Process method for solving casing deformation of gypsum-salt layer segment

Abstract

The invention relates to a process method for solving casing deformation of a gypsum-salt layer segment. The process method comprises the following steps of expanding a gypsum-salt layer and the wellbore diameters of well sections at certain distances up and down by means of an underreamer after finishing drilling of this open time; separately obtaining annular volumes formed by the well section below the gypsum-salt layer and the well section above the gypsum-salt layer and a this open time casing; tripping a pipe string of the casing in a shaft bottom, wherein a classifying hoop and an expansion packer on the pipe string are located 20 m above the gypsum-salt layer; carrying out primary well cementation; injecting cement slurry of corresponding annular volume into a space between the well section below the gypsum-salt layer and the this open time casing; carrying out secondary well cementation; injecting cement slurry of corresponding annular volume into a space between the well section above the gypsum-salt layer and the this open time casing; and freezing the cement slurry, wherein the gypsum-salt layer segment is in a non-sealed state, so that inhomogeneous stress of a stratumis released.

Description

Technical field [0001] The invention belongs to the technical field of petroleum and natural gas drilling, and particularly relates to a process method for solving casing deformation in a gypsum-salt interval. Background technique [0002] At present, many oil fields in China have discovered rich oil and gas reservoirs buried under thick gypsum-salt layers, and have conducted exploration and development. With the passage of time, many old well sealing gypsum-salt casing casings have undergone different degrees of collapse and casing change, which has caused major losses to the oil field and severely restricted the exploration and development process of the oil field. [0003] Reasons for casing collapse deformation (referred to as casing deformation): (1) The gypsum-salt rock will produce plastic flow under the pressure of the overlying strata. If the formation around the well is unevenly stressed, it will be added after cementing. The non-uniform creep stress around the casing wi...

AI Technical Summary

Problems solved by technology

With the passage of time, many old wells have experienced different degrees of collapse and casing change in sealing gypsum-salt layers, which has brought heavy losses to the oilfield and seriously restricted the exploration and development process of the oilfield.

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