Integrated Characterization and Simulation of the Fractured Tensleep Reservoir at Teapot Dome for CO2 Injection Design

Abstract

This paper describes a workflow that fully utilizes the post-stack seismic attributes to derive reliable geologic and fracture models that are validated with multiple blind wells and reservoir simulation. The first step in the workflow is to run post-stack seismic processes, which includes volumetric curvature, post-stack inversion and spectral imaging. The second step consists of using the various post-stack seismic attributes to derive 3D geologic and fracture models. The third step is to use the derived models in a reservoir simulator to verify the validity of the models.This workflow was applied to the Tensleep reservoir at Teapot Dome in Wyoming. A large number of post-stack seismic attributes were generated in time and then depth converted within a 3D geocellular grid. These seismic attributes were used as input in REFRACT TM , Prism Seismic fracture modeling software, to create geologic and fracture models. An effective permeability was estimated by using a linear combination of the scaled fracture density and the matrix permeability. Two reservoirs unknowns were estimated by history matching in a black oil simulator: the strength of the aquifer and the scaling factor used to convert fracture density to fracture permeability. Water cut was matched at all the wells, confirming the reliability and accuracy of the derived geologic and fracture models and the usefulness of the workflow. With the derived dynamic model, a compositional simulator was used to test various CO 2 injection rates and their effects on the breakthrough time.

Dual‐Porosity Flow Diagnostics for Spontaneous Imbibition in Naturally Fractured Reservoirs

“…The Pennsylvanian Tensleep formation forms the main reservoir. The formation consists of aeolian sands, interbedded with sabkha and marine dolomites (Ouenes et al., 2010). The Teapot Dome is considered to be predominantly a Type II fractured reservoir according to Nelson ’ s classification (Nelson, 2001), meaning that the reservoir is a dual‐porosity system where fractures provide the essential permeability and the matrix only contributes to flow.…”

Distribution of Well Performances in Shale Reservoirs and Their Predictions Using the Concept of Shale Capacity

“…The enhanced seismic is used as input in the extended elastic inversion [11][12] (EEI) to create the elastic properties needed to compute the brittleness and used as input in the geologic and fracture modeling effort that uses the neural network 8,9,13 . The stochastic inversion was used in the EEI to create seismic attributes with a resolution of 1 msec which will allow the building of geologic and fracture models that have a vertical resolution of 3 to 5 m, a necessary requirement for proper quantitative characterization of shale reservoirs.…”