环县-正宁地区长9油层组流体包裹体特征及地质意义

Characteristics of Fluid Inclusions in Chang 9 Oil Reservoirs of Huanxian-Zhengning Area and Its Geological Signifiance

运用ZEISS双通道荧光-透射光显微镜、雷尼绍inVia Relflex型显微拉曼光谱仪和Linkam MDS-600冷热台,对研究区长9油层组流体包裹体岩相特征、均一温度/冰点温度和古压力特征进行了研究,并结合研究区地层埋藏史、热演化史厘定了石油的充注史,恢复了长9油层组原油充注时的动力条件。结果表明,研究区长9油层组盐水包裹体和液态烃包裹体主要分布在石英颗粒内的裂隙中,其次在石英次生加大边、胶结物和穿石英颗粒的裂纹中。与油包裹体共生的盐水包裹体均一温度测试和古压力恢复结果表明,研究区长9油层组主要为长7烃源岩生烃增压驱动的一期石油充注,对应地质时间为早白垩世中晚期(105~125Ma),其中石英颗粒内裂隙中与石油包裹体共生盐水包裹体均一温度主要分布在105~130℃,古压力系数集中在1.0~1.5;石英次生加大边及胶结物中的包裹体均一温度主要分布在100~125℃,古压力系数集中在1.1~1.3;穿石英颗粒裂纹的主要分布在120~130℃,古压力系数集中在1.2~1.4;总体上充注次序为石英次生加大边及胶结物略早于石英颗粒内裂纹略早于穿石英颗粒裂纹。

The petrographic characteristic, homogenization temperature / freezing temperature and paleo-pressureof the fluid i^clusions in Chang 9 Formation of Huanxian-Zhengning area were studied using the ZEISS doal-channel fluorescence-transmission lightmicrosco- py, the in Via-Relflex micro Renishaw Raman spectrometer and the Linkam MDS-600 heating/cooling stage. Combined with the burial thermal histories of the study area, the hydrocarbon charging history of the study area was determined, and the dynamic conditions in the hydrocarbon charging stage of Chang 9 oil reservoirs were restored. The results show that the brine and hydrocarbon fluid inclusions in the Chang 9 reservoirs mainly distribute in the fractures within quartz particles, and secondly distribute in quartz overgrowth or cement and the fissures which across quartz particle. The homogenization temperature test result and the paleo-pressure restoration result of the brine inclusions associated with the hydrocarbon inclusions in the Chang 9 reseroirs show that the hydrocarbon in the Chang 9 reservoirs is mainly the first stage charging of Chang 7 source rock,which corresponds to the middle and late period of Early Cretaceous （105-25 Ma） in the geological history-. The homogeneous temperature of the brine inclusions associated with the hydrocarbon inclusions in the fractures within quartz particles mainly distrihutesin 105 -130 ℃ ,and the paleo-pressure coefficient is in the range of 1.0 -1.5; the homogeneous temperature of the inclusions in the quartz overgrowth or cement mainly distributes in 100-125℃, and the paleo-pres- sure coefficient is in the range of 1.1 - 1.3 ;the homogeneous temperature of the inclusions in the fissures which across quartz particle mainly distributes in 120 - 130℃ , and the paleo-pressure coefficient is in the range of 1.2 - 1.4. On the whole,the time order of hydro- carbon charging is the quartz overgrowth or cement,the fissures which across quartz particle,the fractures within quartz particles.