Optimal rate allocation for production and injection wells in an oil and gas field for enhanced profitability

Abstract

An oil and gas field requires careful operational planning and management via production optimisation for increased recovery and long-term project profitability. This paper addresses the challenge of production optimisation in a field undergoing secondary recovery by water flooding. The field operates with limited processing capacity at the surface separators, pipeline pressure constraints and water injection constraints; an economic indicator (Net Present Value -NPV) is used as the objective function. The formulated optimisation framework adequately integrates slow-paced subsurface dynamics using reservoir simulation and the fast-paced surface dynamics using sophisticated multiphase flow simulation in the upstream facilities. Optimisation of this holistic longterm model is made possible by developing accurate second order polynomial proxy models at each time step. The resulting formulation is solved as a Nonlinear Program (NLP) using commercially available solvers. A comparative analysis is performed using MATLAB's fmincon solver and the IPOPT solver for their robustness, speed and convergence stability in solving the proposed problem.By implementing 2 synthetic case studies, our mathematical programming approach determines the optimal production and injection rates of all wells and further demonstrates considerable improvement to the NPV obtained by simultaneously applying the tools of streamline, reservoir and surface facility simulation for well rate allocation.

Adjoint-based well placement optimisation for Enhanced Oil Recovery (EOR) under geological uncertainty: From seismic to production

“…It is observed that within the first 5 iterations, the algorithm is able to find a near optimal solution; the solution of CS2-IP is obtained with fewer number of iterations. Compared to a methodology that requires numerous direct calls to a high-fidelity simulator or an approximation of the simulator's output (as shown in Epelle and Gerogiorgis, 2019c), the herein implemented algorithm attains optimality in fewer iterations. All computations were performed on an Intel Core i7-6700 CPU @ 3.40GHz machine with 4 processing cores.…”

A review of technological advances and open challenges for oil and gas drilling systems engineering

“…The complicated economics, technical operational challenges and the overall multifaceted nature of industrial drilling activities have made it open to multiscale modelling, robust simulation methodologies and state of the art experimentation techniques for accurate understanding of the flow scenarios and optimal parameters necessary for a problem-free operation. [8][9][10] Over the past decades, the field has attracted numerous successful contributions from the chemical, petroleum and mechanical engineering communities for well trajectory optimisation and particle removal/hole cleaning processes. More recently, a body of literature specifically belonging to the process systems engineering community has emerged; majorly targeting wellbore stability challenges with respect to the fracture pressure and pore pressure.…”

Study of Wellbore Instability and Collapse Mechanism for a Layered Continental Shale Oil Horizontal Well

“…Aadnoy [23] established a collapse pressure model that considered both bedding occurrence and shale strength weakening, and analyzed the factors affecting the collapse pressure distribution. Combined with the weak plane strength criterion, Ma et al [24][25][26][27][28][29] established an analysis model for the wellbore stability of layered shale horizontal wells, and analyzed the effects of bedding occurrence and water content on the collapse pressure of horizontal wells. However, the current research on shale wellbore stability in China mainly focuses on the marine shale of Longmaxi Formation in Sichuan, and the wellbore instability of continental shale in the north of Songliao Basin has not been studied.…”