Micro-tube yield increase device and method for marine shallow natural gas hydrates

Abstract

The invention discloses a micro-tube yield increase device and method for marine shallow natural gas hydrates. The device comprises a guide device, a wellhead device, a center tube column, a cable, a thick-wall conduit, micro-tubes and a guide bit. A certain number of micro-tubes are arranged in an underground surrounding hydrate reservoir of the marine shallow natural gas hydrates; the micro-tubes are high-pressure-resistant steel tubes which are provided with holes and have certain flexibility; and micro-tube networks which are uniform, are fixed in interval and are in space distribution are formed on a well segment of the whole hydrate reservoir, thereby forming a non-clogging fixed output channel. The micro-tube yield increase device and method are suitable for multiple marine gas hydrate mining methods such as a pressure-reducing method, a thermal stimulation method and a chemical reagent injection method; and the contact area of the output channel and the hydrate reservoir can be effectively expanded, so that the reservoir permeability is improved, the reservoir heat and mass transfer efficiency and the flow conductivity are improved, and the targets of improving the mining efficiency and achieving economical and efficient mining of the marine shallow natural gas hydrates are achieved.

Description

technical field [0001] The invention relates to the field of commercial exploitation of marine hydrates, in particular to a micro-pipe stimulation device and method for marine shallow natural gas hydrates. Background technique [0002] Natural gas hydrate refers to a cage-shaped crystal substance formed by natural gas and water at a specific temperature and pressure (low temperature and high pressure). It looks like ice and snow. Because it can be ignited, it is commonly called "combustible ice". Natural Gas Hydrate is a clean and efficient emerging energy with huge reserves. The reserves of total organic carbon in gas hydrates on the earth are about twice the sum of oil, natural gas and coal, and the resources of gas hydrates in marine areas account for 99% of the total resources. With the gradual and in-depth research on the exploitation of marine gas hydrates, commercial exploitation is getting closer and closer to the possibility. [0003] At present, the theoretical m...

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Problems solved by technology

On the other hand, the shallow gas hydrate layer on the seabed has experienced less structural movement, low density, and fast deposition rate, and most of them are in the saturated or semi-saturated non-diagenetic stage. The reservoir cementation degree is weak, the sediment particles are loosely arranged, and the strength is low. , clay, silt, and sand-mud mixed layers, mainly cohesive soil and sandy soil; this will cause problems such as easy closure of hydraulic fracturing stimulation cracks and difficult construction of horizontal wells, resulting in the hydration of shallow seabed It is not easy to expand the contact area between production channels and hydrate reservoirs by hydraulic fracturing and building horizontal wells; therefore, there is an urgent need for a method to expand the production channels and hydrate reservoirs in shallow oceans. Stimulation device and method of contact area

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