Low-permeability solid-free completion fluid

Abstract

A low-permeability solid-free completion fluid is characterized by comprising the following components in mass percentage: 20-65% of specific gravity regulator, 1-3% of fluid loss agent, 1-2% of antiswelling agent, 0.05-0.1% of crystallization inhibitor, 0.5-1% of anti-collapse agent, 0.5-1% of corrosion inhibitor and the balance of water, wherein the specific gravity regulator is one or a combination of more than two of zinc chloride, zinc bromide, zinc iodide, zinc sulfate, zinc acetate, zinc chlorate and zinc nitrate; the fluid loss agent is carboxymethyl modified starch; the antiswelling agent is diallyl dimethyl ammonium chloride; the crystallization inhibitor is one or a combination of two of nitrilotriacetic acid and EDTA (ethylene diamine tetraacetic acid); the anti-collapse agent is nitro potassium humate; and the corrosion inhibitor is one or a combination of more than two of sodium molybdate, sodium tungstate and sodium chromate. The low-permeability solid-free completion fluid is large in specific weight, good in stability and resistant to high temperature and high pressure, can reduce the swelling rate of clay, improves the core permeability restoring value and does not generate precipitates.

Description

technical field [0001] The invention relates to a well completion fluid, in particular to a low-permeability solid-free well completion fluid, which is a liquid composition suitable for well completion with low damage and wide density under high temperature and high pressure conditions in the well completion stage. Background technique [0002] Completion engineering is a relatively independent project that connects drilling engineering and oil production engineering. It is a system starting from drilling oil layers, running casing, cementing, perforating, running production strings, draining fluid, and putting into production. project. Oil well completion means that the oil well is going to start producing, and the completion fluid is the liquid that is always in contact with the oil and gas formation during the completion process. The completion fluid mainly has the following functions: 1. Control the formation pressure to stabilize the wellbore, relieve the pressure diff...

AI Technical Summary

Problems solved by technology

Secondly, the formula contains a large number of macromolecular treatment agents. While it is functioning, macromolecules also adsorb, stay and gather in the reservoir, forming a blockage that is difficult to remove and causing damage to the reservoir.

Due to the damage to the reservoir, the core permeability damage can reach more than 30-50%, and the oil well cannot reach the designed production

Images