No abstract

A new UltraSlim™ quad combo has been developed and deployed with log quality very comparable to that of larger tools. The suite of logging tools is backed up by a full complement of swivels, knuckles, flex joints, springs, weights, cable head, and latches adaptable to the situation. The string can be conveyed by wireline using conventional power and telemetry, either through-and-below drill pipe or in a conventional open-hole log run. The combo can also be run in the hole by slickline inside drill pipe, then pumped out and latched beneath the bit, using its downhole battery and memory. The tool string has been logged successfully in more than twenty commercial operations in operator wells and two of Halliburton's test wells. The combo and its peripheral equipment have performed without incident. Some of these log runs were made back-to-back with standard-sized logging equipment for the purposes of certifying that the log quality is comparable. The string features an array induction log with number of coils and spacings identical to its larger siblings, array sonic with dual transmitters, deployable-pad density with PE and caliper, dual-spaced neutron, gamma ray, and borehole environmental measurements. This paper describes the UltraSlim logging system and provides details of its reliability, repeatability, accuracy, and petrophysical performance in comparison to standard-size logging tools, by means of visual and statistical log analysis.

A new, small-diameter ultrasonic scanning logging tool has been field tested and commercially deployed for simultaneous cement-sheath and casing evaluation. The tool is designed for use in 9-5/8-in„ heavy-weight casing down to 4-1/2-in. casing. Enhancements in downhole electronics, computing capabilities, and telemetry transmission allow the new circumferential acoustic scanning tool to operate on 7/32-in., 5/16-in., and 9/32-in. mono-conductor e-line cables, which allow for the data acquisition to be performed off a small foot print cased-hole unit with a smaller, lighter tool at the same logging speed as previous generation tools run off a seven-conductor e-line cable on an open-hole unit. The enhanced portability and evaluation capability in casings as small as 4-1/2 in. make the system ideally suited for land operations. Analysis of the cement data is accomplished with the same statistical variance process that has been widely used over the years to analyze data provided by all ultrasonic logging tools available in the industry, resulting in a robust and easy-to-interpret computed product in traditional, light-weight, and foam cement. The cement-evaluation process uses the measured acoustic impedance of the material in the casing-formation annulus. The casing's internal diameter is obtained from the twoway travel time and the measured borehole-fluid travel time. The casing-wall thickness is determined from the frequency content of the reflected waveform data. Both internal diameter and wall thickness are used to determine internal and external casing wear. Legacy ultrasonic scanning tools could not provide quality data in small-diameter casing because of tool size and tool-fishing constraints and near-field transducer ring-down effects. A new, interactive job-planner program has been developed to optimize data acquisition for casing size, weight, and borehole fluids. The planner determines the number of shots per scan and maximum logging speed required for the tool to provide 100% circumferential coverage without sector gaps or interpolated data. Examples comparing the multi-conductor circumferential acoustic scanning tool and the mono-conductor circumferential acoustic scanning tool in conventional and nonconventional cement slurries are presented.