Simplifying Well Abandonments Using Shale as a Barrier
- Eric van Oort (The University of Texas at Austin) | Maria Juenger (The University of Texas at Austin) | Munir Aldin (Metarock Laboratories, Houston) | Akshay Thombare (Metarock Laboratories, Houston) | Mike McDonald (National Silicates, an affiliate of PQ Corporation) | Alexander Lucas (Total Upstream Danmark A/S) | Frederik Ditlevsen (Total Upstream Danmark A/S)
- Document ID
- Society of Petroleum Engineers
- IADC/SPE International Drilling Conference and Exhibition, 3-5 March, Galveston, Texas, USA
- Publication Date
- Document Type
- Conference Paper
- 2020. IADC/SPE International Drilling Conference and Exhibition
- 4.3.4 Scale, 1.10 Drilling Equipment, 1.6.9 Coring, Fishing, 1.10 Drilling Equipment, 3 Production and Well Operations, 1.6.12 Plugging and Abandonment
- Shale Creep, Zonal Isolation, Shales, Annular Barrier, Well Abandonment
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- 251 since 2007
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Well abandonment is one of the biggest challenges in the oil and gas industry, both in terms of cost and effort as well as the technical hurdles associated with wellbore isolation for an indefinite term. A mechanism that may be exploited to simplify well abandonments is using natural shale formations for the creation of annular barriers. Currently, uncemented annuli often require casing milling and pulling before abandonment plugs can be set, which necessitates the use of a drilling rig. This is an expensive, time- and labor-intensive process, particularly offshore. However, shale creep may naturally form a barrier behind uncemented casing sections. With a qualified annular shale barrier in place, the well may only require the setting of abandonment plugs within the existing casing string(s), a task that can often be done rigless and with significantly less effort.
The work described in this paper presents the results of a rock mechanical investigation into the creep behavior of North Sea shales and their ability to form effective annular barriers. Field core from the Lark-Horda shale was used to conduct dedicated, customized experiments that simulated the behavior of shale confined under downhole effective stress, pressure and temperature conditions to fill in an annular space behind a simulated casing string. Full scale tri-axial rock mechanics equipment was used for testing cylindrical shale samples obtained from well-preserved field core in a set-up that mimicked an uncemented casing section of a well. The deformation behavior of the shale was monitored for days to weeks, and the formation of the annular barrier was characterized using dedicated strain measurements and pressure pulse decay probing of the annular space.
The large-scale lab results clearly show that the Lark-Horda shales will form competent low permeability annular barriers when left uncemented, as confirmed using pressure-pulse decay measurements. They also show that experimental conditions influence the rate of barrier formation: higher effective stress, higher temperature and beneficial manipulation of the annular fluid chemistry all have a significant effect. This then opens up the possibility of activating shale formations that do not naturally create barriers by themselves into forming them, e.g. by exposing them to low annular pressure, elevated temperature, different annular fluid chemistry, or a combination. The results are in very good agreement with field observations reported earlier by several North Sea operators.
|File Size||9 MB||Number of Pages||19|
Ansari, A. A., Libdi, Z., Khan, N., Aslanyan, A., Aslanyan, I., Volkov, M., Makhiyanov, R. (2015, October 26). Triple-Barrier Thickness Scanning Using Through-Tubing Pulse-Magnetic Logging Tool. Society of Petroleum Engineers. doi:10.2118/176655-MS.
Ansari, A. A., Ringrose, D., Libdi, Z., & Larsen, A. G. (2016, August 22). Extending Life for Offshore Wells by Fixing the Integrity High Annulus-B Pressure and Creating Zonal Isolation Using a Novel Remediation Technique. Society of Petroleum Engineers. doi:10.2118/180555-MS.
Desai, P. C., Hekelaar, S., & Abshire, L. (2013, May 6). Offshore Well Plugging and Abandonment: Challenges and Technical Solutions. Offshore Technology Conference. doi:10.4043/23906-MS.
Delabroy, L., Rodrigues, D., Norum, E., Straume, M., & Halvorsen, K. H. (2017, April 5). Perforate, Wash and Cement PWC Verification Process and an Industry Standard for Barrier Acceptance Criteria. Society of Petroleum Engineers. doi:10.2118/185938-MS.
