Optimization of sources for focusing wave energy in targeted formations
Optimization of sources for focusing wave energy in targeted formations
复制标题
在目标地层中聚焦波能源的优化
DOI：
10.1088/1742-2132/7/3/003
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发表时间：
2010
影响因子：
1.4
通讯作者：
L. Lake
中科院分区：
文献类型：
--
作者：
C. Jeong;L. Kallivokas;C. Huh;L. Lake
我们讨论了一种数值方法，用于识别表面激发，这是必要的，以最大限度地提高目标地下地层的响应。动机来自地震后的观察和有限的现场实验，根据记录，石油生产率增加，完全归因于诱发的油藏震动。观察结果表明，将波能聚焦到储层可以作为一种有效的低成本提高石油采收率的方法。在本文中，我们报告了一个通用的方法，允许确定的源激发，当提供了一个所需的最大化的结果在目标地层。我们讨论，例如，如何构建的激励，将最大限度地提高目标区域的动能，同时保持沉默的相邻区域。为此，我们投的问题作为一个反源问题，并使用偏微分方程约束的优化方法来达到一个优化的源信号。我们寻求满足平稳性的增广功能，这正式导致一个三重态，伴随和控制问题。我们使用有限元来解决状态和伴随问题，和迭代计划，以满足控制问题收敛到所寻求的源信号。我们报告的一维数值实验在时域中涉及一个分层介质的半无限的程度。数值计算结果表明，优化波源所产生的目标地层动能可以比盲目选择波源所产生的目标地层动能大几倍，并且可以克服圈闭油藏石油的流动阈值。
We discuss a numerical approach for identifying the surface excitation that is necessary to maximize the response of a targeted subsurface formation. The motivation stems from observations in the aftermath of earthquakes, and from limited field experiments, whereby increased oil production rates were recorded and were solely attributable to the induced reservoir shaking. The observations suggest that focusing wave energy to the reservoir could serve as an effective low-cost enhanced oil recovery method. In this paper, we report on a general method that allows the determination of the source excitation, when provided with a desired maximization outcome at the targeted formation. We discuss, for example, how to construct the excitation that will maximize the kinetic energy in the target zone, while keeping silent the neighbouring zones. To this end, we cast the problem as an inverse-source problem, and use a partial-differential-equation-constrained optimization approach to arrive at an optimized source signal. We seek to satisfy stationarity of an augmented functional, which formally leads to a triplet of state, adjoint and control problems. We use finite elements to resolve the state and adjoint problems, and an iterative scheme to satisfy the control problem to converge to the sought source signal. We report on one-dimensional numerical experiments in the time domain involving a layered medium of semi-infinite extent. The numerical results show that the targeted formation's kinetic energy resulting from an optimized wave source could be several times greater than the one resulting from a blind source choice, and could overcome the mobility threshold of entrapped reservoir oil.