Study On Explosive And Increasing Production Technology Of Open - Pit Test In Low Permeability Gas Reservoir In Sea

N gas field is a typical low porosity and low permeability sandstone gas field of offshore X depression in China. DST Technology is used widely in the exploration wells for this structure. However during DST, poor flow response even no flow response is often observed though it was interpreted as promising zones by logging data. The discrepancy between logging and DST might be the results of poor reservoir properties and formation damage caused by drilling and competition.In order to achieve economic and efficient exploration and development in such offshore gas reservoirs, a systematic study has been done, including literature review, static and dynamic experiments, and simulation. The possible reasons for poor performance during DST and corresponding stimulation solution were also investigated. The conclusions and recommendations of this study can be summarized as follows.Through reviewing field data including core lithology, reservoir properties etc., it is found that N gas field G reservoir is a tight formation with a low pressure coefficient. Via experimental investigation of formation sensitivity in the laboratory, the reservoir demonstrates a weak velocity, salt and alkali sensitivity, as well as a medium-weak water sensitivity, but a medium-strong acid sensitivity.After theoretical and experimental studies on injection induced formation damage, water blocking effects are verified as the major factors leading to the formation damage which further causes formation underperformance during DST.A systematic solution of stimulation based on the self-generating acid system is given in this paper in order to remove the near well damage after a comprehensive consideration of high temperature in formation, well pipe condition, and offshore operation constraints. The achievement includes a self-generating acid system which is optimized by a variety of indoor experiments and a multistage alternating slug injection method whch is designed to prevent the pipe from corrosion. The mixing process was simulated and the process parameters were optimized. This systematic solution has been applied to two wells in this field, and obtained prominent increase regarding well performance.This thesis provides a theoretical base and technical solution for the stimulation of exploration wells for low-permeability G formation in an offshore in gas reservoir N in China.