck drilling and the like need to penetrate complex stratum once occur. The gas drilling is a gas underbalanced drilling technology using pure gas as a circulating medium, has the advantages of timely finding out a hydrocarbon reservoir, protecting the hydrocarbon reservoir, improving the mechanical drilling speed, avoiding leakage, reducing the risk of differential pressure sticking, and the like, and can avoid underground explosion and ensure the drilling safety especially when drilling with a gas reservoir. A large number of constructions prove that the well wall is required to be reinforced in real time under the gas drilling environment so as to form a tight surface layer on the well wall, thereby eliminating risks of lost circulation, collapse and water outlet and ensuring the stability of the well wall. In order to effectively prevent stratum water from being discharged, the following technical measures are adopted in the prior art: 1. The development overview and the hope of the literature 'water injection area pressure control well drilling technology' aims at the problem that the water injection area in the Changqing area causes the abnormal high pressure of a reservoir layer due to long-term continuous water injection, the well control risk is high, an automatic pressure control well drilling matching technology suitable for the block is developed, series of matching equipment such as slim hole stratum water outlet prevention and control is used, and the stratum water outlet prevention and control capability of the block is greatly improved after the technology is applied. 2. Aiming at the drilling construction difficulties such as poor drillability of the clay pot ridge breaking zone stratum of the Tarim basin and extremely easy well leakage and the like, the literature 'research application of air drilling and foam drilling on stratum at the upper part of the clay pot ridge breaking zone' provides an underbalanced drilling technology of applying the air drilling and foam drilling on clay pot and aspiration system stratum of the clay pot zone for the first time. The reasonable construction scheme is found through various analysis of applicability and application risks of the underbalanced drilling process on the upper well section of the new zone. In the actual drilling construction process of the Ke-Xe 1 well, no lost circulation occurs in the underbalanced construction period of the upper well section of the well, the mechanical drilling speed reaches 3.07m/h, the average mechanical drilling speed of the whole well is 2.38m/h, and the good anti-leakage application effect is shown. Meanwhile, the average mechanical drilling speed of the whole well is high, so that the ridge breaking belt of the Tarim basin apron is broken, and the mechanical drilling speed of the salt of the Bachu ridge chilly system is high. 3. The literature of the intelligent identification method of safety risk while drilling of gas drilling considers that the water yield of the stratum in the gas drilling mainly comprises four parts of gas atomization water yield, well wall water absorption capacity, rock debris water absorption capacity and free water yield through analysis and research of stratum water yield in the gas drilling. To calculate the water amount of each portion, analytical studies were performed on each of the four above-mentioned types of water by four tests. Quantitative analysis of the water yield of the formation in the gas drilling is also carried out by using a test means. 4. The research of the literature 'application of the cobalt well technology Bocumi block gravel layer with continuous gas circulation' finds that the drilling sticking occurs after the formation water is discharged, the formation water discharge is the biggest obstruction for implementing dry gas drilling, the water discharge is not the key of the problem, the current technology of how much water is discharged can be completely solved, and the key is timely monitoring and rapid conversion, so that the problems of drilling sticking and well wall instability caused by the formation water discharge are prevented. 5. The literature "research on the construction technology of a