The actual physical and mechanical properties of the reservoir and its stress-strain state (SSS) may differ from the predicted values of the stability model at the pre-drilling stage.
Clay, fractured, weakly cemented or brittle rocks that are exposed to SSS or chemical effects of drilling mud change their elastic-strength properties and are prone to collapse, which leads to a whole range of undesirable consequences.
Rock caving is a valuable source of information about the SSS of the near-well space during drilling. This article discusses the conditions for the appearance and characteristics of rock cavings. Various types of rock cavings obtained during drilling at the perimeter fields of the Gazpromneft group companies are analyzed, and correlations with 1D geomechanical models of well stability are shown.
cavings, wellbore instability, geomechanical support, geomechanical modeling, drilling efficiency, monitoring of drilled rock, stress-strain state, geological and technological research
Al-Bahrani H., Al-Yami A. (2018). Drillstring Vibrations and Wellbore Quality: Where Drillstring Design Meets Geomechanics. Abu Dhabi International Petroleum Exhibition & Conference «Society of Petroleum Engineers». Abu Dhabi, UAE. Available at: (accessed: 22.11.2020). DOI: (in English)
Hamid O., Qahtani A., Alamer S., Sherbeny W. (2018). Mitigating Wellbore Stability Risks through Geomechanical Solutions. Abu Dhabi International Petroleum Exhibition & Conference «Society of Petroleum Engineers». Abu Dhabi, UAE. Available at: (accessed: 22.11.2020). DOI: (in English)
Godwin C., Jacob N., Bariakpoa K., Samuel N. (2020). Evaluation of Optimum Mud Weight Window for Prevention of Wellbore Instability in Niger Delta Wells. IOSR Journal of Engineering, 10, 10, 61-66. Available at: (accessed: 22.11.2020) (in English)
Karimi M. (2013). Drill-Cuttings Analysis for Real-Time Problem Diagnosis and Drilling Performance Optimization. Asia Pacific Oil and Gas Conference and Exhibition «Society of Petroleum Engineers». Jakarta, Indonesia. Available at: (accessed: 25.11.2020). DOI: 10.2118/165919-MS (in English)
Kumar D., Ansari S., Wang S., Ahmed S., Povstyanova M., Tichelaar B. (2012). Real-time wellbore stability analysis: an observation from cavings at shale shakers. AAPG international conference & exhibition «American Association of Petroleum Geologists (AAPG)». Singapore. Available at: (accessed: 23.11.2020) (in English)
Christopher S., Alireza R., Pouria B. (2018). An approach for wellbore failure analysis using rock cavings and image processing. Journal of Rock Mechanics and Geotechnical Engineering, 10, 5, 865-878. Available at: (accessed: 23.11.2020). DOI: (in English)
Renato G., Zuly H., Yair A. (2014). New Approach for Estimating Cavings Volume to Avoid Wellbore Instabilities. Materials of Conference on Rock Mechanics for Natural Resources and Infrastructure «International Society for Rock Mechanics and Rock Engineering Source». Goiania, Brazil. Available at: (accessed: 25.11.2020).
Tsopela A., Bere A., Dutko M., Kato J. (2020). Wellbore Stability and Predicted Cuttings Volume in Deviated Wellbores and Bedded Formations. Materials for 54th U.S. Rock Mechanics/Geomechanics Symposium «American Rock Mechanics Association Source». Available at: (accessed: 25.11.2020) (in English)
Gabitov S.I., Gotsulyak A.S., Cheby`shev I.S., Muxamadiev R.V. (2020). Soprovozhdenie bureniya vy`sokotexnologichny`x skvazhin na osnove integracii metodov geomexaniki i geonavigacii [Support of drilling high-technological wells based on the integration of geomechanics and geosteering] Neftegazovoe delo. - Oil and gas business, 2, 15-23. Available at: (accessed: 22.11.2020). DOI: 10.17122/ngdelo-2020-2-15-23 (in Russian).
Neskromny`x V.V. (2015) Razrushenie gorny`x porod pri provedenii geologorazvedochny`x rabot [Destruction of rocks during geological exploration]. Sib. Feder.un-t. Krasnoyarsk (in Russian).
Al-Rubaii M., Gajbhiye R., Al-Yami A., Alshalan M., Al-Awami M. (2020). Automated Evaluation of Hole Cleaning Efficiency While Drilling Improves Rate of Penetration. Materials of IPTC «International Petroleum Technology Conference». Dhahran, Kingdom of Saudi Arabia. Available at: (accessed: 23.11.2020). DOI: (in English)
Stephen W. (2008). An aid to managing wellbore stability in real time. BP cavings field guide. America. (in English)
Jose F., Lida V. (2019). Wellbore Stability Improvement Using Caving Analysis. International Society for Rock Mechanics and Rock Engineering «Materials of 8th International Symposium Geomechanics». Bucaramanga, Colombia. Available at: (accessed: 25.11.2020). (in English)
Anjanava D., Rohit R., Rajeev R., Jayanta B., Rahul T., Amit S. (2020). Cavings Morphology Analysis: A Critical Geomechanical Tool in Optimizing Drillability. Materials of IPTC «International Petroleum Technology Conference». Dhahran, Kingdom of Saudi Arabia. Available at: (accessed: 22.11.2020). DOI: (in English)
S.I. Gabitov, Lead-specialist, Gazpromneft-Science&Technology Center LLC
75-79 D, Moika River Embankment, Saint Petersburg, 190000, Russia
A.S. Gotsulyak, Сhief-specialist, Gazpromneft-Science&Technology Center LLC
Saint-Petersburg, Russian Federation
I.S. Chebyshev, Сhief-specialist, Gazpromneft-Science&Technology Center LLC
Saint-Petersburg, Russian Federation
T.Z. Akhmetshin, PhD student, Ufa State Petroleum Technological University