A multi-national operator of a significant, mature North Sea field embarked on a multi-well infill drilling program to boost production and enhance the long-term recovery for one of their prized assets. With high operating costs and highly localised payload zones it was essential that these wells were delivered quickly and accurately to ensure maximum economic return for a minimised capital investment.
Having opted for a batch drilling process to optimise rig utilisation the challenge was now to complete and bring the wells online efficiently and cost effectively, but without compromise in long-term well performance.
The READ team discussed the well delivery program with the operator and demonstrated how the application of a ZeroTime logging while working solution would enable determination of optimised Tubing Conveyed Perforating (TCP) space out without the need for stand-alone wireline deployed logging runs. As a result a ZeroTime service was integrated into preparatory clean-up and circulation operations performed with drill pipe.
The relative position of liner and formation acquired by the combination of ZertoTime Gamma Ray (GR) and Casing Collar Locator (CCL) sensors would provide rapid and accurate determination of the space out requirements for subsequent TCP runs. In addition, borehole temperature profiles acquired by the ZeroTime fast response temperature sensor would enable further optimisation of each perforated interval, thereby optimising the connection between well and reservoir.
ZeroTime delivered fast and accurate information of liner placement enabling the operator to ensure correct space out of perforating assemblies on subsequent TCP runs. In addition, the precision map of temperature versus depth enabled the operator to further optimise the perforating process by identifying areas where water flood had already reached and reveal potential sites of unexploited reserves.
Through the elimination of dedicated logging runs, ZeroTime provided significant efficiency gains by providing a faster alternative to conventional wireline logging services. As a direct result, the time saving delivered by the ZeroTime logging while working service equated to over 1.5 days of rig time over the duration of the campaign.
By eliminating the need for a dedicated wireline unit and operating crew, ZeroTime dramatically reduced operating costs, simplified logistics and reduced Personnel On Board (POB) requirements. Through reduction in the number of entries into the well and reduction in personnel on the drill floor, operational hazards were removed resulting in reduced exposure to risk to personnel safety and to the environment.