大井距条件下扇三角洲前缘储层构型表征——以乍得R油田R4区块KIV3组为例

Architecture characterization of fan delta front reservoir under conditions of wide well spacing:a case study of KIV3 Formation on R4 Block of R Oilfield in Chad

以乍得R油田R4区块KIV3组为例,提出大井距条件下动静态资料结合的储层构型表征思路。基于“垂向分期、侧向划界”的储层构型表征方法,以泥质沉积、河道底部滞留沉积为构型单元垂向边界识别标志,侧向上结合高程差异、厚度差异、韵律差异及动静态资料,建立单一水下分流河道和单一河口坝宽厚比经验公式,进行研究区储层构型表征。结果表明:研究区KIV3组储层可识别水下分流河道、河口坝和席状砂3种单砂体构型单元;垂向发育孤立式、叠加式、削截式3类叠置样式,侧向发育孤立型、对接型、切叠型3类接触关系;水下分流河道单砂体厚度在1-9 m之间、侧向延伸宽度在300-900 m之间,河口坝单砂体厚度在1-7 m之间、侧向延伸宽度在300-700 m之间。该方法可降低大井距条件下储层构型表征的不确定性,为乍得R油田R4区块注水开发调整提供地质依据。

In order to solve the uncertainty of quantitative characterization of reservoir architecture under the condition of large well spacing,taking the KIV3 Formation in R4 Block of R Oilfield in Chad as an example,we introduced a reservoir architecture characterization technology that synthetically uses dynamic and static data under the condition of wide well spacing.Based on the reservoir architecture characterization idea of "vertical staging and lateral demarcation",we used argillaceous deposition and channel bottom retention deposition as vertical boundary identification marks.Laterally,the reservoir architecture characterization of the study area is completed by combining the elevation difference,thickness difference,rhythm difference and the empirical formula of width-thickness ration of single underwater distributary channel and single mouth bar established by the method of combining the static and dynamic data.The results show that the KIV3 Formation in the study area has identified three single sand body architecture units:underwater distributary channel,mouth bar and sand sheet.Vertically,three types of vertical stacking styles of single sand body of isolated,superimposed and overlapped are identified.Laterally,three types of lateral contact relationship of single sand body of isolated,docking and overlapped are identified.The width of underwater distribution channel is 1—9 m,and its lateral extension width is 300—900 m.The width of mouth bar is 1—7 m,and its lateral extension width is 300—700 m.The method that synthetically uses dynamic and static data reduces the uncertainty of reservoir architecture characterization under the condition of wide well spacing,the results provide geological basis for the adjustment of water injection strategy in R4 Block.