Study On Water Production Mechanism And Development Measures Of Liuyangpu Gas Reservoir

Liuyangpu gas reservoir is located in the Midwest of Ordos Basin,across Etuokeqian banner of Inner Mongolia Autonomous Region,Yanchi County of Ningxia Hui Autonomous Region and Dingbian County of Shaanxi Province.It is one of the important oil and gas exploration blocks of Sinopec and has broad development prospects.However,in the process of gas testing and production,there are some problems in Liuyangpu gas reservoir,which affect the development effect and process.In order to recognize the water production mechanism of the reservoir,determine the water production source of the gas well,and seek effective development countermeasures,this paper studies the existing problems of Liuyangpu gas reservoir at the present stage.(1)In view of the study block,62 typical cores are selected,and the porosity and permeability experiments,permeability NMR experiments,centrifugal NMR experiments and displacement experiments are carried out.The occurrence of water in reservoir pores is clarified,the characteristics of gas water relative permeability curve are pointed out,and the influence of displacement pressure difference on reservoir water saturation is revealed.(2)Based on the analysis of formation water properties of 35 gas testing wells,it is found that the formation water in the block is mainly calcium chloride type water with good hydrogeological conditions;According to the daily liquid production,it is found that there are differences in horizons and orientations of water producing wells;The liquid production sources of gas wells are divided into three categories: backflow fluid,external interlayer water and primary formation water.(3)According to the characteristics of tight sandstone reservoir in Liuyangpu gas reservoir,the productivity equation considering gas-water two-phase,water lock start-up pressure gradient and stress sensitivity is established,and the influence of each factor on gas well productivity is analyzed.Compared with the original Forchheimer formula,the open flow rate calculated by the productivity equation considering multiple factors is more consistent with the actual situation.(4)Aiming at he1 and tai2 gas reservoirs,two sets of numerical simulation schemes for lithologic gas reservoir development and structural gas reservoir development are established respectively.For lithologic gas reservoir,the factors such as well pattern,gas production speed and reasonable production allocation are analyzed.For structural gas reservoir,the perforation thickness is also analyzed.Finally,according to the comparison of economic effect,the development measures numerical simulation scheme suitable for Liuyangpu gas reservoir is obtained.