Operators report string of Gulf of Mexico discoveries

Operators in the Gulf of Mexico reported a string of discoveries in late January and early February 2009.

The discoveries took place on prospects in the Lower Tertiary and Middle Miocene trends, in deep water, and on a deep prospect on the gulf shelf.

Keathley Buckskin

A group led by operator Repsol YPF SA found more than 300 ft of net pay in Lower Tertiary at the Buckskin No. 1 well 190 miles southeast of Houston in Keathley Canyon Block 872.

Chevron Corp., a 55% interest holder, said Buckskin is 44 miles west of its 2004 Jack discovery, also a Lower Tertiary discovery. Buckskin went to TD 29,404 ft in 6,920 ft of water.

More study is under way on data gathered from the well, and further work is needed to determine the extent and commercial viability of the discovery, the company said.

Repsol YPF SA, with a 12.5% working interest in the prospect, operated the Buckskin discovery well, but Chevron will become operator and conduct all future work. Other Buckskin coowners are Maersk Oil America 20% and Samson Offshore Co. 12.5%.

Walker Ridge Shenandoah

Another Lower Tertiary oil discovery is Shenandoah by Anadarko Petroleum Corp. and partners in Walker Ridge Block 52.

The well, which encountered net oil pay approaching 300 ft in the Wilcox formation, was drilled in 5,750 ft of water to a TD of 30,000 ft.

Anadarko and its partners are evaluating the well’s results and assessing the next steps toward future appraisal activity.

“Initial data indicates the Shenandoah discovery has reservoir properties that appear to be of much higher quality than industry has seen previously in the emerging Lower Tertiary play,” said Bob Daniels, Anadarko senior vice-president, worldwide exploration.

Anadarko operates Shenandoah with a 30% working interest. Partners include ConocoPhillips 40%, private Cobalt International Energy LP 20%, and Marathon Oil Corp. 10%.

Green Canyon Heidelberg

Another group led by Anadarko gauged Anadarko’s seventh discovery since 2005 in the Middle Miocene Trend.

The Heidelberg prospect in 5,000 ft of water in Green Canyon Block 859 cut more than 200 ft of net oil pay in several high-quality Miocene sands. TD is 28,500 ft.

Heidelberg encountered the same-age sands and reservoir characteristics similar to the Caesar-Tonga discoveries 7-14 miles north, and each of the seven discoveries targeted a resource of more than 100 million bbl, Anadarko said.

Heidelberg is 18 miles southeast of Anadarko’s 100% owned Constitution spar, allowing multiple development options after further appraisal, which Anadarko plans to conduct in the second half of 2009.

Anadarko operates GC859 with 44.25% working interest. Partners in the discovery include Mariner Energy Inc. and Eni SPA 12.5% each, StatoilHydro 12%, and ExxonMobil Corp. and Cobalt International 9.375% each.

Cobalt said Heidelberg is adjacent to four 100% Cobalt working interest leases acquired in the March 2008 lease sale for a combined $127.6 million. They are blocks 813, 814, 858, and 902. Cobalt, formed in 2005, has a working interest in 142 gulf leases.

Anadarko’s next prospect is Vito, a 30,500-ft Miocene test in 4,000 ft of water in Mississippi Canyon Block 984 on trend with the Kodiak and Freedom discoveries. Anadarko operates Vito with 20% working interest.

Anadarko plans to spud the Samurai Middle and Lower Miocene prospect in Green Canyon Block 432 in the first quarter of 2009. Anadarko is operator with 33.33% working interest.

Garden Banks Bushwood

Mariner Energy is operator of the Bushwood and Smoothie discoveries.

Bushwood-1, formerly Geauxpher-3, is a conventional deepwater amplitude prospect. Drilled to a TD of nearly 25,300 ft in 2,700 ft of water in Garden Banks Block 463, it logged more than 260 ft true vertical thickness (TVT) of net gas pay in multiple sands, with more than 150 ft TVT of net gas pay found in the deeper exploratory section.

Mariner is operator with 30% working interest. Partners are Energy Resource Technology GoM Inc., a subsidiary of Helix Energy Solutions Group Inc., 35%, Apache Corp. 20%, Deep Gulf Energy II LLC 10%, and Deep Gulf Energy LP 5%.

Mariner’s 100% owned Smoothie-2, a deep shelf prospect in 60 ft of water in South Timbalier Block 49, went to TD of more than 20,100 ft and logged more than 200 ft TVT of net gas pay in multiple zones.

Friesian confirmed

Plains Exploration & Production Co., Houston, confirmed the Friesian deepwater discovery and plans to deepen the well to 32,500 ft to test sands that flowed at high rates at the giant Tahiti structure two blocks west.

Shell Offshore Inc. cut more than 120 ft of net oil pay at the Friesian-1 discovery well in Green Canyon Block 599 in November 2006. TD is 29,414 ft.

