塔中地区奥陶系油气充注期次的流体包裹体证据

Fluid inclusion evidence for charge stages of hydrocarbon in the Ordovician traps of Tazhong area,Tarim Basin

依据包裹体显微测温技术和PVT模拟方法,对塔中地区不同井位、埋深的奥陶系储集层流体包裹体进行了显微测温和捕获压力恢复。基于采集样品在地史中共处相同油气运聚系统的背景,结合各井埋藏史和热史,通过＂分井定期、分期校深＂的方法,对均一温度进行归一化校正处理,提高了利用温度信息对油气充注期次进行统计分析的分辨能力。研究结果表明,塔中地区奥陶系储集层内曾发生6期典型的油气充注事件。与油同期的盐水包裹体捕获压力恢复结果与当时正常压力系统下的埋藏深度吻合,进一步证实了132℃以下5期油气充注事件的发生;另一期（156~176℃）为热事件影响所致。油源和埋藏热演化条件分析揭示,包括轮南地区在内的整个塔北隆起、中央隆起的中西段及两者所夹持的满加尔凹陷以西地区,都是晚期生油并充注成藏的远景区。

Based on the microscopic thermometry technology and PVT simulation method of fluid inclusions,the trapped temperature and pressure of inclusions which come from Ordovician reservoirs at different drill-holes and buried depths in the Tazhong area were measured and calculated.All the samples belong to one hydrocarbon migration system.In combination with burial history and geothermal history and the method of ＂to ascertain stages of fluid filling in individual drillholes first,then to calibrate temperature by stages＂,the homogenization temperature of aqueous inclusions was calibrated in order to enhance the capability to determine charge stages by inclusion temperature data.Six stages hydrocarbon charges occurred in the Ordovician reservoirs.The first five periods of hydrocarbon charges below 132 ℃ are confirmed by the coincidence of the normal-pressure burial depth and the restored trapped pressure of inclusions.The highest temperature stage（156-176 ℃） was caused by abnormal thermal event.The analysis of oil source and thermal evolution reveals that Tabei uplift（including the Lunnan area）,the middle-west section of Tazhong uplift,and the western Manjiaer Sag are areas potential for late accumulated hydrocarbons.