Strong-thixotropy expansion-type high strength chemical blocking agent for blocking water in horizontal well

Abstract

The present invention relates to a strong-thixotropy expansion-type high strength chemical blocking agent for blocking water in horizontal wells, including the following components by weight: 54-63 parts of superfine cement; 2-5.3 parts of calcium carbonate powder; 0.1-0.3 parts of cellulose; 1.4-1.9 parts of a regulator; and 33-39 parts of water. The production steps include: sequentially adding the cellulose, the regulator, the calcium carbonate powder and the superfine cement to water and stirring to uniform, thus the mixture of the blocking agent is prepared. The blocking agent has a strong thixotropic property, can quickly form a network structure when the pump injection is stopped and lose mobility, and can effectively remain in a horizontal well hole and annulus. The volume produces expansion after solidification, the strength is high and the blocking effect is permanent. The annulus gap between a horizontal effluent section or a screen pipe and a ground layer can be completely blocked, and the purpose of reduction of water content in horizontal wells is achieved.

Description

technical field [0001] The invention relates to a chemical plugging agent for water plugging of horizontal wells in oil fields. The plugging agent is mainly used for water plugging of horizontal wells in oilfield casing completion and chemical separation and water plugging of the outer annular space of horizontal well pipes in screen completions. Background technique [0002] In recent years, the number of horizontal wells in my country's oilfields has increased sharply, and it has become an important technical means to speed up production capacity construction, improve oil recovery efficiency, and increase recoverable reserves in the development process of the petroleum industry. one of the factors. For example, the comprehensive water cut of horizontal wells in Dagang Oilfield has reached over 70%, and other oilfields such as Jidong also have this problem to varying degrees. However, due to the special well structure and completion method of horizontal wells, the water plu...

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Problems solved by technology

Due to the particularity of the well type and completion method, the plugging agents and techniques commonly used in vertical wells cannot meet the needs of water plugging in horizontal wells

Especially in the screen completion mode where there is no open hole packer outside the pipe to divide the interval, because the inside and outside of the slotted pipe and the formation are connected with each other, the plugging agent cannot be injected into the water outlet layer to achieve the purpose of water blocking, and can only be used through the isolation screen The water outlet section is blocked by means of annulus between the wall and the rock wall

[0004] At present, the plugging agent used for horizontal well water plugging in China is mainly polymer gel, and the plugging agent strength is less than 1MPa. Whether it is plugging the water-producing layer or the outer annular space of the pipe, it cannot fully meet the production pressure difference requirements of horizontal wells, and The temperature resistance is poor, and the overall water blocking effect is poor

In addition, although cement plugging agents commonly used in oilfields have high strength and long validity period, they have poor injectability and shrink in volume after solidification, so they cannot completely plug the horizontal annulus and cannot be used in water plugging in horizontal wells.

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