Batch Drilling of Two Wells Underway, Cameroon
Gaz du Cameroun S.A. (GDC), the Company’s Cameroon gas producing and distributing subsidiary, announces that following spudding of well La-107 on November 1 2016, it has successfully drilled, cased and cemented the uppermost, 18⅝” section of the well to a depth of 400 metres. Operations on La-107 were then suspended as planned and the rig was skidded a distance of 10 metres along the rail system to the La-108 well location. The 1500 HP Komako 1 drilling rig, owned and operated by Savannah Oil Services Cameroon S.A., is a rail-mounted drilling rig and can skid between the two wells in a matter of hours.
Well La-108 was spudded on the 12th November 2016 and has been drilled and cased to a depth of 400 metres. Currently, Savannah is drilling the 17½” hole section on La-108, after which the rig will be skidded back to the La-107 well to drill its 17½” hole section.
The gas bearing target horizons, from which it is anticipated both new wells will produce, are in the Upper Cretaceous (Campanian and Santonian) Logbaba Formation, which is a thick sequence of interbedded sands and shales found at depths between 1,700m and 3,200m below the surface.
Rig Skidding and Batch Drilling
The 2016/17 drilling campaign at Logbaba is designed as a ‘batch drilling’ operation. As a well is drilled, the equipment, drilling fluids, drilling services and specialist personnel required vary for each hole section. In a batch drilling operation, the rig is moved back and forth between the wells, progressing through all the hole sections until the wells have reached target depth. The Komako 1 rail mounted drilling rig is designed for this type of operation.
Significant cost saving and efficiencies are realised from a batch drilling programme, as materials and services are mobilised to the site, employed on both wells for each hole section and then demobilised when no longer required. In a conventional back-to-back two well drilling campaign the equipment and materials are all mobilised as required for the first well and then all equipment remains on standby rental until it is required again on the second well, three or four months later. With batch drilling the Company avoids having significant amounts of equipment and services on standby for 3 or 4 months between wells.