The validity of error model predictions of wellbore position accuracy is highly dependent on the application of rigorous quality control procedures to the survey data. Concern has been expressed within the SPE Wellbore Positioning Technical Section (WPTS, formerly ISCWSA) that failure to apply the necessary operational procedures may be commonplace, raising questions about the reliability of the survey data so generated. Directional survey data that does not conform to its model’s predictions represents a risk in terms of lost production, damage to infrastructure and loss of life.
This paper lists all sources of error, describes internal data checks that are capable of identifying many of them, and highlights those that are missed and which will therefore require alternative QC measures. Real wellbore survey data are used to illustrate how the use of inadequate QC procedures can lead to invalid survey data being accepted as valid.
The paper is the product of collaborative work within the SPE WPTS.