New Generation of Modular Production Logging Array Tool that Enhances Flow Profiling in Hostile Environment and Complex Well Design
Authors: Tveritnev A. , Almansoori N. , Manea A. , Benfriha M. , Escobar J. , Donzier E. , Schoepf V. 
Published: October 2023

Production logging in horizontal wells is challenging by nature. The situation becomes even more complicated in depleted fields where three-phase flow is encountered frequently. Identifying water and gas entry points for shutting them off, assessing the smart completion effectiveness, and identifying poor performing zones for stimulation treatment are key applications for production logging diagnostics in horizontal holes. This paper highlights the effectiveness of the new generation production logging array tool in evaluating the flow profile in hostile logging environment that contains tar, sticky material, and debris, which represent a real challenge for the conventional production logging array tools.

The conventional production logging array tools typically provide very reliable flow profiles whenever the downhole conditions are optimal. However, the presence of tar, sticky materials and debris in downhole conditions remains the main challenge for all the conventional PL array tools. A new PL array logging tool has been designed which allows to deploy in the hole a dense array of multi-physics micro-sensors. The instrument includes optical, electrical, mechanical, magnetic, acoustic, pressure, and temperature transducers achieving unprecedented performance for water – oil – gas – solids identification as well as for the measurement of respective phases velocities. The micro-sensors inherit from MEMS (Micro_Electro_Mechanical_Devices) technology integrating within a tiny housing the sensing elements, analog and digital electronics, computing power and communication capabilities, having all the functions of a millimeter size downhole tool able to withstand the high pressure, high temperature, corrosive fluids of downhole environment. Beyond metrology this unique architecture also provides key advantages in terms of reliability and robustness, indeed, the array of independent micro-sensors offers redundancy and lowers the risk of global tool failure. Combining the new array tool with the spectral noise and pulsed neutron logs makes it possible to evaluate the completion integrity, flow behind the pipe and formation fluid saturation in a single trip. The case study will present the new technology and the results from the individual analysis that will demonstrate how they can be integrated to improve the understanding of the downhole panorama.

The case study presented in the paper represents the first field deployment of the new generation production array tool in one of the most complicated operating environments in production wells where the conventional production logging array tool has failed to provide valid data. The new technology has overcome the hostile downhole environment and provided reliable PL data that successfully allows evaluating the downhole flow profile and identifying the exact oil and gas entry points accurately. The case study demonstrates how spectral noise and pulsed neutron data can successfully complement the downhole analyses obtained from specialized production logging sensors in these high-angle wells. The case study represents a horizontal well equipped with a smart completion. The logging objectives include production and saturation profiling, identifying the gas entry points, evaluation of flow behind casing, and diagnosis of leaks in the completion. The objectives have been achieved successfully by the new production array tool in combination with the spectral noise and pulsed neutron logging.

The case study presented will demonstrate how operators can benefit from the effective use of the new generation of production logging array tool to define the production profile and identify fluid entry points in hostile environments that represents a challenge for the conventional production logging array tools. The improved understanding of the downhole fluid dynamics increases the probability of successful interventions, optimizing production efficiency, and overall improving field and reservoir economics.