Production Logging Horizontal Wells Using Hybrid Optical/Electrical Platform for Real-Time Coiled Tubing Operations
Authors: Al-Harthi Muhammed , Al-Anizi Abdulaziz , Danish Syed Muhammad , Quero Philippe , Torres Carlos Alberto 
Published: March 2020

This paper discusses an innovative reservoir diagnostic solution for oil wells using a hybrid plug-n-play platform conveyed via coiled tubing (CT). It further highlights the unique characteristics of this system, delving into the first field operations for a major customer. This step-change telemetry and data collection technology will now give operators comprehensive reservoir understanding, shrinking their learning curve for completion optimization, and further enabling customized solutions by featuring a single-trip concept with minimal equipment requirements.

Existing solutions for real-time CT operations normally rely on electrical-conductors, fiber-optics, or mud-pulse telemetry. Each one of these options has its pros and cons, but none of them can satisfy all critical operational needs simultaneously. Fiber-optics-based systems do not allow continuous power supply. Conductor-based systems cannot support the continuously emerging "distributed" sensing services based on optical reflectometry. Mud-pulse telemetry systems have limited data bandwidth while requiring continuous circulation. A hybrid optical/electrical platform represents a significant evolution in CT telemetry. Based on combined optical/electrical communication, this "single-trip" intervention concept provides complementary diagnostic services while delivering regular CT intervention work.

A successful multi-well campaign of real-time production logging was performed with a major customer in the Middle East. A hydrocarbon flow profile was identified across an extended-reach, horizontal, oil-bearing, open-hole section. The hybrid optical/electrical platform enabled all required conventional remedial well interventions before or after the main log. Prior operations with conventional e-line CT imposed severe limitations in terms of complementary services that could be delivered as part of the same campaign: wellbore cleanout, nitrogen lifting, acid pumping, etc. Use of the novel hybrid electric and fiber-optic platform with the full support of real-time production logging enabled a successful execution of this campaign. With its negligible outer diameter, and chemical and abrasion-resistant encapsulation, the hybrid cable does not affect the normal operating envelop of CT operations. The downhole assembly features a flow-through sensor module that can be used independently or simultaneously with wireline adapters for real-time production logging and more. The sensor module provides critical information to ensure operations are performed under the best conditions, including a casing collar locator, gamma ray to correlate, weight on bit and torque to protect the logging tools in case of restrictions, pressure, temperature, tool face, and vibrations. A flow-through camera can also be included into the string for further insight.

The introduction of the new hybrid fiber optic and electric conductor platform represents the next technological evolution in well intervention. It increases equipment reliability and efficiency and, more importantly, enhances real-time monitoring and diagnostic capabilities to better achieve customer objectives. Notoriously complicated operations, like multilateral well re-entries and downhole tool manipulations, can now also be optimized and will benefit from the newly introduced system.