Integrated Characterization and Simulation of Multisection Areas in Hugoton and Panoma Gas Fields

Saibal Bhattacharya, Martin K. Dubois, Alan P. Byrnes, Geoffrey C. Bohling, and John H. Doveton
Kansas Geological Survey, University of Kansas, Lawrence, KS

The Hugoton and Panoma gas fields, North America's largest, produce from thirteen fourth-order marine-nonmarine sedimentary cycles of the Wolfcampian Chase and Council Grove Groups, respectively. A fine-layered cellular geomodel was constructed for these fields using a four step workflow: 1) define lithofacies in core and correlate to wireline log curves and geologic variables (depositional environment and relative cycle-position), 2) train a neural network and predict lithofacies at non-cored wells, 3) populate a 3D cellular model with lithofacies using stochastic methods, and 4) populate the model with petrophysical properties and fluid saturations using facies-specific equations based on core data. The fine-scale model was upscaled to 25 layers for simulation.

Simulation studies were carried out at 3 multi-section data-rich areas. Production/pressure history matches were obtained at both Chase and Council Grove wells over 50-plus years when communication was allowed between Council Grove and Chase. The model showed no excess flow-capacity when wells produced free of rate-constraints. Also, simulator-calculated bottom-hole shut-in pressures approximated recorded surface shut-in pressures at infill Chase and Council Grove wells (upon completion) while simulator-calculated layer-pressures closely matched layer-specific drill stem test data indicating differential depletion between layers. Material-balance calculations also indicated communication between Chase and Council Grove wells.

Simulation studies validated original-gas-in-place, layering, and permeability distribution in the Hugoton-Panoma geomodel. Under-produced zones/intervals at higher pressures were identified and their remaining potential simulated. Production decline rates at Chase and Council Grove wells were estimated to remain above 2% over 20 years.