Plugging agent capable of enhancing plugging performance of drilling fluid as well as plugging method and application thereof

Abstract

The invention discloses a plugging agent capable of enhancing the plugging performance of a drilling fluid, and a plugging method and application thereof, and the method comprises the following steps:step 1) selecting two different types of plugging agents according to the fracture condition of a drilling stratum, wherein one plugging agent is inert particles, and the other plugging agent is a deformable polymer; step 2) adding two different types of plugging agents into the drilling fluid, wherein the addition amount of the inert particles is 2.0%-4.0% of the drilling fluid and the additionamount of the deformable polymer is 1.0%-3.0% of the drilling fluid; and step 3) pumping the drilling fluid with the two different types of plugging agents into a drilling well, enabling inert particles in the drilling fluid to quickly enter a stratum crack bridge to form an inner plugging layer, and performing micro-crosslinking deformable plugging by the deformable polymer on the basis of the inner plugging layer formed by the inert particles to form an outer plugging layer.

Description

technical field [0001] The invention belongs to the technical field of enhancing the performance of drilling fluid, and in particular relates to a plugging agent capable of enhancing the plugging performance of drilling fluid and its plugging method and application, which can be applied to water-based drilling fluid or oil-based drilling fluid. It is suitable for drilling operations in shale gas horizontal wells, shale oil horizontal wells or carbonaceous mudstone horizontal wells that have high requirements for the plugging and anti-collapse performance of drilling fluid. Background technique [0002] With the large-scale development of unconventional gas reservoirs marked by shale gas at home and abroad, the application of oil-based drilling fluids is becoming more and more extensive. Compared with traditional water-based drilling fluids, oil-based drilling fluids are widely used in shale gas drilling because of their good inhibitory, lubricating, and rheological propertie...

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Problems solved by technology

[0008] The object of the present invention is to overcome above-mentioned deficiencies in the prior art, provide a kind of plugging agent that can strengthen drilling fluid plugging performance and its plugging method and application, overcome 1 in the prior art: existing plugging agent size is relatively small Most of the shale pores in my country are at the nanometer level. In the past, the conventional plugging agent has a large particle size, which is far larger than the shale pore size. It is difficult to seal micro-pores and micro-cracks, which will cause the filtrate to enter the formation and cause the well wall to become unstable; 2 : Adopt the method that improves drilling fluid density, the drilling fluid fluid of higher density invades stratum micropore, microfracture more easily, adds the generation of formation microfracture, causes borehole wall to spall and collapse; 3: in existing method, there are many All kinds of plugging agents are blocked by mixing different particle sizes of plugging agents together, only focusing on the particle size of plugging agents, relying on the accumulation of plugging substances, lack of research on the formed plugging layer, and no research on the formed plugging According to the previous theory to guide on-site plugging, the plugging effect is not good and other problems

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