Exploration discoveries

	Vol. 230 No. 8
ARTHUR BERMAN, CONTRIBUTING EDITOR, bermanae@gmail.com

Africa-Middle East. Tullow Oil made two oil discoveries in the Albert Basin of western Uganda with its Kigogole-3 and Wahrindi-1 wells. The Kigogole-3 well on Block 2 found 50 ft of pay in Kasamene sands (Miocene–Pliocene) and an additional 15 ft of pay in a new pay zone above the main reservoir. Kigogole-3 is located along the south shore of Lake Albert near the Kigogole-1 discovery and Heritage OilÕs Warthog discovery on adjacent Block 1, both announced last year. Kigogole-3 was drilled to a TD of 1,886 ft, and Tullow operates with 100% interest. Tullow estimates that overall reserve potential on the block may exceed 1 billion bbl. The Wahrindi-1 well was drilled in the Victoria Nile Delta Block 2, about 8 mi southwest of Kigogole-3, to a TD of 4,265 ft. Tullow announced that it is an oil discovery, but no further information has been released.

Noble Energy's Tamar-2 appraisal well confirmed the Dalit-1 discovery in Tamar Field on the Matan Block offshore Israel. The reserve estimate for the Tamar discovery has been increased from 5.0 to 6.3 Tcf as a result of the new well. It was drilled about 3.5 mi northeast of the Dalit-1 well to a TD of 16,880 ft in 5,530 ft of water. The gas-water contact was found in the lower reservoir, but no water contact was identified in the upper reservoir. Noble operates with 36% working interest in partnership with Isramco Negev 2 (28.75%), Delek Drilling (15.625%), Avner Oil Exploration (15.625%) and Dor Gas Exploration (4%).

Nigerian National Petroleum Corporation (NNPC) and Sinopec discovered oil with the Kakaku-1 well drilled on Niger Delta Block OML64 in Nigeria. The well tested 1,284Ð3,110 bopd from 50 ft of pay, and was drilled to a TD of 11,150 ft.

China National Petroleum Corporation (CNPC) has made an apparent oil discovery with its Faringa W-1 well on the Agadem Block in the Termit Basin in Niger. Oil reserves are estimated to be more than 324 million bbl from 100 ft of pay in the well, which was drilled to a 14,305-ft TD.

Americas. Anadarko Petroleum made a discovery with its Samurai well on Green Canyon Block 432 in the deepwater US Gulf of Mexico. The well found 120 ft of net pay in several Miocene reservoir intervals. It is located 12 mi north of the Marco Polo platform and was drilled to a TD of 31,700 ft in 3,400 ft of water. Anadarko operates with 33.3% interest in partnership with Murphy Oil and Samson Offshore, each with a 33.3% interest.

ExxonMobil's Guarani appraisal of its Azulao-1 discovery is a dry hole on Santos Basin Block BM-S-22 in the pre-salt play in Brazil. The Azulao discovery was announced in January 2009 as one of the most significant discoveries made to date in that play with more than 10 billion bbl of estimated recoverable oil reserves. The failure of the Guarani appraisal well, however, suggests that reserves may be less than previously announced. The well was drilled about 200 mi off of Sao Paulo state in 7,342 ft of water. ExxonMobil operates with 40% interest in partnership with Hess (40%) and Petrobras (20%).

ExxonMobil has made four gas discoveries in the Horn River Basin in northeastern British Columbia, Canada. The company expects that these wells will each produce between 16 and 18 MMcfd, although the wells are not flowing at those rates currently. The Montney-Horn River play is not new, and was developed commercially with vertical wells a decade ago. While the Horn River is a true shale lithology, the Montney is a siltsone-sandstone reservoir, according to my sources in Canada. Peters & Company Ltd.Õs Andrew Boland told the Financial Post that the Montney and Horn River Shales currently produce about 225 MMcfd but could potentially flow 4–5 Bcfd with the drilling and completion methods used by ExxonMobil. Boland also said that the commercial threshold for the play is $6Ð7/Mcf. ExxonMobil and Imperial Oil hold 250,000 acres in the play.

Asia-Pacific. ConocoPhillips' Poseidon discovery may contain reserves of 16–20 Tcf on Block WA-315-P in the Browse Basin offshore Western Australia. The discovery, about 300 mi north of Broome, was announced in May 2009. The well was plugged and abandoned after losing a logging tool, although several drillstem tests apparently were successfully completed in the 15,749-ft subsea well. ConocoPhillips operates with 51% interest, and Karoon Gas Australia holds the remaining 49%.

Premier Oil made a discovery with its Ca Rong Do (Red Emperor) well drilled on Block 07/03 in the Nam Con Son Basin offshore Vietnam. The well found 295 ft of oil and gas pay and was drilled to a 12,501-ft TD. It is located about 350 mi southeast of Ho Chi Minh City in the South China Sea. Premier Oil operates with 30% interest in partnership with Vietnam American Exploration (40%) and Pearl Oil (30%).

Europe. Talisman Energy made an oil discovery with the Grevling well on Block 15/21 in PL038D in the Norwegian sector of the North Sea. Oil reserves are estimated between 40 and 130 million bbl. Talisman operates with 40% interest, and Det Norske and Petoro each hold 30% interest.

Wintershall discovered oil and gas with its Grosbeak 35/12-2 well on Block 35/12 (PL378) in the Norwegian sector of the North Sea. Recoverable reserves are estimated between 35 and 190 million boe from Upper Jurassic Viking and Brent reservoirs. The well was drilled to a TD of 8,242 ft in 1,181 ft of water, about 22 mi northeast of Fram Field. Wintershall operates with 40% interest in partnership with Premier Oil, Norwegian Energy Company and Spring Energy Norway, each with 20% interest.

Repsol made two oil discoveries with its Lubina and Montanazo wells about 23 mi off the northern coast of Spain. The Lubina well tested rates of 3,000 bopd and was drilled to a 7,874-ft TD. The Montanzo tested 3,700 bopd and had a 7,723-ft TD. Pay was found in Mesozoic limestone reservoirs. Repsol operates with 75% interest in partnership with Gas Natural subsidiary Petroleum Oil & Gas (17.7%) and Compania Espanola de Petroleos (7.3%).

Arthur Berman is a geological consultant specializing in petroleum geology, seismic interpretation and database design and management. He has over 20 years working for major oil companies and was editor of the Houston Geological Society’s Bulletin. He earned an MS in geology from the Colorado School of Mines.