Experimental Setup and Method for Evaluating Hydrate Formation and Accumulation Behavior in Deepwater Drilling

Abstract

The invention discloses an experimental device and method for evaluating formation and aggregation behaviors of hydrate in deepwater drilling. The experimental method comprises a high-pressure reaction kettle, a high / low-temperature incubator, a gas control system, a return pressure unloading system and a data acquisition system, wherein a middle barrier and a side barrier are arranged in the inner cavity of the high-temperature reaction kettle; a fluid flowing channel is formed in one side of the side barrier; an air inlet and an air outlet are formed in the top of the high-pressure reaction kettle; a lower air inlet is formed in the bottom of the high-pressure reaction kettle; both the upper air inlet and the lower air inlet are connected with the gas control system; the air outlet is connected with the return pressure unloading system. The experimental device aims at drilling fluid systems of natural gas hydrate stratum drilling, frozen earth drilling and ocean drilling, the process that decomposition gases or shallow gases of hydrate in drillings or stratums enter shaft annuluses to form hydrate can be simulated, and furthermore the influence of annulus circulation channels upon formation and aggregation behaviors of the hydrate and the capability of drilling fluid upon the formation and aggregation behaviors of the hydrate can be evaluated and simulated.

Description

technical field [0001] The invention relates to the field of natural gas development, in particular to an experimental device and method for evaluating hydrate formation and accumulation behavior in deepwater drilling. Background technique [0002] Natural gas hydrate is an ice-snow-like crystalline compound with a cage structure composed of water molecules and hydrocarbon gas molecules. It has the characteristics of high energy density, wide distribution, and large reserves. It is a potential new and alternative energy source. , also known as "combustible ice" or "solid gas". The guest molecule of natural gas hydrate is mainly methane, and when the amount of methane in the guest molecule is greater than 99%, the hydrate can be called methane hydrate. [0003] Gas hydrates are widely distributed in the polar permafrost and shallow seabed sediments, and the stored natural gas content far exceeds the known natural gas reserves. However, natural gas hydrates also bring certai...

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Problems solved by technology

[0004] At present, domestic studies have focused on the formation of hydrates during the rising of gas bubbles in a liquid environment, but there is no research on the formation and accumulation of hydrates in the process of gas bubbling and resistance in the process of rising (simulating the invasion of wellbore annulus during conventional deepwater oil and gas drilling). During the drilling and production of natural gas bubbles or hydrates, the rising of gas bubbles entering the wellbore annulus due to the decomposition of cuttings or formation hydrates is hindered)

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