Abstract

Wireline production logging provides a tool to measure reservoir performance downhole. This is a particularly valuable tool in multiple zone completions as each interval's contribution to the total well performance can be measured. This information is especially valuable in mature producing areas where reservoir pressure declines have not been distributed evenly from zone to zone. The use of electrical submersible pump (ESP) as a lift mechanism presents specific challenges to the application of production logging tools (PLT) into these wellbores. The difficulty increases when there is insufficient clearance between the ESP and the casing for the logging tools to pass, such as in the case of wells completed with 7 inch (18 cm) casing. This situation is encountered in a large majority of ESP lifted wells in Central Sumatra. Existing solutions to this challenge have proved to suffer from reliability and cost constraints.

A multi-disciplinary team was formed to focus on this problem, analyze the existing methods, and develop possible alternative solutions. Three existing techniques were identified and two new methods were developed by the team. Safety, reliability, practicality, and cost factors were reviewed for each. A simple technique allowing the logging tools and cable to be run in the hole ahead of the ESP was determined to show the most promise and tested in an observation well. This resulted in some minor improvements and a field trial was initiated.

The new method has now been used successfully in 7 wells without a failure. The information gained has helped to allocate oil production in multiple zone completions, evaluate production potentials, and increase oil production.