Hydrocarbon accumulation law of lithologic reservoirs of middle Yanchang Formation in Jiyuan area, Ordos Basin
Online published: 2010-06-15
Based on sedimentary characteristics, provenance analysis, sedimentary evolution and reservoir distribution, the reservoir types of middle Yanchang Formation in Jiyuan area, Ordos Basin are studied. The result shows that Chang 8 to Chang 4+5 oil layers ofYanchang Formation are mainly dominated by lithologic reservoirs and lithologic-structural reservoirs, which mainly developed in delta front, subaqueous fan and delta plain close to lakeshore line. The types and distribution of Chang 8 to Chang 4+5 reservoirs in Jiyuan area are mainly controlled by sedimentary provenance. The sand bodies that pinch-out to northeast and southeast are likely to form lithologic reservoirs, and the scale is controlled by the size of sand body. However, the sand bodies that pinch-out to southwest and south only form lithologic-structural reservoirs when superimposed with nose structures, and their scale is controlled by the size of sand body and nose structure at the same time. The sedimentary provenance in the west of the study area are weakened graduallywhile the sedimentary provenance in the north and northeast are strengthened gradually during the deposition stage of Chang 8 to Chang 4+5 oil layers, which causes the change of reservoir types and distribution. It indicates that lithologic reservoirs mainly developed in Chang 8 oil layers, and lithologic-structural reservoirs mainly developed in Chang 7 to Chang 4+5 oil layers.
PAN Jianguo , WEI Pingsheng , ZHANG Huquan , TAN Kaiju . Hydrocarbon accumulation law of lithologic reservoirs of middle Yanchang Formation in Jiyuan area, Ordos Basin[J]. Lithologic Reservoirs, 2010 , 22(2) : 84 -89 . DOI: 10.3969/j.issn.1673-8926.2010.02.015
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