Technical Research Of Gas Testing And Welltest Method In Yaoyingtai Volcanic Gas Reservoir

Yaoyingtai block volcanic gas reservoir located in Changling fault depression of southern Songliao basin has some characteristics such as large permeability difference and severe heterogeneity. The gas reservoir mainly distribute in 3 539-3 810 m so formation has features of high temperature and pressure, 21% CO2, dense lithology, low permeability, and high corrosion. Sodium formate completion fluid was optimized to avoid the solid precipitate invasion and second pollution to formation, which were produced by the combination of killing fluid and acid gas contained in formation fluid. By optimizing TCP perforation parameters and software, we could check intensity of TCP+DST combination testing string, reasonable flow/shut in time and frequency, testing pressure and testing method. Accordingly, comprehensive and accurate formation parameter data were acquired, thereby ensuring structure safety of testing string under high temperature and high pressure. The ground testing process control technic of high temperature and high pressure well including the method of twostep throttle, first insulation and reasonable glycol plugging inhibitor and gas hydrate prevention and treatment technology were used to realize classification throttle and continuous discharge jet test. Productivity equation to reflect the formation energy was obtained by optimizing well testing method of modified isochronal method and working system. Using electronic doff hanging device can leave testing instrument at any designed depth of wellbore and solve the problem of erosion emerged with steel wire staying in wellbore for too long time and steel wire seizing because of glial adsorption. Combined with recognition of the gas reservoir geology, different seepage models were selected to deal with the testing data to gain real physical parameters, thereby having better guidance for the early development deployment of yaoyingtai gas reservoir.