Petrophysical Characterization of the Barnett Shale: Progress Report

Petrophysical Characterization of the Barnett Shale: Progress Report Jeff Kane Bureau of Economic Geology PBGSP Annual Meeting February 27-28, 2006

Overview • Database construction • Geophysical log analysis model • Texas United Blakely #1 • Summary Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Database construction • Wireline database: • 7 wells with geochemical data • 2 with log data • 1 with mineralogy data • 1 with limited P & P data • 1 with capillary pressure data • 2 with core descriptions Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Database construction • Many of these core data were recently provided by Dan Jarvie of Humble Geochemical Services. Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Geophysical log modeling • A quick historical perspective • Mineralogical model • Kerogen issues Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Geophysical log modeling – some history • Much of the methodology used today to come from work performed on the T.P. Sims #2 core (ResTech, 1991) • This methodology derives from work done earlier on the Devonian Shale (GRI, 1989) • Few data have been published subsequently. Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Geophysical log modeling - Mineralogy Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Geophysical log modeling - Kerogen Kerogen is a wildcard • It appears as porosity on logs • It has a nominal density of about 1.0 to 1.2 g/cc (but it is probably more variable) • It has a hydrogen index of about 0.65 to 0.70 (water = 1.0) Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Geophysical log modeling - Kerogen (from Guidry and Olszewski, 1990) where: Wk is the weight of kerogen TOC is the weight fraction of total organic carbon S1 is the weight fraction of free oil CS1 is the weight fraction of carbon in the free oil Ck is the weight fraction of carbon in the kerogen Guidry and Olszewski (1990) suggest 0.87 and 0.75 for CS1 and Ck respectively. Jarvie (1999) recommends a value of 0.83 for CS1. Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Geophysical log modeling - Kerogen where: Vk is the volume fraction of kerogen Wk is the weight of kerogen rB is the bulk density rk is the kerogen density Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Geophysical log modeling - Kerogen • The preceding is from derived from core data, not log data • Initially, correlations have to be developed to estimate kerogen volume from logs • This work is currently in progress Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Geophysical log modeling • We have a mineralogical model of clay, quartz, calcite, dolomite, pyrite, apatite, kerogen, and fluids (water and gas) • We have a set of logs that have known or estimated responses to each of these model points • We can construct a set of equations to describe these relationships Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Geophysical log modeling • This leads to a set of simultaneous equations that allow us to solve for the volumes of the geologic constituents present • This is fundamentally the same approach used by programs such as ELAN™ and OPTIMA™ • We use the Geolog™ package MultiMin™ Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Overview of what the logs show Texas Blakely #1 wireline log analysis Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Texas United Blakely #1 Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Summary • We have just begun to build an extensive Barnett database • We already have a basic model to analyze the Barnett from wireline logs • Work to date suggest that logs will be of great value in providing detailed data on Barnett mineralogy and facies. More core-based work is necessary to verify this and and refine our initial model Jeffrey A. Kane, Bureau of Economic Geology , PBGSP Annual Meeting, 2/27-28/2006, Austin, TX

Petrophysical Characterization of the Barnett Shale: Progress Report