Field-Wide Production Logging Campaigns: An Essential Health Check for Your Oil Fields
Authors: Al-Hashmi Loayd , Asslman Waleed , Allawi Ghanim , Qutob Hani , El-Halfawi Sami , Kalathingal Paul 
Published: February 2011

Abstract
Production logging tool (PLT) provides a valuable mechanism in judging how wells are performing in terms of well integrity, zonal isolation and the contribution of each perforation set to the total well production or injection. Interpretation of the results of production logging campaigns sets the scene for workover operations needed to keep the field producing at its optimum production potential.
The project covered by this paper addresses the massive campaign of conducting production logging operations on 228 wells in six of the oil fields in southern Iraq. Site visits on a well by well basis were made prior to the job execution to ensure the quality and integrity of wellhead equipment. Project planning and management activities were carried out from the Dubai office. Coordinating a project of that magnitude, which involved diverse teams from different companies, requires professional project planning and coordination to enable the project to stay on track and achieve excellent results. Through-tubing production logging tools were run three times in each well at different speeds. Quick interpretation results were done shortly after the job and full interpretations were completed within a few days from running the logs.
The operation scheduled duration was six months. Accurate alignment of facilities (camp), Equipment (four wireline units), and more than 200 personnel (7 different teams from Weatherford and 3rd party service companies) was essential for the successful implementation of the project plan. Through good coordination and communication with various parties involved, the non-productive-time (NPT) was kept to a minimum. Professional analysis and interpretation of the logging results was used to define the accurate production profile status of the wells in consideration.
Production logging provides downhole measurements of fluid parameters on a zone-by-zone basis to yield information on the type of fluid flowing both inside and near the borehole. Production logging is an essential tool in the evaluation of the completion efficiency, detection of mechanical problems, evaluation of treatment efficiency, monitoring production and injection performance and identifying reservoir boundaries for field development. Several sensors are usually utilized such as thermometers, flow meter spinners, calipers, noise and radioactive tracers. Production logs can determine which perforated zones are contributing to the flow and what the fluid properties of those fluids are. PLT can also measure downhole conditions of pressure and temperature, define thief zones or other unwanted fluid exits, measure the flow rates and show if there are any injection water losses to the annulus. The analysis of the logging campaign helped to identify the extent of downhole well problems and devise adequate measures to tackle those problems in order to maximize the projection and injection of wells under consideration.
This paper shows how a well planned and executed field-wide production logging campaign can be performed to the highest quality and Health, Safety and Environmental compliance standards, while managing to be completed ahead of the planned completion date.