Kohl, Thomas

Meixner, Jörg

Müller, Birgit

Schimschal, Stefan

Stricker, Kai Robin

Wessling, Stefan

English

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Drilling Induced Borehole Breakouts - New Insights From LWD Data Analysis

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KIT – The Research University in the Helmholtz AssociationDrilling induced borehole breakouts – new insights from LWD data analysisK. Stricker, S. Schimschal, T. Kohl, J. Meixner, B. Müller and S. Wessling kai.stricker@kit.eduInstitute of Applied GeosciencesDivision of Geothermicsagw.kit.eduMotivation Conclusion and PerspectivesInfluence of drilling processesBorehole breakouts (Tingay et al., 2008):Occurrence of breakoutswhen stresses around theborehole are higher than thestress required to generatecompressive failure of theborehole wallOrientation parallel tominimum horizontal stress σhMud weight has to beadjusted accordingly toprevent breakoutsSchematic cross sections of borehole breakouts(Hillis and Reynolds, 2000)Theoretical backgroundCircumferential stressOverview of relevant drilling processes(SOG, 2019):Pipe trips: (Partial) removal of thedrill stringConnections: Extension of the drillstring by an additional segmentMethodology and software developmentTemporal breakout evolution1• Software development in JewelSuite2• Identification and collection of useful datasets3• Analysis of image logs4• Analysis of drilling operations5• Evaluation of drilling parameters and correlation to drilling operations6• Sensitivity analysis of drilling induced pressure changes7• Investigation of time-dependent borehole instability effectsMethodologySoftware developmentBasis for development: Previously developed MATLAB prototypeProgramming language: C# (development environment: Microsoft VisualStudio)Platform: JewelSuite (BHGE 3D Reservoir Software)Major challenge: Visualization of image log data (no implementation in theJewelSuite framework available)  pixel-by-pixel realizationDesign: The main graphical user interface of the software is divided into:Left Panel: multiple user controls to manipulatethe displayed data in the plotsRight Panel: plots for image, caliper, bit andimage tool depth as well as time basedpressure and temperature dataToolbar: multiple user controls to e.g.load/save breakout data or screenshots of theviewLeftpanelRight panelToolbarSoftware prototypeReferencesSupported byClear relation between breakouts andtripping operations / flow-off events Cause for occurrence?Frequency of tripping events withinbreakout intervals one order ofmagnitude higher than outsideFlow-off events (switched-off pumps)also occur more frequently withinbreakout intervalsRelationship between drilling processes and pressure anomalies (mostly negative)Observations of increasedbreakout depth extent andopening angles by using relogimagesComparison of different imagesin the same BHA potentiallyenables the temporal analysisof breakout evolutionsFrequency of tripping and flow-off events during breakout sectionsComparison of images for the identification of drilling-related breakout developmentRelog images of the same wellbore sectionHillis, R. and Reynolds, S. (2000): The Australian stress map. Journal of the Geological Society, 157, 5: 915-921.SOG (2019): Schlumberger Oilfield Glossary. https://www.glossary.oilfield.slb.comTingay, M., Reinecker, J. and Müller, B. (2008): Borehole breakout and drilling-induced fracture analysis from image logsWessling, S., Bartetzko, A., Pei, J. and Dahl, T. (2012): Automation in Wellbore Stability Workflows. SPE Intelligent Energy International, Utrecht, The Netherlands, 27-29 March 2012.Observation of a relation between drilling processes and breakoutsNegative pressure variations may have contributed to thedevelopment of breakoutsBreakouts tend to grow both azimuthally and in their depth extentFuture research could benefit from the availability of relogs and/ormultiple image logging tools in the same wellboreAzimuthal LWD logs provide images of the borehole wall, which arewidely used for the analysis of borehole breakoutsThese breakouts develop when the circumferential stress aroundthe borehole wall exceeds the compressive strength of the rockUncertainty on how drilling processes (such as tripping) influencethe development of breakoutsPressure windowModified after Wessling et al. (2012)Angle (°) Caliper (in) Time (h)TimeDepth(m)Depth(m)Pressure(MPa) Temperature(°C)TimeTime (h)Pressure(MPa)Dpeth(m)Temperature(°C)Log resistivity (Ohmm)Angle (°C) Angle (°C)Log resistivity (Ohmm) Log density (gcm-3)Depth(m)Depth(m)Pressure(MPa)Temperature(°C)Time (h)Angle (°C) Angle (°C) Angle (°C) Angle (°C) Angle (°C)Depth(m)Depth(m)Depth(m)Depth(m)Depth(m)Original logLog resistivity(Ohmm)Relog 1Log resistivity(Ohmm)Relog 2Log resistivity(Ohmm)Relog 3Log resistivity(Ohmm)Relog 3Log resistivity(Ohmm)

Drilling induced borehole breakouts - new insights from LWD data analysis

https://publikationen.bibliothek.kit.edu/1000105885/95816795

Drilling induced borehole breakouts - new insights from LWD data analysis

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