An operator in Oman needed to assess the cement bond in a recently drilled and completed horizontal well, which had not yet been fracture stimulated. They called upon Welltec®, for the only tractor on the market that can perform reliably in high temperatures. The well temperature was estimated around 347°F (175°C) and the Well Tractor® is rated to run in temperatures up to 400°F (~200°C).

The proven track record, high HSE standards and service quality of Welltec were another selection criteria. The operator’s objective was to evaluate the cement bond behind the 4 1/2" liner in a tight gas appraisal well, to ensure well integrity and zonal isolation prior to a staged, hydraulic fracture stimulation.

This was the first horizontal well in a high profile gas field and it was important for the operator to assess the 'fracability' and production behavior, as this would have implications for the further field development. The data was a prerequisite for adaptation of suitable fracture designs (transverse fractures) in case sub-optimal bond was detected.

To ensure high quality and HSE, the daily operations were initiated with a Toolbox Talk that allowed the operator, the service provider and the logging company to discuss and agree on the operating procedures.

Due to debris obstruction in the hole, a clean out run was performed retrieving rubber and metal debris. Once a clear path had been ensured, the CBL toolstring was run in hole to a hang-up depth at 15,918 ft (4,852m) at which point the Well Tractor was activated and conveyed the toolstring down to target depth 18,533 ft (5,649m).

The well was pressured up to 2,000 psi and logging performed from TD to the Top-of-Liner (TOL) at 15,420 ft (4,700m). When TOL was reached the Well Tractor conveyed the toolstring back to target depth for a second pass, logging up with zero surface pressure. Once the second log concluded, the toolstring was returned to surface.

The operation was completed as planned with no lost time incidents. Total operating time for the CBL operation was six and a half hours. The operator acquired the necessary logging data to move on to the frac job with confidence.