The Plains-operated Friesian-2 confirmation well in Block 643 at 3,300 ft south of the discovery well is at 28,989 ft and cut 389 net ft of oil-saturated Miocene sands. It encountered 219 net ft of high-quality oil pay in three main sand lobes totaling more than 210 ft thick and a fourth sand lobe with 179 ft of oil pay that wasn’t fully evaluated.

The four pay sands, all full to base with oil, are the uppermost field pays at Tahiti field 8 miles west across the basin syncline. Existing data show strong geologic and pressure correlation with the initial Miocene field pay sands at Tahiti.

Plains and its partners plan to deepen Friesian-2 to test the main equivalent sands at Tahiti such as the M15, M18, M21A, and M21B, several of which flow-tested at more than 25,000 b/d of oil. The Ocean Monarch semisubmersible is expected to arrive in March to deepen Friesian-2.

Early stage commercialization initiatives for Friesian production are under study with multiple parties to target initial output by 2012, Plains said.

BHP Billiton Petroleum Corp. assigned a 25% stake in the Fuerte North and Fuerte Sur blocks off northwestern Colombia to state company Ecopetrol SA.

The assignment gives the two companies 50-50 interests in the blocks, in the Caribbean north of Panama.

BHP Billiton signed contracts for the blocks in April 2006, and Colombia’s National Hydrocarbons Agency executed joint operating agreements in June 2007.

Each block covers 1.2 million acres in 50-2,700 m of water in the Sinu basin west and southwest of Cartagena. There is no oil or gas production in the areas. BHP shot 3D seismic surveys in the area.

Anadarko Petroleum Corp. began shooting 4,700 sq km of 3D seismic on blocks 15, 16, and 17 in the Atlantic off Liberia.

The shoot is to be used to develop deepwater Cretaceous fan prospects on the frontier basin.

Anadarko operates the blocks with 40% working interest, and the 3D survey is the largest in the company’s history.

Neon Energy, private Perth explorer, signed a production sharing contract with PetroVietnam on Block 120 in the South China Sea southeast of Da Nang.

The block covers 8,500 sq km in 50-1,000 m of water in the southern Song Hong basin.

Neon is operator with 100% participating interest. The work program is to shoot 2D seismic and drill one exploration well within 4 years.

The block is 260 km or more north of oil and gas fields in the Mekong and Nam Con Son basins.

Eden Energy Corp., Vancouver, BC, was producing 1.24 MMcfd of gas from eight wells in White River Dome field in Colorado’s Piceance basin as of Jan. 28, 2009.

Sales are still to begin at several wells, and the time to install gathering lines and commence sales has exceeded estimates. The company doesn’t plan to drill more wells in 2009 as plunging gas prices have severely reduced cash flow.

Eden is earning interests from EnCana Oil & Gas (USA), operator of the 20,000-acre Ant Hill Federal Unit southwest of Craig in Rio Blanco County on the east side of the field. Primary reservoirs are the Cameo coal and Williams Fork sandstones of the Cretaceous Mesaverde Group at an average of 8,100 ft.

Petrohawk Energy Corp., Houston, reported having replaced 419% of its production in 2008, mainly from North Louisiana shale and tight gas fields where 80% of its proved reserves are located. The yearend 2008 reserves figures for Louisiana are Elm Grove field 685 bcfe, the Haynesville shale 163 bcfe, and Terryville field 112 bcfe.

The company also had 173 bcfe of proved reserves in the Fayetteville shale in Arkansas.

Gulf Coast

Dual lateral Austin chalk gas wells in Giddings field are “highly economical” even at present drilling costs and commodity prices, said GeoResources Inc., Houston.

Having operated 10 successful wells to date in Grimes County, Tex., the company is moving to drill its sixth dual lateral well, Hoke Cole 1-H.

Hurst Bay 1-H, its fifth dual-leg well, is to be on production by mid-February. It went to 14,500 ft true vertical depth, has one lateral of 7,692 ft, and has a second leg kicked off 1,000 ft into the first lateral and drilled 5,253 ft.

The previously reported Bax 1-H dual lateral well’s initial production rate exceeded 21 MMcfd on Nov. 20, 2008. It is now at 13 MMcfd and produced 1 bcf of gas in its first 60 days.

GeoResources, with 15 more locations to drill, plans to spud a new well every 60-75 days and will consider adding a second rig as drilling costs fall.

Anadarko Petroleum Corp.’s total operated and nonoperated gross sales reached 827 MMcfd of coalbed methane from the Powder River basin in late 2008.

The volumes were up 7% from the quarter ended Sept. 30 and up 33% from the last quarter of 2007. Gross operated sales hit a single-day high of 482 MMcfd in late 2008.

Fourth quarter well spuds totaled 372 operated and nonoperated wells in Powder River and 101 operated and 30 nonoperated wells at Atlantic Rim for all of 2008.