具有弱夹层的封闭油藏中的瞬态渗流

多层油藏分为层间无窜流的油藏和层间有窜流的油藏。本文研究了层间有弱渗透夹层的两层油藏中两种情形的瞬态渗流,包括单层打开的瞬态渗流和一层注入、一层采出的两层油藏的瞬态渗流。用面积平均方法求出了弱渗透夹层封闭油藏中瞬态渗流的平均压降。分析表明:在渗流前期,层间窜流量逐渐增大,在后期层间窜流量趋于稳定;在单层开采的情况下:初期两层压降不同,非打开层的压降有滞后现象,并且隔层渗透率越小,油井工作强度越弱,滞后时间越长;后期两层压降趋于一致,可以作为一层油藏处理。在一注一采的油藏中,当注采量相同时,两层压降在后期趋于不同的稳定值;当注采量不同时,两层压降在后期趋于一致,但不能达到稳定。

Transient Flow in Sealed Reservoirs With Weak Cross-flow Interlayer

The transient flows in layered reservoirs contain flows with cross-flow and without cross-flow. The transient flow in two-layered reservoirs with weak cross-flow interlayer is investigated, including two cases, one is the flow in radical layered reservoirs with production in single zone, another is the flow in one-dimensional layered reservoirs with a producing well and a injection well in different zones. the analytical solution of transient average pressure drop is derived based on area average method, and two examples flows are computed and the pressure drops are drawn in log-log coordinates. The results show that the cross-flow rate increases with the time lapse in early period, and reaches a steady state in the late period. For the flow with single production zone, the average pressure drop is different in early period, and remains steadily in the late period. For a smaller permeability of interlayer zone, the delaying time gets longer when the correlative pressure drop from one of the opening zone. At later time the flow in the layered reservoirs can be regarded as flow in single reservoir. For the flow in one-dimensional layered reservoirs with a producing well and a injection well in different zones, the flow can be regarded as single dimensional flow. When the producing rate is equal to the inputting rate, the average pressure drops of two layers is different in all period and reach different steady states. When the producing rate is different from the injection rate, the average pressure drop of two layers coincide with each other, but unable to reach a steady state.