Gel water shutoff agent of high-temperature low-permeability storage layer

Abstract

The invention provides a gel water shutoff agent of a high-temperature low-permeability storage layer. The gel water shutoff agent of the high-temperature low-permeability storage layer comprises the following components: 2-20wt% of a host, 0.5-5wt% of a cross-linking agent and the balance of water, wherein the host comprises a host A and a host B; the host A comprises 2-acrylic acid-1,1-dimehtyl ethyl ester, 2,2-bis(3,5-dibromo-4-hydroxyl phenyl) propane, 2, 2', 6, 6'-tetrabromobisphenol A; the host B comprises acrylamide, hydrolytic polyacrylamide or non-hydrolytic polyacrylamide, wherein a mass ratio of the host A to the component B is 1 to (1-2). The gel water shutoff agent provided by the invention is suitable for the high-temperature low-permeability storage layer and low in base fluid viscosity, and is easily injected to the deep part of the low-permeability storage layer, and has good viscosity, high tensile strength, high adhesive power, good high temperature resistance and good thermal stability after being cross-linked.

Description

technical field [0001] The invention relates to a water shutoff agent, in particular to a gel water shutoff agent suitable for high-temperature and low-permeability reservoirs, and belongs to the field of petroleum production engineering. Background technique [0002] In the middle and late stages of oil and gas field development, injection water or side and bottom water often occurs, causing production wells to be flooded or even shut down. Especially in recent years, in the field of oil and gas reservoir exploration and development, with the rapid development and deepening of natural gas development, the problem of water production from gas wells has become increasingly prominent. Compared with oil wells, water outflow from gas wells is more likely to cause low production or shutdown of gas wells. Especially for gas wells with high temperature and low permeability, there are very few related technologies that can be used for reference at home and abroad at present on how t...

AI Technical Summary

Problems solved by technology

Compared with oil wells, water outflow from gas wells is more likely to cause low production or shutdown of gas wells, especially for high-temperature, low-permeability gas wells, how to effectively control water, there are few related technologies that can be used for reference at home and abroad

[0003] Existing chemical water blocking agents generally have disadvantages such as poor temperature resistance, weak gel strength, and short stability period, while silicate water blocking agents are easy to react with calcium and magnesium ions in the reservoir to form precipitates, which cannot be implemented Chemical descaling will cause permanent damage to the formation, thus limiting the use of this type of water blocking agent

At present, there are very few chemical water shutoff agents suitable for high-temperature and low-permeability reservoirs above 120 °C at home and abroad. In the water shutoff operation of horizontal wells in high-temperature gas reservoirs abroad, PAtBA polymer water shutoff has been successfully used. The agent uses the copolymer of acrylamide and tert-butyl acrylate as the main agent. The copolymer and the crosslinking agent are injected into the ground to undergo a crosslinking reaction to form a gel and block the water layer. However, the water blocking agent has some shortcomings: the base liquid High viscosity, not easy to inject into low-permeability reservoirs, and the gel strength is weak, and the adsorption capacity to the matrix is ​​also weak