PUBLICATION RIGHTS RESERVED PUBLICATION RIGHTS RESERVED THIS PAPER IS TO BE PRESENTED AT THE INTERNATIONAL TECHNICAL MEETING JOINTLY HOSTED BY THE PETROLEUM SOCIETY OF CIM AND THE SOCIETY OF PETROLEUM ENGINEERS IN CALGARY, JUNE 10 TO 13, 1990. DISCUSSION OF THIS PAPER IS INVITED. SUCH DISCUSSION MAY BE PRESENTED AT THE MEETING AND WILL-BE CONSIDERED FOR PUBLICATION IN CIM AND SPE JOURNALS IF FILED IN WRITING WITH THE TECHNICAL PROGRAM CHAIRMAN PRIOR TO THE CONCLUSION OF THE MEETING.

Abstract

A new cement integrity tool has been developed, the Segmented Bond Tool (SBT), which affords a complete cement bond analysis in one logging pass. An may of transmitter receivers, mounted on six pads, arc utilized to extract quantitative measurements of the cement bond in six 60 degrees segments around the borehole. In addition, by effectively mounting the transmitters and receivers in contact with the casing wall through the use of pads, many of the problems common to the standard mandrel-type tools are effectively eliminated. Experimental laboratory tests indicate that angular resolution of the tool is 60 degrees as expected and that channels as small as 15 degrees can be detected.

From conception of this new generation CBL to final product several rigid parameters were demanded. Briefly these are:

  1. Ease of interpretation.

  2. Eliminate ambiguity of conventional bond logs by quantitatively depicting the bond condition around the casing (i.e. channelling).

  3. Complete data acquisition in one logging pass in all casing sizes 4-1/2' to 13-5/8 in both vertical and deviated wellbores.

  4. Be unaffected by gasified wellbore fluids, fast formation and slight tool decentralization.

The purpose of this paper is to determine the success of the SBT in fulfilling these goals. Presented here arc four Canadian examples from widely varied areas having casing strings cemented with various slurries.

Introduction

As discussed in Lester's Paper (CWLS 1989) and as summarized below, the evolution of cement bond logging has resulted in four distinct tool types:

  1. Standard Tool

    Utilizes a single transmitter and dual receivers usually mounted at 3 and 5 foot intervals, with the amplitude measured at the 3 foot interval. Attenuation is calculated from this amplitude. The VDL is derived from the 5 foot spacing (Pardue et al 1962). The data collected is effected by tool centralization. wellbore fluid condition, transducer variations, fast formations. and calibration problems.

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