Research On Jurassic Reservoir In Maling-Chenghua Area Remaining Oil Distribution Law

The Jurassic reservoir in MaLing-ChengHua area developed in1971.Now most of the reservoir has reached into the stage of middle-high water cut (82.8%).The production level of geological reserves is8.4%, which is below the calibration recovery21.9%. Remaining recoverable reserves is9.78million tons. Because of the complex condition of wellbore and well nets not perfect, part of the Jurassic reservoir in Maling-Chenghua decline amounted to30%per year. Decreasing space reduction is large, and economic benefit is good.This paper aims at the problems of MaLing-ChengHua area, which is water cut increase of oil wells, water pressure rise of water wells, injection and production reaction not good and the complex of water drive characteristics rules. We chose the Zhong1area, Bei1area and Nanshi area of MaLing oil field and Hua49area of HuaChi oil field as the research areas. First of all, we studied the basic geological features of the research areas. Then, our research is based on the fine division and correlation of small layers, sedimentary microfacies, reservoir physical property and microscopic pore structure, combined with the dynamic development information. Finally, we are re-classification and evaluation on reservoirs. According to the different blocks of the research area characteristics, we predict the remaining oil enrichment areas. Paper made the following main several points:1. The main type is braided river sedimentation in Yan10reservoir of Nanshi area and Hua49area, while delta plain parfaeies mainly exists in Yan9reservoir. The main type is delta plain parfaeies in Yan10reservoir of Zhong1area and Bei1area, while delta front parfaeies mainly exists in Yan9reservoir.2. The main rock type of reservoir rocks in Yan10in study area is feldspar detritus quartz sandstone, while feldspar sandstone mainly exists in Yan9reservoir. During diagenesis, the reservoir experienced strong compaction, dissolution, metasomatism and cementation. But fracture diagenesis is relatively weak.3. Rock properties, sedimentary and configuration will all influence the formation of oil reservoir in study area; the factors of gas aggregation level are sedimentary facies and distribution of sandbody; and reservoir rock characteristic and configuration.4. Through the static and dynamic combination, We respectively set up the reservoir comprehensive evaluation standard of Zhong1area, Bei1area, Nanshi area and Hua49area. We divided Yan9and Yan10reservoir into I, II and III three class.5. We studied the production performance data and formation pressure of the study area. We find that I class reservoir have flooded, II class reservoir is the main production of layer, III clsass reservoir is using less.6. We conjoint analysis reservoir classification results of small layer, reservoir sedimentary, reservoir structure and exploiting dynamic character. We found that the remaining oil mainly distributed in II class and III clsass reservoirs of the high positions of structures or rivers edges. These areas are the main direction of further potential tapping.