Micro foam foaming agent and its well drilling liquid system formula

Abstract

A microfoam generating agent for low-pressure or under-balance drilling of well and a well-drilling liquid containing it are disclosed. Their preparing proesses are also disclosed. Said well-drilling liquid features fine foam, high resistance to high temp (more than 120 deg.C), salt and calcium, low density, and high effect on protecting oil-bearing stratum.

Description

Technical field: [0001] The invention relates to a micro-foam foaming agent used in low-pressure drilling or underbalanced drilling and its drilling fluid system formula. Background technique: [0002] At present, domestic oil fields use ordinary foam drilling fluid in the process of low-pressure drilling or underbalanced drilling. The foam drilling fluid is used in the wellbore and ground drilling fluid circulation equipment. Due to the large foam particle size and high gas content, the water supply efficiency of the mud pump is poor. The foam fluid returned to the wellhead must be mechanically degassed before adding a foaming agent and re-inflating to achieve effective circulation, which inevitably increases the drilling cost. Using water-in-oil drilling fluid or oil-in-water drilling fluid for low-pressure drilling or underbalanced drilling, in addition to safety and cost factors, the ability of this type of drilling fluid to reduce the proportion of equivalent mud at the...

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Problems solved by technology

[0003] In order to overcome the problems of large foam particle size, high gas content, and poor water supply efficiency of mud pumps in the wellbore and surface drilling fluid circulation equipment of common foam drilling fluids, the present invention provides a microfoam foaming agent and its drilling fluid. The liquid system formula, using the micro-foam foaming agent of the invention and the drilling fluid material compatible with it, can form a micro-foam drilling fluid formula with fine foam, strong high temperature resistance (>120°C), good salt and calcium resistance, The drilling fluid system has the advantages of low density, good oil layer protection effect, and strong ability to carry cuttings, and the drilling fluid does not affect the water supply efficiency of the mud pump during the surface circulation process, and can also reduce drilling costs

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