基于断陷盆地注水口识别的陡坡带近源扇体研究——以石臼坨凸起南部陡坡带秦皇岛A构造东三段为例

为探讨断陷盆地陡坡带近源扇体的发育规律，利用三维地震资料和钻井资料，在"源-汇"理论指导下对秦皇岛A构造近源扇体展开研究。结果显示:石臼坨凸起的中生界火山岩潜山为秦皇岛A构造提供充足的沉积碎屑。提出"隐性古沟谷"概念，解决了物源区无古沟谷输砂的问题。在构造重新落实的基础上，结合古断距恢复和古地貌恢复识别出了平行断裂型古转换带。发育在坡折带上的古转换带可以作为古水系进入盆地的入口，从而确定陡坡带近源扇体的发育位置。在物源分析、注水口识别、古地貌恢复的基础上，建立了隐性古沟谷-平行断裂型古转换带控砂模式。在该模式指导下，利用基于灰度共生矩阵的属性优化技术，精细刻画了近源扇体的平面形态。已钻井QHDA1井打在了秦皇岛A构造"二台阶"上的扇缘部位，未钻遇扇体的根部，故而储层不发育。研究区有利勘探区带位于构造"一台阶"的扇根部位。

Study of Proximal Source Fans on the Actic Region Based on Water Injection Nozzle Identification in a Rifted Basin: A case from the Qinhuangdao A structure in the Bohai Bay Basin,China

The developmental process of proximal source fans in the Qinhuangdao(QHD) 'A' structure in the actic region of a rifted basin were investigated by applying 3D seismic and drilling data to source-sink landscape dynamics theory. The results show that the buried Mesozoic volcanic hills in the Shijiutuo Uplift provided sufficient sedimentary debris to produce the QHD A structure. The novel concept of "implicit incised valley" is proposed to solve the problem in which no known ancient valleys exist in the provenance for transporting sand. A new interpretation of the tectonics shows that fossil transfer zones in parallel faults enable the restoration of the ancient fault-throws and paleogeomorphology in the region. The fossil transfer zones in the slope-break zones became the entrances to a paleo-drainage network into the basin, and thus determined the location of the proximal source fans in the steep slope zone. Provenance analysis of water injection nozzles and paleogeomorphology were established by a sand model utilizing the implicit incised valley approach and a parallel fault transfer zone. This model described the plane shapes of the proximal source fans in detail, using 3D seismic attribute optimization technology based on gray-level co-occurrence matrix (GLCM)texture analysis. Because Well QA1 penetrated the edge of the fan at the second step of the QHD A structure and not the root of the fan, no useful reservoir was found. The most favorable exploration zone is located at the root of the fan at the first step of the QHD A structure.