Study On The Seepage Law Of Ultra-Deep Natural Gas Reservoirs And Single Well Productivity Evaluation

With the development of mining technology,the key areas of exploration and development have developed from medium-shallow gas reservoirs to deep-super deep gas reservoirs.During the development of gas reservoirs,a series of changes will occur:changes in pores,changes in physical properties,changes in seepage capacity,and complication of gas-water relations.Effective use of low-permeability reserves,maintaining stable production of gas reservoirs,and increasing recovery rates are facing challenges.The special geological characteristics of ultra-deep oil and gas reservoirs make exploration and development more difficult,and it is urgent to expand and improve new theory of oil and gas reservoir engineering to adapt to the new field of ultra-deep layers.The northwestern Sichuan area is an important gas-producing area in the Sichuan Basin.The Qixia Formation gas reservoir in the Shuangyushi block has shown good prospects for natural gas exploration and has become a hot spot for exploration by CNPC Southwest Oil and Gas Field Company.In this paper,the gas reservoir is taken as the object,using relevant geological data,comprehensive application of gas reservoir engineering,reservoir physics,seepage mechanics and other subject knowledge,through physical simulation experiments and related mathematical software calculations to study the Qixia Formation gas reservoir in Shuangyushi block Spatial characteristics,reservoir physical characteristics,and storage type division according to core porosity and permeability test results;laboratory high-temperature and high-pressure instruments and devices are used to study the permeability stress sensitivity characteristics,seepage capability characteristics,and gas-water phase permeability characteristics of different core types;Through the combination of seepage capacity experiment and mathematical software,the lower limit of physical properties of different types of reservoirs under extreme economic production is predicted;the core productivity is simulated by the low pressure drop method,and the gas production characteristics of different physical properties and different core types in series combination are obtained And forecast the recovery factor.The research methods and research results of this paper will provide theoretical support for the subsequent efficient development of ultra-deep gas reservoirs.