Characteristics Of Depositional Facies Through-going And Prediation Of Favorable Zones Of Es2-Es1 Maxi Area

Maxi area lies in the northern part of the Raoyang sub-depression of the Jizhong depression.And it is 700 km~2. This area is an abundant oil and gas zone, the Es2 and Esl member are the major oil producing pays. Because reservoir conditions superior structural traps have been drilled. Therefore, comprehensive exploration of lithology reservoir is particularly important.The core mission of this paper is sedimentary facies distribution and favorable reservoir zones' forecast. The paper follows a path from point (well) to line (cross section), to surface (map), to area (field),based on the reservoir sedimentology, high-resolution sequence stratigraphy, with the analysis of geology, well log etc , Es2- Esl of Maxi area were divided carefully into the units of member, on the basis of the isochronous stratigraphy framework, the depositional system was researched carefully, and the sedimentary evolution was summarized. Following research fruits are achieved:1. The application of high-resolution sequence principles, combined with logging, core analysis, a relative of the district, such as the stratigraphic framework. In time, such as stratigraphic framework of regional purpose of Es2-Esl was divided into two tertiary sequences, seven quarternary sequences.2. Through the core observation and description, the paper has pointed out that the cores have been divided into sandstone category, mudstone and siltstone categories and nine lithofacies , and each lithofacies with the naming of the code of conduct.3. The paper has established the electrofacies model of region of interest, and seven depositional subfacies have been recognized: distributary bay, flood plain, delta plain, delta front, coastal lake, shallow lake and semi-deep lake.4. The Es2 is fluvial facies - flood plain - (braid) delta - coastal lake deposition system ;overall rough clasolite development; braid delta development in the eastern and north-east of the area, its source of supply is adequate; while the western region, south and northwest of relative shortage of supply sources, meandering river - flood plain - delta sediments are predominate facies.5. The shallow lake and semi-deep lake are main facies of the area in Esl, to the upper set of shallow lake - delta is predominate in the the upper set; the area experienced a rapid water immersion in the early of the sha 1 member; then, the lake waters began slowly declined ; the size of deposition is smaller;it is pass through from fluvial-delta to coastal lake-shallow lake ;the area has semi-deep lake and deep lake in the deeper department.6. The sources came from several different directions. The main source for early is short axis, but in the later stage ,the source of the long axis is sronger. Deposition of the eastern steep slope with more performance for "smaller and more," sedimentary system performance for the lobate and fan-shaped; while the western slope with the lack of sources, it is almost shore-bar facies around Renqiu buried hill; longitudinal axis of source is sufficiently; most delta showed the shape of crowfoot or lobate in Nanmazhuang area where source is adequate.7. The sedimentary evolution of study area experienced the formation and development and shrinking of lake in Eogene, source is relative lack in Es2 ; there is a set of thick source rocks in Es1 when the lake is larger and source is more sufficiently.8. The favorable reservoir zones(Lithology reservoir) lies axis of the length's delta front .The slope of Renqiu buried hill developed shore-bar deposition in local area, could serve as a good reservoir. Under above research ,it's call to strengthen these favorable areas for exploration.