轮古西地区奥陶系鹰山组储层地质特征及综合预测

The Geologic Characteristics and Synthetic Reservoir Prediction of Ordovician Yingshan Formation in the West Lungu area

轮古西地区奥陶系鹰山组储层为典型碳酸盐岩潜山储集层,储集空间以洞穴、孔洞和裂缝为主,具横向变化大、非均质性强、埋藏深、成藏条件复杂等特点,仅靠单一储层预测技术很难有效预测其平面展布特征,因此,需从多个角度利用多种技术方法相互印证来综合预测储层。本文在储层区域地质背景研究基础上,应用古地貌分析技术、相干体技术和分频技术,研究确定了区内岩溶区带、断裂及整个储层空间分布规律和展布特征。研究表明,区内岩溶区带自东向西依次为岩溶高地、岩溶陡坡和岩溶缓坡。岩溶高地区内岩溶发育,断裂较发育,储层连续性较好,呈枝状,局部区域内储层连续性较差,呈点状;岩溶陡坡内储层发育情况受古地貌和深断裂双重控制;岩溶缓坡区内储层发育很差。

Reservoirs of Ordovician Yingshan Formation in the Lungu area are a typical carbonate reservoir of buried hill, whose reservoir spaces include mainly cavern, solution porosity and fractures. In view of the characteristics of carbonate reservoirs in the study area such as great lateral variation, strong heterogeneity, deeply burial and complex hydrocarbon pooling conditions, any one single method is difficult to predict the spatial distribution of these reservoirs. Thus, it is necessary to utilize several methods to mutual confirm and synthetically predict the reservoir characteristics. Based on the reservoirs＇ geological setting, several methods such as paleo-relief recovery technique, coherence cube technique and frequency decomposing technology were utilized to determine the spatial distribution of paleo-karst area, fractures and the entire reservoirs, respectively. The results show that paleo-karst area from the east to the west is the upland, steep slope and gentle slope of karst area. The karst and faults are developed in the upland of the paleo-karst area, and the reservoir with the dendritic distribution has good continuity. However, the reservoir of some areas in the upland with the point distribution has bad continuity. The reservoirs in the steep slope of the paleo-karst area were controlled by the paleo-relief, but the reservoirs in the gentle slope of the paleo-karst area were badly developed.