Abstract
Liquid-rich shale (LRS) wells have shown abrupt changes in production rates and fluid composition. In order to maintain high liquid hydrocarbon production rates over the life of well, as well as proper reserve estimation, a better understanding of the in-situ reservoir fluids is required. In this work, an investigation is performed on the areal and vertical geospatial fluid property variations across the Barnett and Eagle Ford. Available Barnett PVT data was adjudged as entirely nonrepresentative and a multi-contact recombination procedure has been implemented to improve estimates of in-situ reservoir composition. Eagle Ford is known to be highly under-saturated and with no concerns about representativeness identified through data validation, these were accepted and utilized without modification. Ternary diagrams indicating fluid type, vertical variations of OGR, C7+ and API gravity were investigated. Maps were created to review areal variations of these properties (API gravity, C7+, and initial OGR), and finally the decline of OGR with time was studied.
Our study used publicly available data to confirm compositional variation across the Barnett and Eagle Ford. Regions were defined based on initial producing OGR and the decline of this property with time. The created maps present not only ranges and trends for OGR, API gravity and well stream C7+ parameters but the methodologies can be applied to assessing other fields.
