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2. Oil and Gas Resource Assessmentstop
A. Liard Basin Oil and Gas Resource Assessment B. Whitehorse Trough Oil and Gas Resource Assessment C. Bonnet Plume Oil and Gas Resource Assessment D. Kandik Basin Oil and Gas Resource Assessment E. Peel Plateau and Plain Oil and Gas Resource Assessment F. Old Crow Basin Oil and Gas Resource Assessment G. Beaufort-Mackenzie Basin Oil and Gas Resource Assessment H. Eagle Plain Oil and Gas Resource Assessment Yukon Oil and Gas Exploration Regions Yukon is located in the northern portion of the large geologic province known as the Cordillera, consisting of relatively young mountain belts ranging from Alaska to Mexico. Like most of the Cordillera, Yukon is composed of a diverse array of rock types that record more than a billion years of earth history. In Yukon two main geologic components are largely separated by the Tintina Fault, a major northwest-trending fault with approximately 420 km of right lateral strike-slip displacement. Northeast of the Tintina Fault is a thick, older sequence of sedimentary rocks deposited upon a stable Precambrian cratonic basement marking the western margin of ancestral North America. These sedimentary rocks preserve an Early Paleozoic east to west transition from platform carbonate (east) to basinal shale (west). Platform carbonate deposition ceased in Middle Devonian and shale deposition extended far to the east. During Carboniferous and Triassic normal, clastic marine, shelf sedimentation resumed. Overlying these earlier sedimentary successions is a structural foreland belt and several intermontane basins developed in response to deformation and uplift of the western margin of North America during the Jurassic-early Tertiary Cordilleran deformation. Southwest of the Tintina Fault the Yukon is composed of a younger, complex mosaic of suspect terranes that originated elsewhere and were amalgamated and accreted to the stable ancestral North America sedimentary package during the Cordilleran deformation. Eastern suspect terranes are pericratonic, and western terranes are underlain by oceanic crust. Yukon contains eight structural and sedimentary basins suitable for the formation and preservation of hydrocarbons. Seven of these basins occur within the sedimentary rocks of ancestral North America, and one occurs within the suspect terranes southwest of Tintina Fault. Five of the basins occur in northern Yukon, and two are located in southern Yukon. Geology within the basins northeast of Tintina Fault is essentially the same as that in the Western Canada Sedimentary Basin. The only hydrocarbon production in Yukon comes from the Kotaneelee Field in the Liard Plateau area, located in the far southeast corner of the territory.
Yukon Oil and Gas Resource Assessments Oil and gas resource assessments for the different exploration areas of the Yukon have been completed by National Energy Board and Geological Survey of Canada. These assessments have been periodically updated to incorporate new geological field information from Yukon and exploration plays in other areas. Most of these areas have little or no well information. Basin analysis was routinely undertaken to provide background for developing conceptual hydrocarbon plays. Since conceptual plays have no defined pools or discoveries, probability distributions of reservoir parameters such as prospect area, reservoir thickness, porosity, trap fill, and hydrocarbon fraction are compiled to aid in the assessment. Hydrocarbon assessments completed by the Geological Survey of Canada are based on probabilistic methods using the PETRIMES software. NEB assessments were completed using the @RISK software extension to Excel spreadsheet software. Due to the nature of conceptual assessment results and since no discovered pool sizes are available to constrain sizes of undiscovered accumulations, the uncertainties in oil and gas play potential and pool size estimates for a given range of probabilities are necessarily greater than the ranges derived by discovery process analysis used for assessing mature plays.
Coal Resources The Yukon government and the Geological Survey of Canada (GSC) cooperated on two high-resolution aeromagnetic surveys in the Peel Plateau, Bonnet Plume Basin and Eagle Plain areas. More than 62,000 line-km were flown at 800-metre spacing. Visit http://gdcinfo.agg.nrcan.gc.ca for more information.
