塔河油田奥陶系缝洞型油藏油水流动规律

基于对塔河油田奥陶系缝洞型油藏地质特征及开发特征的认识，建立了概念缝洞结构模型和实际地质模型，采用流线模拟方法探讨了各模型的油水流动规律。研究结果表明：①塔河油田孔、洞、缝空间结构复杂，可分为未充填溶洞、部分充填溶洞、全充填溶洞和裂缝贯穿充填溶洞等4种，不同类型储集体生产特征差异大，井间连通性较好，但横向驱替弱。②研究区不同缝洞结构模型内油水流动规律不同，未充填溶洞内流体均匀流动，在底水驱替下油水界面呈现水平抬升特征；部分充填溶洞在下部充填区表现为底水锥进特征，而上部未充填区油水界面趋于水平抬升，水封下部溶洞内的剩余油；全充填溶洞与砂岩油藏油水流动特征一致，底水锥状驱替；中大尺度裂缝穿过充填溶洞时，裂缝为油水流动的高速通道，呈现裂缝水窜特征，在油井钻遇的充填洞一侧沿缝面到井底呈水锥特征，而缝外侧溶洞内原油基本未动用，为高角度裂缝屏蔽剩余油。③研究区在天然能量开发条件下，流体流动仅受井周有效储集体发育规模控制，以垂向流动为主，单井有效动用范围局限；多井生产时，井间流线仅在油水界面以下相连且分布范围较广，井间干扰少；注水开采期间，井间流线仍以垂向分布为主，仅在底部统一水体位置注采时，井间连接较好，注入水横向驱替弱。

Oil-water flow law of Ordovician fractured-vuggy reservoirs in Tahe Oilfield

Based on the geological and production characteristics of Ordovician fractured-vuggy reservoirs in Tahe Oilfield,the conceptual fracture-vuggy model and actual geological model were established,and oil-water flow law of each model was discussed by using streamline simulation method. The results show that:(1)The fracturevuggy reservoirs in Tahe Oilfield have complex spatial structure composed of caves,pores and fractures. There are four types of caves including unfilled caves,partially-filled caves,fully filled caves and fully filled caves through with fractures. The production characteristics of different types of reservoirs differs greatly,the connectivity between wells is good,but the lateral displacement is weak.(2)The oil-water flow laws are different in different types of fractured-vuggy structure models. In unfilled caves,the fluid flowed uniformly,and the oil-water interface presented a horizontally rise under the displacement of bottom water. For the partially-filled caves,the bottom water coning in the lower filled zones was obvious,while in the upper unfilled zones,the oil-water interface tended to rise horizontally, which resulted in water sealing the remaining oil in the lower caves. In fully filled caves, the characteristics of bottom water coning are obvious,and the oil-water flow laws are similar with sandstone reservoirs. For the fully filled caves through with large-scale fractures,the fracture was a high-speed channel for oilwater flow,where water channeling happened easily. On the side of the filled cave drilled by a production well, water along the fracture was coning to the bottom of the well. However,the crude oil in the cave outside the fracture is basically undeveloped,that is the remaining oil shielded by high-angle fractures.(3)During the natural energy development process,the oil-water flow is mainly vertical and controlled by the scale of the effective reservoirs around the well,and the producing scale of single well is limited. During multi-well production,the streamline between wells is only connected below the oil-water interface and is widely distributed,and there is no or less inter-well interference. During the water-flooding development process,the streamlines between injectionproduction wells are still mainly distributed vertically. The streamline connection is better only in bottom water position. The lateral displacement of injected water is weak.