Midland Basin Wolfcamp D SuperEORTM
A well near the center of the Midland Basin, producing from the Wolfcamp D shale, was selected for modeling of the SuperEORTM process. A PVT analysis was used to develop a tuned Equation of State (EOS); a compositional reservoir simulation model was constructed using available geological and well completion data, and the well production and pressure data were history matched.
The history match parameters were then utilized to forecast oil recovery via the SuperEORTM process. Maximum bottomhole pressure was limited to the initial reservoir pressure of 6000 psig. A single stage was modeled to reduce simulation time, and the results upscaled to the number of stages in the completed well.
The graph below compares the projected oil recovery of oil from the well, producing via unoptimized SuperEORTM cyclic injection, versus primary (pressure depletion) production. Optimization of the SuperEORTM process will provide additional oil recovery, as the composition of the injectant, injection rates and pressures, and production rates and pressures would be adjusted during the SuperEORTM operation.
The oil production rate from the modeled well, showing about 5 years of primary production prior to the start of SuperEORTM. The oil production rate increased to a peak of about 3200 BOPD after the first few cycles. Prior to SuperEORTM simulation start, this well was producing 32 BOPD.
SuperEORTM cumulative oil recovery, at a maximum injection bottomhole pressure of 4000 psig, is compared to CO2 and natural gas HnP EOR oil recovery, both at a maximum bottomhole pressure of 6000 psig. As the graph shows, incremental oil recovery via CO2 HnP is about 1.4X primary, while natural gas (90% C1, 8% C2, 2% C3) shows very little incremental oil recovery. SuperEORTM may recover as much as 6.9X primary EUR in the modeled well. Data shown for a single fracture stimulation stage portion of the well.
The graphs and data shown are excerpted from SPE 206186.