North Carolina Forestry Association 2013 Annual Meeting October 3, 2013 Shale Gas 101: Natural Gas Exploration / Development: A North Carolina Perspective presented by Dr. Kenneth B. Taylor, P.G. State Geologist of North Carolina and Chief N.C. Geological Survey Division of Energy, Minerals, and Land Resources Kenneth.b.taylor@ncdenr.gov (919) 707-9211
The 1823 organic act which created the North Carolina Geological Survey (NCGS) tasked us to examine, describe and map the geology, geologic hazards, and mineral resources of North Carolina and publish these findings in NCGS reports and maps. Provide unbiased, impartial and relevant technical information to all parties. The NCGS is the custodian of rock cores, cuttings, geophysical logs, etc.
Conventional Hydrocarbons are cooked and migrate from the source rocks to permeable reservoir rocks. Hydrocarbons continue to migrate until trapped by a dome, fold, fault (structural trap) or change in reservoir rock (stratigraphic trap). Hydrocarbons are recovered using vertical wells which are hydraulically fractured.
Esso No. 1 Hatteras Light Drilling and analysis in 1946; 10,044 ft total depth (TD), deepest drilled well in State;drilled 100+ feet into basement rock; no shows oil or gas
Esso No. 2 Pamlico Sound API No. 32-055-2; Drilling and analysis in 1947; 6,410 ft TD to L. Cretaceous; no shows of oil or gas
Well Count by County (Summary) Total number of oil/gas test wells 128 (126 plugged and abandoned with two wells Simpson #1and Butler #3 shut-in (under bond of $5,000 each). First: Craven County in 1925 Great Lakes #2 total depth 2,404 ft. Last: Lee County in 1998 Butler #3 total depth 2,550 ft. Top five counties: (1) Onslow with 22 wells; (2) Carteret and Brunswick tie with 16 wells; (4) Dare with 15 wells; (5) Hyde with 10 wells.
The most active exploration years, those with ten or more wells completed are: 1971 with 19; 1969 with 13; 1959 with 11; and 1966 with 10.
Well Count by County Beaufort 5 wells Bertie 1 well Bladen 1 well Brunswick 16 wells Camden 2 wells Carteret 16 wells Craven 2 wells Currituck 2 wells Dare 15 wells Duplin 1 well Gates 1 well Hertford 1 well Hyde 10 wells Jones 1 well Lee 8 wells New Hanover 3 wells Onslow 22 wells Pamlico 4 wells Pasquotank 1 well Pender 8 wells Tyrrell 5 wells Washington 2 wells Wilson County 1 well
Eastern North Carolina Petroleum Show Reports 7 wells reported shows: Camden : show of gas while drilling(?) in L. Cret. (?). Carteret : show of gas in unknown formation Dare : show of gas in L. Cret.(?): prod. test, no details Hyde Pamlico Sound: show of oil in U. Cret.(?): oil fluorescence in sidewall core Pamlico : (1) show of oil & gas. Pender : show of oil & gas: no details Tyrrell : show of oil & gas, poss. in basement rock: prod. test, no details Source: USGS Briefing to NC Legislature s Offshore Drilling Panel: www.ncleg.net/documentsites/committees/oeesc/4.../resources-usgs.pdf
Unconventional or Continuous Hydrocarbons are cooked and cannot migrate from the source rocks due to low permeability (rocks do not have inter-connected pathways to permit fluids or gases to flow through the rocks). In order to release the hydrocarbons, a significant increase in the rock permeability is required using hydraulic fracturing. Wells are drilled with horizontal laterals so the a larger volume of source rock is in contact with the well bore.
MESOZOIC BASINS North Carolina Geological Survey
Map showing the distribution of Mesozoic basins in North Carolina (from Reid and Milici, 2008). Deep River Basin 150-mile-long northeast trending half-graben (rift basin) with a steeply dipping eastern border fault. ~7,000 feet of Triassic strata. Lake deposits similar to African rift valley lakes. ~59,000+ acre prospective area. Total petroleum system containing: Source rock Seal Traps / reservoir Relatively untested exploration area.
Generalized cross section From Olsen and others, 1991
Sediments are predominantly gas prone with some oil shows. TOC data exceeds the conservative 1.4% threshold necessary for hydrocarbon expulsion. Organic matter derived from terrestrial Type III woody (coaly) material and from lacustrine Type I (algal material). Thermal alteration data (TAI) and vitrinite reflectance data (%Ro) indicate levels of thermal maturity suitable to generate hydrocarbons. Reid and Milici (USGS OFR 2008-1108)
Kerogen type and maturity (Tmax) multiple wells Simpson #1 LE-OT-1-98 Dummitt Palmer #1 - LE-OT-82 Bobby Hall #1 LE-OT-2-83 LE-C-4-45 BDH-9 USBM2
Fact Sheet 2012-3075 -- Assessment of Undiscovered Oil and Gas Resources of the East Coast Mesozoic Basins of the Piedmont, Blue Ridge Thrust Belt, Atlantic Coastal Plain, and New England Provinces, 2011 released June 2012. Methodology: Numerical, conservative approach computed by the U.S. Geological Survey. Deep River Basin: Mean 1,660 billion cubic feet of gas (BCFG); Mean 83 million barrels of natural gas liquids (MMBNGL). Dan River Danville Basin: Mean 49 BCFG; no natural gas liquids.
Note the unassessed basins such as the Cumberland- Marlboro basin. There may be more shale gas potential than is currently known.
Source: USGS briefing
QUESTIONS?