The Characteristics Of Reservoir Of Chang 8 In Yanhewan Area Of Ansai Oilfield

Yanhewan area of Ansai oilfield is located in the north of Shaanxi Province, whose structure is located in the mid-east shanbei slope. According to the low degree research of Ansai area reservoir of Chang 8 and clear understanding, this study takes the large number of previous research results as the prerequisite, the discipline theory and the comprehensive method of the application of reservoir geology, petroleum geology, and at the same time, using a variety of research on the testing method and experimental analysis of testing data to study the reservoir characteristics of Chang 8, finally completed the forecast of the favorable area. The research obtains the following important conclusion and understanding:(1) The Chang 8 of Yanhewan area is delta front sedimentary environment。 It is a process of gradually increasing basin from Chan 822 to Chang 811 there are 7-8 main rivers in Yanhewan area, and the Channel width of Chang 812 and Chang 811 is broad; the sandstone stretch in the North East-west direction, and each small layer sandstone connectivity is better. The sandstone of Chang 812 and Chang 821 is in large scale.(2)Reservoir is mainly gray, dark gray fine stuff feldspathic sandstone, with good sorting, clastic particles to subangular, cementation types to film and pore-film. The types of pore mainly includes intergranular pore, followed by feldspar dissolved pores and small amount of zeolite dissolution pore. Chlorite cementation mightily, and high content of carbonate cements.(3)The effect of mechanical compaction, cementation, dissolution in the Chang 8 of Yanhewan area Reservoir is relatively strong, meanwhile, the sandstone diagenetic evolution of chang 8 has entered the middle diagenetic stage A.(4)Through the comprehensive study of reservoir macro characteristics and microscopic characteristics, we make the comprehensive classification and evaluation of reservoir by analyzing all kinds of tests data. Furthermore;to figure out Yanhewan area reservoir of Chang 8 is mainly controlled by lithology, physical control, and it is a typical lithologic oil and gas reservoirs of the Ordos basin.(5)Effective shielding effect is one of the necessary conditions for oil and gas accumulation; At the same time, the micro pore structure of reservoir plays an important role in oil-bearing of reservoir According to the study area containing oil control factor, forecast the advantageous area of Chang 8, in which the reservoir of Chang 812 and Chang 821 is better than others, and The Chang 812. Chang 821 reservoir, the advantages of large range of better favorable area, and the advantages of large range of these is more widespread, so these will be the main consideration of strata for exploration or development research areas for the next.