Well completion cleaning solution and application thereof

Abstract

The invention provides a well completion cleaning solution. The well completion cleaning solution comprises the following components in parts by weight: 100 parts of water, 1-3 parts of a pH regulator, 0.5-10 parts of a thickening agent, 0.5-5 parts of a cross-linking agent and 10-30 parts of a cleaning agent. The reservoir protection effect of the well completion cleaning solution prepared by theinvention for a deep water protection reservoir is good, the reservoir is not polluted, and the permeability recovery value reaches 90% or above; the well completion cleaning solution for the deep water protection reservoir can effectively replace a synthetic base drilling fluid, and is basically free of mixed magma, the mixed magma quantity is furthest reduced, and the reducing rate of the mixedmagma quantity is 90% or above; a good cleaning effect is achieved, cleaning on well walls can be realized, the cleaning efficiency reaches 90% or above, and wetting reversal can be realized.

Description

technical field [0001] The invention relates to the technical field of petroleum drilling engineering, in particular to a well completion cleaning fluid and its application. Background technique [0002] Oil and gas exploration and development in deep water and ultra-deep water areas are the focus of future oil exploration and development, and have begun to take shape at home and abroad. However, there are still some technical problems in oil and gas exploration and development in deep water and ultra-deep water areas that need to be resolved urgently. In deep water and ultra-deep water areas, due to under-compacted formations, low formation fracture pressure, and many shale-containing formations, the problem of wellbore stability is prominent; due to the low ambient temperature in deep water and ultra-deep water areas, if gas invades the drilling fluid, it is easy to form hydration objects and block the pipe. Synthetic-based drilling fluids are an effective way to solve th...

AI Technical Summary

Problems solved by technology

Synthetic-based drilling fluids are an effective way to solve the above problems, but when drilling synthetic-based drilling fluids, especially when drilling open-hole wells, there are often several technical bottlenecks: 1) brine-based completion fluids and Synthetic-based drilling fluids have poor compatibility, and brine-based completion fluids are required to complete wells after drilling reservoirs, which will form an emulsion layer with the filtrate of synthetic-based drilling fluids and damage the reservoir; 2) brine-based completion fluids will interact with synthetic The base drilling fluid forms a mixed layer, and the mixing amount of the mixed layer is often very large. After returning to the drilling platform, its storage, transportation and disposal will cause very large financial and space difficulties

[0003] Researchers have done a lot of research on cleaning fluids for synthetic or oil-based drilling fluids. For example, application numbers 201310545773.3, 201610438760.X and 201510990331.9 disclose cleaning fluids suitable for oil-based drilling fluids, but the currently disclosed cleaning fluids are only It is to clean the drilling fluid and prepare for the subsequent cementing operation in order to improve the cementing quality. The completion cleaning fluid in the prior art cannot achieve the purpose of protecting the reservoir, nor can it reduce the mud mixing. quantity

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