عنوان مقاله [English]
Production wells in offshore shared oil fields require well technical services. These services are done by two types of well technical services groups, named wellhead services group and wire-line services group. Production wells in offshore shared oil fields require well technical services and lack of the services affect production productivity of oil wells. In fact, due to supply limitations, there are fewer well technical services groups compared to the number of oil wells. Failure to service oil wells by well technical services groups based on a predetermined plan, will lead to considerable loss in production performance of oil wells and hence higher costs. But stopping production process is one of the requirements in giving some services to oil wells and so this leads to exceeding oil production of competitor neighbor countries and increasing opportunity cost for us. Therefore, in these conditions, balancing between servicing with stopping production process and minimizing stopping production will be very important. Firstly, we propose a mixed integer programming model for the problem considering new applicable and practical features which have not been introduced before. Secondly, we develop algorithms based on Benders and L-shaped exact methods. Also, we develop algorithms based on Lagrangian relaxation heuristic method in seven states. Each state contains eliminating some selective constraints of the proposed mathematical model and adding to its objective function to obtain best constraint selection. In fact, our goal is to produce a variety of lower bounds. In order to evaluate performance of the developed algorithms, we generate various small to large instances and then apply the algorithm on simulated instances. Computational results indicate that algorithms based on L-shaped and Lagrangian relaxation methods produce better lower bounds. Also with growing model, algorithms based on Lagrangian relaxation method are able to produce better lower bounds with respect to the algorithms based on L-shaped method in a short time.