The Endeavour well drilling project is located approximately 60 miles offshore, off the east coast of Trinidad. The field is one of the world's largest gas fields, which will result in a significant gas reserve, meeting the energy needs of Trinidad and Tobago.
Endeavour well is the third in a three-well programme being drilled by Challenger and its partners on block 5(c), which is approximately 80,000 acres in size. The other two wells are Victory and Bounty which were discovered in 2008, on 14 January and 13 August, respectively. Combining the three wells, the estimated recoverable reserves could cross over four trillion cubic feet (tcf) of natural gas.The three wells were selected from the interpretation of a 760km² three-dimensional (3D) seismic data set covering the block and offsetting producing fields.
The project is developed by Canada-based oil and natural gas company Challenger Energy Corporation in association with its partners Canadian Superior Energy and BG International. The production from the Endeavour well is expected to start by 2012.
Endeavour project background
Trinidad has proved to be a basin with a great deal of potential with multiple and large exploration and development opportunities. Natural gas from the country easily accesses the world's largest natural gas markets and supplies about 80% of the US's liquefied natural gas (LNG), which is very important to the North American natural gas supply.
In 2004, Challenger Energy entered into a participation agreement with Canadian Superior Energy to explore for oil and gas on the Mayaro / Guayaguayare bay block with the Petroleum Company of Trinidad and Tobago.
The block was awarded to joint venture companies in May 2004 and the company commenced exploration activity in Trinidad and Tobago during 2007 on its block 5(c) holding. On 20 February 2008, the company began operations on the second exploration well (Victory). $290m has already been spent on the project.
Development in drilling
Challenger Energy Corporation, along with its partners, started drilling operations for the Endeavour well on 28 August 2008. It is being done by the Kan Tan IV semi-submersible drilling rig in about 1,000ft of water.
The drilling process faced many challenges. After reaching a depth of approximately 16,921ft subsea in the final section of the well, the drilling was stopped due mechanical failure in the Kan Tan IV's drilling equipment – the travelling block.
The fault was repaired by the rig owner Sinopec and drilling started again in mid-December 2008 in a separate section, as the previously drilled final section was no longer practicable due to well bore damage that occurred during the well control operations. Well control operations were initiated to manage an uncontrolled flow into the well that occurred during routine drilling operations while replacing a worn drill bit.
The Endeavour well has been drilled to a final total depth of approximately 17,426ft subsea. The geological data obtained from the drilling indicates that the machine has penetrated the main targeted zone and, that the well has encountered approximately 162ft of gross reservoir quality sands over a 168ft interval to this point.
Flow testing
Canadian Superior started extensive preparations of flow testing of the Endeavour well offshore Trinidad on block 5(c) at the end of January and testing commenced on 1 March 2009.
During the initial flowing period of approximately 16 hours, a peak flow rate of 60.1 million standard cubic feet of gas a day (mmscf/d) was obtained – the maximum rate allowed under the testing equipment specifications.
A final flow rate of 56.4mmscf/d was measured with a 48/64in choke with a flowing well head pressure of 4,122psi. Dry natural gas with a gas gravity of approximately 0.584 and 0.3% CO2 flowed from the well, with no production of water and condensate or solids during the initial flow period.
Expenditure
Challenger is paying one third of the costs of the initial exploration programme on block 5(c) to earn a 25% interest in the production sharing contract covering the block, while Canadian Superior is paying 26% and BG International 40% to maintain a 45% and 30% working interest, respectively.
Endeavour completion
All drilling operations on the Endeavour well are expected to be over by the first half of 2009, followed by the release of the drilling rig.
source: www.offshore-technology.com
