断陷盆地剥蚀厚度恢复的构造沉积综合法

Structural-sedimentary synthetic method for restoring denuded thickness in rift-subsidence basin

（1.中国石油化工股份有限公司西南油气分公司勘探开发研究院，四川成都610081；2.中国地质大学资源学院，湖北武汉430074；3.中海油深圳分公司研究院，广东广州510240；4.中国石油化工股份有限公司西北油气分公司勘探开发研究院，新疆乌鲁木齐830001）

Exploration and Exploitation Institute, Southwest Petroleum Branch Company, SINOPEC, Chengdu 610081,China

珠江口盆地惠州凹陷古近系为断陷盆地，珠琼二幕和南海运动使古近系的文昌组和恩平组遭受区域性剥蚀，之后进入持续海相沉积阶段，剥蚀前的地层古地温场、声波时差等特征被再次沉积改变，利用常规剥蚀恢复方法无法准确恢复文昌组和恩平组的剥蚀厚度。针对此，提出了构造沉积综合法。在分析盆地构造沉积特征的基础上，从剥蚀动力学角度出发，采用地震最小剥蚀厚度、构造沉积综合法剥蚀厚度、单井剥蚀厚度和井震关系的研究思路，进行剥蚀厚度恢复。对惠州凹陷古近系文昌组和恩平组剥蚀厚度恢复结果进行了分析，认为文昌组受剥蚀作用较强，在区域上存在较大差异，总体上剥蚀厚度较大；恩平组受剥蚀作用较弱，剥蚀厚度较薄。该方法对恢复断陷盆地剥蚀厚度具有较好的效果。

The Paleocene of Huizhou depression at Zhujiangkou basin is a rift-subsidence basin.Its Wenchang and Enping formations were regionally denuded by Zhuqiong and Nanhai movement,and then entered continuous marine deposition period,the characteristics of paleo-geothermal field and acoustic moveout of the formations before erosion were changed by deposit again.So,conventional methods can not accurately restore the denuded thickness of Wenchang and Enping formations.In order to solve the problem,starting from denudation dynamics,we adopted minimum denuded thickness from seismic data,denuded thickness from structural-sedimentary synthetic method,denuded thickness from single well and well-to-seismic relationship,to restore the denuded thickness of Wenchang and Enping formations.The restoration results were analyzed.The analysis showed that Wenchang formation was suffered stronger denudation,the denuded thickness is largely different in the whole region and is the thicker generally;Enping formation was suffered weaker denudation,and the denuded thickness is relatively thin.The method has good effect for restoring the denuded thickness of rift-subsidence basin.