海上油田单水平井和多分支井组合开发方案优选方法

Combined stochastic and discrete simulation to optimise the economics of mixed single-horizontal and multilateral well offshore oil developments

提出了一种寻找海上油田单水平井和多分支井开发之间的最优平衡的综合方法,对模型进行了详细阐述,并进行了案例研究。该方法可以在考虑钻井、储集层物性、地面设施和财务分析的情况下得到净现值最高的油田配置。模型采用随机扰动和马尔可夫链蒙特卡罗法来求解全局最大净现值问题,采用混合整数线性规划、改进的Dijkstra算法和Levenberg-Marquardt优化方法来求解流量分配问题。模型可给出最优开发方案建议,包括可以获得最高净现值的井口平台数量、多分支井和单水平井数量及其连接方式。研究表明,模型可得到石油设施的最优使用效果,并协助规划和决策。图12表4参41。

Multilateral wells promise cost savings to oil and fields as they have the potential to reduce overall drilling distances and minimize the number of slots required for the surface facility managing the well. However, drilling a multilateral well does not always increase the flow rate when compared to two single-horizontal wells due to competition in production inside the mother-bore. Here, a holistic approach is proposed to find the optimum balance between single and multilateral wells in an offshore oil development. In so doing, the integrated approach finds the highest Net Present Value(NPV) configuration of the field considering drilling, subsurface, production and financial analysis. The model employs stochastic perturbation and Markov Chain Monte-Carlo methods to solve the global maximising-NPV problem. In addition, a combination of Mixed-Integer Linear Programming(MILP), an improved Dijkstra algorithm and a Levenberg-Marquardt optimiser is proposed to solve the rate allocation problem. With the outcome from this analysis, the model suggests the optimum development including number of multilateral and single horizontal wells that would result in the highest NPV. The results demonstrate the potential for modelling to find the optimal use of petroleum facilities and to assist with planning and decision making.