Device and method for evaluating effect of gradient strengthening cementing fluid in deep water weak cementation stratum

Abstract

The invention discloses a device and method for evaluating the effect of a gradient strengthening cementing fluid in a deep water weak cementation stratum. Thedevicecomprises an air compressor, wherein the air compressor communicates with a pressure regulating pump, and the pressure regulating pumpcommunicates with a grouting cylinder; the grouting cylinder includes a cylinder body, and the cylinder body is provided with a plurality of pressure discharge holesdistributeduniformlyin the cylinder body in the circumferential direction;the cylinder body is internally provided with a rock core,a grouting hole is formed in the center position of the rock core, anda first end cover is arranged at the upper end of the cylinder body; a second end cover is disposed at the lower end of the cylinder body, a threaded hole is formed in the central position of the first end cover, and the threaded hole is internally connected with a grouting pipe in athreaded mode; and one end of the grouting pipe penetrates through the threaded hole and extends to the grouting hole, and the other end of the grouting pipe is connected to the pressure regulating pump. The device and method have the important engineering significance for completely solving the problem of cementing quality in the deep water weak cementation stratum and ensuring long-term safe mining of deep water oil wells.

Description

technical field [0001] The invention relates to the technical field of drilling and cementing of oil and gas wells, in particular to a device and method for evaluating the effect of gradient strengthening cementing fluid in deep-water weakly cemented formations. Background technique [0002] my country's South China Sea oil reserves are about 1.7×10 9 m 3 , the natural gas reserve is about 5.38×10 12 m 3 , most of which are concentrated in deep water areas. With the depletion of onshore oil and gas resources, the South China Sea, known as the "second Persian Gulf", has gradually become one of the main battlefields of my country's oil and gas resource development strategy. At present, the country regards the exploration and development of large offshore oil and gas fields as the top priority of its energy development strategy. [0003] In recent years, with the advancement of offshore drilling and production technology, my country's offshore oil industry has entered the ...

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Problems solved by technology

[0006] However, the implementation of grouting reinforcement technology requires the use of grouting pipes to inject the solidified grout into the formation. If it is applied to the cementing construction of deep-water weakly cemented formations, the injection process of the solidified grout will be difficult to implement, which is mainly reflected in the following three points: ① If grouting is used The grout pipe pumps the solidified grout, and the placement and recovery of the grout pipe is difficult to solve

② If the solidified slurry is used to wash the formation in the annular space by means of pressurized circulation, it is difficult to ensure the contact time between the solidified slurry and the formation, and the good effect of fully solidifying the target layer cannot be achieved

③ If the solidified slurry is added to the cement slurry, due to the difference in properties between the solidified slurry and the cement slurry, the hydration of the cement slurry will be greatly affected, thereby affecting the cementing quality of the weakly cemented formation

However, at this stage, the research on the evaluation methods and evaluation devices for the effect of gradient enhanced cementing fluid on deep-water weakly cemented formations is almost in a blank stage.

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