A multi-national operator of a mature North Sea field was experiencing steadily declining hydrocarbon production and increasing water cut. Faced with the reduction in performance, low intervention efficiency and increasing cost of extraction, the operator sought to intervene in order to isolate the source of water.
A water injection well was targeted for intervention to optimise its injection profile through the manipulation of Sliding Sleeve Devices (SSD) installed in the liner. With high operating costs and high operational complexity on a long reach horizontal well, the challenge was to perform fast and effective intervention in order to enhance hydrocarbon recovery and achieve maximum economic benefit.
The READ team were invited to discuss the objectives of the intervention and in order to maximise intervention efficiency recommended the application of injection performance evaluation services and ZeroTime logging while working services, deployed on coiled tubing in memory logging configuration.
Injection performance evaluation surveys would provide insight of the initial injection profile prior to SSD manipulation and verification of final redistributed injection profile post SSD manipulation. ZeroTime surveys, utilising Casing Collar Locator, fast response temperature and borehole pressure sensors would be integrated into SSD manipulation operations to provide direct confirmation of successful manipulation and final SSD status, eliminating the need for stand-alone diagnostic surveys.
Having established the initial injection profile, the operator targeted a number of SSDs for manipulation. However, due to a combination of the wells age and long horizontal reach, manipulation of these SSDs proved to be difficult.
While surface tension readings provided by the coiled tubing system proved inconclusive and often misleading, the intelligence provided by ZeroTime enabled reliable and accurate diagnosis of SSD positions. This clarity of information revealed a number of sleeves that required additional action before successful manipulation was achieved, dramatically increasing the effectiveness of the mechanical intervention.
ZeroTime enabled the operator to eliminate multiple stand-alone diagnostic surveys, the intervention efficiency resulting in time savings estimated to be in excess of 40 hours and with three less runs in hole. With all the targeted SSDs successfully manipulated the operator achieved their desired injection profile on the first attempt, resulting in increased hydrocarbon production and positive economic impact.