夹层研究在水平井开发厚层底水油藏中的应用——以曹妃甸11-6油田Massive砂体为例

Interlayer research application in horizontal well development of thick bottom water reservoir-a case of Massive sand in Caofeidian11-6 oilfield

渤海海域曹妃甸油田群油藏类型主要为河流相底水油藏,全部采用水平井开发,储层内部不稳定分布的夹层是影响底水油藏开发效果最关键的因素,厘清夹层的分布模式及其对底水的控制规律对底水油藏开发非常重要。以曹妃甸11-6油田Massive砂体为例,通过钻穿含油储层的少量探井、水平井的领眼井等进行小层精细对比,确定了夹层空间分布的总体框架,利用水平井含水率上升规律、供液能力和地层压力等生产动态特征与夹层的响应规律,建立厚层辫状河储层的夹层分布模式,分析了夹层分布模式对底水运动规律的控制作用。研究结果表明,Massive砂体纵向上主要发育2期主力夹层,部分水平井同时受2期主力夹层的共同遮挡,并根据夹层对底水的遮挡能力,划分为强遮挡、中遮挡和无遮挡3类。指导了中、高含水期剩余油分布研究和调整策略,部署调整井23口,平均单井累积增油量为17×104t。

Bottom water reservoir is the main reservoir type in the Caofeidian oilfield characterized by fluvial facies in Bohai Bay. It is developed by large-scale horizontal wells. Discontinuous interlayer distribution in the reservoir is the key factor that affects development of the bottom water reservoir. So it is very important to study the interlayer distribution and its controlling effect on the bottom water. Taking Massive sand in Caofeidian11-6 oilfield as an example,3D framework of the interlayer distribution was obtained through fine correlation of layers in the appraisal wells and pilot wells that penetrating into oil-bearing reservoirs. The interlayer distribution pattern in thick braided river reservoir was established according to the relationship between interlayer and production performance response of water cut rise,fluid production capability,formation pressure etc. And the control of the pattern on the bottom water movement was analyzed. The research suggests that two main phases of interlayers developed in the Massive sand longitudinally block some of the horizontal wells simultaneously. According to the bottom water blocking ability,the interlayers are divided into three classes:strong barrier,middle barrier and no barrier. This method guides the study of remaining oil distribution and adjustment strategy of the bottom water reservoir in middle-high water cut periods. Finally,23 adjustment wells have been deployed and the average incremental oil for single well is 17×104t.