Identifying Completion Problems (Tubing String Leaks, Poor Cement Jobs, etc.) Using Oil Geochemistry

The same type of oil geochemistry (oil fingerprinting) data used to assess reservoir compartmentalization and allocate commingled production can be used to identify problems with well completions, such as:

1. Tubing string leaks. Using an excellent case study from the Gulf of Mexico, Hwang and Elsinger, (1995) illustrate the use of oil geochemistry (gas chromatography) to infer a leak in one string in a dual tubing string completion. A subsequent work over of this well confirmed the breach of the tubing string at the point suggested by the oil geochemistry. The breach evidently resulted from the omission of a blast joint that should have been installed at the point of the eventual rupture, but which had inadvertently been installed one tubing length shallower (R. J. Elsinger, personal communication to M. McCaffrey). Similar problems have been identified in other fields using the same approach. For example, Kaufman et al. (1997) applied the same oil fingerprinting techniques to identify tubing string leaks in the Greater Bergan Field, Kuwait.
2. Communication between zones behind casing due to poor cement jobs, and
3. Ineffective stimulation of a given interval.

With all of these applications, the relative abundance of various compounds in the petroleum are used to identify completion problems by allowing produced fluids to be tied to specific reservoir intervals. For more information on the technique described here, or to discuss a specific project, e-mail us at info@oiltracers.com, or call us at (214) 584-9169.

References

Hwang R. J. and Elsinger R. J. (1995). Detecting production tubing leak by time resolved geochemical analysis of oils. Society of Petroleum Engineers, 355-367.

Kaufman, R. L., H. Dashti, C. S. Kabir, J. M. Pederson, M. S. Moon, R. Quttainah, and H. Al-Wael, 1997, Characterizing the greater Burgan Field: Use of geochemistry and oil fingerprinting: SPE Paper No. 37803, p. 385-394.