Method of hierarchical optimization of wells gas rates taking into account the structure of the gas collection network on the gas condensate field

Aim. The aim of the research is to develop and approve the procedures for distributing the flows of the extracted product across the wells and the elements of the gas collection network, which is optimal in terms of the maximum gas condensate production criterion when fulfilling the task for the total gas extraction and restrictions on the allowable ranges of gas well flow rates.

The choice of operating modes for gas and gas condensate wells and the distribution of production flows through the gas collection network are interrelated tasks, which require their coordinated solution. The implication of the proposed models and algorithms is aimed at fulfilling this condition.

Materials and methods. The proposed optimization algorithms are non-linear programming methods.

Procedures for approximating functions of one variable are connected to the optimization algorithms.

Results. The proposed models and algorithms are based on the decomposition of the original general model, consisting of four levels: wells, clusters, general cluster gas pipelines and a complex gas treatment plant. Firstly, this makes it possible to perform calculations separately for each level. Secondly, the solution of a problem with a large number of unknown variables at each level is replaced by the solution of a series of problems, each of which contains a smaller number of unknown variables. This makes it possible to perform optimization of real infield gas gathering networks. The algorithms not only search for the values of the required variables, but also plot the dependences of the well flow rates for gas condensate on the well flow rates for gas, as well as gas condensate flow rates on gas flow rates for each element of the gas gathering network.

Conclusions. The calculations performed have showed the possibility of increasing the condensate withdrawals at a constant level of total gas extraction with the use of the proposed models and algorithms. A subsequent check based on integrated modeling has showed that there were no technological complications in the gas gathering system when the optimum scenario was implemented.

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