辫状河三角洲前缘储层隔夹层表征及剩余油预测——以彩南油田彩9井区三工河组为例

Characterization of barrier-intercalation and remaining oil prediction in the braided river delta front reservoirs:An example from the Sangonghe formation in block Cai9 of Cainan oilfield

彩南油田9井区三工河组经过多年的注水开采,剩余油分布复杂,为了进一步提高油田剩余油的开发效果,研究储层隔夹层的分布是关键。以三工河组二段J1s22和J1s23层为例,分析现代沉积、野外露头资料及岩心观察结果,统计5口取心井不同层次类型的隔夹层,绘制不同测井曲线两两组合交会图;根据注水井与采油井之间的动态响应关系,通过井间精细对比建立隔夹层分布的静态模式。结果表明:三工河组二段隔夹层类型划分为单层间隔层、单砂体间夹层及单砂体内夹层3个层次,可根据交会图识别不同类型的隔夹层;研究区有4种剩余油分布模式:顺夹层倾向注采强对应、顺夹层倾向注采弱对应、逆夹层倾向注采强对应、逆夹层倾向注采弱对应;静态模式与实际生产情况吻合度较高,具有较高的可靠性。该研究结果对油藏后期剩余油挖潜具有指导作用。

Due to years of water-injection recovery,the remaining oil distribution is quite complex in Sangonghe formation in block Cai9.In order to further improve the development effect of the remaining oil in the oilfield,it is essential to clarify the distribution of barrier-intercalation in the reservoir.For this purpose,we take the J1s2 2and J1s3 2layers of the Sangonghe formation as an example.According to outcrop and core observation,we divided barrier intercalations of the Sangonghe formation second segment into three hierarchies:Barriers between the two single layers,intercalations between the two single sandbodies and intercalations in a single sandbody.Acoording to the statistics of value of well log that different hierarchies barrier-intercalations derived from five coring holes in study area corresponded to,we draw its two combinations into intersection graph.The results show that different types of barrier-intercalations can be identified according to the identification interval divided by the intersection graph.On this basis,according to the dynamic response relationship between water injection wells and oil production wells,we can establish static model of barrier-intercalations distribution through interwell fine contrast.According to the production situation,it shows that the static mode is in good agreementwith the actual production,and it has good reliability.Based on previously established barrier-intercalations distribution mode,we can summed up the four remaining oil distribution patterns combined with practical production and development data:Injection production strong correspondence along inclination,injection production weak correspondence along inclination,injection production strong correspondence reverse inclination,injection production weak correspondence reverse inclination.The result plays a guiding role in further tapping of potential of remaining oil in future.