射孔水平井产能预测方法

为了预测射孔水平井的产能,在Joshi推导水平井产能公式所用模型的基础上,引入了三径向流模型,采用等值渗流阻力法,建立了孔眼未射穿污染带和孔眼射穿污染带2种情况下射孔水平井产能预测模型,考虑了孔深、孔密、孔径、相位、污染带的半径与污染程度、压实带的厚度与压实损害程度、水平井水平段长度等因素对产能的影响,流动机理更加符合油藏实际。利用所建立的产能预测模型进行参数敏感性分析,结果表明,射孔水平井产能随着孔深、孔径、孔密、相位、水平井水平段长度等参数的增大而增大,随着压实带厚度和压实损害程度的增大而减小,对水平井水平段长度、孔深、孔密、压实损害程度的敏感性较大,对相位、孔径、压实带厚度的敏感性较小;孔眼射穿污染带时产能指数对射孔参数的敏感性比孔眼未射穿污染带时低。工程设计时,应尽量增加水平井水平段长度、孔深、孔密,避免过高的压实损害程度。     

Water flooding optimization with adjoint model under control constraints简

The oil recovery enhancement is a major technical issue in the development of oil and gas fields. The smart oil field is an effective way to deal with the issue. It can achieve the maximum profits in the oil production at a minimum cost, and represents the future direction of oil fields. This paper discusses the core of the smart field theory, mainly the real-time optimization method of the injection-production rate of water-oil wells in a complex oil-gas filtration system. Computing speed is considered as the primary prerequisite because this research depends very much on reservoir numerical simulations and each simulation may take several hours or even days. An adjoint gradient method of the maximum theory is chosen for the solution of the optimal control variables. Conven-tional solving method of the maximum principle requires two solutions of time series： the forward reservoir simulation and the backward adjoint gradient calculation. In this paper, the two processes are combined together and a fully implicit reservoir simulator is developed. The matrixes of the adjoint equation are directly obtained from the fully implicit reservoir simulation, which accelera-tes the optimization solution and enhances the efficiency of the solving model. Meanwhile, a gradient projection algorithm combined with the maximum theory is used to constrain the parameters in the oil field development, which make it possible for the method to be applied to the water flooding optimization in a real oil field. The above theory is tested in several reservoir cases and it is shown that a better development effect of the oil field can be achieved.     

基于序列二次规划算法的油藏动态配产配注优化

油藏动态配产配注已经成为实现油田效益最大化的有效措施之一。为提高优化运算速度,处理非线性不等式约束,将序列二次规划算法应用到油藏动态配产配注求解过程中。应用序列二次规划算法将求解变量最优值的非线性优化问题转化为一系列的求解变量搜索方向的二次规划子问题,控制变量的搜索方向采用伴随方法和Broyden-Fletcher-Goldfarb-Shanno(BFGS)方法得到,迭代求取控制变量最优值。实例验证结果表明,总注入量等式约束条件下的最优开发方案,累积产油量增加12.8%,累积注水量下降11.1%,累积产水量下降22.3%,含水率下降4.16%;总注入量不等式约束下的最优开发方案,累积产油量增加29.1%,累积注水量下降26.9%,累积产水量下降30.3%,含水率下降4.16%。但是,在不等式约束情况下,由于注采失衡,油藏压力大幅下降,易造成后期开发能量不足;需对总注入量及采出量进行等式约束或在不等式约束的基础上添加约束下限。运用该方法对胜利油区埕岛油田27A区块进行方案调整优化,结果表明,优化后的采出程度相对于优化前提高0.92%,净现值增长35%。     

多层合采油藏启动压力及层间干扰

层间非均质油田多层合采时,由于渗透率差异及流体性质不同会产生层间矛盾,因此有必要研究提液的有效性。为了系统、定量地研究合采的组合方式,开展了渗透率级差及黏度级差对层间干扰程度的实验,测定了低渗层位的启动压力随影响因素的变化。基于实验结果,建立了非均质多油层油藏模型,推导了考虑层间干扰的产能公式。通过实例计算,证明该方法正确且可行。