贝尔凹陷基岩潜山致密储层裂缝分布预测

Fracture prediction of bedrock buried hill tight reservoirs in Beier Depression

贝尔凹陷基岩潜山储层属低孔低渗-超低孔超低渗型致密储层,构造裂缝是其主要的储集空间。预测致密储层构造裂缝的分布规律是寻找优质储层、提高油气藏勘探成功率的前提和保障。文章根据贝尔凹陷基岩顶面构造形态及基底断层分布特征,利用"曲率法"和"有限元数值模拟法"对"与褶皱相关裂缝"和"与断裂相关裂缝"成因的两种裂缝发育带的分布进行了预测。结果表明,贝尔凹陷基岩顶面与褶皱相关裂缝发育带主要沿构造走向分布,分布于贝西次凹贝302-贝13井及贝D4井东部、贝中断隆带霍10井周边及贝42-贝16井一线、贝中次凹内希13-希5-德8井附近。与断裂相关裂缝发育带主要分布于贝西次凹西南部及中部、贝中断隆带贝30井附近、贝中次凹东北部德8井附近及西南部希5井周边。岩心观察表明贝16井基岩潜山顶部主要发育构造曲率控制下的溶蚀性裂缝,与裂缝预测结果相一致,证明了预测方法的合理性。

Bedrock buried hill reservoirs in Beier Depression belong to tight reservoirs with low to ultralow porosity and low to ultralow permeability ,and have structural fractures as the main reservoir spaces .Mapping of these structural frac-tures is the premise and guarantee for looking for high quality reservoirs and improve exploration success rate .According to the top structural form of bedrock and distribution of basement faults in Beier Depression , we mapped two types of structural fractures by using curvature method and finite element numerical simulation method .One is fracture related to folds and the other is fracture related to faults .The fold-related fracture on top of the bedrock in Beier Depression are dis-tributed mainly along strike ,and are located in east of well Bei302-Bei13 and BeiD4 of west Beixi sub-depression,pe-riphery of well Huo10 and Bei42 to Bei16 of Beizhong fault-uplift zone,and periphery of well Xi13-Xi5-De8 of Be-izhong sub-depression .The fault-related fractures are mainly distributed in the southwest and central of Beixi sub-depres-sion,periphery of well Bei30 of Beizhong fault-uplift zone,and periphery of well De8-Xi5.Cores observation shows that curvature-controlled dissolution fractures are common on top of the bedrock in well Bei 16,which coincides with fracture prediction results .