Optimization of the gas transporting scheme of gas gathering and transporting system in the oilfield in the operational mode of shutdown

The associated gas processing system is affected by the gas-oil ratio change and the imbalanced gas supply between winter and summer, so the venting system for associated gas often suffers the following problems, such as device maintenance, device accident shutdown and imperfect gas transporting pipeline network. To solve the problems of existing gas gathering and transporting system, the optimal distribution scheme of flow direction and rate of gas gathering and transporting pipeline network was prepared under the constraints of different operational modes (such as normal operation, single-device shutdown and double-device combination shutdown) to decrease the venting volume of associated gas as much as possible. Based on the known parameters of gas gathering and transporting pipeline network, e.g. size, pressure, flow rate and gas gathering point operation, the minimum of the sum of gas venting rate and gas transporting rate was set as the object function, and the processing capacity of the unit and the flow direction and rate of fluid in the pipeline network were set as the decision variables. Based on this, a modified arrangement scheme of gas gathering transporting system was proposed, including adding the auxiliary pipeline and increasing the gas transmission pressure. Finally, the feasibility and reliability of the model were verified with the associated gas gathering and transporting pipeline network in the oilfield as the example.