The paper presents a case study from integrated modeling of a group of gas-condensate fields tied to a single gathering and processing system. The adaptive approach to integrated simulations is set forward based on models at the scale of a reservoir, wells, surface gathering and processing facilities with varying degree of detail. Depending on the tasks set the integrated simulation may incorporate models which range both in complexity and degree of refinement created both in specialized commercial simulators as well as in the authors' know-how implemented as an in-house program code.

The solutions and algorithms are developed for combining models by means of communicating data and boundary conditions. The coupling of the reservoir, wells, gathering and processing network models is implemented via data transfer only in one direction (autonomous mode). The coupling of the wells model and gathering system model is implemented in the balance mode (slave mode) at the wellhead to the choke. With the help of successive calculations this mode ensures convergence of pressures, temperatures and flow rates simulated in the given models. Thus gas production is redistributed among the producing wells subject to various operating constraints (maximum drawdown, maximum pipe pressures, hydrate-free production) with the help of optimization algorithms used for simulating different production scenarios for planning the cluster field development project.

The proposed algorithms are implemented as a program code. For commercially available software packages the modeled data is communicated via public interfaces. The integration of the know-how solutions and mass balance models in MS Excel is performed via packeted communication or special integration modules.

The elaborated approach was utilized for the optimization of surface infrastructure and simulation of the performance indicators for a group of gas-condensate fields under one integrated development project. For optimization purposes a simplified integrated model of the producing asset was applied which allows for a large number of simulations run within a reasonable time window for four years' field life (development period). Based on the results of the optimization to simulate the best scenarios a full-scaled integrated model was utilized which included a reservoir model from Tempest, dynamic model from Pipesim and a model of the gas processing facility implemented in the in-house software package RS-Simulator.

The integrated simulation of a gas-condensate group of fields helped to optimize the production profiles based on the existing and future infrastructure. The simulations in the integrated model were used to adjust and modify the configuration of a single gathering facility and develop the best operational modes for the system. Adjusted improved timing was scheduled for commissioning new compressor units and additional high-pressure lines.