Kansas Geological Survey, Open-file Rept. 2007-6
Martin K. Dubois, Alan P. Byrnes, Saibal Bhattacharya, Geoffrey C. Bohling, John H. Doveton, and Robert E. Barba
KGS Open File Report 2007-6
The Hugoton geomodel provides a comprehensive lithologic and petrophysical view of a mature giant Permian gas system. Fine-scale cellular models are particularly important for modeling thin-layered, differentially depleted reservoir systems (Hugoton), and methods used in building the model demonstrate the construction of a cellular petrophysical model for a giant field. The study also demonstrates the benefits of pooling proprietary geologic and engineering data in settings having multiple operators.
In the Hugoton, accurate determination of water saturations is problematic due to filtrate invasion, necessitating the use of lithofacies-based petrophysical properties to estimate water saturations. Core-based calibration of neural-net prediction of lithofacies using wireline-log signatures, coupled with geologically constraining variables, provided accurate lithofacies models at well to field scales. The 10,000-mi2 (26,000-km2) model provides shelf-scale three-dimensional view of thirteen shoaling-upward cycles vertically stacked in a low-relief shelf setting. Differences in petrophysical properties among lithofacies and within a lithofacies among different porosities illustrate the importance of integrated lithologic-petrophysical modeling and of the need for closely defining these properties and their relationships. Lithofacies models, coupled with lithofacies-dependent petrophysical properties, allowed the construction of a 3-D geomodel for the 70-year-old Hugoton field that has been effective at the well, section (1 mi2, 2.6 km2) and multi-section and field scales. History-matched reservoir simulations validate the static model and demonstrate differential depletion of the layered system. Most remaining gas is in low-permeability intervals. The model suggests that the 35 TCF gas produced from the 12,000 wells in the field represents approximately 65% of the initial gas in place.
The model provides a tool to predict lithofacies and petrophysical properties distribution, water saturations, and initial gas in place, and a quantitative basis for evaluating remaining gas in place, particularly in low-permeability intervals. It will help direct field management and production practices that could enhance ultimate recovery. The model also provides a "fast-forward" view of similar giant reservoir systems worldwide.
OFR 2007-6.1--Cover, Table of Contents, and Introduction, by Martin K. Dubois and Alan P. Byrnes (PDF, 2.2 MB)
OFR 2007-6.2--Geologic Setting, by Martin K. Dubois (PDF, 1.5 MB)
OFR 2007-6.3--Depositional Model, by Martin K. Dubois (PDF, 2.2 MB)
OFR 2007-6.4--Reservoir Characterization, by Alan P. Byrnes, Martin K. Dubois, and John H. Doveton (PDF, 2.3 MB)
OFR 2007-6.5--Technology to Manage Large Digital Datasets, by Geoffrey C. Bohling (PDF, 1 MB)
OFR 2007-6.6--Static Reservoir Model, by Martin K. Dubois, Geoffrey C. Bohling, and Alan P. Byrnes (PDF, 6 MB)
OFR 2007-6.7--Water Saturations and Free Water Level, by Alan P. Byrnes and Martin K. Dubois (PDF, 1.7 MB)
OFR 2007-6.8--Reservoir Communication, by Alan P. Byrnes, Martin K. Dubois, Saibal Bhattacharya, and Robert E. Barba (PDF, 6.2 MB)
OFR 2007-6.9--Reservoir Simulation, by Saibal Bhattacharya, Martin K. Dubois and Alan P. Byrnes (PDF, 9.2 MB)
OFR 2007-6.10--Original and Remaining Gas in Place, by Martin K. Dubois (PDF, 3.6 MB)
OFR 2007-6.11--Conclusions, by Martin K. Dubois, Alan P. Byrnes, and Saibal Bhattacharya (PDF, 138 kB)
Fitting Variograms to Hugoton/Panoma Facies and Porosity Data, by Geoffrey C. Bohling and Martin K. Dubois (PDF, 840 kB)
Hugoton Geomod4 Build (PDF, 12 MB)
Core Data and Descriptions Database (MS Excel file, 10 MB)
Using the Batch LAS Curve Processing Tools in BatchCurveProc.xls, by Geoffrey C. Bohling (PDF, 122 kB)
BatchCurveProcessing.xls (MS Excel file, 118 kB)
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Kansas Geological Survey, Energy Research
Updated April 9, 2007
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