The role of surface and subsurface integration in the development of a high-pressure and low-production gas field

摘要

Against a background of gradual changes in the global energy consumption structure, clean natural gas still plays an indispensable role in satisfying energy needs. Xushen gas field in Songliao Basin has held the balance in gas-producing areas in China since its exploitation in 2004, especially by "using a gas to supply oil output'' strategy in Daqing oilfield. However, the difficulties and beneficial results of development in the field are challenged by the very cold climate, poor reservoir property and high amounts of CO2 in natural gas. An investigation of the heat-tracing measures for preventing the formation of natural gas hydrates and selection of stainless steel pipes and a high-pressure equipment to restrain CO2 corrosion in Xushen gas field operation was carried out recently. In this paper, the hydraulic and thermal characteristics of gas gathering pipelines is studied, including a discussion on the effect of high pressure and low production on the formation of natural gas hydrates during transportation and the determination of technical limits for inhibiting the formation of hydrates under different conditions. Subsequently, the gas production process, including purification and defoaming parameters in a high-pressure and low-production field, is optimized. The results indicate that the surface engineering construction would take up more than 30 % of the total investment in gas field development, especially in high-pressure and low-production areas, and that it would be necessary to design a simplified production process for multi-well gathering and single-well rotation. Meanwhile, the role of surface and subsurface integration would be better played by improving the key production units such as wellbore throttling, gathering pipe heat tracing, corrosion inhibitor injection and gas purification disposal. This study will contribute to obtaining the maximum benefits in green gas field development.