Reservoir Characteristics And Pediction For Favorable Areas Of Chang3 Formation In Maling Area

Taking chang 3 formation in Ma Ling area in Ordos Basin as research object, applying the sedimentology, petroleum geology and other related science theory, according to amount of datum of drilling, logging, oil testing and other analysis and testing data, the depositional system and sand body distribution characteristic of oil pools were analysed in detailed in this article, and the controlling factor and characteristic were extensively studied. The reservoir forming distribution regularities have been summarized, on which, favorable targets were selected. The main conclusions and understanding were as follows:The depositional system and sand body distribution characteristic of Chang 3 formation in Ma Ling area were systematically discussed. It is concluded that: Chang 3 formation mainly belongs to sedimentary system of fluvial controlled shallow water deltaic depositional system. The research area is situated in the delta plain subfacies, where Multi-stage meandering stream sandstone bodies have formed the favorable reservoir sand body.The sandstone has the characteristics of high quartz, low feldspar, high contents of rock debris and high garnets. The sandstone distributed west-south and east-north direction, which controlled by the southwest, and have many erosion source areas.The chang 3 sandstone reservoir of study area are mainly feldspthic lithic sandstone and lithic sandstone, with particle supported, moderate to fine in separation, sub-angular and sub-rounded in psephicity, medium textural maturity and high compositional maturity, whose pore type is mainly ntergranular pores and feldspar dissolved pores. Based on these research, the reservoirs were classified in four types, combined with study of the sedimentary characteristics, reservoir property and porosity type.Analysing of distribution of the oil reservoir shows that excellent trap conditions was developed in chang 3 formation in Mma ling area. Delta plain subfacies is the oil and gas enrichment zone, range of the secondary pores growth caused by the difference of diagenesis is the manly position of accumulation.According to integrated geological study, a set of criteria for the classification of reservoirs in this area was confirmed, based on which 26 favorable area were optimized, contains 6 type ? targets,10 type ? targets and 10 type ? targets.