Composite lubricant for drilling fluid, as well as preparation method and application of composite lubricant

Abstract

The invention discloses a composite lubricant for drilling fluid. The composite lubricant is mainly prepared from the following raw materials in parts by mass: 60 to 90 parts of fatty alcohol-polyoxyethylene ether, 30 to 60 parts of fatty acid ester, 20 to 40 parts of waste animal fat, 5 to 10 parts of vinyl benzene, 5 to 9 parts of water-soluble carbon black, 2 to 5 parts of graphene substances, 1 to 3 parts of an extreme pressure anti-wear reagent, 1 to 3 parts of a dispersing agent, and 1 to 3 parts of a defoamer. The preparation method comprises the following steps: uniformly mixing and stirring the fatty alcohol-polyoxyethylene ether, the fatty alcohol-polyoxyethylene ether, the waste animal fat and vinyl benzene; adding the water-soluble carbon black, the graphene substances, the extreme pressure anti-wear reagent, the dispersing agent and the defoamer sequentially, performing mixing and stirring, and cooling the raw materials to 50 to 70 DEG C while stirring, so as to form uniform emulsion. The composite lubricant is high in temperature resistance and anti-pressure capacity, and can still keep good lubricating property under high-temperature and high-pressure conditions, biodiesel fuel is taken as a raw material for the main components of the composite lubricant, and no polluted component is contained.

Description

technical field [0001] The invention relates to the field of oilfield drilling preparation, in particular to a composite lubricant for drilling fluid and its preparation method and application. Background technique [0002] With the development of oil exploration and development to the deep and offshore, more and more deep wells, ultra-deep wells and special process wells are drilled, especially the drilling of ultra-high temperature and ultra-high pressure formations, which also put forward higher requirements for drilling fluids. [0003] Due to the high proportion of clay contained in shale formations, it is easy to hydrate, which has a great negative impact on drilling operations. During the drilling process, there are often problems such as wellbore instability, hole diameter expansion, pipe sticking, torque and resistance increase, etc. A series of downhole complex situations have increased the difficulty of drilling. In oil drilling and completion operations, various...

AI Technical Summary

Problems solved by technology

[0004] The main purpose of the lubricant used in general drilling fluid is to reduce the frictional resistance and the viscosity coefficient of the mud cake, but its own temperature resistance is relatively poor, and the lubrication effect is significantly deteriorated under the conditions of high temperature and high salt, which increases the pressure during deep well drilling construction. Differential pressure sticking, the drill pipe is easy to depressurize, especially in irregular well diameter and deviated wells and directional wells, the wear of the drill pipe increases

[0005] In addition, most of the drilling lubricating oils in the prior art are mineral lubricants, the main components of which are hydrocarbon compounds. This type of lubricating oil itself is not environmentally friendly, and will remain in water and soil during use, causing environmental pollution. When the pollution is serious, it will also cause toxicity to the microorganisms in the soil, which seriously limits the application range of the lubricant itself, which is not conducive to the continued expansion of applications.