【作者】 闫栋栋；

【导师】 杨满平；

【作者基本信息】 燕山大学 ， 油气田开发工程， 2009， 硕士

【摘要】 我国油田的储层以陆相砂岩沉积为主,非均质性明显。经过长期的注水开发后,地下已经形成了相对固定的注采连通对应关系。注入水总是沿着高渗层、段率先到达采油井底,水驱效率低。随着水驱程度的加深,地下注采状况更为复杂,油藏开发难度大。不稳定注水技术是一种针对非均质油藏的开发方法,其优势在于维持现有井网分布的前提下,通过改变生产工作制度而提高注入水的波及面积,降低产出液的含水率,提高原油的采出程度。目前对不稳定注水机理研究仅局限在现场实验,没有形成一套完整的理论,这就有必要对其进行进一步的研究,从而使其指导生产。非均质性的强弱直接影响着不稳定注水的效果。毛细管力与地层弹性力发挥的作用与地层的润湿性有关,在不稳定注水不同阶段发挥着不同的作用。根据不稳定注水机理建立了不稳定注水微观模型来模拟储层不同停注采半周期内采油量与采液量的关系。编写了周期注水微观机理分析程序,对其理论进行了验证,为今后不稳定注水实验提供新的研究方向。对取自我国东部某油田低流度油藏岩心进行了“气泡法”启动压力测试与单相渗流实验。实验表明,流度越低,启动压力梯度越高,且它们之间满足相关性非常高的乘幂变化关系。通过对岩心单相渗流实验得到的数据进行分析归纳,得到了其流体非线性渗流段启动压力梯度的计算式。对相渗特征曲线进行了渗流特征理论分析,得到了最小启动压力梯度与拟启动压力梯度的理论值及启动压力梯度与驱替压力梯度的关系函数。由非线性渗流区长度的数学表达式可知,流度越低,其非线性渗流区越宽。更多还原

【Abstract】 Reservoirs in China mainly belong to fluvial reservoirs, which show heterogeneity sharply. After long time waterflooding development, it have formed the relatively Injection-production relation underground. Injecting water always flow along the high permeability parts to oil wells, which made waterflooding efficiency low. With deepening of waterflooding degree, injection-production relation become more complex which made it difficult for reservoir exploitation. Unsteady waterflooding is a method aimed at heterogeneity reservoir exploitation. Unsteady waterflooding is a way of heterogeneous reservoirs exploitation. Without changing well distribution, it can increase water injection area, decrease water content ratio of the produced fluid and increase degree of reserve recovery though changing working system. However, research of unsteady waterflooding mechanism is just confined in oil field experiments, which hasn’t formed a completed theory. Further research is needed to conduct the production.Degree of reservoir heterogeneity directly affects the effect of unsteady waterflooding. Capillary force and the reservoir elastic have relations with reservoir wettability, which play different roles in different step of unsteady waterflooding.According to unsteady waterflooding mechanism, microscopic model was built to simulate the relations between oil production and produced fluid at different step of injecting and non- injecting. Program of analysis is also design to verify the method. All the work provides a new analysis method to future unsteady waterflooding experiments.Bubble method threshold pressure gradient tested and single-phase seepage flow experiments have been done whose cores come from a low mobility reservoir of oilfield, which lies in the eastern of China. The results showed that the seepage flow of low mobility reservoir has threshold pressure gradient and nonlinear seepage flow feature. The lower mobility is, the higher threshold pressure gradient is. The threshold pressure gradient has high relativity power correlation with mobility. An equation is also got to calculate the threshold pressure gradient in nonlinear seepage flow by analyzing to the data got form the single-phase seepage flow experiments. Analyzing to the nonlinear seepage flow feather, minimum threshold pressure gradient and pseudo-threshold pressure gradient were got. Function of relation between threshold pressure gradient and displacement pressure gradient was also proposed. Based on mathematic expression for the area of nonlinear seepage flow, the lower mobility is, the wider nonlinear seepage flow area is.更多还原