Cellulose type compound system drilling fluid filtrate loss reducer and preparation method thereof

Abstract

The invention relates to a cellulose type compound system drilling fluid filtrate loss reducer and a preparation method thereof and aims to provide a cellulose type drilling fluid filtrate loss reducer low in cost, excellent in filtrate loss reduction performance and rheological property, environmental friendly and suitable for saltwater-based mud. The cellulose type compound system drilling fluid filtrate loss reducer is prepared from, by weight, 0.6-0.9% of PAC (polyanionic cellulose), 0.06-0.18% of nanocelluloe whiskers and the balance saltwater-based mud, wherein in the saltwater-based mud, the mass fraction of sodium chloride is 14-16%, the mass fraction of bentonite is 2.5-3.5%, and pH of drilling fluid is 9.5-10.5. The cellulose type compound system drilling fluid filtrate loss reducer has excellent synergistic filtrate loss reduction effects; high-temperature high-pressure filtrate loss and API filtrate loss after ageing of a drilling fluid system are remarkably reduced, a shear thinning property is more evident, PAC consumption is reduced by 50% maximally, and accordingly cost is greatly reduced.

Description

technical field [0001] The invention relates to a fluid loss control agent with superior fluid loss control performance and rheological properties and a preparation method thereof, in particular to a cellulose compound system drilling fluid fluid loss control agent and a preparation method thereof. Background technique [0002] Fluid loss additives are also called fluid loss control agents and fluid loss additives. During the drilling process, the drilling fluid is easy to lose water, and the filtrate of the drilling fluid invades the formation, which will cause the shale to hydrate and expand. In severe cases, the well wall will be unstable and various downhole complex situations will occur. Damage to oil and gas formations. The filter cake formed by water loss can prevent further water loss and protect the well wall. But the filter cake should not be too thick, otherwise it is easy to cause "drill sticking" and other situations. Therefore, forming a filter cake with low...

AI Technical Summary

Problems solved by technology

Cellulose is a fluid loss reducer commonly used in drilling fluids. It has the advantages of extensive sources and environmental friendliness, but it also has the following disadvantages: single action, large amount of addition, and due to the existence of ether bonds and ester groups, its Poor resistance to high temperature and salt

However, the amount of CNC added is large, and the addition method of each component and the effect of the addition amount on the water loss reduction effect have not been studied. In addition, the experiment was carried out in freshwater base pulp, and the application effect in salt water base pulp was not studied. The effect after aging and the effect under high temperature and pressure have not been explored

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