Leaking stoppage cement slurry for well cementation and preparation method thereof

Abstract

The invention relates to leaking stoppage cement slurry for well cementation and a preparation method thereof. The leaking stoppage cement slurry consists of the following components in parts by weight: 100 parts of oil-well cement, 50-150 parts of water, 0.01-8 parts of fibrilia, 1-20 parts of dispersing agent, 1-20 parts of filtrate reducer, 5-50 parts of alkali regulator, 1-10 parts of retarder and 0-1 part of defoaming agent, wherein the dispersing agent is lauryl sodium sulfate or sodium hexametaphosphate; the filtrate reducer is 2-acrylamide-2-methylpropanesulfonic acid or hydroxyethylcellulose; the alkali regulator is silicon powder; the retarder is sodium lignin sulfonate or citric acid; the defoaming agent is dimethyl silicon oil or tributyl phosphate; and the fibrilia is one or the mixture of two or more of jute, flax, hemp, ramie and sisal. The invention effectively solves the problem of leakage loss of cement slurry and inherent brittleness of set cement in the well cementation process on the premise of meeting various engineering performances required by the well cementation and provides the guarantee for subsequent operation of oil well gas.

Description

technical field [0001] The invention relates to a plugging cement slurry used in oil and gas field drilling and cementing and a preparation method thereof. Background technique [0002] Lost circulation is a complex downhole situation that flows into the formation under the pressure difference of various working fluids during various downhole operations such as drilling, cementing, well completion, testing or workover. For cementing engineering, lost circulation refers to the phenomenon that drilling fluid, cement slurry or other working fluids leak into the formation during cementing. According to statistics, the incidence of lost circulation in the world accounts for about 20%-25% of the total number of wells, and the cost of lost circulation in the global oil industry is as high as hundreds of millions of dollars every year. In recent years, the number of lost wells drilled in domestic oil and gas fields has been increasing. In 1990, there were 853 major lost circulatio...

AI Technical Summary

Problems solved by technology

[0004] At the same time, cement stone is a porous and brittle material, which has many inherent defects: low tensile strength, poor fracture resistance, and low impact strength

The destruction of cement will inevitably weaken or lose the sealing effect on underground oil, gas, and water layers, causing interlayer channeling and corroding the casing, and in severe cases, the oil and gas well will be scrapped

[0005] At present, polymer fiber, ceramic fiber, asbestos fiber, carbon fiber, glass fiber, etc. are often used in plugging cement slurry, but these fibers have the following problems: ceramic fiber, asbestos fiber, carbon fiber, glass fiber are not uniformly dispersed in the cement slurry; The temperature resistance of the material fiber is poor; the plugging effect is not ideal

Therefore, in production practice, these fiber cement slurries are difficult to meet the plugging and toughening requirements of the sealing section of oil and gas wells, and ultimately affect the cementing quality of oil and gas wells

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