Enayatpour, S., Thombare, A., Aldin, M., & van Oort, E. (2019, September 23). Exploiting Shale Creep Deformation to Create Annular Barriers for Well Plugging and Abandonment: Experimental Investigation and Numerical Simulation. Society of Petroleum Engineers. doi:10.2118/195966-MS.
Ferg, T. E., Lund, H.-J., Mueller, D. T., Myhre, M., Larsen, A. G., Andersen, P., Field, D. (2011, January 1). Novel Approach to More Effective Plug and Abandonment Cementing Techniques. Society of Petroleum Engineers. doi:10.2118/148640-MS.
IHS Markit (November 2016). Decommissioning of Aging Offshore Oil and Gas Facilities Increasing Significantly, with Annual Spending Rising to $13 Billion by 2040, IHS Markit Says, https://news.ihsmarkit.com/press-release/energy-power-media/decommissioning-aging-offshore-oil-and-gas-facilities-increasing-si
Hsieh, P. A., Tracy, J. V., Neuzil, C. E., Bredehoeft, J. D., & Silliman, S. E. (1981, June). A transient laboratory method for determining the hydraulic properties of ‘tight’ rocks—I. Theory. In International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts (Vol. 18, No. 3, pp. 245–252). Pergamon.
Joneja, G., Nafikova, S., Reid, J., Rublevskyi, A., & Salazar, J. (2018, March 6). Perf-and-Wash Cement Placement Technique as a Cost-Effective Solution for Permanent Abandonment of a Well with Multiple Permeable Zones: A Case Study from North Sea, UK. Society of Petroleum Engineers. doi:10.2118/189580-MS.
Kristiansen, T. G., Dyngeland, T., Kinn, S., Flatebø, R., & Aarseth, N. A. (2018, September 24). Activating Shale to Form Well Barriers: Theory and Field Examples. Society of Petroleum Engineers. doi:10.2118/191607-MS.
Kutchko, B.G., Strazisar, B.R., Huerta, N., , 2009. CO2 Reaction with Hydrated Class H Well Cement under Geologic Sequestration Conditions: Effects of Flyash Admixtures. Environ. Sci. Technol. 43, 3947–3952. doi:10.1021/es803007e.
Lavery, D., & Imrie, A. (2017, March 14). The Silver Lining to Squeezing Salts: Practical Cased Hole Logging and Interpretation Method Determines if Mobile Formations Act as Annular Barriers for Plug and Abandonment Applications. Society of Petroleum Engineers. doi:10.2118/184720-MS.
Lavery, D., Jambunathan, V., & Shafikova, G. M. (2019, June 15). Turning a Negative into a Positive: Shale Annular Barrier Identification for Plug and Abandonment. Society of Petrophysicists and Well-Log Analysts (SPWLA). doi:10.30632/T60ALS-2019_LL.
Le-Minous, J. C., Mutti, D., Bouvet, A., Unanue-Rodriguez, I., Chang, A., Massie, I., Schnell, E. (2017, March 14). Permeability Study of API Class G and B Cements Considering Seawater and WBM Contamination. Society of Petroleum Engineers. doi:10.2118/184613-MS.
Lucas, A., Stokkeland, T. A., Jackson, D., & Ingram, S. (2018, September 24). Improving the Understanding, Application and Reliability of the Perforate, Wash and Cement Technique through the Use of Cement Bond Logs, Tool Enhancements and Barrier Verification via Annular Pressure Monitoring. Society of Petroleum Engineers. doi:10.2118/191528-MS.
Wood MacKenzie (January 2018). Decommissioning – will the time ever be right? https://www.woodmac.com/news/editorial/are-cost-rises-inevitable-for-global-upstream2/
Zhang, J., Mahbod, P., Shafer, R., Mueller, D., & Anderson, C. (2019, May 13). Multi-String Isolation Logging - A Cost Effective Solution for P&A. Society of Petroleum Engineers. doi:10.2118/195607-MS.