Comprehensive Liner Inspection Using Smart Integration of Acoustic and Caliper Logs

Abstract

Abstract A well integrity system is comprised of a complete evaluation of both cement placement and tubular condition. In this regard, casing degradation evaluation is of primary importance to ensure that the well is capable of producing for its complete lifecycle. Evaluation techniques include mechanical calipers which have been the traditional and conventional technology in the past half century or so are capable of assessing the internal pipe condition. More recently, high resolution ultrasonic imaging has been introduced that determines casing thickness by transmitting pulse-echo waveforms to excite the casing in its thickness mode through the principles of resonance. In the work this paper presents, a holistic interpretation approach is used by integrating two technologies of acoustic and mechanical measurements for identifying the liner tortuosity in a deep exploratory well in Pakistan. This work pertains to the production liner section (7-inch) across which the operator was facing problems while running the string down. The well was a newly drilled exploratory well and the operator wanted to ensure the integrity of the well and identify possible bottlenecks restricting the tool movement within the wellbore. Therefore, it was decided to acquire extended data and not rely on a mono-source evaluation. A six-arm mechanical caliper log was acquired subsequently followed by an ultrasonic acoustic pulse-echo measurement; data from both the sources was integrated to obtain the borehole profile for detailed evaluation and analysis. Comprehensive corrosion evaluation was performed using ultrasonic and caliper data. Ultrasonic data was processed and oriented by using industry-standard software to azimuthally identify the damaged zone across the 7-in liner section. In addition, caliper data was also analyzed in detail through borehole section plots at individual depths of the damaged zone. Resultantly, both datasets were integrated into a single log display to diagnose and identify the liner buckling with the observed metal loss. Dynamic and integrated corrosion evaluation helped to holistically identify the well's tubular integrity concerns. As a result, with this unique integration, accurate borehole geometrical profiling was assessed that would allow for more robust planning of future well intervention and completion activities.