Strong-inhibition strong-blocking drilling fluid

Abstract

The invention relates to the technical field of drilling fluid for petroleum drilling, particularly to high-inhibition strong-blocking drilling fluid. The drilling fluid comprises, by weight, 0.5%-15% of a strong inhibitor, 0.5%-7% of a strong blocking agent, 0.5%-5% of bentonite and 0.2%-6% of a fluid loss agent. The drilling fluid has strong inhibiting effect on hydration of strong water-sensitive mud shales through high concentration K+ generated after dissolution of the strong inhibitor; simultaneously, anions generated after the dissolution of the strong inhibitor take the absorption action with the surface of clay through the absorption capacity so as to form protective films on the surface of the clay, and therefore the hydration of the clay is prevented; and the strong blocking agent can achieve strong blocking to strong water-sensitive mud shale stratums with micro-cracks to form isolating films in the real sense, and therefore instability of well walls of the strong water-sensitive mud shale stratums is prevented. The drilling fluid has the advantages of being good in blocking, strong in inhabitation, good in lubricity, stable in high temperature property, small in damage to reservoir stratums, free of pollution and capable of improving the production efficiency.

Description

technical field [0001] The invention relates to the technical field of drilling fluid for petroleum drilling, and is a drilling fluid with strong inhibition and strong plugging. Background technique [0002] Drilling fluid is a working fluid that has many functions during drilling, such as carrying and removing cuttings, cooling and lubricating the drill bit, balancing formation pressure, protecting the stability of the wellbore wall and protecting the oil layer from damage. Its performance directly affects drilling efficiency and downhole drilling. Safety and cost control are important components of drilling engineering technology. In drilling engineering, we often encounter strong water-sensitive mud shale formations, which are likely to cause complex accidents such as bit bagging, well wall collapse, well diameter reduction, torque increase, and drilling tool jamming, which will bring great harm to drilling engineering. . In order to solve the above problems, in the pas...

AI Technical Summary

Problems solved by technology

These anions do not contribute positively to the performance of the entire drilling fluid system. On the contrary, due to the existence of a large number of anions, the salinity of the drilling fluid increases, which reduces the use efficiency of other treatment agents to a certain extent.