南堡凹陷周边地区古生界潜山油气成藏条件分析

Hydrocarbon pool forming conditions of paleozoic buried hill in peripheral of Nanpu sag

为分析南堡凹陷周边地区古生界潜山的油气成藏特点与油气聚集规律,探讨影响油气成藏的主要因素,对寒武-奥陶系野外岩石露头进行实地观测和调研,对野外及岩芯取样进行偏光薄片鉴定、铸体薄片鉴定、化学全分析、物性分析、扫面电镜、X射线衍射等分析。研究结果表明:储层主要岩石类型为石灰岩和白云岩;油气的主要储集类型有孔隙、裂缝以及洞穴,其中裂缝充填严重,晚期未充填的构造缝对油气聚集有利;碳酸盐岩基质孔隙度低;油气运移的通道主要为断层和不整合面,并形成沿断层和不整合面的联合运移模式;油源是潜山油藏形成的关键,侧向对接程度直接影响油气富集程度,构造转向或拐弯部位是有利的聚油构造部位。

In order to observe and investigate Cambrian-Ordovician rock on the spot, some analyses such as thin section analysis, casting section and chemical analysis, physical property analysis, scanning electron microscope and analysis, X-ray diffraction analysis were made, and the dominating reservoir forming factors were discussed in peripheral of Nanpu sag. The results show that the main rock types of reservoir consist of limestone and dolomite. The primary types of reservoir space include hole, fissure and cave, yet the fissure is filled heavily, and the/ate unfilled structural fracture is favorable for hydrocarbon accumulation. It is characterized by the lower matrix porosity for carbonate. The pathways of oil and gas migration mainly include the fault and the unconformable surface, which constitute the ＂fault-unconformable＂ hydrocarbon migration pattern. In this area oil source is the key to the formation of buried hill reservoir, lateral jointing affects the oil and gas enrichment degree directly, and the position of fault turning is favorable for oil accumulation,