基于储层构型的渗流单元刻画方法及应用——以珠江口盆地文昌C油田为例

Characterization Method and Application of Seepage Units Based on Reservoir Configuration:A case study of the Wenchang C oilfield in the Pearl River Mouth Basin

文昌C油田珠海组二段一油组纵向多期砂体相互叠置,内部结构复杂、非均质性强,目前已进入“双高”采出阶段,剩余油分布规律不明。厚储层平面上受断层分布及不同构型单元储层质量差异的影响,水驱规律呈现明显分区性;纵向上受砂体复杂内部结构及隔夹层分布控制,水驱顺层突进现象明显,水驱规律不明确制约油田下步调整挖潜。在精细构型研究基础上,结合毛管压力等微观孔喉参数,利用判别函数对渗流单元进行定量刻画,弥补了传统FZI划分流动单元不够精细的问题,更契合生产动态。明确了两种剩余油控制模式:一是渗流单元差异平面控油模式;二是渗流屏障遮挡垂向控油模式。结果表明:研究区平面划分5个井区,纵向划分15个单层,共划分60个含油单元,结合生产动态得到每个渗流单元的采出程度及剩余油分布规律,针对性地提出了7项措施,有效提高了本油田开发效果,同时也为类似复杂厚层砂岩油藏剩余油挖潜提供经验借鉴。

In the Wenchang C oilfield,the second member and first member of the Zhuhai Formation,and the vertical multi-phase sandbodies,all overlap.The internal structure is complex,and the heterogeneity is strong.At present,production has entered the“double height”stage,and the distribution of the remaining oil is unknown.Influenced by the fault distribution and reservoir quality of different configuration units on the plane of thick reservoirs,the water-flooding stratum phenomenon is clearly divided longitudinally into zones controlled by the complex internal structure of the sandbody and the distribution of interlayers.The unclear water-flooding mechanism restricts the oilfield’s next step of adjusting potential.Based on a detailed description of the structure of the sandbody,the percolation units were described by combining the micropore throat parameters(e.g.,capillary pressure)from structural research,which made up for the problem that the traditional flow zone indicator(FZI)division of the flow unit was not fine enough,and more closely matched the production dynamics.It is clear that there are two remaining oil control modes:first,seepage-level differential oil control;second,configuration interface oil control.The results show that the study area is divided into five well areas and 15 single layers vertically.The combination of plane and section indicates a total of 60 oil-bearing units.Combined with production dynamics,the production degree and remaining oil distribution in each seepage unit are obtained.Seven targeted measures are proposed,which will effectively improve the development of this oilfield.At the same time,the results provide experience and references for tapping the remain-ing oil potential of similar complex thick sandstone reservoirs.