Gas Field Deliverability Forecasting: A Coupled Reservoir Simulator And Surface Facilities Model

Abstract

To determine if a gas contract can be satisified now and in the future, it is necessary to forecast the performance of the gas reservoir, the gas inflow into the sandface, the multiphase pressure losses in the wellbore and gathering system and the field facilities. Surface production models which rigorously model from the sandface to the plant gate are available. However, these surface packages model reservoirs simply, in most cases as tank-type reservoirs. Comprehensive 3 dimensional reservoir simulators are available, but typically only include simple surface networks which don`t adequately model multiphase flow in complex gathering systems. This paper describes the procedures used in a joint venture by two software vendors to combine an existing reservoir simulator and an existing surface facilities model into a single forecasting tool. Relatively small changes were made to each program. In the new model, the black oil reservoir simulator provides the formation pressure and water to gas ratio for each well. The surface facilities model then calculates the multiphase flow pressure losses in the wellbore and gathering system, plus the corresponding flow rates for each well. The actual production required from each well to satisfy the pipeline contractual requirements, over each time step, ismore » computed by the surface facilities model and relayed back to the reservoir simulator. The time step is determined dynamically according to the requirements of each program. The performance and results from the coupled model are compared to that of running each model separately for a gas storage field in the USA and for a gas production field with bottom-water. It is shown that running each model separately does not account for all the factors affecting the forecast.« le

Original document

The different versions of the original document can be found in:

• https://digital.library.unt.edu/ark:/67531/metadc1389617/m2/1/high_res_d/10174422.pdf

• http://www.onepetro.org/google/Papers/SPE/eLibrary_Papers/petsoc/1994/94ATMB/PETSOC-94-62/PETSOC-94-62-P.pdf?id=PETSOC-94-62&soc=PETSOC,

http://dx.doi.org/10.2118/94-62

• https://www.onepetro.org/conference-paper/PETSOC-94-62,

http://www.osti.gov/scitech/biblio/10174422,

https://academic.microsoft.com/#/detail/1970443124