有机地球化学方法识别中等生物降解油藏油水界面

Organic geochemistry method to identify oil-water contact in middle
biodegraded reservoir

江凯禧 彭丽 何文祥 陈祖林 朱俊章 姚长华 葛岩

中海油能源发展股份有限公司工程技术分公司非常规技术研究所，天津300452 长江大学地球环境与水资源学院，湖北 武汉 430100 中海油实验中心，天津300452 中海石油有限公司深圳分公司技术部，广东 广州 510240

CNOOC Energy Technology ＆ Services Technical Institute of Unconventional Hydrocarbon, Tianjin 300452, China School of Earth Environment and Water Resources, Yangtze University, Wuhan 430100, China Experimental Center of CNOOC, Tianjin 300452, China Shenzhen Branch of CNOOC Ltd., Shenzhen 510240, China

利用有机地球化学方法确定中等生物降解油藏LH11￣1的油水界面深度，以取心率高的LH11￣1￣2井为实验对象，对35个岩心和岩屑样品进行Rock￣Eval和GC/MS实验分析。岩心样品饱和烃GC/MS分析表明，其生物降解程度为3—5级，且随深度增加而逐渐加强。样品含油量、Pow值、（S1+S2）/R、重质油指数、饱和烃生物降解特征、伽马蜡烷/奥利烷等6个有机地化参数均在1 250.9 m处异常变化，揭示储层岩石烃类含量、组成、物理化学性质及生物降解级别沿油水界面方向具规律性变化，但在油水界面处异常，据此1 250.9 m是LH11￣1￣2井新确定的油水界面深度，与测井解释相差3.8 m，可能与油水过渡带范围较大有关。表明利用有机地球化学方法，可较好地识别中等生物降解礁灰岩油藏的油水界面。
关键词 有机地球化学；油水界面；生物降解；饱和烃GC/MS

In order to determine the oil-water interface of middle biodegraded LH11-1 reservoir using the method of organic geochemistry and taking the high coring rate well LH11-1-2 as the experimental object, thirty-five cores and cuttings samples are analyzed by Rock-Eval and GC/MS. The analysis of saturated hydrocarbon GC/MS in core samples shows that the biodegradation grade is 3 to 5 and gradually increases with depth. Six organic geochemical parameters as oil content, Pow values, (S1+S2)/ R, heavy oil index, the biodegradable characteristics of saturated hydrocarbon and Gammacerane/Oleanane are significant changes at 1,250.9 m. It reveals that the hydrocarbon content, constitute, physicochemical properties and biodegradation grade in reservoir rock change regularly along the oil-water interface and abnormality in the oil-water interface. Hereby, the depth of 1,250.9 m is the new oil-water interface，which is 3.8 m deeper than that of log interpretation， being related to the large oil-water transition zone. This study shows that the organic geochemistry method can identify the oil-water interface in middle biodegraded reef reservoirs.

10.6056/dkyqt201402011