By Phaedra Friend Troy
Tullow (LON:TLW) reported that the Owo-1 sidetrack well in the Deepwater Tano block offshore Ghana has confirmed the discovery, encountering a “significantly extended” column of high-quality light oil, as well as additional gas and condensate accumulations.
Drilled by the Sedco-702 semisubmersible in 1,428 meters of water, the Owo-1 sidetrack well reached a total depth of 3,998 meters. Results from the sidetrack well’s drilling wireline logs and samples of reservoir fluids verify that Owo is a major oil field.
“The Owo-1 sidetrack has proved a very substantial 200-meter gross oil column in the heart of the Owo oil field and new condensate and gas accumulations below,” said Angus McCoss, exploration director for Tullow.
While the Owo-1 discovery well encountered 53 meters of net oil pay, the sidetrack, which was drilled just .6 kilometers to the east of the original well, transected another 16 meters of net oil pay in the lower part of the same channel system. Pressure data shows that the sidetrack oil pay is in communication with the discovery reservoirs, confirming at least 69 meters of total net pay in a 200-meter gross oil column.
Additionally, below the Owo oil field, 13 meters of net condensate pay was discovered, and 6 meters of net gas pay was transected in the deepest sand encountered. No water was located in any of the hydrocarbon-bearing reservoirs in either the discovery well or the sidetrack well.
After testing and logging operations are complete, the Owo sidetrack well will be suspended for future use as an appraisal or development well.
“Appraisal wells are currently being planned to extend the main Owo oil discovery up-dip and down-dip, to appraise the adjacent Tweneboa oil and gas condensate accumulation and, to refine further our estimates of recoverable resources of both fields,” McCoss said. “The discovery of very material volumes of light oil in Owo and the fact that the oil is concentrated in high quality channel sands greatly enhances our outlook for the efficient future development of both the Owo and Tweneboa fields.”
The Owo field is located about 60 kilometers offshore Ghana and about 30 kilometers west of the Jubilee field, which is on the West Cape Three Points block.
The Sedco 703 rig will remain on the Deepwater Tano block to drill the Onyina-1 exploration well that is targeting a large Campanian prospect between the Tweneboa and the Jubilee fields.
Tullow holds 49.95 percent interest in and serves as operator of the Deepwater Tano license. Partners on the block include Kosmos Energy with 18 percent, Anadarko with 18 percent, Sabre Oil & Gas with 4.05 percent, and the Ghana National Petroleum Corporation with a carried 10 percent.
Tullow sidetrack confirms Owo-1 as major oil discovery offshore Ghana
By Phaedra Friend Troy