TITLE PAGE Creating a Geologic Play Book for Trenton-Black River Appalachian Basin Exploration Semi-Annual Report Reporting Period Start Date: October 1, 2004 Reporting Period End Date: March 31, 2005 Principal Authors: Douglas G. Patchen, Katharine Lee Avary, John M. Bocan, Michael Hohn, John B. Hickman, Paul D. Lake, James A. Drahovzal, Christopher D. Laughrey, Jaime Kostelnik, Taury Smith, Ron Riley and Mark Baranoski April 2005 DOE Award Number: DE-FC26-03NT41856 West Virginia University Research Corporation P.O. Box 6845, Morgantown, WV 26506-6845 University of Kentucky Research Foundation 109 Kinkead Hall, Lexington, KY 40506-0057 New York State Museum Institute Room 3140 CEC, Albany, NY 12230 Ohio Division of Geological Survey 4383 Fountain Square, Columbus, OH 43224 Pennsylvania Geological & Topographic Survey 400 Waterfront Drive, Pittsburgh, PA 15222-4745 West Virginia Geological & Economic Survey 1 Mont Chateau Road, Morgantown, WV 26508-8079 DISCLAIMER “This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.” ii ABSTRACT The Trenton-Black River Appalachian Basin Research Consortium has made significant progress toward their goal of producing a geologic play book for the Trenton- Black River gas play. The final product will include a resource assessment model of Trenton-Black River reservoirs; possible fairways within which to concentrate further studies and seismic programs; and a model for the origin of Trenton-Black River hydrothermal dolomite reservoirs. All seismic data available to the consortium have been examined. Synthetic seismograms constructed for specific wells have enabled researchers to correlate the tops of 15 stratigraphic units determined from well logs to seismic profiles in New York, Pennsylvania, Ohio, West Virginia and Kentucky. In addition, three surfaces for the area have been depth converted, gridded and mapped. A 16-layer velocity model has been developed to help constrain time-to-depth conversions. Considerable progress was made in fault trend delineation and seismic-stratigraphic correlation within the project area. Isopach maps and a network of gamma-ray cross sections supplemented with core descriptions allowed researchers to more clearly define the architecture of the basin during Middle and Late Ordovician time, the control of basin architecture on carbonate and shale deposition and eventually, the location of reservoirs in Trenton Limestone and Black River Group carbonates. The basin architecture itself may be structurally controlled, and this fault-related structural control along platform margins influenced the formation of hydrothermal dolomite reservoirs in original limestone facies deposited in high energy environments. This resulted in productive trends along the northwest margin of the Trenton platform in Ohio. The continuation of this platform margin into New York should provide further areas with good exploration potential. The focus of the petrographic study shifted from cataloging a broad spectrum of carbonate rocks that occur in the Trenton-Black River interval to delineation of regional limestone diagenesis in the basin. A consistent basin-wide pattern of marine and burial diagenesis that resulted in relatively low porosity and permeability in the subtidal facies of these rocks has been documented across the study area. Six diagenetic stages have been recognized: four marine diagenesis stages and two burial diagenesis stages. This dominance of extensive marine and burial diagenesis yielded rocks with low reservoir potential, with the exception of fractured limestone and dolostone reservoirs. Commercial amounts of porosity, permeability and petroleum accumulation appear to be restricted to areas where secondary porosity developed in association with hydrothermal fluid flow along faults and fractures related to basement tectonics. A broad range of geochemical and fluid inclusion analyses have aided in a better understanding of the origin of the dolomites in the Trenton and Black River Groups over the study area. The results of these analyses support a hydrothermal origin for all of the various dolomite types found to date. The fluid inclusion data suggest that all of the dolomite types analyzed formed from hot saline brines. The dolomite is enriched in iron and manganese, which supports a subsurface origin for the dolomitizing brine. Strontium iii isotope data suggest that the fluids passed through basement rocks or immature siliciclastic rocks prior to forming the dolomites. All of these data suggest a hot, subsurface origin for the dolomites. The project database continued to be redesigned, developed and deployed. Production data are being reformatted for standard relational database management system requirements. Use of the project intranet by industry partners essentially doubled during the reporting period. iv TABLE OF CONTENTS Page Title Page i Disclaimer ii Abstract iii Table of Contents v Executive Summary 1 Results and Discussion 3 Conclusions 98 References 99 List of Acronyms and Abbreviations 104 v EXECUTIVE SUMMARY This report documents further progress of the Appalachian Oil and Natural Gas Research Consortium (AONGRC) to create a geologic play book for Trenton-Black River exploration in the Appalachian basin. The AONGRC organized a Trenton-Black River Research Team, consisting of recognized experts currently employed by the state geological surveys in Kentucky, Ohio, Pennsylvania and West Virginia, and the New York State Museum Institute, and then recruited seventeen