论文详情
近期, 川中地区JT1井在震旦系—古生界钻遇多套厚层滩相储层, 井旁地震剖面可见基底断裂发育, 该井多层系测试均获得油气发现, 展示出川中地区立体勘探潜力。利用最新高品质二维和三维地震、重磁、时频电磁、钻测井等资料, 分析川中简阳—中江地区基底断裂特征及其对震旦系—古生界地层沉积及成藏的控制作用。研究发现, 简阳—中江地区发育众多北西、北东走向基底断裂, 基底断裂发育于前震旦系裂谷边界及裂谷内幕隆凹转换带。基底断裂控制了灯影组沉积前隆凹格局, 并在兴凯地裂、加里东运动、峨眉地裂等时期不同程度(显性、隐性)继承性活动产生断垒断堑, 控制了纵向上大面积震旦系—古生界叠置有利相带区展布: 灯影组丘滩体建隆区位于前震旦系隆起高地貌部位, 沿北西向和北东向基底断裂分布; 二叠系茅口组滩体发育于断垒高地貌处, 沿北西向基底断裂分布; 二叠系爆发相火山岩主要沿垒堑转换带的基底断裂(火山通道)分布; 长兴组滩体沉积于火山岩喷发后形成的火山锥上方, 沿北西向基底断裂分布。简阳—中江地区基底断裂不仅控制着德阳—安岳裂陷槽寒武系优质烃源分布, 也控制着纵向多层系滩体沉积及古岩溶以形成优质储层, 控制储层间致密遮挡带分布, 基底断裂作为疏导形成良好源储配置, 震旦系—古生界成藏条件佳, 立体勘探潜力大。
Recently, well JT1 and others in the Central Sichuan Basin have drilled multiple sets of thick beach facies reservoirs in the Sinian Paleozoic, and basement fractures have developed in the seismic section beside the well.Oil and gas discoveries were obtained in a multilayer system test of this well, demonstrating the three-dimensional exploration potential in Central Sichuan.Based on the latest high-quality two-and three-dimensional seismic, gravity, and magnetic, time-frequency electromagnetic, drilling, and logging data, the characteristics of basement faults in the Jianyang-Zhongjiang area in the Central Sichuan Basin and their control over the Sinian-Paleozoic stratigraphic sedimentation and hydrocarbon accumulation formation were analyzed in this study.Many NW-and NE-trending basement faults have developed in the Jianyang-Zhongjiang area.Basement faults developed in the pre-Sinian rift boundary and uplifted the sag transition zone within the rift.The basement fault controls the pre-sedimentary uplift and depression pattern of the Dengying Formation, generates fault horsts and grabens in different degrees(dominant and recessive) during the Xingkai rift, Caledonian movement, and Emei rift, and longitudinally controls the distribution of a large area of the Sinian-Paleozoic superimposed favorable facies belt The uplift area of the Dengying Formation is located in the high geomorphic part of the pre-Sinian uplift and is distributed along the NW and NE basement faults.The beach body of the Permian Maokou Formation developed in the Horst highland fault and is distributed along NW basement faults.The volcanic rocks of the Permian explosive facies are mainly distributed along the basement fault(volcanic channel) of the Horst graben transition zone, and the beach body of the Changxing Formation is deposited above the volcanic cone formed after the volcanic rock eruption and is distributed along the NW basement faults.The basement fault in the Jianyang-Zhongjiang area controls the distribution of Cambrian high-quality hydrocarbon sources in the Deyang-Anyue rift trough and the vertical multi-layer beach deposition and paleokarst to form high-quality reservoirs and control the distribution of dense shielding zones between reservoirs.As a guide, the basement fault formed a good "source reservoir configuration." The Sinian-Paleozoic has good hydrocarbon accumulation-forming conditions and great potential for three-dimensional exploration.