河南濮城油田沙二上2+3砂层组末端扇沉积特征及剩余油分布

Sedimentary characteristics of the terminal fan deposits and distribution of residual oil in the upper oil reservoirs of the second member of the Shahejie Formation in the Pucheng Oil Field,Henan

本文以濮城油田沙二上2+3砂层组为例,分析了末端扇储层的沉积特征,建立了末端扇沉积模式,确定了剩余油分布。末端扇储层分为近端亚相、中部亚相和远端亚相,中部亚相的分流河道微相是主要储集砂体。剩余油平面上主要集中在分流河道侧翼过渡区及近水道漫溢、远水道漫溢和分散的井网难控制的小透境体中,垂向上集中在正韵律顶部和反韵律底部等物性差的地方。二砂组主要富集在S23、S24小层的近气顶区,三砂组主要富集在S34、S35小层的濮53、文17断块构造高部位及注采不完善的地区。

Exemplified by Nos. 2 ＋ 3 sand sets in the upper oil reservoirs of the second member of the Shahejie Formation in the Pucheng Oil Field, the present paper deals with the sedimentary characteristics and model for the terminal fan reservoirs and distribution of residual oil. The terminal fan facies may be subdivided into the proximal fan, middle fan and distal fan subfacies. The distributary channel microfacies of the middle fan subfaeies is believed to be the main reservoir sandstones. The residual oil is concentrated to the transitional zones of the flanks of the distributary channel microfacies, proximal overbank, distal overbank and lens which are difficult to be controlled by well spacing patterns. Vertically, the residual oil tends to be enriched in the areas with poor physical properties such as the top of the normal rhythmic successions and base of the reverse rhythmic successions. More precisely, the residual oil occurs in the areas near the gas cap in S2^3 and S2^4 beds of No. 2 sand sets, and structural hizhs of Pu-53 and Wen-17 fault blocks within S3^4 and S3^5 beds of No. 3 sand sets.