A kind of plugging agent for drilling fluid and preparation method thereof

Abstract

The invention discloses a blocking agent for drilling fluid and a preparation method thereof. The blocking agent for the drilling fluid is prepared from a thermosensitive deformation hydrophobic material, a thermosetting hydrophobic material, a rigid solid particle material, vegetable oil and solvent oil. The preparation method comprises the steps that the mixture of the thermosetting hydrophobic material and the plant oil is added into the cooled thermosensitive deformation hydrophobic material, sufficient stirring is carried out, the rigid solid particle material and the solvent oil are added, and then sufficient stirring is carried out. The blocking agent can effectively block various holes and microcracks with the diameters smaller than 20 micrometers, the permeability of the holes and the microcracks is lowered from 10<-5> md to 10<-6> and even 10<-7> md, and the filter loss is reduced; the blocking agent is easy to disperse and suspend in the drilling fluid without agglomeration or sedimentation, contains no emulsifying agent, can be used in drilling fluid in a water station, can also be used in drilling fluid in an oil station, and has the blocking and anti-sloughing acting effects. The preparation method is easy and convenient to implement, low in cost and applicable to industrial large-scale production.

Description

technical field [0001] The invention relates to the field of oil and gas drilling, in particular to a plugging agent for drilling fluid and a preparation method thereof. Background technique [0002] Well collapse is one of the most serious hazards in oil and gas drilling engineering. Wellbore stability in shale formations in oil and gas drilling has always been an important responsibility of drilling fluids. Years of drilling fluid anti-collapse technology research has shown that wellbore instability is closely related to the invasion of drilling fluid filtrate in the wellbore. Preventing the penetration of drilling fluid filtrate into the shale well wall is the key point of drilling fluid anti-collapse technology. Although the filter cake of drilling fluid can greatly reduce the penetration rate and percolation rate of wellbore drilling fluid into formation pores or fractures, the filter cake formed by the action of drilling fluid fluid loss control agent If it is chang...

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Problems solved by technology

[0008] There are already existing types of plugging agents for drilling fluids in existing oil and gas drilling, such as sulfonated bitumen, emulsified bitumen, emulsified paraffin, etc. Although these plugging agents have anti-collapse plugging effects, they all have a disadvantage: The composition of the plugging agent is single, either a single asphalt material or a single white oil emulsion, which does not contain a rigid solid material with a bridging effect, resulting in the lack of bridging materials and a single filling material in the actual application of these plugging agents However, the anti-slump plugging efficiency is not ideal, and it is not enough to further reduce the permeability of the filter cake, which can only reduce the permeability of the filter cake from 10 to 10. -4 md reduced to 10 -5 md, further reduction in filter cake permeability is difficult to achieve

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