基于三维模型的低渗透非均质储层单砂体全缝长压裂改造与剩余油挖潜

Revelation on remaining oil and full length hydraulic simulation of single sand bodies based on 3D models in low permeability heterogeneous reservoirs

考虑到对陆相非均质储层压裂缝扩展规律及储层改造程度认识不足,首先通过测井曲线对鄂尔多斯盆地王窑区块目标层段进行单砂体细分,采用常规测井、特殊测井与沉积微相特征结合开展油藏三维物性与岩石力学场建模,其次进行随井间储层和应力场变化的全缝长压裂数值模拟,最后通过裂缝的展布情况与油田动态数据结合,对非均质储层动用程度进行分析。研究认为三角洲前缘多期河道侧向叠置砂体储层单砂体在垂向差异大,侧向变化快,因此须突破传统的压裂数值模拟方法,基于实际三维模型的单砂体全缝长压裂模拟更为合适。所提方法在鄂尔多斯盆地实施后增产效果明显,实施井次成功率高达90%以上,平均日增油2 t以上,说明该方法可应用于低渗非均质储层开发中后期的剩余油挖潜。

Crack propagation laws in continental heterogeneity reservoir and the actual development of reservoir reconstruction processes are poorly understood. In this study w,e divided single sand body in a target zone in the Wangyao zone of Ordos Ba-sin by using logging curves. Combining conventional logging and special logging, as well as sedimentary microfacies modeling of reservoir, we built a three-dimensional model of rock mechanics. Then, we carried outfull-length fracturing simulations of interwell reservoir and varying stress field. Through the distribution of cracks and the field performance data, we analyzed the producing degree in heterogeneous reservoirs. Our results indicate that significant variations of single sand body in tight sand-stone reservoirs are present, therefore, fracturing simulations of single sand body based on real data of 3D models are needed. Through applications in Ordos Basin in recent years, increased production rate is obvious, and over 90% success rate is reported among the implemented wells, with an average of more than 2 t/d production increase. The successful application suggests that the method is suitable for improving the residual oil potential in the mid-late development of low permeability heterogeneity reservoir.