gas exploration companies to form an industry-government-academic partnership. This “Trenton-Black River Appalachian Basin Exploration Consortium” (the Consortium), agreed to co-fund and conduct the research effort. This project has three main objectives: 1) to develop an integrated, multi-faceted, resource assessment model of Trenton- Black River reservoirs in New York, Ohio, Pennsylvania, Kentucky and West Virginia; 2) to define possible fairways within which to conduct more detailed studies leading to further development of the gas resource in these reservoirs; and 3) to develop an integrated structural-stratigraphic-diagenetic model for the origin of Trenton-Black River hydrothermal dolomite reservoirs. Researchers have examined and interpreted all of the seismic data that are currently available to the consortium. To aid in the correlation between well logs and seismic profiles, synthetic seismograms were made for key wells, providing an intermediate correlation step between geophysical logs and seismic data. These seismograms, together with the revised 3-D velocity models, have enabled researchers to identify formations tops on seismic, and to begin the process of mapping these tops and stratigraphic intervals throughout the basin. A database has been created for the seismic and well log data. This collection of seismic, geophysical well log and well stratigraphic top data has continued to increase in size over the past 6 months. Stratigraphers have examined and scanned approximately 1,800 geophysical logs and measured and described 16 cores from across the basin. Approximately 500 of the scanned logs have been converted to vector (LAS) format for use in regional cross sections. A network of 18 cross sections has been generated, along with a series of preliminary isopach maps that are based on formation tops interpreted from approximately 1,000 well logs, plus core and sample descriptions. A better understanding of the basin architecture during deposition of the Trenton Formation has emerged from this effort, and production can be seen to be related to this basin architecture, which itself could be structurally controlled. A preliminary depositional model for Trenton rocks consisting of two platforms with an intervening sub-basin has been developed and placed within this architectural framework. Cross sections, isopach maps, core descriptions and the presence of hydrocarbon reservoirs all support the validity of this model. To date, 605 thin sections have been analyzed by conventional petrographic microscopy, and 130 core samples have been examined with scanning electron 1 microscopy and energy dispersive x-ray spectroscopy. A pattern of basin-wide marine and burial diagenesis of original limestone facies has emerged from this effort. Six diagenetic stages have been recognized, four of which are marine diagenesis and two of burial diagenesis. This dominance of marine and burial diagenesis resulted in rocks of low porosity and permeability and poor reservoir potential. Commercial amounts of porosity, permeability and petroleum accumulation appear to be restricted to areas of the basin where secondary porosity developed in association with hydrothermal fluid flow upward from the basement along faults and associated fractures. To better understand the origin of the four different dolomite types that have been observed, researchers are conducting stable isotope, strontium isotope, trace element and fluid inclusion analyses. More than 1,200 samples have been analyzed for stable isotopes of oxygen and carbon. Oxygen isotope values for samples from New York wells clearly indicate that the fluids from which the rocks formed was not sea water. Data from Ohio suggest a similar origin. Strontium isotope data suggest that the fluids that made the dolomite passed through continental basement rocks or immature feldspar-rich siliciclastics prior to making the dolomite. Trace elements are being analyzed for Fe and Mn, which are essentially absent in sea water but are common in subsurface brines. The Fe and Mn concentrations that were observed support a burial origin for the dolomites. Fluid inclusions trapped in dolomite crystals represent the original fluid from which the crystals formed. Therefore, fluid inclusions can be analyzed to determine the temperature and salinity of the original fluid and to gain information on the environment of formation. All of the fluid inclusion and geochemistry results to date support a hydrothermal origin for all of the various dolomite types that occur in the Trenton Limestone and Black River Group across the study area. The project database and intranet continue to be developed and expanded; data from all project tasks are posted on the website, as are all presentations made at consortium meetings. Approximately two thirds of the company partners were represented at a recent meeting of the entire consortium. Presentations made by research team members at this day-long meeting serve as the basis for this technical report. During the recent consortium meeting, several company partners expressed an interest in providing more data to the research teams. The general consensus of the entire consortium was that incorporating these new data into the effort would result in a final product that would be more beneficial to industry and to the funding agencies. However, everyone present also agreed that to fully analyze and integrate results from these additional data would require additional time beyond the original scope of the project. Following the consortium meeting, the Project Director made a lengthy presentation to NETL staff members, after which the advantages of a no-cost extension were discussed. 