Pulsed neutron spectroscopy is commonly used in the Malay Basin for cased hole formation evaluation to assess development potential and reserve opportunities. Sandstone formations in many fields have caused complications due to sand deposition in mature wells, making logging operations difficult. This work explores the enhancement of operational efficiency on remote offshore platforms by utilizing coiled tubing to convey pulsed neutron evaluation, thereby addressing the demands associated with facilitating more-effective well access operation and formation evaluation assessment.

Electric coiled tubing (e-coil) systems have expanded evaluation logging applications; however, lifting heavy e-coil reels onto offshore sites, especially remote platforms, remains challenging. Battery-powered tools transmitted via fiber optic–enabled real-time coiled tubing (FOERCT), which although widely used in the past decade, have limitations such as restricted power supply and logging time. To overcome these challenges, our work introduces contemporary hybrid cables, similar in size and weight to traditional fiberoptics but with high-power transmission capabilities called monocable-enabled real-time coiled tubing (MERCT) This innovation provides an efficient means of tool conveyance in offshore coiled tubing logging and enables broader remote platform operations.

The application introduced in this work harnesses hydraulic capabilities to supplement sand cleanout procedures preceding cased hole evaluation. Traditionally, these operations involve the deployment of two separate services, which increases the operational footprint and extends the time required for completion. The application of MERCT has effectively reduced the total bottomhole assembly length by eliminating battery subs, consequently obviating the necessity for offshore pressure deployment. This strategic modification significantly bolsters overall operational safety and has yielded a 83%-time savings compared to a traditional deployment method. The single-service deployment and simplification represents a twofold enhancement in efficiency when compared to the previously utilized pulsed neutron logging method.

This advancement enables the development of lightweight coiled tubing logging solutions that are well suited for the challenges posed by offshore environments, including surface and topside constraints. The synergy and plug-and-play setup offered by this innovative approach reduce equipment footprint and simplify the overall execution of operations. This leads to safer deployments while maintaining equivalent levels of effectiveness and efficiency.