Research Status and Prospects of Waterless Fracturing Technology in Coal Reservoir
The coalbed methane industry in China has entered a new stage of development.With the continuous innovation of hydraulic fracturing technology,it is also faced with problems such as huge consumption of water resources,serious damage to coal reservoirs,and insufficient fracture expansion.Therefore,it is imperative to find an alternative waterless fracturing technology.Three kinds of waterless fracturing technologies suitable for coal reservoir are summarized(supercritical CO2 fracturing,liquid N2 fracturing,foam fracturing)in this paper,and the mechanism of its action,theoretical innovation and the development status of domestic field application are deeply analyzed.The advantages and disadvantages of each waterless fracturing technology are compared and evaluated.The results show that waterless fracturing technology can effectively reduce the damage of coal reser-voir,avoid clay swelling and water locking effect.At the same time,it can promote the formation of complex fracture network,shorten the gas detection time,and achieve significant increase in production.Waterless fractu-ring technology can be well applied to the reconstruction of coal reservoir secondary fracturing,which has good environmental benefits and technical feasibility.However,it also has problems such as difficulty in carrying proppant and high equipment operation and maintenance cost.Finally,this research put forwards the prospect of the future development of waterless fracturing technology.It is suggested that field pilot tests of waterless fractu-ring technology for coalbed methane blocks should be gradually carried out in the future,and relevant operation parameters should be optimized and determined.Strengthen the research and development of special surface-un-derground process equipment and facilities such as low temperature cooling circulation system.It is suggested to carry out optimization experiments of low density proppant and fracturing fluid thickener.Further find ways to improve the stability of N2/CO2 foam fracturing fluid system under high temperature and pressure environment.
coal reservoirwaterless fracturingcoalbed methanesupercritical CO2 fracturingliquid N2 fractu-ringfoam fracturing
NETL
NSTL
万方数据
维普
