Developing and Applying Fluid Properties for the Wara Formation, Greater Burgan Field, Kuwait: A Supergiant Field With Variable API Oil Gravity

API gravity vs. Depth correlations were developed for the Greater Burgan Field. The results of this work dramatically changed the determination of fluid PVT properties for the field which were used in Build-up analysis, wellbore flow correlations, simulation model initialization and OOIP estimates. Past PVT studies based solely on fluid sample analyses failed to honor the heavy oil or tar near the oil-water contact. Additional API gravity Vs depth data available from core data, and initial production tests were incorporated into the analysis. As a result, new correlations were developed which recognized values down to 10° API near the original OWC. Previous correlations did not have oil gravity samples lower than 24° API gravity. Introduction The Greater Burgan field located in southeastern Kuwait was discovered in 1938 but production from the field did not begin until 1946. The "Super Giant" field covers a surface area of about 320 square miles. Production from the Greater Burgan Field has been primarily from the middle Cretaceous clastic reservoirs of the Wara and Burgan (third & fourth sand) formations which are separated by the carbonate Maddud formation as shown in Fig. 1. The Burgan formation is the major producer in Greater Burgan with the Wara formation having produced approximately 10% of the field's total production. The Greater Burgan field is comprised of four distinctive structural culminations. These structures are identified as the Ahmadi, Magwa, Burgan and NE Burgan areas. Recent work has recognized that each of these areas are characterized by different PVT properties which are mostly likely attributed to the original oil migration and fill-up history of the Greater Burgan field. Past studies conducted by Kuwait Oil Company (KOC) in 1960 and 1995 did not incorporate API gravity data from non-PVT sources. API gravity vs. depth data available from core data, and initial production tests were added to the data sets used in previous studies. This more comprehensive data set was normalized and then curve fit with exponential equations. Four distinctive correlation trends for the Ahmadi, Magwa, NE Burgan and Burgan areas were developed from this work. The aim of this paper is to highlight the variability of PVT properties that can occur both vertically and areally in large fields like Greater Burgan and their impact on simulation results and other analyses.