2 RESULTS AND DISCUSSION Structural and Seismic Analysis and Mapping Structural and seismic analyses are being carried out to characterize the major geologic structures of the study area and to determine as closely as possible their timing relative to the fracturing, dolomitization and hydrocarbon charging of reservoirs in the Trenton-Black River interval. To accomplish this, members of the Structural and Seismic Analysis and Mapping research team developed and implemented the following work plan: • Data Acquisition -- Seismic, well logs and stratigraphic well tops • Load Seismic data – Digital SEGY files into Kingdom Suite – Raster images into PetraSeis • Load Well Data – Digital LAS files into Kingdom Suite & Petra – Raster images into Petra • Load preliminary (i.e. any available) well tops • Use sonic logs for synthetic seismogram creation and creation of velocity model • Correlate log tops to reflecting seismic horizons • Interpret stratigraphy and structure from seismic • Use velocity model to transform depths in time to depths in feet subsea • Create 3D surfaces from seismic horizon and well-based stratigraphic tops elevations • Merge products with those of the other consortium members Traditional subsurface data derived from well logs have been integrated with seismic data to map the Precambrian surface, including fault locations and major structural axes, which may be indicators of potential Trenton-Black River dolomitized and/or fractured target areas. In addition, contour maps are being constructed using the two combined data sets to develop the following: • Base of Devonian Shale • Top of Ordovician • Kope Formation • Utica Shale • Trenton Formation • Black River Limestone • Knox Unconformity • Pre-Knox sediments (Conasauga Group, Rome Formation, etc.) 3 • Basal sandstones • Major structural features (especially those affecting dolomitization) In developing these maps, well-data tops agreed to by the five research agencies are being used together with two-way–travel times from available seismic data. The two- way-travel times are being converted to elevations in feet (relative to mean sea level) based on sonic data and formation tops data from the well logs. Seismic Data Existing seismic data already available for this study at the five research agencies form a general data base for the project. Each of the sponsoring companies, however, has been and is being solicited for contributions of additional data. The additional data are considered critical to meet the objectives of this part of the study. A summary of the collected seismic data and potential seismic data contributions are illustrated in Table 1 below. As a result of the seismic data contributed by the five research agencies and industry, the following datasets were made available and loaded into the Kentucky Geological Survey’s (KGS’s) seismic interpretation workstations: • Digital and paper data made available by the KGS, covering eastern Kentucky, West Virginia, and parts of Pennsylvania and New York • Digital data made available by the New York State Museum, covering parts of western New York • Paper data made available by the Pennsylvania Geological Survey, covering part of western Pennsylvania • Digital data made available by North Coast Energy, covering small parts of West Virginia • Digital and paper data made available by the Ohio Division of Geologic Survey within Ohio • Digital data from Abarta Oil and Gas for data in eastern Kentucky • Digital 3-D data made available by Talisman Energy in southwestern Ontario. The map in Figure 1 shows the extent of the data that are currently available for seismic interpretation in the project. 4 Table 1. Company Results Abarta DATA: 2 lines in central KY Belden and Blake* Waiting to see who will contribute, concerned, confidentiality; data now Talisman’s Cabot No data available Ceja Don’t know; checking with attorneys again; originally committed; no shot point map Compton No U.S. data Enervest (CGAS) Checking with new owners and partners on Saybrook 3-D data EOG possible work in EOG office with some NY data Equitable Seisco owns former Equitable data; Checking with Seisco on requested PA, OH data EXXON** Will allow for 3rd party data GeoData* Will give permission of 3rd party data; checking with Exxon on joint CNG data Great Lakes Checking contracts with partners; skeptical; no shot point map NY State Museum DATA: western NY PA Geological Survey DATA: western PA North Coast DATA: several lines in WV Petro Evaluation Sending DATA for Musking. Co. OH thru John Foreman; possibly more Pioneer SEI data; difficult to obtain; no shot point map Seisco** DATA: covers much of KY, WV; some in PA, NY; KGS has rights Seismic Exchange** Visited in ¾; concerned; issues: rights and sharing; want +$; shot point maps Seneca Visited in ¾; data in PA; issues: confidentiality, rights, access; shot point map Schlumberger Not contacted for seismic data Talisman DATA: 3-D part Rochester Field, Ont.; 2-D data on NY/PA border being sent Texas Keystone Talked with John Taylor; will send stick maps of available data; WV data likely Ultra SEI data; may allow consortium work at their Denver office only; PA CGG map rec’d Vintage Unable to provide licensed data to consortium * Now owned by Capitol C Energy Operations ** Not a sponsor *** Robert Gaston, Consultant 5