Reservoir stimulation technologies for the ultra high temperature heterogeneous carbonate gas reservoir in Yangshuiwu buried hill

The carbonate reservoir of Yangshuiwu buried hill is characterized by ultra high temperature (170-200 ℃), high pressure and strong heterogeneity. Three sets of layered reservoir sections are vertically developed. And in recent years, the reservoir stimulation effect has not been satisfactory. The research results show that the main factors controlling the reservoir stimulation effect in this area are as follows. First, the engineering design of reservoir stimulation is not suitable for the geological characteristics of strong heterogeneity. Second, the perforation thickness is excessive, leading to short propagation length of single-layer stimulated fracture. Third, existing fluid system and its configuration are not applicable to the formation of long fractures. Fourth, casing fracturing mode often brings damage to casing and annulus cement sheath, and consequently results in potential risks, such as casing damage and sustained casing pressure. To deal with these problems, a series of special matching technologies were developed by conducting technological research and field practice. First, decrease reservoir stimulation thickness, improve fracturing stimulation intensity and increase lateral stimulation area. Second, optimize the configuration of fracturing fluid, and improve fracture network support strength. Third, optimize construction technology and innovate in the fracture conductivity maintenance technology. Fourth, optimize string technology and reduce risk accidents. These technologies have been applied in two wells in Yangshui buried hill, and good results have been achieved, which provide technical reference for high temperature deep carbonate reservoir reconstruction