Oil and Gas Exploration Regions
Oil and Gas Resource Potential
A. Liard Basin Oil and Gas Resource Assessment Click here to open a map of this region ( Geological Summary The Liard Basin lies between the Rocky Mountains to the south and the Mackenzie and Franklin Mountains to the north. The area includes the physiographic Liard Plateau and portions of the southern Mackenzie and Franklin Mountains. It constitutes the northernmost extension of the Western Canada Sedimentary Basin. Cambrian through Middle Devonian sedimentary rocks consist dominantly of miogeoclinal platform limestones and dolostones transitioning westward to marine shales. Within the carbonates is locally a Manetoe facies dolomite consisting of coarsely crystalline, diagenetic, hydrothermal dolomite. This diagenetic facies has cavernous porosity and is the principal reservoir and target for gas in the area. Unconformably to conformably overlying the carbonates are fissile, grey to black marine shales of the Devonian to Carboniferous Besa River Formation. To the east the Besa River Formation is transitional to carbonates of the Flett and Prophet formations. The Carboniferous deltaic complex of the Mattson Formation overlies the marine shales of the Besa River Formation. The Mattson Formation delta prograded to the west-southwest. It contains friable and porous sandstones interbedded with siltstones and shales. Some coal measures are present. Permian and Triassic strata consist dominantly of shallow water shales and siltstones of the Fantasque and Toad-Grayling formations. Cretaceous marine sandstones and shales unconformably overlie all other units in the map area. Several small hornblende-bearing Tertiary trachytes intrude the sedimentary rocks in the westernmost part of the basin. Structures within the Liard Basin are characterized by northwesterly to northeasterly trending box folds and east-verging and west-verging thrust faults. Topographic lows are typically underlain by synclines containing Triassic and Cretaceous siliclastic sedimentary rocks. Exploration History The first recorded evidence of active petroleum exploration was in 1955 with reconnaissance field work by California Standard (Chevron). The first well in the Yukon was SOBC Shell Beavercrow YT K-02 completed in 1963. 13 wells have been completed in the Yukon. Approximately 570 line-kilometres of two-dimensional seismic has been completed. Yukon contains portions of three fields: Beaver River Field, Kotaneelee Field, and La Biche Field. The Beaver River Field in Yukon is a former producer from well PanAm C-1 Beaver River YT G-01. Production from the Kotaneelee gas field is ongoing. Both of these fields consist of pools and prospects hosted in fractured, diagenetic hydrothermal dolomites of the Manetoe facies within carbonates of the Middle Devonian Arnica, Landry and Nahanni formations. Gas is structurally trapped in closures formed by anticlines, normal faults, and reverse faults. Seal and source for the reservoirs is provided by shales of the Besa River Formation. Commonly gas is trapped on top of water. Plays Six expected plays were identified in the Liard Basin area. Five are gas with one (Cretaceous Chinkah clastics) being gas with potential oil. One play, the Manetoe facies dolomite play is established with proven discoveries, former production from the Beaver River gas field and current gas production from the Kotaneelee gas field (two wells, Duke Energy gas pipeline). This play is a sour, acid, dry gas play and is considered the most significant one for the region.
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B. Whitehorse Trough Oil and Gas Resource Assessment Click here to open a map of this region ( Geological Summary Whitehorse Trough in south-central Yukon is a mainly gas-prone basin containing Mesozoic to Cenozoic strata in an intensely faulted and folded intermontane setting. It is elongate and extends in a northwestsoutheast trend from just north of Carmacks to the near Dease Lake, British Columbia. Whitehorse Trough contrasts with all other hydrocarbon areas in Yukon in that it is underlain by oceanic basement of the allochthonous Stikine and Cache Creek suspect terranes. Basement therefore consists of basalt flows with associated shales, bedded cherts and limestones. Whitehorse Trough was first initiated in Middle to Late Triassic as a forearc basin located immediately east of an emerging ancestral Lewes River volcanic arc and west of a west-dipping subduction zone. Deposition within the basin continued through Middle Jurassic with more than 7,000 metres of basin fill constituting the Lewes River and Laberge groups. Lithologic facies delineate a general west to east transition in depositional environments from prograding deltas with associated coarse and fine clastic rocks (west) to marine, fine clastic rocks (east). Conglomerate occurs throughout the succession as localized deposits. Limestone reefs are locally present in the lower part of the stratigraphy in linear belts along the west and central portions of the Trough. Unconformably overlying this sequence is a succession of