The Research Of Control Factors Of Chang 1 Reservoir In JiYuan Area

Aimming at the reservoir formation features of Chang1 reservoir in YanChang group of JiYuan area in Ordos basin, the macroscopic structural features of reservoir rocks are studied by classifying precipitation facies and calculating throughgoing forms of sedarenites. Determination of canonic cut planes in JiYuan area, the type and controlling factors of Changl reservoir is definite. Based on the productive deploy, the distributive regular patterns have been summed up by depositional features, and then deploying comments of drilling deep zones and shallow layers bave been proposed. The conclusions go as following:1.The reservoir is controlled by northeastern and northwestern depositional systems. The northwestern one is the chief one in BaoZiWan area, and the northeastern one is in AnBian-WuQi area. The tow depositional systems converge in WangPanShan-YuanCheng area.2.There are overwater and underwater depositional environments in JiYuan area. The location of lake strandline is in the line of Geng55-Luol-A9 wells. The south of this line is the environment of delta front.3.The sand body controlled by northwestern provenance is distributed in north north west. The sand body controlled by northeastern provenance is the subsea river course in delta plain and delta front because of the long transporting distance and deep lake basin.4.The Diagn stage of Changl reservoir is late A, and the environment is alkaline.Because the carbonate cements jam primary intergranular pore, the porosity is low. From Chang2 to Changl reservoir, physical property of reservoir has the features of small intergranular pore, large feldspar emposieu, low porosity and bad physical property.5.There are two formation patterns and three reservoir forms in Changl reservoir. One pattern has made the microcrack as the transporting system created by lengthwise sand body of distributary channel and basal faulting. Another pattern is that the oil-gas travels through the released area of pressure which is created by cutting action of YanChang group. The three reservoir forms are that:The first one is structure-lithology reservoir controlled by sang body and differential compaction in the highland and slope in JiYuan area. The second one is fractured hydrocarbon reservoir affected by tectonic movement and crustal stress. The third one is discordant barrier reservoir created by large weather-worn pore and covered by mudstone of Yan9.6.There are two ranges of profitability for prospecting(Geng 49 well field, Yuan 16-Yuan157 well field) because of development extents of sand body, conditions of migration, controlling of structure and split to oil-gas and preservative extent of layers.