Inhibition type reservoir-protection drilling fluid

Abstract

The invention provides an inhibition type reservoir-protection drilling fluid which not only has better drilling fluid performance, but also has stronger stability, has an inhibition effect on a strong alkali-sensitive stratum, and can protect a reservoir. The drilling fluid comprises a drilling fluid raw stock and an additive uniformly mixed in the drilling fluid raw stock. The additive comprises the following components in percentage by weight: 0.3%-0.5% of modified asphalt powder, 0.3%-0.5% of a natural high polymer material and 2%-3% of carboxymethyl modified starch, based on the weight of the additive and the volume of the drilling fluid raw stock. By adding the methyl modified starch, the natural polymer material and the modified asphalt powder, the colloidal property of the drilling fluid is adjusted, and the chip carrying property, the suspension property, the lubricity and the mud cake quality of the drilling fluid are improved, so that the drilling fluid has better performance and long-time stability.

Description

technical field [0001] The invention belongs to the field of low-permeability oil reservoir production well drilling, and relates to a drilling fluid, in particular to an inhibiting type protection reservoir drilling fluid. Background technique [0002] At present, in the production wells of low-permeability oilfields, during the drilling process of low-permeability reservoirs, foreign fluids and solid phases invade the reservoirs or the original state of the reservoirs is destroyed due to external reasons, resulting in a decrease in reservoir permeability and porosity, thereby affecting oil and gas. Tibet exploration and development effect. Because the formation of low-permeability reservoirs contains a large amount of clay minerals that are easy to hydrate and expand, the drilling fluid filtrate will cause hydration, expansion, dispersion and migration of clay minerals after entering the reservoir, resulting in blockage of reservoir pore channels. At the same time, becaus...

AI Technical Summary

Problems solved by technology

The polymer in the drilling fluid filtrate enters the pores and is adsorbed on the surface of the small pores and throats, resulting in a significant drop in permeability

There are certain polymers in the drilling fluid, which can only function under alkaline conditions, and the drilling fluid without polymers cannot effectively carry cuttings to achieve the purpose of cleaning the wellbore

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