Jurassic to Lower Cretaceous fluvial conglomerates with associated sandstones and shales constituting the Tantalus Formation. This nonmarine succession marks closure of Whitehorse Trough and deposition of a molasse succession shed from uplift of the former trough and surrounding terranes. The entire stratigraphic succession is intruded by Cretaceous to early Tertiary granitoids, mainly in the south part of the Trough. These granitoids formed largely in response to an east-dipping subduction zone located west of the Whitehorse Trough. The dominant structural trend in Whitehorse Trough is northwestsoutheast with abundant folds and faults. The core of the Trough is an anticlinorium with younger rocks occurring on both the west and east margins. Deformation occurred in the interval between Middle Jurassic and Middle Cretaceous. Exploration History The first recorded active petroleum exploration was in the 1950s. Exploration was ongoing sporadically until 1981, consisting largely of evaluation of the stratigraphic sections for petroleum prospectivity. Since 1981 no permits have been issued for the area. No private seismic surveys or wells have been completed for the area. During 2004 a two dimensional seismic survey was jointly funded by Yukon Geological Survey and Geological Survey of Canada across the northern part of the Trough. Results from that survey are still pending. Plays Five gas plays and two oil plays were identified for Whitehorse Trough. Six of the plays are structural and only one is stratigraphic. The Tantalus plays include all the Mesozoic clastic rocks above the sub-Middle Jurassic unconformity and therefore includes the Tanglefoot Formation in the Laberge Group. The Takwahoni plays include the coarse clastic rocks in the Laberge Group, and the Inklin plays correspond to the fine clastic rocks in the Laberge Group. The Lewes River structural play includes all structural traps in the mainly clastic strata in the Lewes River Group. The Lewes River stratigraphic play is restricted to the Upper Triassic carbonate reefs in the Lewes River Group. All plays are based on analogies with established plays in other basins. The plays are conceptual in nature and therefore highly risky. Whitehorse Trough contains abundant bituminous to semi-anthracite grade coal measures in the Jurassic Laberge Group and the Jurassic- Cretaceous Tantalus Formation. Coals have been mined historically in the Carmacks area for local use. Potential for gas from coal methane exists but has not been considered in this assessment.
C. Bonnet Plume Oil and Gas Resource Assessment Click here to open a map of this region ( Geological Summary The Bonnet Plume Basin is an intermontane, fault-bounded basin within the Northern Yukon Fold Complex located at the intersection of the north-trending Richardson fault array with the Mackenzie fold front. The basin developed as a depositional site in early Late Cretaceous in response to strike- and dip-slip faulting. It contains extensive nonmarine late Cretaceous to Tertiary sandstone, shale, conglomerate and coal which constitute the Bonnet Plume Formation. Unconformably underlying the Bonnet Plume Formation are Lower Paleozoic marine shales and limestones of the ancestral North America miogeocline. Most of the Bonnet Plume Basin coincides with the Richardson Trough, a north-trending zone of marine deep water shale and chert deposition with shallow water carbonate platform deposition occurring both to the west (Yukon Stable Block) and the east (Mackenzie-Peel shelf). This platform to basin transition is uniformly overlain by euxinic siliceous black shales of the Middle Devonian Canol Formation and shales and siltstones of the Late Devonian Imperial Formation. Compressional deformation occurred during Late Cretaceous to Early Tertiary as part of the Cordilleran Orogen. Exploration History No seismic surveys have been completed, and no wells have been drilled. The nearest well is the Toltec Peel River YT N-77, drilled 20 kilometres to the northwest in the Peel River valley in 1968. An east-west gravity profile was completed across the centre of the basin in 1979 to determine if gravity methods could be used to interpret structure in areas with limited surface control and no subsurface information. The Bonnet Plume Formation contains some of the thickest and most extensive coal deposits in the Yukon. Drilling by Pan Ocean Oil of 37 shallow holes in 1978-1980 delineated a proven reserve in one deposit of 121 million tonnes. Coal within the basin is considered to have extensive gas from coal potential. Plays Three conceptual gas plays and three speculative gas plays have been identified within the Bonnet Plume Basin. Statistical analysis has been completed for the conceptual plays. Significant gas potential is predicted for stratigraphic and structural traps within the Lower Paleozoic facies transition from carbonate to shale. Gas potential from stratigraphic and structural traps related to the non-marine Bonnet Plume Formation is much smaller. Geochemical evidence indicates that there is probably not much oil potential in the area.
