Temporary leakage-stopping agent for well drilling shielding and its application

Abstract

The temporary leakage-stopping agent is developed for stopping leakage in well drilling and reducing damage to oil reservoir. It consists of swelling material, bridging material, stuffing material and inhibitor material. The swelling material is nanmu rood powder, contton boll and other water swelling material of grain size below 838 micron and capable of forming fibrous gel; the bridging material is flaky mica of grain size 97-381 micron; the stuffing material may be common or light calcium carbonate of grain size below 117 micron; and the inhibitor material may be polyacrylonitrile sodium salt, polyacrylonitrile potassium salt, polyacrylonitrile ammonium salt, potassium humate or their mixture.

Description

technical field [0001] The invention relates to an additive used in the drilling process, in particular to a leak-proofing, leak-stopping and reservoir protection agent and its application in the drilling process. Background technique [0002] During the drilling process, lost circulation is an unavoidable phenomenon that often occurs. Among them, permeability leakage is the most common. Once lost circulation occurs, in addition to wasting drilling fluid and increasing drilling costs, when the loss is serious, the fluid column pressure in the well will not be able to balance the formation pore pressure and formation collapse pressure, resulting in more serious consequences such as well kick and well collapse. . At the same time, the leakage occurring in the well section of the reservoir, in addition to causing reservoir damage, may also lose the opportunity to discover oil and gas layers for exploration wells, and may reduce oil and gas recovery for development wells. [...

AI Technical Summary

Problems solved by technology

But both have certain problems, such as DF-1, the plugging effect is not bad, but the effect of protecting the oil and gas layers is poor. According to the permeability recovery test of the reservoir core, the increase value of the permeability recovery rate of the reservoir core is generally 10 %, it is difficult to achieve the purpose of protecting oil and gas reservoirs

The 891 temporary plugging agent not only has a poor plugging effect, but also has a strong viscosity increase phenomenon, which brings a lot of inconvenience to the field application. If it is necessary to add diluent to dilute, etc. Leakage prevention and plugging technology of one-way pressure sealant, Central Plains Drilling and Production Technology, 1988(4); He Jin, Application of combined plugging materials in eastern Sichuan, Petroleum Drilling and Production Technology, 1994(4); Huang Lei and Zhang Jianhua, Shan Application of pressure temporary plugging agent in protecting oil and gas layers, Drilling Fluid and Completion Fluid, 1992(4); Wang Houyan, Wang Qiuju and Zhang Yun, Application of plugging technology while drilling in Zhongyuan Oilfield, 1995(2); Ministry of Geology and Mineral Resources Report on the results of scientific research projects of the Bureau: Research on the Application of Drilling and Completion Fluid Technology to Prevent Oil and Gas Layer Damage in the Lunpola Exploration Area of ​​Tibet (P13~18, P30~35)