Weakly cemented hydrate reservoir simulation wellbore construction device and method

Abstract

The invention discloses a weakly cemented hydrate reservoir simulation wellbore construction device and method.The device comprises a cavity and an embedded pipe assembly, the cavity is provided with a fluid connector, and the cavity is provided with a measuring point; the embedded pipe assembly comprises an embedded pipe, a simulation sleeve and a central oil pipe from outside to inside, and the embedded pipe assembly extends into the cavity; the simulation sleeve is arranged in the embedded pipe, a lifting channel is formed in the pipe wall of the simulation sleeve, and the lifting channel penetrates out of the pipe wall of the simulation sleeve and forms a lifting liquid space with the top of the embedded pipe; the center oil pipe is arranged in the simulation sleeve, a consolidation channel is arranged in the center oil pipe, a fracturing channel is formed between the center oil pipe and the simulation sleeve, one end of the fracturing channel is arranged in the cavity and connected with a sealing piece, and a plurality of perforations are formed in the end, close to the sealing piece, of the simulation sleeve. The hydrate generation and decomposition process is tested through a laboratory condition simulation method, so that the necessary conditions of hydrate generation and decomposition are tested, and the well cementation quality problem of the deepwater weakly cemented stratum is fundamentally solved.

Description

technical field [0001] The invention relates to the technical field of petroleum drilling, in particular to a device and method for constructing a simulated wellbore of a weakly cemented hydrate reservoir. Background technique [0002] The distribution area of ​​natural gas hydrate is mostly in the seabed sediments with soft cementation and loose structure, such as continental slopes, ocean troughs, and trenches in the northern hemisphere, and land permafrost. The low temperature of weakly cemented formations in deep water satisfies one of the conditions for the stable existence of hydrates. Natural gas hydrate layers are widely distributed in the South my country Sea. [0003] During the surface cementing process in offshore deep water, the heat generated by cement hydration causes the temperature near the wellbore to rise rapidly, which easily leads to the decomposition of hydrate. Therefore, how to avoid the reduction of cementing quality caused by hydrate decomposition ...

AI Technical Summary

Problems solved by technology

However, due to the strength difference between the weakly cemented formation and the cement sheath and the stress fluctuation caused by the disturbance of the shallow seabed flow, the cement sheath is brittlely damaged. Therefore, the cement slurry system cannot fundamentally solve the problem of cementing quality in the weakly cemented formation.

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