The Industry Steering Committee on Wellbore Survey Accuracy
The Industry Steering Committee on Wellbore Survey Accuracy (ISCWSA) is seeking to dispel the confusion and secrecy currently associated with wellbore surveying and to enable the industry to produce consistent, reliable estimates of survey-tool performance in today's wells. This will be achieved through the production and maintenance of standards covering the construction and validation of tool error models.
Work focused initially on MWD systems. They provide a large proportion of the total directional survey data world-wide and, because of their similarities between suppliers, are more amenable to specification standardisation than other types of survey tool.
There is no formal membership of the Committee and its meetings are open to all who wish to attend. The committee has held 33 meetings to date.
The results of the work on an error model for a basic directional MWD service has been presented in SPE 56702 'Accuracy Prediction for Directional MWD' by Hugh Williamson at the 1999 SPE Annual Technical Conference and Exhibition in Houston, Texas, held from the 3-6 October 1999.
An updated version of this paper (SPE 67616) has been published in the December 2000 edition of SPE Drilling and Completion (Volume 15, Number 4) on pages 221 to 233.
A gyro error model has been produced and published in paper SPE 90408 'Prediction of Wellbore Position Accuracy When Surveyed With Gyroscopic Tools' by Torgeir Torkildsen, Stein Havardstein, John Weston and Roger Ekseth.
Depth issues have been investigated and the results published as SPE 95611, "Quantification of Depth Accuracy", which was presented at the SPE Annual Technical Conference, Dallas, 9-12 October 2005.
The ISCWSA is affiliated to the SPE as the Wellbore Positioning Technical Section and has a web site with the SPE at: www.spe.org
Note: The ISCWSA does not approve tool error models for supplier specific survey tools.
More information on the ISCWSA may be obtained from the Committee chairman;