鄂尔多斯盆地中-东部下石盒子组八段辫状河储层构型

基于国内外研究成果建立了辫状河构型模式，并利用测井、野外露头及气井动态资料，对鄂尔多斯盆地中-东部下石盒子组八段（盒八段）辫状河储层进行构型解剖。在野外露头中识别出河道带，心滩与河道充填，单元坝与心滩内水道，大型倾斜层与中型交错层，中型平行层与小型交错层共5级构型单元。运用所测量交错层系厚度资料推算露头剖面中心滩长为1 163~1 592 m，宽为282~390 m，该推算值与实际测量值相符合。对野外露头和苏里格气田密井网区盒八段储层构型解剖表明：河道带砂体、心滩砂体之间发育多成因的、连续的渗流屏障，连通性较差；心滩内部渗流屏障规模较小，因此可将心滩视为独立的储渗单元。运用成像测井资料推算出苏里格气田盒八段辫状河心滩长为602~1 243 m，宽为143~302 m，大部分心滩规模小于目前气田的井距和排距；气井动态资料也证明目前的井网密度下，有效储层井间连通性较差，因此苏里格气田具备加大井网密度的潜力。

Reservoir architecture of braided river in Member 8 of Xiashihezi Formation,central-eastern Ordos Basin

In the light of previous studies on braided river architecture model, the logging, field outcrop and gas well dynamic data are used for architectural analysis of braided river reservoirs in Member 8 of Xiashihezi Formation (He 8 Member), central-eastern Ordos Basin. The architectural units of five levels are identified from field outcrop, i.e., channel belt, channel bar and channel fill, unit bar and cross-bar channel, large-scale inclined strata and medium-scale cross strata, as well as medium-scale planar strata and small-scale cross strata. Based on the measured thicknesses data of cross strata, it can be speculated that the channel bar on outcrop profile has a length of 1 163-1 592 m and a width of 282-390 m, which is consistent with the actual measurement data. As indicated by the architectural analysis of the outcrop and the reservoirs in He 8 Member of dense well spacing zone, Sulige gasfield, multi-genesis continuous flow barriers are formed with poor connectivity in the sand bodies of channel belt and channel bar; while the flow barriers inside the channel bar are small in size, so channel bar can be considered as an independent flow unit. Using the imaging logging data, it can be speculated that the braided-river channel bar in He 8 Member of Sulige gasfield has a length of 602-1 243 m and a width of 143-302 m, and most channel bars have a smaller scale when compared with the well spacing and row spacing of current gas field. In addition, the dynamic data of gas wells also prove that under the current well density, effective reservoirs have poor inter-well connectivity, so Sulige gasfield has the potential for well network densification.