Water-based drilling fluid suitable for shale gas development

Abstract

The invention provides a water-based drilling fluid suitable for shale gas development. The water-based drilling fluid is prepared from the following raw materials in volume on the basis of water: 100 percent of water, 2 to 6 percent of lubricating agents, 1 to 5 percent of inhibitors, 1 to 5 percent of blocking anti-collapse agents, 1 to 5 percent of shale blocking agents, 1 to 5 percent of nanometer blocking agents, 1 to 3 percent of fluid loss additives, 1 to 3 percent of additives, 0 to 0.4 percent of shearing potentiator, 0.1 to 0.6 percent of pH regulator and 0 to 300 percent of weighting agents. The water-based drilling fluid has low filter loss, shale cracks can be effectively blocked, and the stability of a well wall is increased; the lubricating performance is good, and the problems of friction and torque caused by a shale gas horizontal well are preferably solved; the rheological property is excellent.

Description

technical field [0001] The invention relates to a drilling fluid used in the field of petroleum drilling engineering, in particular to a water-based drilling fluid suitable for shale gas development and drilling. Background technique [0002] The exploration and development of shale gas has gradually emerged in China, forming a certain scale of exploration and development, and entering a stage of rapid development. At present, the common drilling fluid is oil-based drilling fluid. Oil-based drilling fluid has excellent shale stability and lubricating properties, and has strong pollution resistance and can be recycled. It has become an essential key technology for shale gas development. . However, the disadvantages of high cost and environmental protection of oil-based drilling fluid are also particularly prominent. Therefore, it is particularly important to study a set of water-based drilling fluid system suitable for shale gas drilling in combination with the geological ch...

AI Technical Summary

Problems solved by technology

[0008] The above water-based drilling fluid systems all have certain shortcomings and deficiencies: ① only consider the wellbore stability of shale from the perspective of inhibitors, which is not targeted; ② the high-temperature and high-pressure filtration of the water-based drilling fluid It cannot reach the same level as oil-based drilling fluid, and cannot meet the requirements of shale gas development and drilling for wellbore; ③The lubrication coefficient of water-based drilling fluid system is high, and cannot reach the same level as oil-based drilling fluid. improve