Variable diameter centralizer activated by chemical signal and method of use thereof

Abstract

The invention discloses a chemical signal-activated variable-diameter centralizer and a using method thereof, which belong to the field of oil and gas well engineering. The steel belt buckle of the variable-diameter centralizer is fixed to the central position of the centralizing bar of the single-arch elastic centralizer by welding, and the steel belt is located at the middle position of the steel belt buckle; the chemical signal activation lock is fixed on the head of the steel belt by screws; The structure of the chemical signal activation lock consists of a cylinder body, a cylinder body cover, a rotating plate, a pull rod, a pull block, a spring, a baffle, an anti-friction ring, a filter paper, a screw, a rotating shaft and a washer; After the position, change the PH of the drilling fluid by adding sodium hydroxide into the drilling fluid, the aluminum hydroxide solid in the chemical signal activation lock is dissolved, the two compressed springs are released, the baffle plate goes up, the rotary plate rotates, and the pull rod pulls out the pull block , the steel belt is released, and the centralizing strip is in the state of springing; thereby ensuring the centering of the casing; shortening the casing running time; finally improving the cementing quality and prolonging the service life of the oil and gas well.

Description

technical field [0001] The invention belongs to the field of oil and gas well engineering, and in particular relates to a variable-diameter centralizer activated by a chemical signal and a use method thereof. Background technique [0002] Casing centering is an important prerequisite to ensure cementing quality. Poor casing centering can easily cause problems such as eccentric flow of cement in the annular space, retention of drilling fluid, replacement of grooves, and partial loss of cement sheath after solidification, resulting in failure to seal between layers; At the same time, poor casing centering will also make it difficult to fully utilize the performance of cementing technology and material technology, and cannot guarantee the quality of cementing. Various experimental data and field practice show that when the casing centering degree is greater than 67%, the cement slurry displacement efficiency can be guaranteed by adjusting the rheological properties of drilling ...

AI Technical Summary

Problems solved by technology

The most effective way to improve the centering degree is to use centralizers. At present, rigid centralizers and elastic centralizers are mostly used. However, the outer diameter of rigid centralizers is very small, so they cannot be used in irregular well sections, pot belly well sections, and candied haws well sections. Play a centralizing role, and the centralizing strip with large deformation in the elastic centralizer is likely to increase the frictional resistance of the casing running into the well

Therefore, there is an urgent need for a variable-diameter centralizer, which binds the centralizing strip before entering the well, and solves the problem of large frictional resistance when the casing is run into the well

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