塔河一区夹层控制型剩余油挖潜技术

Technology of Tapping the Potential of Remaining Oil controlled by the Interlayers in the Tahe No.1 Block

塔河一区为辫状河平原亚相分流河道沉积的底水油藏,夹层较为发育。纵向上发育3套夹层,与相邻储层物性差异大,遮挡效果明显;平面上夹层展布面积小,但多套夹层相互遮挡,形成较大的遮挡范围,对剩余油控制作用明显。油藏进入中高含水期后,研究剩余油的成因和分布特征是开展调整挖潜的基础。针对塔河一区3套夹层对剩余油分布的控制,应用剩余油测井和数值模拟方法,研究了剩余油的分布。结果表明,塔河一区夹层控制型剩余油主要有两种类型:由于夹层遮挡形成的低渗部位剩余油及高部位的井间剩余油。结合夹层纵向分布及平面遮挡连片的展布特征,通过生产直井低渗段剩余油,在井间动态关系明显的井组应用井组优化,挖潜井间剩余油,通过注入介质改变井周压力场,实现对井周剩余油的调整挖潜,取得明显增油效果。经过两年的矿场实践,油藏开发效果得到明显改善。

Tahe No.1 block belongs to bottom water reservoirs ,which is deposited by distributary channel of braided river plain subfacies with well-developed interlayers.Three sets of interlayers have been identified vertically,which have dramatic differences in physical properties with the adjacent reservoirs and have obvious block of the fluid.Although distribution area of the interlayers on the plane is small,multiple sets of interlayers constitute a large barrier and obviously control the distribution of remaining oil.The investigation of the distribution characteristics and origin of the remaining oil provides the base for adjustment and improvement of the remaining oil recovery after the oil reservoirs entered the middle-high water cut period.Remaining oil logging and numerical modeling are applied to the distribution research of the remaining oil controlled by the three sets of interlays in the Tahe No.1 block.The results indicate that there are two types of the remaining oil： one is at the low-permeability position formed by interlayer barrier and the other is at the higher inter- well locations.According to the characteristics of the vertical and plane distribution of the interlayers ,the low- permeability intervals in the vertical wells are produced and well groups with obvious inter-well dynamic relationship are optimized so as to recover the inter-well remaining oil.Also,media is injected to change the pressure field around wells and then the remaining oil around wells will be produced.After a two-year practice in the field ,the remaining oil recovery has been significantly improved.