Emulsifying and flushing spacer fluid for improving cementing quality of oil-based drilling fluid and preparation method of emulsifying and flushing spacer fluid

Abstract

The invention discloses an emulsifying and flushing spacer fluid for improving the cementing quality of an oil-based drilling fluid and a preparation method of the emulsifying and flushing spacer fluid. The spacer fluid is prepared from the following components in parts by weight: 200 parts of water, 5-10 parts of a surfactant, 70-75 parts of base oil, 4-15 parts of a suspension stabilizer, 0.2-3.0 parts of a fluid loss agent, 0.2-2.0 parts of a tackifier, 0.2-5.0 parts of a diluent, 80-400 parts of a weighting agent and 0.05 part of a defoamer, wherein the surfactant is prepared from cocoanut fatty acid diethanolamide CDEA and alkyl glycoside APG in a weight ratio of 1: 2. The emulsifying and flushing spacer fluid which has an emulsifying structure with permeating, dissolving, volume-increasing, carrying functions and the like has a preferable flushing capacity to the oil-based drilling fluid and mud cakes adhered to a casing wall. The surfacant molecules in the spacer fluid can be adsorbed on the surfaces of a casing and a well wall to improve the interfacial wettability, so that cement slurry and the casing and the well wall are better contacted and cemented, and therefore, the first and second interfacial cementation qualities for well cementation are improved.

Description

technical field [0001] The invention relates to an emulsified flushing spacer fluid and a preparation method thereof for improving the bonding strength of the cementing primary and secondary interfaces and the cementing quality under oil-based drilling fluid drilling conditions. Background technique [0002] Due to the oil-based drilling fluid has stable performance and strong anti-pollution ability, it can inhibit the water absorption and expansion of clay minerals in shale and other reservoirs, which is conducive to maintaining the stability of the wellbore wall. The liquid has been widely used in complex formations such as mud shale and salt-gypsum layers, and in special drilling techniques such as extended-reach wells and high-temperature deep wells. However, the oil-based drilling fluid has high viscosity and strong adhesion, which makes it difficult to flush the casing and the well wall, so that there is a certain thickness of uncurable layer between the cement slurry ...

AI Technical Summary

Problems solved by technology

At present, for oil-based drilling fluid cementing in China, the adjusted oil-based drilling fluid is often used as the flushing fluid, and the spacer fluid in use has a single function, poor effect and is not systematic

Especially in complex well sections such as the horizontal section of horizontal wells and the deflection section of highly deviated wells, the casing centering degree is poor and the displacement efficiency is low. needs

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