DEVELOPMENT OF UNCONVENTIONAL RESERVOIRS: FLUID CHARACTERIZATION, STIMULATED RESERVOIR VOLUME DETERMINATION, AND PRODUCTION FORECASTING IN THE STACK

Abstract

The Mississippian-age Meramec Series is one of the primary producing intervals of the Sooner Trend in the Anadarko Basin of Canadian and Kingfisher (STACK) counties, Oklahoma and is currently among the most sought-after hydrocarbon plays in the US. It is a low permeability and low porosity play; therefore, an understanding of reservoir limits, fluid and petrophysical characterization, stimulated reservoir volume (SRV), and expected recovery is critical to the development planning of these reservoirs. This thesis will integrate many different engineering concepts in order address all of these crucial points of understanding. In this thesis, first I establish an integrated workflow for multi-component fluid characterization, stimulation region limits and hydraulic fracture dimension estimation and apply the workflow to a study area of the Meramec interval in the STACK play of Oklahoma. Rate transient analysis (RTA) is used to characterize porosity, permeability, fracture dimensions and drainage areas. Subsequently, an Equation-of-State (EOS) model is established for the study area spanning the liquids-rich zone to high Gas-Oil Ratio (GOR) region. The EOS model is refined via compositional reservoir simulation by matching initial producing GORs field-wide and imposing compositional variations that would be observed due to thermal maturity. Reservoir parameters are then refined using the enhanced fluid model, and the integrated workflow is repeated until convergence. From there, I zoom into a single well and utilize a history matching process with the use of flow simulation to understand the extent of the SRV. Within this workflow, a dual porosity model is utilized. Initially, a very large fracture network is created and the injection of fracturing fluid is history matched. From the results of stress changes from this history matched model, the SRV is extracted. This region then becomes the only region with enhanced fracture properties, and the model is history matched again. These results generate an understanding of how the SRV is affected by hydraulic fracturing. Then I introduce an adaption of the modified Hall Analysis that allows for very quick diagnosis of fracture efficiency. It is found that from certain properties of the introduced dHI (derivative of the Hall Integral) plot, a qualitative understanding of total fracture area and volume can be obtained. I’ll also show a couple sample applications of the methodology go show how it can potentially be used. Finally, with the model used to in history matching of the injection of hydraulic fracturing fluid, initial production is history matched. From the results of this history match, I gain an even better understanding of the enhanced properties of the SRV. This history matched model is then utilized in forecasting efforts in an attempt to understand just how much hydrocarbon can potentially be recovered from the area.