苏里格气田苏X区块剩余气分布及井网加密方案研究

Study on remaining gas distribution and well pattern thickening program in Su X block of Sulige Gas Field

苏里格气田苏X区块已开发富集区内井网逐渐完善,由于外围区域地质条件差,为了保持区块稳产,需要进行富集区剩余气分布及井网加密方案研究。基于致密气藏低渗透、压裂生产的特点,对常规数值模拟方法进行优化,采用毛管力标定平衡初始化、储层分类相渗控制、局部调整渗透率和传导率的方法模拟压裂生产,精细拟合气井产量和井底流压,旨在通过模拟地层压力和储量丰度的变化,定量表征剩余气分布,优选剩余富集区。在从地质和开发两方面分析剩余气分布影响因素的基础上,综合现有井网、有效储层和剩余储量的分布特征,将剩余储量类型定性划分为4种(井网未控制型、复合砂体内阻流带型、水平井漏失型、射孔不完善型),进而针对不同类型剩余储量分别进行加密方式论证和加密井位优选,制定加密方案,预测开发指标。在SX-11-11S试验井区实施了8口加密井,综合评价Ⅰ类井占比为87.5%,预测采收率提高8.2%,效果良好。

The well pattern in the developed enrichment areas of Su X block of Sulige Gas Field is gradually improving.Due to the poor geologic conditions in the peripheral areas,it is necessary to study the distribution of remaining gas in the enrichment areas and well pattern thickening programs in order to keep stable production in the block.Based on the characteristics of tight gas reservoir with low permeability and fracturing production,the conventional numerical simulation method is optimized.The method of capillary pressure scaling and balance initialization,reservoir classification and phase-permeability control,local adjustment of permeability and conductivity to simulate fracturing production and fine fit gas well production and flowing bottom hole pressure,is designed to quantitatively characterize the distribution of remaining gas and optimize the remaining enrichment areas by simulating the changes of formation pressure and reserve abundance.Based on analyzing the factors affecting the remaining gas distribution from the aspects of geology and development,and integrating the distribution characteristics of the existing well patterns,effective reservoirs and remaining reserves,the remaining reserves are qualitatively divided into four types:well pattern uncontrollable,blocking zone in composite sandbodies,loss circulation in horizontal wells and imperfect perforation.Then,for different types of remaining reserves,the infill modes are demonstrated and the infill wellsites are optimized,the infill programs are established,and the development indices are predicted.Eight infill wells were implemented in SX-11-11S test well area,the comprehensive evaluation showed that classⅠwells accounted for 87.5%,and the predicted recovery factor increased by 8.2%,with good results.