After the successful completion of the Maari development drilling programme, the Ensco 107 jack-up last week began drilling the Manaia-1 appraisal well to tap into a reservoir which is assessed to contain 57.8mmbbls. The Manaia field _is located about 10km south-west of the Maari field, and drilling is being undertaken as an extended reach well from the Maari wellhead platform. The new drilling, expected to take 47 days, underlines the surge of optimism among the explorers the structures in the Maari field and adjacent to it will turn the project into NZ’s biggest oil producer from reservoirs which might in aggregate contain 150-200mmbbls.

The Maari development programme involving the drilling of 5 production wells and 3 water injection wells in the Moki reservoir was completed on July 26, considerably ahead of the forecast mid-August schedule. Two of the production wells required short workovers to repair a damaged valve. One of the participants in Maari, Sydney-based Horizon Oil which holds 10% of the project, says at the end of August it will report full production rates and performance when all 5 production wells are on line. It says the indications are of significantly higher oil-in-place than anticipated when development started. Reserves were then put at around 50 to 60mmbbls. To the end of June 2m barrels of oil were shipped to refineries from the FPSO Raroa.

Cue Taranaki Pty which holds 5% of the Maari project says the Manaia-1 well is expected to confirm the presence of an oil column established by the Maui-4 exploration well drilled in 1970. The well intersected an oil accumulation in the Mangahewa Formation reservoir which tested at 575 barrels of oil a day. Two additional oil accumulations in Maui-4 were encountered in the Moki Formation (main reservoir of the Maari field) but were not tested at the time. If hydrocarbons are established by the Ensco 107 rig the well will be completed and tied into the Maari facilities for subsequent testing and production.

Once the Ensco rig completes the Manaia-1 well, it is scheduled to drill a well into the M2A reservoir which lies 50 metres above the Moki Formation, (from which the Maari wells at full production will have a daily output of 35,000 barrels a day). The M2A well is expected to take 27 days to drill. The reservoir is assessed to have 43mmbbls.

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