High-Integrity Wellbore Surveying
- Roger Ekseth (Gyrodata) | Torgeir Torkildsen (SINTEF) | Andrew G. Brooks (Baker Hughes) | John L. Weston (Gyrodata) | Erik Nyrnes (Statoil) | Henry F. Wilson (Baker Hughes) | Kazimir Kovalenko (Gyrodata)
- Document ID
- Society of Petroleum Engineers
- SPE Drilling & Completion
- Publication Date
- December 2010
- Document Type
- Journal Paper
- 438 - 447
- 2010. Society of Petroleum Engineers
- 1.6 Drilling Operations, 1.9 Wellbore positioning
- directional surveying, electronic magnetic instruments, system quality control methods, gyroscopic instruments, survey practices
- 4 in the last 30 days
- 1,103 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 10.00|
|SPE Non-Member Price:||USD 30.00|
Position-uncertainty estimates are used to determine if there is adequate probability of hitting a geological target, of avoiding collision with offset wells, and of drilling a successful relief well in the event of a blowout. These high-value decisions are based on tool-error-model predictions, the validity of which is highly dependent on the application of rigorous quality-control (QC) procedures to the survey data. Directional surveys that do not conform to their model?s error predictions represent a risk in terms of lost production, damage to infrastructure, and loss of life.
This paper documents weaknesses in conventional directional-survey QC procedures. Theoretical considerations, statistical analyses of real survey data, and real examples of failed surveys that have made it through conventional QC procedures without detection are presented. The paper defines principles for survey-program design and implementation to eliminate these weaknesses. It proposes a new set of minimum requirements for survey validation.
Where the cumulative QC data do not support the model, it is necessary to adjust the model to fit the data. In the longer term, it might be possible to rework the tools and procedures in the hope of meeting the original model's specification, but the uncertainty estimate assigned to a survey must be valid at all times.
The methods described in this paper are capable of ensuring valid positional data and should be incorporated into standard practice. However, to implement these techniques correctly and consistently, it is probably necessary to establish a specialized supervisory function, responsible for the integrity of wellbore positioning across a company's entire operation.
This paper is the product of a collaborative work within the SPE Wellbore Positioning Technical Section (SPE-WPTS), and combines two previous papers on the subject by Ekseth et al. (2006, 2007).
|File Size||643 KB||Number of Pages||10|
Brooks, A.G., Gurden, P.A., and Noy, K.A. 1998. Practical Application of aMultiple-Survey Magnetic Correction Algorithm. Paper SPE 49060 presented atthe SPE Annual Technical Conference and Exhibition, New Orleans, 27 September-1October. doi: 10.2118/49060-MS.
de Lange, J.I., Twilhaar, G.D.N., and Pelgrom, J.J. 1988. Accurate Surveying: An Operator'sPoint of View. Paper SPE 17213 presented at the SPE/IADC DrillingConference, Dallas, 28 February-2 March.doi: 10.2118/17213-MS.
Delafon, H. 1989. Evaluating the accuracy of directional surveys.Offshore 49 (2).
Ekseth, R. 1998. Uncertainties in Connection with the Determination ofWellbore Positions. Dr.-ing. Thesis, Norwegian University of Science andTechnology (NTNU), Trondheim, Norway.
Ekseth, R., Kovalenko, K., Weston, J.L., Torkildsen, T., Nyrnes, E., Brooks,A., and Wilson, H. 2006. TheReliability Problem Related to Directional Survey Data. Paper SPE 103734presented at the IADC/SPE Asia Pacific Drilling Technology Conference andExhibition, Bangkok, Thailand, 13-15 November. doi: 10.2118/103734-MS.
Ekseth, R., Torkildsen, T., Brooks, A., Weston, J., Nyrnes, E., Wilson, H.,and Kovalenko, K. 2007. High-Integrity Wellbore Surveys:Methods for Eliminating Gross Errors. Paper SPE 105558 presented at theSPE/IADC Drilling Conference, Amsterdam, 20-22 February. doi:10.2118/105558-MS.
Hartmann, R.A. 1996. MATQUS, ASurvey Quality System for Solid State Magnetic Survey Tools. Paper SPE36431 presented at the SPE Annual Technical Conference and Exhibition, Denver,6-9 October. doi: 10.2118/36431-MS.
Nyrnes, E. and Torkildsen, T. 2005a. Analysis of the Accuracy andReliability of Magnetic Directional Surveys. Paper SPE 96211 presented atthe SPE/IADC Middle East Drilling Technology Conference and Exhibition, Dubai,12-14 September. doi: 10.2118/96211-MS.
Nyrnes, E., Torkildsen, T., Haarstad, I., and Nahavandchi, H. 2005b. ErrorProperties of Magnetic Surveying Data. Paper presented at the SPWLA 46th AnnualLogging Symposium, New Orleans, 27-29 June.
Nyrnes E., Torkildsen T., and Nahavandchi H. 2005c. Detection of GrossErrors in Wellbore Directional Surveying with Emphasis on Reliability Analyses.Kart Og Plan 65: 98.
Thorogood, J.L. 1989. Directional Survey OperationsManagement. J Pet Technol 41 (12): 1250-1252.SPE-19462-PA. doi: 10.2118/19462-PA.
Thorogood, J.L. 1990. Instrument Performance Models andTheir Application to Directional Surveying Operations. SPE Drill Eng 5 (4): 294-298. SPE-18051-PA. doi: 10.2118/18051-PA.
Torkildsen, T. 2000. Acceptance Values for MWD Directional Surveying.Presented at the 12th Meeting of the Industry Steering Committee on WellboreSurvey Accuracy, Houston, 5 October.
Torkildsen, T., Håvardstein, S.T., Weston, J., and Ekseth, R. 2008. Prediction of Wellbore PositionAccuracy When Surveyed with Gyroscopic Tools. SPE Drill & Compl 23 (1): 5-12. SPE-90408-PA. doi: 10.2118/90408-PA.
Williamson, H.S. 2000. AccuracyPrediction for Directional Measurement While Drilling. SPE Drill &Compl 15 (4): 221-233. SPE-67616-PA. doi:10.2118/67616-PA.
Wilson, H. and Brooks, A.G. 2001. Wellbore Position Errors Caused byDrilling Fluid Contamination. SPE Drill & Compl 16(4): 208-213. SPE-75329-PA. doi: 10.2118/75329-PA.