苏里格致密砂岩气藏废弃地层压力研究

Study on abandonment formation pressure of Sulige tight sandstone gas reservoirs

针对现有废弃地层压力计算方法在确定气井废弃地层压力时,未考虑应力敏感而造成计算结果存在一定误差的问题,基于气井的稳定产能方程,建立了考虑储层应力敏感的致密砂岩储层气井废弃地层压力计算方法,分析了废弃产量、废弃井口压力、压敏系数等因素对气井废弃地层压力的影响。研究表明:地层系数及压敏系数对气井废弃地层压力较为敏感;考虑应力敏感时计算的废弃地层压力与实际废弃地层压力更为接近,误差仅为3.3%。

For the problem that errors often occur on the final result because of neglecting the influence of stress sensitivity by using the existing methods to calculate abandonment formation pressure.A new method to calculate abandonment formation pressure was established in this paper through a steady deliverability equation considering stress sensitivity and practical conditions based on gas reservoir theory.And the new method had further evaluated the effect of abandonment rate,abandonment wellhead pressure,and stress sensitivity of abandonment formation pressure.The results show that formation factor and pressure sensitivity coefficient is more sensitive to abandonment formation pressure;the calculated abandonment formation pressure considering stress sensitivity is closer to the actual value,and the error is only 3.3%.