Low-permeability reservoir natural gas hydrate exploitation fracturing and sand prevention combined process method

Abstract

The invention relates to a low-permeability reservoir natural gas hydrate exploitation fracturing and sand prevention combined operation process method. The process method comprises the steps of hydraulic sand blasting perforation and fracturing string tripping-in, forward washing, lower-layer hydraulic sand blasting perforation primary fracturing, lower-layer sand prevention medium main fracturing, sand prevention medium filling operation, upper-layer hydraulic sand blasting perforation, fracturing, sand washing operation and the like. According to the process method, a hydraulic jetting toolis used, one or more jetting hole channels are formed in a reservoir through the water hammer effect, micro-cracks are generated in a near-wellbore zone, then the micro-cracks are pressed open and extend through the end sand removal fracturing technology, meanwhile, a sand prevention medium is used for filling the micro-cracks, end sand removal is achieved, and a plurality of short and wide high-flow-conductivity fracture zones are formed in a low-permeability reservoir; and effective transformation yield increase and sand prevention of the lower layer are guaranteed, multi-section dragging fracturing of a horizontal well of the argillaceous low-permeability reservoir can be implemented, reservoir transformation with high heterogeneity and large physical property difference is achieved, seepage conditions are improved, and the purpose of combining yield increase and sand control is achieved.

Description

technical field [0001] The invention relates to a combination process method of hydraulic sandblasting, perforation, fracturing and sand control for natural gas hydrate exploitation of low-permeability reservoirs, and belongs to the technical field of natural gas hydrate exploitation stimulation-sand control. Background technique [0002] Natural gas hydrate, an ice-like solid formed by methane and other gases and water molecules under high pressure and low temperature conditions, is increasingly attracting great attention from all countries in the world as the most ideal potential alternative energy in the new century. Gas hydrates occur in polar permafrost and in sediments hundreds of meters below the seabed at depths of 500 meters or more, and are stable in low temperature and high pressure environments. At present, many researches have been carried out on the synthesis, decomposition and exploitation of natural gas hydrates at home and abroad. Most of the experimental re...

AI Technical Summary

Problems solved by technology

However, each sand control method or stimulation technology has its own characteristics and adaptability. For natural gas hydrate exploitation reservoirs, the lithology is muddy silt fine sand formation with poor cementation strength and the reservoir is heterogeneous and ultra-low permeability. Characteristics, conventional hydraulic fracturing and sand control technology applied to hydrate reservoir stimulation and sand control effects are not ideal, there is no effective process method suitable for gas hydrate reservoir geology, fluid characteristics production stimulation and sand control

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