Characteristics of fault zones and their control on remaining oil distribution at the fault edge: a case study from the northern Xingshugang Anticline in the Daqing Oilfield, China

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• 作者：Xiao-Fei Fu ; Xiao Lan ; Ling-Dong Meng ; Hai-Xue Wang ; Zong-Bao Liu…
• 刊名：Petroleum Science
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：13
• 期：3
• 页码：418-433
• 全文大小：13,449 KB
• 刊物主题：Mineral Resources; Industrial Chemistry/Chemical Engineering; Industrial and Production Engineering; Energy Economics;
• 出版者：Springer Berlin Heidelberg
• ISSN：1995-8226
• 卷排序：13

文摘

Most major oil zones in the Daqing Oilfield have reached a later, high water cut stage, but oil recovery is still only approximately 35 %, and 50 % of reserves remain to be recovered. The remaining oil is primarily distributed at the edge of faults, in poor sand bodies, and in insufficiently injected and produced areas. Therefore, the edge of faults is a major target for remaining oil enrichment and potential tapping. Based on the dynamic change of production from development wells determined by the injection–recovery relationship at the edge of faults, we analyzed the control of structural features of faults on remaining oil enrichment at the edge. Our results show that the macroscopic structural features and their geometric relationship with sand bodies controlled remaining oil enrichment zones like the edges of NNE-striking faults, the footwalls of antithetic faults, the hard linkage segments (two faults had linked together with each other to form a bigger through-going fault), the tips of faults, and the oblique anticlines of soft linkages. Fault edges formed two types of forward micro-amplitude structures: (1) the tilted uplift of footwalls controlled by inverse fault sections and (2) the hanging-wall horizontal anticlines controlled by synthetic fault points. The remaining oil distribution was controlled by micro-amplitude structures. Consequently, such zones as the tilted uplift of the footwall of the NNW-striking antithetic faults with a fault throw larger than 40 m, the hard linkage segments, the tips of faults, and the oblique anticlines of soft linkage were favorable for tapping the remaining oil potential. Multi-target directional drilling was used for remaining oil development at fault edges. Reasonable fault spacing was determined on the basis of fault combinations and width of the shattered zone. Well core and log data revealed that the width of the shattered zone on the side of the fault core was less than 15 m in general; therefore, the distance from a fault to the development target should be larger than 15 m. Vertically segmented growth faults should take the separation of the lateral overlap of faults into account. Therefore, the safe distance of remaining oil well deployment at the fault edge should be larger than the sum of the width of shattered zone in faults and the separation of growth faults by vertical segmentation.KeywordsFault edgeFault zone structureSegmentation growthMicro-amplitude structureSealingSafety distance