苏里格气田致密储集层定量描述技术

Application of Quantitative Characterization Technology for Tight Reservoirs in Sulige Gas Field

鄂尔多斯盆地苏里格气田单砂体薄且有效储集层与围岩阻抗差异小,因而常规反演难以精细描述储集层。为了提高致密砂岩气藏储集层"甜点"钻遇成功率,有效指导水平井设计,以苏里格气田某区块为研究区,将地质统计反演与泊松比反演有机结合,对储集层进行定量描述。首先以Xu White(徐怀特)模型为指导进行岩石物理建模及横波曲线拟合;然后在利用地震属性分析、谱分解定性预测厚砂带展布的基础上,通过Monto Carlo算法进行地质统计反演,精细刻画了二叠系石盒子组盒8段4套小砂层;运用叠前弹性参数反演,基于多点地质统计学的地质建模等技术,定量描述了有效储集层厚度、物性及空间展布。在实际应用中取得良好效果,为苏里格气田致密砂岩气藏水平井的上钻提供了技术支持。

Sulige gas field in Ordos basin is characterized by the thin sand body and the little difference of wave impedance between effective reservoir and surrounding rock, which lead to difficult fine description of the reservoirs by conventional inversion approach. In order to improve the successful prediction rate of tight sand gas reservoir ＂dessert＂ for guiding the horizontal well designing, this paper takes a block in Sulige gas field as the target, combines geologic statistical inversion with Poisson＇ s ratio inversion and makes quantitative description of the reservoir. Firstly, conduct petrophysical modeling and S-wave curve match using Xu White model; based on the seismic attribute analysis and spectral decomposition prediction of the thick sand distribution, by means of Monte Carlo statistical inversion, well describe four sets of thin sand layers of He-8 member of Shihezi formation of Permian in this gas field, and quantitatively describe the effective reservoir thickness, physical properties and spacial distribution by using elastic parameters prestack inversion and geo-modeling technologies. The case study shows that this quantitative characterization technology is effective with good effectiveness, providing technical support for its efficient development by horizontal well process.