D. Kandik Basin Oil and Gas Resource Assessment Click here to open a map of this region ( Geological Summary Kandik Basin is a structural basin containing Paleozoic-Mesozoic sedimentary rocks within the Northern Yukon Fold Complex. It straddles the Yukon-Alaska border 650 kilometres north-northwest of Whitehorse and 907 kilometres southeast of Prudhoe Bay, Alaska. The basin is elongate to the southwest with about 60% of the area located in Alaska. It consists of three separate areas with preserved Mesozoic sedimentary rocks which are surrounded by exposed Precambrian- Paleozoic outcrops. To the south the Basin is bounded by the Tintina Fault with some 420 km of right-lateral strike-slip displacement. Basin basement consists of marlstones, diamictites, quartzites and siliceous carbonates of the Proterozoic Tindir Group. Unconformably overlying these strata are numerous Lower Paleozoic carbonateshale cycles with lesser intermittent siliciclastic sedimentation intervals. Recurrent Cretaceous marine clastic wedges separated by unconformities overlie the earlier interbedded carbonate-shale intervals. The uppermost succession consists of nonmarine conglomeratic sandstone and grit which unconformably overlie the Cretaceous marine succession. The area was unglaciated during the Pleistocene; alluvial sediments occur along river valleys. The basin formed as a structurally controlled depositional site in late Early Cretaceous. Subsequent Cordilleran Orogen compressional tectonics in Late Cretaceous and early Tertiary produced folds and faults within the basin. Exploration History Petroleum exploration in Kandik Basin began in 1970 with the drilling of the INC Husky Amoco Black-Fly YT M-55 well. Inexco conducted a reflection and refraction seismic survey in the winter of 1971which acquired approximately 180 line-km of data in three areas along the eastern margin of the basin. Two additional holes were drilled in 1971 (Porcupine YT G-31) and 1972 (Mallard YT O-18). All three holes were drilled on structures. None of the wells encountered hydrocarbons. In Alaska three wells were drilled in the interval 1976-1977. Two of these wells were spudded north of the area considered to be part of Kandik Basin for assessment purposes. Plays There are no discovered reserves in the basin. Oil staining has been observed in outcrop in carbonates and calcareous sandstone in the Alaska portion of the basin. Six conceptual oil and gas plays (three for oil and three for gas) were identified in the Kandik Basin. The Upper Cretaceous/Tertiary nonmarine play has limited extent, occurring dominantly in the southern part of the basin. Reservoirs for Mesozoic marine structural plays are dominantly clastic sedimentary rocks, and reservoirs for Paleozoic structural plays are mainly carbonate rocks. The Mesozoic marine structural oil play occurs entirely within Alaska. All plays are considered to have a high probability of existing. An important risk in each of the plays is the extent of erosion and unroofing which may have increased the chance of breached seal or closure.
$ Yukon encompasses 35% of play area Wells
E. Peel Plateau and Plain Oil and Gas Resources Assessment Click here to open a map of this region ( Geological Summary The Peel Plateau and Plain is a prospective hydrocarbon region in the Northern Interior Platform north of the Mackenzie Mountains and east of the Richardson Mountains. It contains a Lower Cambrian to Upper Cretaceous stratigraphic succession with a maximum thickness of approximately 4.5 km. Geologically it is similar in setting to the Western Canada Sedimentary Basin. Lower and Middle Paleozoic sedimentary rocks were deposited in a continental margin setting and contain the platform carbonate to basinal shale transition. Upper Paleozoic interbedded shales, siltstones and shales overlie this carbonate to shale transition. Locally isolated carbonate mounds may be present within this Upper Paleozoic clastic succession. The Paleozoic successions are unconformably overlain by a Mesozoic clastic succession of sandstone, siltstone and shale deposited within a developing foreland basin east of the Cordilleran Orogen. The Peel Plateau encompasses all sedimentary rocks which exhibit folding and thrusting related to the Cordilleran Orogen. It has been subdivided into two structural domains with the surface trace of the Trevor fault being the boundary between the two domains. The Plateau domain west of the Trevor fault is underlain largely by Lower Paleozoic basinal shales of Richardson Trough. The Lower Paleozoic stratigraphy in the Peel Plateau domain east of the Trevor fault consists dominantly of platform carbonate. The Peel Plain is east of the Peel Plateau and corresponds to all the undisturbed, relatively flat-lying sedimentary rocks east of the Cordilleran Orogen deformation front. Exploration History Surface exploration began in the mid 1950s. The first well (Shell Peel River YT-J21 was completed in 1965. Eighteen additional wells were drilled between 1965 and 1977 for a total of 42,319 metres. Drilling resulted in several gas shows but no established economic reserves or production. Over 3,000 line-kilometers of seismic surveys were completed in the 1960s and 1970s. 500 line-kilometers of this data, ranging from fair to good quality, is available to the public in the information files of the National Energy Board. Plays Peel Plateau and Plain was divided into three structural domains (two within Peel Plateau and one constituting Peel Plain) for assessment purposes. Eight gas plays have been identified within these three structural domains. The plays consist of different structural and stratigraphic traps in the Paleozoic sedimentary rocks and the overlying Mesozoic sedimentary rocks. Gas prospectivity increases in an overall easterly direction with the greatest prospectivity being for the Peel Plain. There is significant potential for natural gas with a summed mean play potential of approximately 2.9 Tcf in 88 pools. The largest pool is expected to occur in Mesozoic clastic rocks of the Peel Plain. No crude oil potential was estimated due to the lack of suitable maturation and source.
