Preparation method and application of a plugging agent while drilling for oil-based drilling fluid

Abstract

The invention discloses a preparation method of a plugging-while-drilling agent for oil-based drilling fluid. Material, 40%-60% oil-absorbing intumescent granular material and 10%-25% oil-wettable composite fiber material are evenly mixed, dried, stirred and pulverized, and particle size screening makes the particle size of the LWD plugging agent 70% in the 0.075mm~0.5mm; the oil-wettable composite fiber material is modified vegetable fiber, and all components of the oil-based drilling fluid plugging agent are oil-wettable materials or inert materials, which have good compatibility with oil-based drilling fluids. The plugging effect will not be weakened for a long time; the main component is oil-absorbing expansive material, which can expand well in white oil and diesel oil. Under the action of pressure difference, it is squeezed into micro-fractures and then oil-absorbing and expanding, and then fills the fractured stratum to improve the The success rate of plugging while drilling; good strength and elasticity, high compressive strength and shear resistance, can deform and fill cracks in the formation.

Description

technical field [0001] The invention relates to the technical field of oil and natural gas drilling, in particular to a preparation method and application of a plugging agent while drilling for oil-based drilling fluid. Background technique [0002] As an important drilling fluid system, oil-based drilling fluids are widely used in highly difficult and complex wells such as shale gas horizontal wells. Shale gas wells in the Sichuan-Chongqing area have developed fractures and micro-fractures in the Longmaxi Formation, with concentrated folds and folds, and are prone to leakage and collapse. Oil-based drilling fluids are different from water-based drilling fluids in terms of density, morphology, dispersibility, surface wettability, and mud cake formation capabilities. At present, there are few types of plugging materials suitable for oil-based drilling fluids, the success rate of plugging is low, and leakage often occurs after plugging, resulting in a lot of time cost and los...

AI Technical Summary

Problems solved by technology

[0007] 1. Most of the fiber plugging agent materials used are plant fibers, which have poor compatibility with oil-based drilling fluids. After long-term circulation, the plugging effect is reduced, and re-leakage is prone to occur;

[0008] 2. Elastic deformation materials such as styrene-butadiene rubber are mostly used in the proportion of plugging agent materials, and the pressure bearing capacity decreases under high temperature and high pressure in the formation;

[0009] 3. Calcium carbonate has the largest specific gravity in the proportion of the plugging agent. The calcium carbonate in the above-mentioned patents is pure calcium carbonate powder with different meshes, which can be regarded as a pure substance and is used as an elastic material. Calcium carbonate with different meshes Poor filling compaction, affecting plugging effect

Images