CNOOC Ltd. made an oil discovery and spudded a second exploratory well on the Haute Mer A license offshore Congo (Brazzaville), said 20% interest owner Oryx Petroleum Corp., Calgary.
The E-1 exploratory well targeting the Elephant (formerly Xiang) prospect is to be tested in early 2014 as part of a multiwell drilling and testing program on the license.
Oryx said overall results are consistent with expectations. Reservoir quality, crude quality, and viscosity appear to be better than anticipated while the areal extent of the reservoir appears to be slightly smaller than expected.
The Jasper Explorer drillship drilled E-1 to a total depth of 2,497 m in 550 m of water 80 km offshore. E-1 was targeting a deeper turbiditic Tertiary play similar to the play being exploited in fields adjacent to the Haute Mer A license area, such as the Total-operated Moho Bilondo producing field and the Chevron-operated Block 14 in Angola. E-1 primary targets were the Tertiary Miocene N5 and N3 reservoir intervals.
The E-1 well was drilled 4.5 km southeast of the Libonolo Marine-1 (LIBM-1) well drilled in 1997 by Elf Congo. LIBM-1 resulted in a discovery in the N5 interval. Excellent reservoir quality was encountered with heavy 14° gravity oil present.
Based on the preliminary data, E-1 encountered 30 m of gross interval (20.3 m net) of crude oil and 102 m of gross interval (58.8 m net) of natural gas in the N5 interval and 16 m of gross interval (9.2 m net) of crude oil in the N3 interval. It encountered water in other secondary targeted intervals.
Porosity is 24-36% in N5 and 27-33% in N3. Preliminary analysis of oil samples recovered from the crude oil bearing sands indicates that the crude oil is 18° gravity.
Reservoir size and immovable oil with high viscosity and low recoverability are the principal geologic risks associated with the prospect, Oryx said. If preliminary analysis is confirmed during testing, the E-1 well will be considered a successful commercial discovery consistent overall with predrill estimates.
The drillship, under contract for a two plus one drilling campaign, has spudded the H-1 well targeting the Horse prospect (formerly Ma). H-1 will be drilled to a total depth of 5,462 m in 1,038 m of water 80 km offshore in the western part of the license. Primary targets are the Tertiary N3 reservoir, a turbiditic play, and the deeper Cretaceous reservoir, an Albian carbonate play.
Other wells drilled in adjacent license areas targeting the Albian age cretaceous carbonate play have yielded discoveries by Total at N’Kossa, N’Soko, Moho Bilondo, and Moho North and by Chevron on Block 0 in adjacent Angola (Cabinda). Oil quality is anticipated to be light in the Cretaceous and heavier in the Tertiary. Oryx expects the well will reach total depth in late 2013.
The Jasper Explorer will test H-1 well, if successful, before testing the Elephant discovery. Subject to a successful test at E-1, CNOOC intends to drill the first appraisal well in the license area on the Elephant discovery. The appraisal well will likely test potential outer extension of the discovered N5 sands while also probing similar channel sands in the N5 interval.