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F. Old Crow Basin Oil and Gas Resource Assessment Click here to open a map of this region ( Geological Summary In northwestern Yukon, the Old Crow Basin is a Tertiary intermontane basin within the Northern Yukon Fold Complex. It is flanked by intensely deformed and uplifted Proterozoic to Mesozoic sedimentary rocks of the British Mountains, Richardson Mountains, Old Crow Range and Keele Range. The Old Crow Basin consists of essentially flat-lying Tertiary to Recent, nonmarine sediments with coals unconformably overlying a Proterozoic to Mesozoic basement with a suggested relief of up to 800 m. This basement relief is caused by either east-west trending marginal faults or syncline-anticline fold structures. Mesozoic strata are thought to be imperfectly preserved beneath this Eocene unconformity with their erosion occurring over the structural highs. Rocks in the region have been deformed by two major orogenic episodes: an Early Devonian Ellesmerian compressional orogeny, and the latest Cretaceous to Tertiary Cordilleran compressional orogeny. Exploration History Petroleum exploration in the Old Crow Basin has been quite limited. Approximately 2000 line-km of reconnaissance seismic was shot in the basin between 1969 and 1972. An extensive gravity survey was completed by Gulf Oil Canada Ltd. in 1973. No wells have been drilled. The nearest well is the Socony Mobil-W.M. Molar P-34 well drilled in northern Eagle Plain, 50 kilometres to the southeast. Plays Tertiary sediments are likely too immature and sparingly structured to have significant hydrocarbon potential, although there is some potential for biogenic gas. There is little, if any, oil potential in the area. Three conceptual gas plays and three speculative gas plays were defined in the Old Crow Basin area on the basis of petroleum geology considerations such as structural style, dominant reservoir lithology and thermal matural. Conceptual gas plays for the Old Crow Basin consist of conglomerates of the Carboniferous Kekiktuk Formation, carbonates of the Carboniferous Lisburne Group and Mesozoic sandstones preserved beneath the Tertiary cover. The greatest gas potential or volume occurs in the Upper Paleozoic carbonate play.
