Abstract

The current economic structure of the petroleum industry often requires multiple completions with production from each zone commingled to reduce completion costs. However, these multiple completions require a different approach to analyze the effectiveness of both the original completion and possible later stimulation treatments. To reduce the financial impact of individual zone testing, it is possible, and even desirable, to run production logs to detect each zone contribution to the total production rate.

Wells are encountering multiple pay zones in many areas that are uneconomical to treat and stimulate individually. These pays are treated and evaluated together, consequently leading the completion and/or reservoir engineer to question the effectiveness of the treatment and/or completion. If attempts are made at stimulating the multiple pays, there may be concerns if each zone was exposed to the desired treatment. Well testing, using either draw-down and/or buildup, are more expensive and complicated with multiple completions.

With production logs its is possible to determine the type and rate of the produced fluids from each individual zone in a timely manner. By comparing the logging tool responses before and after stimulations it is possible to determine the effectiveness of the stimulation. This will allow the engineer to determine if the zone was stimulated, needs further treatment, what the optimal treatment is for each zone, and provides valuable information for the next well in a timely, cost-effective fashion.

This paper will suggest guidelines for running production logs and will demonstrate the usefulness of using these tools when evaluating multi-zone completion effectiveness. Several examples are provided highlighting the use of production logs to analyze multi-zone completions.