Annulus protective liquid of annulus mechanical seat sealed oil-gas well and applications thereof

Abstract

The invention relates to an annulus protective liquid of annulus mechanical seat sealed oil-gas well and applications thereof. The protective liquid is composed of the following components in percentage by weight: 10 to 14% of emulsifier, 0.1 to 0.5% of foaming agent, 0.1 to 0.3% of foam stabilizer, 25 to 28% of oil phase, 0.5 to 1.0% of corrosion inhibitor, and the balance being water. The emulsifier, foaming agent, foam stabilizer and corrosion inhibitor are mixed, then water and oil phase are added to prepare stable emulsion; then gas with a stable chemical property is introduced into the emulsion to form stable foamed emulsion; and the stable foamed emulsion is injected into an oil sleeve annulus and is automatically separated into layers of gas, oil, and water under the effects of the temperature and pressure in the cylindrical well and the surface tensions of different components. The provided annulus protective liquid can protect the oil sleeve annulus, has a good corrosion inhibiting speed, does not generate an upward force on the wellhead, and can prevent the aging of the packer. Furthermore, the cost of annulus protective liquid is reduced.

Description

technical field [0001] The invention relates to an annulus protection fluid for oil and gas wells and water injection wells, in particular to an annulus protection fluid for annulus mechanically seated oil and gas wells and its application. Background technique [0002] During the development of oil and gas fields at home and abroad, in order to protect the inner wall of the casing and the outer wall of the tubing from H 2 S and CO 2 Corrosion, etc., mainly adopt the method of injecting high-efficiency protective fluid into the annulus of oil casing. When the oil and gas well is drilled, the annulus protection fluid is injected above the casing annulus packer to fill the annulus of the oil casing and isolate the annulus of the oil casing from the production fluid. [0003] Annulus protection fluids are generally water- or oil-based hydrocarbon-based fluids. Its specific function is to provide a stable balance pressure inside and outside the oil and gas well casing, and to...

AI Technical Summary

Problems solved by technology

[0012] 1. When water-based annular protection fluid is used in oil and gas wells, there are the following problems: (1) When the temperature is low in winter, the water-based liquid at the wellhead is easy to freeze and block, and the brittleness of the wellhead steel becomes greater at low temperatures, which may affect the wellhead device. stability

(3) When discharging the annular protection fluid at the wellhead, a specific container and subsequent liquid treatment are required, and there are certain safety and environmental hazards

(4) Water-based protective fluid generally contains dissolved gases such as oxygen and carbon dioxide, which makes it difficult to control the corrosion of carbon steel tubing and casing

[0013] 2. When oil-based annulus protection fluid is used in oil and gas wells, there are the following problems: (1) Packer rubber tubes are prone to aging and damage after soaking in oil base for a long time

The cost is relatively high, and the cost of oil-based protection fluid for a well reaches 300,000 to 500,000 yuan / well

(3) After the annulus fluid is filled, the volume of the annulus protection fluid in the closed annulus will expand and hold pressure, which will cause problems such as the top of the wellhead and the need for regular pressure relief.

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