G. Beaufort-Mackenzie Basin Oil and Gas Resource Assessment Click here to open a map of this region ( Geological Summary The Beaufort-Mackenzie basin of northern Yukon is an Arctic margin basin underlain by complexly faulted and folded Proterozoic through Tertiary sediments. The area is flanked to the south by exposed Proterozoic and Lower Paleozoic sediments of the British Mountains and Richardson Mountains. It contains four tectono-stratigraphic assemblages separated by major regional unconformities: a lowermost Proterozoic clastic assemblage forming the economic basement, Lower Paleozoic sedimentary rocks delineating a carbonate platform to marine basin transition with dominantly basinal shales in the area of interest, Carboniferous to Lower Cretaceous nonmarine clastic sedimentary rocks transitioning to shallow marine and intertidal deposits, and Lower Cretaceous to Tertiary northward prograding delta deposits. Upper Cretaceous sedimentary rocks include foreland flysch deposits from extensively eroding uplands of the Cordilleran Orogen. The dominant structural fabric is related to Cretaceous-Tertiary contractional deformation of the Cordilleran Fold Belt during the Cordilleran Orogeny. Structures form an arcuate trend with east to southeast strikes in the northwestern Yukon rotating to a northsouth trend in the eastern Yukon. Tight folds, thrust faults, strike-slip faults, and extensional faults all formed as part of this deformation. Earlier deformation features related to the Ellesmerian Orogeny and Jurassic-Cretaceous extension are locally discernable through the later overprinting. Exploration History Seismic surveys in the Mackenzie Delta area in the early 1960’s delineated large structures in favourable stratigraphic successions. These early surveys led to the drilling of two dry wells in 1962. Further exploration led to the discovery of oil in Cretaceous sandstones in 1969. In 1970 a major gas find was made in Lower Cretaceous sands. In 1977 the focus of exploration switched offshore to Tertiary targets. In the Beaufort-Mackenzie region, 53 oil and gas discoveries, both onshore and offshore, have been made. Forty-four of these discoveries occur in the Tertiary basin. 247 wells have been completed to date. Drilling on the Yukon portion of the basin to the west has been very limited. Three wells were completed showing no hydrocarbons and limited reservoir potential. Plays The potential for significant hydrocarbon accumulations in the region is derived from the combined presence of numerous and diverse trapping configurations, good to excellent petroleum source rocks in favourable stratigraphic positions and reservoir-quality strata in the sedimentary succession. However, significant risks associated with lack of porosity development in Paleozoic and Mesozoic strata and thermal maturity considerations reduce overall hydrocarbon potential. The complex geology and anticipated high exploration risks associated with all defined exploration plays in the region suggest that considerable seismic survey work and exploration drilling are required to properly evaluate the North Coast hydrocarbon potential. There are no discovered reserves in the Yukon portion of the Beaufort- Mackenzie basin. Hydrocarbon resource assessment for the area encompasses portions of Yukon and GNWT. The assessment analyzed six conceptual and immature plays. The mean estimates for total oil and gas potential for all coastal plain plays are 294 MMbbls of oil and 1,473 Bcf of gas. The results indicate that four gas fields greater than 100 Bcf are expected in the region. Even though geological risk factors are substantial, significant gas potential is predicted.
* Yukon encompasses 2.5% of play area Wells
H. Eagle Plain Oil and Gas Resource Assessment Click here to open a map of this region ( Geological Summary Eagle Plain, in northcentral Yukon, is an underexplored structural basin with proven Cretaceous, Carboniferous, and Devonian gas and oil measures within the Northern Yukon Fold Complex. It has a maximum sediment thickness of 5,800 m. During Cambrian through Carboniferous time it was the site of continuous subsidence and deposition as part of the western continental margin miogeocline. Lower Paleozoic platform carbonates of the Bouvette and Ogilvie formations are bounded and interfinger with carbonaceous basinal shales of Richardson Trough on the east. During Late Paleozoic sedimentation is dominated by clastic sediments with lesser carbonate. Paleozic sedimentary rocks are in turn unconformably overlain by Cretaceous marine siltstone, shale and sandstone deposited as a foreland succession in response to Cordilleran deformation. North-trending anticlines, synclines and thrust faults related to Cordilleran deformation occur throughout the basin. The basin is divided into the northern Bell sub-basin and the South Eagle sub-basin, the sub-basins being separated by the east-west trending Eagle Arch. Exploration History Surface exploration began in the mid 1950’s. The first well (Peel Plateau Eagle Plain YT No. 1 N-49) was completed in 1958. The first discovery well (Chance YT No. 1 M-08 was completed in 1960. The most recent wells were drilled in 1985. A total of 33 wells have been drilled; several of these contained hydrocarbons in one or more zones. A total of 9,952 line kilometers of two-dimensional seismic survey lines have been completed in Eagle Plain with only 8% of that being shot since 1975. Seismic coverage is largely in the southern end of the basin. In most cases gravity and magnetic surveys were conducted concurrently with the seismic. Discovered resources contain 83.7 Bcf gas and 11.1 MMbbls oil. All of the currently discovered hydrocarbons are found in the South Eagle sub-basin. Plays Fifteen different petroleum plays were identified in the Eagle Plain area (nine gas and six oil). These encompass a variety of structural and stratigraphic traps. Several plays are considered established as they have yielded proven discoveries. The others have petroleum shows in this basin or other basins and are therefore considered immature. Most of the wells drilled to date have stopped in Devonian and younger rocks; only six wells have tested the Lower Paleozoic stratigraphy.
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Last Updated 10-10-2005