Inner tube-free drillable-retrievable grading cementing well completion technology

Abstract

The invention relates to an inner tube-free drillable-retrievable grading cementing well completion technology, and the technical scheme thereof comprises the following steps: (1) arranging a conventional cement head internally provided with a rubber plug matched with the drillable-retrievable grading cementing well completion technology on the mouth of the well; (2) increasing hydraulic pressurein a sleeve by a by-pass port below the cement head to a designed value, and performing setting construction by a drillable-retrievable grading cementing well completion tool; (3) boosting pressure until sudden drop of the pressure after setting construction, opening a well completion tool circulating channel, and performing mud circulation; (4) performing cement mud well cementation, replacing rubber plug and implementing closure procedure construction of the drillable-retrievable grading cementing well completion tool circulating channel; (5) waiting on cementing; and (6) spooning the rubber plug and matched accessories thereof by descending a bit hook. The invention has the beneficial effects of strong compatibility with a conventional grading cementing well completion technology, little change of the prior art, low construction risks and low construction cost, and can be applied in oil-water wells in various types in need of grading cementing well cementation and well completion construction.

Description

1. Technical field: [0001] The invention relates to an oil-gas well completion technology in an oil field, in particular to a step-by-step cementing completion technology that can be drilled without an inner tube. 2. Background technology: [0002] The staged cementing process is mainly used for oil-water wells that require segmented cementing. Generally, a staged cementer is used as a circulation tool, and an open hole packer is used as a cement supporting tool to implement cementing and completion of the section above the open hole packer. At present, there are two types of graded cementing processes commonly used: one is the graded cementing process without inner pipe, which needs to use a drill bit for drilling plug construction in the later stage, and the drill bit will cause damage to the casing during construction, especially for fixed cementing. The wells with complex structures such as facing wells and horizontal wells are seriously damaged; the other type is the in...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to aim at the above-mentioned defects existing in the prior art, to provide a stepwise cementing completion process that can be drilled without an inner tube, and to solve the problem of damage to the casing and the cementing of the inner tube during the plugging process of completion without an inner tube. It is easy to cause the problem that the inner pipe is sealed in the downhole

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