High-Efficiency, Driller-Friendly Wireline Logging
Authors: Hoyle D. , Tourillon V. , Webb P. , Soliman H. 
Published: December 2007

Abstract
The basic wireline logging tool string has been reengineered to greatly improve wellsite efficiency and reduce the rig time associated with wireline operations. The integrated string features more robust electronic packaging and mechanical design that meets the higher, more rigorous logging-while-drilling shock standards. Figure 1 depicts the new platform and the standard string. Compared to conventional wireline equipment, the new equipment is less than half as long, weighs half as much, and its logging speed is twice the logging speed of the standard tool. The new string features integrated sensors, a shorter pad section and a new tool body design that improves the quality of the data in difficult hole conditions. Innovative technology has been incorporated into the string to provide downhole cable tension and tool movement measurements for real-time speed correcting the raw data and depth matching.
Dramatic reductions in rig-up and rig-down times, higher logging speeds and faster wellsite data processing were documented during worldwide field tests. Over a wide range of environmental conditions, more than 100 wells in five countries were logged during the field test. Reliability of the new integrated string proved to be more than three times higher than existing technology. Overall operating time savings of 30% were achieved on many of the wells. The shorter length of the new tool string means less rathole must be drilled. In addition the ability of the string to traverse short radius-of-curvature wells and wells containing severe doglegs has been demonstrated in the field tests with drillstring-conveyed logging equipment. A compact compression/tension sub can be run with the string to monitor the stress on the tool during drillstring-conveyed logging. Figure 2 lists the specifications of the new platform.

Introduction
The PLATFORM EXPRESS string represents a fundamental reinvention of wireline logging technology. The word Platform represents the concept of a platform of integrated sensors rather than a set of individual tools screwed together into a very long tool string. The word Express connotes the high efficiency of the new system.

Description
The initial PLATFORM EXPRESS configuration includes a new standard in formation evaluation sensors. The traditional triple combo suite of resistivity and porosity measurements has been upgraded and expanded to include microresistivity, imaging and tool movement measurements. Figure 3 shows the two versions of the PLATFORM EXPRESS string.
Starting at the bottom, the PLATFORM EXPRESS string includes a choice of resistivity measurements with either the AIT Array Induction Imager tool or the HALS High-Resolution Azimuthal Laterolog Sonde. Both tools include the latest advances in resistivity sensor design and specifications. The HRMS High-Resolution Mechanical Sonde has an integrated pad that is pressed against the formation. The pad has two new interlaced sensors: the three-detector lithology density and the microcylindrically focused log. Optimum tool positioning and pad contact are achieved by flex joints in the tool that act as hinges to allow the sonde body to travel in and out of washouts.
Above the mechanical sonde is a single power supply and electronics cartridge. The gamma ray and neutron porosity measurements are reengineered into a single sonde. This section of the string also houses the high-speed telemetry electronics and an accelerometer that provides real-time speed correction and automatic depth-matching of the curves. It also provides real-time well deviation data.

High-Resolution Mechanical Sonde
The HRMS sonde is a hydraulically powered sonde. Its main function is to provide an application force for the density and microresistivity pad, and also a caliper measurement for the hole diameter measurements. The HRMS sonde is at the heart of the articulated architecture of the PLATFORM EXPRESS string. Hinge joints allow optimum positioning of sensors in the borehole; the upper section of the tool is run in contact with the borehole wall, which is optimum for the neutron measurement. The hinge joints act like knee joints. They flex in one plane to keep the tool, and particularly the pad, aligned with the borehole axis. By restricting the motion to one direction only, the string has minimum potential energy when its skid faces down in deviated wells.