Advanced Production Logging of Horizontal Wells in North Oman

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper IPTC 13309, ’Advanced Production Logging Review of a Number of Horizontal Wells in the North of Oman,’ by T.K. Chang, SPE, Schlumberger, and L. Mieles and P.J. Tarabbia, SPE, Petroleum Development Oman, originally prepared for the 2009 International Petroleum Technology Conference, Doha, Qatar, 7-9 December. The full-length paper reviews the advanced-production-logging jobs performed during 2006–07 in several fields in north Oman. The paper includes the following: Prejob planning, recommended logging procedures, operational planning and considerations for different types of wells, and well-completion strategy Factors influencing horizontal production-logging jobs Evaluation, log quality control, and interpretation of results Success-rate optimization through candidate selection and best practices Introduction Petroleum Development Oman began drilling horizontal wells in the north of Oman in the 1980s. Since then, most development projects have used a high proportion of horizontal and multilateral wells to access reserves. Historically, downhole inflow patterns encountered in these horizontal wells have been challenging to measure and interpret. Recently, a viable production-logging tool (PLT) was identified to increase understanding of real-time three-phase flow to assist in production optimization and proper well and reservoir management. The full-length paper reviews and analyzes a number of logging jobs conducted in the fields of north Oman. With any well-related operation, it is important to discuss the success rate of obtaining data. Fig. 1 shows the success rate of the PLT in the producing oil fields of north Oman. Successful jobs are indicated by green and unsuccessful jobs by red. “Technical success” (amber) is on the basis of whether the logging objectives set before the job were met. In some cases, well-workover entries were performed on the basis of the findings from the PLT job, and some production gains have been recorded. The high success rate (13 successful logging jobs out of 18) was partially a result of proper candidate selection, but mostly a result of proper planning. Of the five unsuccessful jobs, two were a result of tool failures and three were either failure to log the entire interval of interest or inability to log because of operational constraints, giving poor-quality data.