This paper describes how a commonly encountered problem with logging deep, hot holes throughout the United States was overcome through the cooperation of a major oil company, service company, and national laboratory. First, we review the past, unreliable performance of standard industry tools during long logging runs at high bottom hole temperatures through actual field examples. Next, we discuss the innovative tool redesign that keeps the inside of the tool cool without increasing the outside diameter of the tool. Finally, we present a comparison of the hot hole and standard tool operating performance in both the laboratory and numerous field examples.
Hot hole logging technology, developed by Los Alamos National Laboratory (LANL) for their geothermal project, was incorporated into cased-hole logging tools that are operated by a wireline company. These tools were retrofitted for the specific use in a well, in a deep gas field in Beckham County, Oklahoma. The cased hole logging tools (gamma ray, neutron, and casing collar logs) were redesigned and constructed through the joint project. The laboratory's oven test of the tools indicated that the hot hole tools would last three times longer under 400F (204C) bottom hole conditions. During the logging run in the deep wells in Beckham County, in western Oklahoma, the standard cased-hole logs failed within two to four hours. However, the hot hole logs ran successfully for two consecutive (six hours) logging runs (a total of 12 hours). Subsequent to this application the retrofitted tool has proved to be equally effective in South Texas and Wyoming.
A growing number of oil and gas fields throughout the world are being developed at deeper depths and higher temperatures. Tool failure due to high temperatures is a common occurrence throughout the U.S. (including: South Texas, Mobil Bay, Oklahoma, and Wyoming). Presently, industry tools must be run repeatedly, and the results pieced together, in order to achieve a satisfactory log. The hot hole logging technology eliminates the waste involved in repeat runs (i.e., electric line runs, rig costs, and tool repair costs).
The standard cased hole logging tools (sondes) that were available in the market prior to this effort involved older technology.