碳酸盐岩裂缝性油藏建储气库气井产能评价

利用华北油田碳酸盐岩潜山油藏改建地下储气库，具有构造较为完整、圈闭规模大以及裂缝系统渗流条件较好的优势，对保障京、津、冀等地区安全平稳供气，具有非常重要的意义。虽然前期针对华北油田某裂缝性碳酸盐岩块状底水油藏改建地下储气库的可行性开展了相关的研究工作，但都是基于油井采油指数类比气井采气指数方法进行评价的，存在一定的局限性和偏差。为此，以可压缩气体地层稳定渗流理论为基础，根据潜山储层裂缝系统的地质特点，引入了气体半球渗流和等效气井打开半径的概念，最终推导出了碳酸盐岩裂缝性油藏建库气井稳定渗流产能方程。通过对华北油田某潜山油藏的实例计算表明：由于该油藏裂缝系统物性条件很好，无论气库运行在高压还是低压条件，稳定渗流计算得到的地层产气能力都很高，可以认为地层气体基本为无限供流条件。

The evaluation method of a gas well productivity for a underground gas storage on a fractured carbonate oil reservoir

The underground gas storage (UGS) rebuilt on the carbonate rock and buried hill oil reservoir at the Huabei (North China) Oilfield has some advantages such as complete structure, large trap scale and favorable percolation condition in the fractured system. This UGS is significant for supplying gas steadily and safely for Beijing, Tianjin and Hebei Province. Although previous studies were conducted on the feasibility of rebuilding a UGS on a fractured carbonate oil reservoir at the Huabei Oilfield, the evaluation had some limitations and deviations by the analogy based method of the oil productivity index between an oil well and a gas well. On the basis of formation steady percolation theory of compressible gas, and according to the geological features of the fractured system of buried hill reservoirs, this paper introduced the concept of gas hemispherical percolation and equivalent gas well discovery radius, and finally derived the equation of gas well steady percolation production capacity for building a UGS on the fractured carbonate rock reservoir. By means of the calculations on a real example at a buried hill reservoir in the Huabei Oilfield, it demonstrated that the fractured oil reservoir has favorable petrophysical property and the production capacity of formation gas is very high no matter the gas storage runs under high pressure or low pressure, and the formation is thought to have basic infinite gas flow condition.