- Created on Sunday, 29 August 2010 10:33
Vanco Ghana Ltd. signed a Petroleum Agreement covering the Cape Three Points Deep Water block with the Ghanaian authorities in August 2002, as part of a strategy to explore the Tano Basin along the transform margin of Africa where the presence of active petroleum systems enhances the potential for deepwater oil and gas discoveries.
Later in 2002, Vanco Ghana conducted a 3,323 line kilometer 2D seismic program to further evaluate the block. The new data revealed the presence of previously unknown large compressional folds and structures. A 1,500 square kilometer 3D seismic program was then conducted in 2005 to further define the structural and stratigraphic prospects in the block.
The 2007 Mahogany discovery, now known as the Jubilee Field, located only 50 miles from the Cape Three Points Deep Water block, is estimated to hold up to 1.8 billion barrels of recoverable oil. The discovery has triggered extensive exploration activity in the region, including several wells planned by Vanco Ghana and other operators in the emerging transform margin play.
LUKOIL Overseas Holding Ghana Ltd. joined Vanco Ghana and GNPC (the Ghana National Petroleum Corporation) in the project in 2007. Subsequently a new Petroleum Agreement covering the Cape Three Points Deep Water block was ratified by Parliament on 30 June 2009, triggering a five-year period of intense exploration activity in the block.
The Dzata-1 well was drilled to evaluate an anticline which exhibits a dramatic "gas cloud" and other direct hydrocarbon indicators. Completed in February 2010, the well discovered a gross hydrocarbon column of 94 meters containing 25 meters of net hydrocarbon pay in stacked reservoir sandstones of Albian age. Fluid samples recovered at the surface indicate that the pay interval consists of a volatile black oil bearing zone below a gas-condensate bearing zone. The Dzata Appraisal Plan was submitted to the Minister of Energy in November 2010 and approved in February 2011. Meanwhile, Fugro was contracted to acquire a 3D seismic program covering 1,664 square kilometers in the block, which was completed in March 2010.
The Ocean Rig Olympia drillship was contracted to conduct a multi-well drilling campaign in Ghana and Cote d’Ivoire. The drilling unit mobilized to Ghanaian waters in May 2011.
• The program commenced with the Dzata-2A, which was drilled to appraise the areal extent of the Dzata Discovery. The well encountered poor reservoir quality at the target horizon and as a result, Dzata does not appear to be a commercial discovery but may merit further appraisal and may become commercial at a later date.
• Cheetah-1X was drilled to evaluate slope fan potential reservoirs of Turonian and Cenomanian age. The well encountered good quality Cenomanian reservoir rock, which was unfortunately found to be water-wet.
An extensive exploration work program is in progress to evaluate the drilling results, recalibrate seismic data, integrate CSEM data acquired in 2011 and prepare for resumed drilling activity.
ANNOUNCEMENT OF DZATA WELL DISCOVERY
consortium of three companies, LUKOIL Overseas (56.66%), US Vanco (28.34%) and Ghana National Petroleum Corporation, GNPC (15%), has discovered a significant hydrocarbon accumulation in the Dzata structure of the Cape Three Points Deep Water Block in the Gulf of Guinea offshore the Republic of Ghana. The discovery was announced at a meeting in Accra today between Vagit Alekperov, President of OAO LUKOIL, and John Mills, President of the Republic of Ghana.
The total area of the block is about 5,200 square kilometers, while the water depth within the block ranges from 200 meters to 3,000 meters. The Dzata-1 structure lies at a depth of almost 2 kilometers. The Dzata-1 well, drilled to a depth of some 4.5 kilometers from the sea level, tapped a 94-meter-thick hydrocarbon column containing a 25-meter multilayer oil and gas pay. The primary reservoir sandstone contains gas and light oil. The well was drilled by a semi-submersible drilling unit for deepwater drilling, equipped with a dynamic positioning system. At present, the drilling is completed, the well is plugged and temporarily abandoned. The newly discovered hydrocarbon reserves are assumed to be quite significant. A program of detailed field appraisal will help assess and commercialize the discovery.
The agreement for exploration and development of the Cape Three Points Deep Water Block was signed in 2002. In 2005, a 3D seismic survey covering 1,500 square kilometers and a geological engineering study were carried out in the block. LUKOIL joined the project in 2007. On April 1, 2009, the Government of Ghana, LUKOIL, Vanco and GNPC signed a new exploration and development agreement for the block, which was ratified by the Parliament of Ghana on June 30, 2009.
“The Dzata discovery confirms the high prospectivity of Ghana’s deepwater shelf and creates an opportunity to efficiently develop the hydrocarbon resources with the application of state-of-the-art technologies”, Mr. Alekperov commented.