SIMULATING INJECTION-PRESSURE RESPONSE WITH REAL-WORLD DATA AND A HIGH-RESOLUTION MODEL OF THE ARBUCKLE GROUP, SOUTH-CENTRAL KANSAS

The Cambrian-Ordovician Arbuckle Group is a thick carbonate aquifer of critical importance to oil production, wastewater disposal, and future long-term storage of CO2. Injection into the aquifer is also linked with recent seismicity in the midcontinent. Here, a 136 km x 105 km geologic model of the Arbuckle Group in south-central Kansas is developed from a dataset of 29,601 Kansas oil, gas, and disposal wells. Wireline logs from over 1,000 wells are used to correlate formation tops and ensure the accuracy of industry-provided tops (29,591 wells). Arbuckle structure and stratigraphy are modeled and layered with high resolution throughout the model area. The 3D cellular model is populated with petrophysical properties collected from Arbuckle core analysis, drill-stem tests, dynamic data (pressure fall-off tests and downhole pressure monitoring), and 50+ Arbuckle penetrating wireline logs. The model is used to perform simulations using two unique datasets: (1) wastewater injection volumes from 319 injection wells in the model area are used to simulate Arbuckle pressures during the period of increasing seismicity (2010 through 2016) and (2) UIC (Underground Injection Control) Class I wells within the model area provide long-term pressure data. By upscaling drill-stem test permeability and core analysis porosity to the tightly layered model, we achieve an excellent pressure-history match and report permeability ranging from milliDarcy to Darcy for the Arbuckle. This iteration is then up-scaled to constrain basement properties through injection simulation and basement pressure-response at depths of earthquake epicenters. The history-matched model can predict pore-pressure response at depth and inform rate-reduction decisions to mitigate injection-induced seismicity.