Rapid and Low-Cost Methodology To Obtain an Updated Compositional Model of Produced Fluids Using Separator Discharge Data Analysis

摘要

Fluid characterization data used to build representative reservoir fluid models for reservoir and production engineering is generally scarce and very costly, due to the expense of fluid sampling and analysis and, operational related problems of well intervention. The problem turns more dramatic when the field to be studied has been producing for some time and its bottom-hole pressure has reached the bubble point. In those cases, initial reservoir fluid data is more difficult to be used as some portion of the hydrocarbon's heaviest or lightest components, whether oil or gas is produced, may have been left in the reservoir and initial PVT data is no longer valid or very difficult to match to current fluid behavior. One of the most common practices of obtaining fluid data is by taking well bottom-hole samples, or by obtaining surface oil and gas mixture samples and analyzing them in the lab using recombined methods. Due to the costs involved, including loss of time and production, operating companies do not obtain fluid data with the required frequency. Accordingly, engineers are left with the only option of using non-updated or insufficient data that will affect the outcome of their simulation studies. This work describes a rapid and low cost methodology to obtain an updated compositional model for produced fluids using gas chromatography, oil characterization and GOR from analysis of the separator fluid discharge. The required samples are easily collected with low cost to the operating company. Then, a case history is shown where compositional fluid models obtained with the proposed method are used in well, surface network and process facility simulation models, withexcellent results. A comparison of field data against the simulation model results is also shown.