Investigation on Mixed Oil-Cement for Wellbore Integrity Using Acoustic Velocity

Abstract:

Oilwell cementing is part of completing a well prior to production. As a casing is installed after a section of the well is drilled, cement is pumped downhole. Reservoir fluid such as oil which may encroach into the wellbore due to naturally fractured or unconsolidated formation would mix with the cement pumped downhole. Recent studies have shown that the presence of oil affect cement quality to an extent where the cement compressive strength is greatly reduced. Early detection of possible oil contamination into cement may prevent well integrity problem. With intense application of acoustic principle into wellbore, however, not many references available to detect the presence of oil in cement system using this principle. This study investigates whether acoustic waves can detect oil in cement. Class G cement is mixed with both water and brine where crude oil is then added to the mixture. The resulting slurry were cured using High Pressure High Temperature (HPHT) curing chamber at 120°C and 4,000 psi for 24 hours and is then cored into 1-inch cylinder. SonicViewer-SX is used to propagate acoustic waves through the core sample where the transit time is recorded and analyzed. It is found that oil can be detected in cement using acoustic waves since oil-filled samples have slower P-waves and S-waves velocities than cement-filled samples. The case is also proven when water is replaced by brine as the mixing fluid which oil-filled samples have lower P-waves and S-waves velocities to that of cement-filled samples.

• Periodical: Key Engineering Materials (Volume 740)
• Pages: 190-194
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.740.190
• Online since: June 2017
• Authors: Syahrir Ridha, Luluan Almanna Lubis, Riau Andriana Setiawan*, Javad Mohar bin Razif Mohar
• Keywords: Acoustic Wave, Class G, Compressive Strength, Oil in Cement, Velocity

References

[1] J. Cooper, 'Wellbore Integrity.. ' Say What?, Energy Procedia, vol. 1, no. 1, p.3617–3624, (2009).

DOI: 10.1016/j.egypro.2009.02.157

[2] A. Velayati, B. Tokhmechi, H. Soltanian, and E. Kazemzadeh, Cement slurry optimization and assessment of additives according to a proposed plan, J. Nat. Gas Sci. Eng., vol. 23, p.165–170, (2015).

DOI: 10.1016/j.jngse.2015.01.037

[3] N. S. Alias, S. Ridha, and U. Yerikania, Effect of Chemical EOR on Class G Oilwell Cement Integrity under Elevated Conditions, Procedia Eng., vol. 148, p.1066–1073, (2016).

DOI: 10.1016/j.proeng.2016.06.593

[4] Thomas R. Kline, Sulfur Pit Assessment and Repair Strategies, (2014).

[5] I. Odler and J. Colán-Subauste, Investigations on cement expansion associated with ettringite formation, Cem. Concr. Res., vol. 29, no. 5, p.731–735, May (1999).

DOI: 10.1016/s0008-8846(99)00048-4

[6] S. P. Ejeh and O. A. U. Uche, Effect of crude oil spill on compressive strength of concrete materials, J. Appl. Sci. Res., vol. 5, no. 10, p.1756–1761, (2009).

[7] T. Ogbonna, A., Okoro, E., Daraha, Laboratory Investigation of the Effect of Crude Oil Spill on Engineering Properties of Concrete, J. Mech. Civ. Eng., vol. 10, no. 2, p.11–17, (2013).

[8] M. F. Kaplan, The effects of age and water/cement ratio upon the relation between ultrasonic pulse velocity and compressive strength of concrete, Mag. Concr. Res., vol. 11, no. 32, p.85–92, (1959).

DOI: 10.1680/macr.1959.11.32.85

[9] R. K. Anderson, D. A., and Seals, Pulse Velocity as a Predictor of 28- and 90-Day Strength, JP ACI J. Proc., vol. 78, no. 2, p.116–122, (1981).

DOI: 10.14359/6929

[10] M. Vergara, L., Miralles, R., Gosálbez, J., Juanes, F., Ullate, L., Anaya, J. Hernandez, M., and Izquierdo, NDE ultrasonic methods to characterize the porosity of mortar, NDT E Int., vol. 34, no. 8, p.557–562, (2001).

DOI: 10.1016/s0963-8695(01)00020-2

[11] H. -W. Herb, A. T., Grosse, C. U., Reinhardt, Ultrasonic Testing Device For Mortar, Otto-Graf J., vol. 10, no. 1, p.144–155, (1999).

[12] A. Boumiz, C. Vernet, and F. C. Tenoudji, Mechanical properties of cement pastes and mortars at early ages, Adv. Cem. Based Mater., vol. 3, no. 3, p.94–106, (1996).

DOI: 10.1016/s1065-7355(96)90042-5

[13] R. D'Angelo, T. J. Plona, L. M. Schwartz, and P. Coveney, Ultrasonic measurements on hydrating cement slurries, Adv. Cem. Based Mater., vol. 2, no. 1, p.8–14, (1995).

DOI: 10.1016/1065-7355(95)90034-9

[14] C. Boutin and L. Arnaud, Mechanical characterization of heterogeneous materials during setting, Eur. J. Mech. A. Solids, vol. 14, no. 4, p.633–656, (2003).

[15] T. P. Philippidis and D. G. Aggelis, An acousto-ultrasonic approach for the determination of water-to-cement ratio in concrete, Cem. Concr. Res., vol. 33, no. 4, p.525–538, Apr. (2003).

DOI: 10.1016/s0008-8846(02)00999-7

[16] API RP 10B-2, Specification for Cements and Materials for Well Cementing, 23rd ed. (2002).