【摘要】 天然气勘探证实徐家围子断陷兴城气田营城组营四段砂砾岩具有较好勘探潜力.为指导该气田下一步的勘探开发,需要确定砂砾岩沉积相类型及其时空演化.利用钻井、岩心、测井和地震资料,对兴城气田营四段砂砾岩的沉积特征、沉积相类型和沉积环境演化进行了研究.营四段砾石以细砾和中砾为主(粒径主要在2—20mm),分选差,成分复杂,以中-酸性熔岩和中-酸性火山碎屑岩为主.砂砾岩颜色、粒度、结构、沉积构造、岩石相、测井相以及沉积序列特征指示其为砾质辫状河三角洲相沉积,以三角洲前缘亚相为主,并主要沉积了水下分流河道、河口坝微相.营四段上亚段砾石磨圆度较好,砂砾岩沉积厚度大,且横向上连片性好,属于长流程砾质辫状河三角洲沉积,构成了气田砂砾岩的主力储层段;下亚段砾石磨圆度差,砂砾岩层薄且面积小,细粒杂基含量增加,为短流程砾质辫状河三角洲沉积,储层不发育.更多还原

【Abstract】 Hydrocarbon exploration demonstrated that the sandy conglomerates of the fourth member of Yingcheng formation(FMYF) in Xingcheng gas field of Xujiaweizi fault depression have some potentialities.To offer guidance for next prospection and development of this field,it needs to make sure of type of the conglomerates and their time and space evolutions.Based upon drilling,core,logging and seismic data,the sedimentary characteristic,facies type and environment of the sandy conglomerates are explored.The gravels are mainly composed of pebbles and cobbles(grain diameter mostly between 2 and 20mm) with poor sorting and multiple compositions that basically include intermediate and acidic lavas and pyroclastic rocks.The color,grain size,texture,sedimentary structure,lithofacies,log facies and depositional succession of the sandy conglomerates indicate deposits from gravel-dominated braided delta,which mainly developed delta front that mostly consist of underwater distributary channels and mouth bars.The gravels are better rounded within the upper part of FMYF,and the formed sandy conglomerates show great extension in space and could be deposited from grave-dominated braided delta with long flow,so that they make up of the main reservoirs of this sandy conglomerate gas field.The lower part of FMYF have poor rounded gravels and thin sandy conglomerates which spread limitedly with increasing fine groundmass content and could be deposited from grave-dominated braided delta with short flow;therefore,the reservoir are scarce.更多还原