湘中涟源凹陷油气成藏与保存条件

PETROLEUM ACCUMULATION CHARACTERISTICS AND PRESERVATION CONDITIONS OF LIANYUAN SAG IN THE CENTRAL HUNAN

针对湘中涟源凹陷油气藏成藏期次和时间以及油气藏破坏、改造等进行详细研究,发现存在多期油气充注。利用沥青、包裹体分析,印支之前曾有过油的充注,在印支早期、晚期共发生二期天然气充注。印支期既是高成熟天然气充注期,又是构造圈闭形成时期,燕山期只对前期气藏起破坏、改造作用。总结了4种油气藏破坏、改造、保存样式,即原生油气藏后期无改造样式,原生油气藏后期简单改造样式,原生油气藏后期多期改造样式,原生油气藏后期完全破坏样式。分析认为涟源凹陷3个构造带油气藏保存条件各异,西部构造带保存最差,中部较好,东部最好。

Based on the analysis of asphalts and inclusions in Lianyuan sag of Central Hunan, a study on the accumulation periods, destruction and transformation of oil and gas reservoirs has been researched. The result shows that the oil and gas charging occurred during pre-Indo-China movement, with earlier Indo-China movement and later Indo-China movement two times charging naturally. Indo-China Stage was not only high-matured gas time but also structural traps formed time, while Yanshan Stage played a destructive and transformative role on earlier traps and reservoirs. Four destruction, transformation and preservation models of reservoir are proposed, such as original reservoirs without destruction, original reservoirs with little destruction, original reservoirs with serious destruction, and original reservoirs with total destruction. Finally, it comes to a conclusion that three tectonic zones of Lianyuan sag have different preserving conditions, from west to east, the conditions become better and better.