HT cement bond logging
- Total depth 18,533 ft (5,649m)
- Estimated TOC 15,420 ft (4,700m)
- Max. deviation 87.56°
- Max. temperature 173°C @ TD
- Max. pressure 8,700 psi
When Petroleum Development of Oman (PDO) needed to assess the cement bond in a recently drilled and completed well, which had not yet been fractured, 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 excellent service quality of Welltec were another selection criterion, in addition to the relative costs and logistical challenges of mobilizing a CT unit.
The operator wanted to evaluate the cement bond behind the 4 1/2" liner in a horizontal, tight gas appraisal well, to ensure well integrity and zonal isolation prior to a staged, hydraulic fracture stimulation.
This well was the first 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 cement bond evaluation 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 so-called toolbox talk allowing operator, service provider and logging company to discuss and agree on the operating procedures.
Due to debris obstruction in the hole, a junk basket run was performed retrieving rubber and metal debris. Once a clear path had been ensured, the CBL toolstring was run in hole to hang up depth at 18,533 ft (5,649 m) at which point the Well Tractor was activated and conveyed the toolstring down to Target Depth (TD) 18,533 ft (5,649 m).
The well was pressured up to 2,000 psi and logging performed from TD to Top-of-Cement (TOC) estimated at 15,420 ft (4,700 m). Once TOC was reached and, the Well Tractor conveyed the toolstring back to TD for a second pass, logging up with zero pressure. Once the second the log concluded the toolstring was returned to surface.
The operation was completed satisfactorily with no lost time incidents and the total operation time was 28 hours and 45 minutes. The operator achieved the necessary logging data enabling optimum fracture design.