(1) Schlumberger Oilfield Services, East Ahmadi, Kuwait
ABSTRACT: New Approach to Analysis Behind Casing Using Cased Hole Resistivity, Geochemical Logging, Epithermal Neutron Cases from Kuwait
Evaluation behind casing was achieved several years ago using thermal neutron decay
time measurements. Recently, several breakthrough technologies have improved and expanded
the ability to see behind the pipe. Cased hole resistivity, geochemical logging, and
epithermal neutron logging are the main tools used for these evaluations.
In this paper, we will illustrate several examples in which these technologies were used for successful evaluations. The first example will cover a well that was logged in openhole conditions, and then re-logged after casing was set. A comparison of the results confirms the accuracy of formation evaluation behind casing. The geochemical results were used in combination with the epithermal neutron data to predict a density measurement behind casing.
The second example illustrates the case of a well that could not be logged in openhole conditions because of bad hole conditions. results of the cased hole evaluation gave the client the essential answer to complete the well successfully.
The third example covers an old well that was analyzed using the cased hole resistivity and the thermal neutron decay time technique. The comparison with the very old resistivity log on the well was rather interesting . since it showed more oil at present which could have migrated.
The evaluations described in the paper represent the first use of this technology in Kuwait. Wells were operated either by the Kuwait Oil Company, which is the national oil company in Kuwait, or Joint Operations, which covers the neutral zone between Saudi and Kuwait.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.