The Johan Sverdrup Field: Origin of Sulfate-Rich Formation Water and Impact on Scale-Management Strategy
- Kari Ramstad (Statoil ASA) | Ross McCartney (Oilfield Water Services Limited) | Henriette Dorthea Aarrestad (Statoil ASA) | Siv Kari Lien (Statoil ASA) | Øystein Sæther (Statoil ASA) | Rita Iren Johnsen (Statoil ASA)
- Document ID
- Society of Petroleum Engineers
- SPE Production & Operations
- Publication Date
- February 2017
- Document Type
- Journal Paper
- 73 - 85
- 2017.Society of Petroleum Engineers
- Water management, Geochemistry, Scale control, Formation water, Field development
- 0 in the last 30 days
- 336 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 5.00|
|SPE Non-Member Price:||USD 35.00|
The Johan Sverdrup field will, at maximum, contribute 25% of the total oil production from the Norwegian Continental Shelf (NCS). Plateau production from the fully developed field is estimated at 550,000 to 650,000 BOE/D. Geochemical formation-water interpretation and development of a scale-management strategy have been performed to ensure high well productivity and process regularity of the field.
Uncertainty over the composition of formation water made the decision to inject normal seawater or low-sulfate seawater into the reservoir for pressure support a challenge. Water compositions in samples obtained from appraisal wells were unusual for the Norwegian North Sea, being sulfate-rich with negligible barium. This was suspected to be an artifact of drilling-fluid contamination, and corrections were applied to obtain representative estimates. These estimates confirmed that the formation waters had variable salinity (21–48 g/L chloride), and were indeed sulfate-rich (94–746 mg/L) and barium-depleted (<6 mg/L). The compositions may reflect (a) mixing of formation waters across the field over geological time and/or (b) interactions with the underlying Zechstein group (anhydrite). The focus here is on issue (b) because a detailed evaluation of local/regional aquifer movements in geological time, communication patterns, and flow restrictions is beyond the scope of this paper.
Three appraisal wells in the Geitungen Terrace showed barium-rich formation water outside the main reservoir area where no underlying Zechstein group was present. Initially, there were concerns about the scaling risks associated with mixing sulfate- and barium-rich formation waters. However, present geological understanding indicates insignificant aquifer volumes with barium, implying that full-field development and scale strategy do not need to consider barium-rich water.
Scale predictions were performed for various strategies: formation-water production, seawater injection, produced-water reinjection, and low-salinity/low-sulfate-water injection. Moderate strontium sulfate (SrSO4) and calcium carbonate (CaCO3) scalings are expected in the production wells. If third-party barium-rich waters are tied in, the topside barium sulfate (BaSO4) scaling risk increases.
This work has shown
- Careful evaluation of formation-water samples/analyses reduces uncertainties associated with water compositions and increases confidence in results and decisions.
- Underlying geology can influence formation-water compositions.
- Good-quality water sampling is important for later-phase field development and scale management.
The implications for field development are
- Seawater will be injected into the reservoir for pressure support, with no need for a sulfate-removal plant.
- Produced-water reinjection will gradually replace seawater to minimize environmental impact.
- Downhole scale-inhibitor injection has been recommended to protect the upper completion.
|File Size||1 MB||Number of Pages||13|
Al-Ashhab, J., Al-Matar, H., and Mokhtar, S. 2006. Techniques Used to Monitor and Remove Strontium Sulfate Scale in UZ Producing Wells. Presented at the Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 5–8 November. SPE-101401-MS. http://dx.doi.org/10.2118/101401-MS.
Eroini, V., Anfindsen, H., and Mitchell, A. F. 2015. Investigation, Classification and Remediation of Amorphous Deposits in Oilfield Systems. Presented at the SPE International Symposium on Oilfield Chemistry, The Woodlands, Texas, 13–15 April. SPE-173719-MS. http://dx.doi.org/10.2118/173719-MS.
Goodwin, N., Walsh, J. M., Wright, R. et al. 2011. Modeling the Effect of Triazine Based Sulphide Scavengers on the In Situ pH and Scaling Tendency. Presented at the SPE International Symposium on Oilfield Chemistry, The Woodlands, Texas, 11–13 April. SPE-141583-MS. http://dx.doi.org/10.2118/141583-MS.
Johnston, C., Sutherland, L., and Herman, T. 2014. The Influence of Turbulence (or Hydrodymanic Effects) on Strontium Sulphate Scale Formation and Inhibitor Performance. Presented at the SPE International Oilfield Scale Conference and Exhibition, Aberdeen, 14–15 May. SPE-169760-MS. http://dx.doi.org/10.2118/169760-MS.
Kharaka, Y. K. and Hanor, J. S. 2014. Deep Fluids in Sedimentary Basins. In Treatise on Geochemistry, second edition, eds. H. D. Holland and K. K. Turekian, Vol. 7, Chapter 7.14, 471–515. Oxford: Elsevier. http://dx.doi.org/10.1016/B978-0-08-095975-7.00516-7.
Lien, S. C., Lie, S. E., Fjellbirkeland, H. et al. 1998. Brage Field, Lessons Learned After 5 Years of Production. Presented at the SPE European Petroleum Conference, The Hague, The Netherlands, 20–22 October. SPE-50641-MS. http://dx.doi.org/10.2118/50641-MS.
Mackay, E. J., Collins, I. R., Jordan, M. M. et al. 2003. PWRI: Scale Formation Risk Assessment and Management. Presented at the SPE International Symposium on Oilfield Scale, Aberdeen, 29–30 January. SPE-80385-MS. http://dx.doi.org/10.2118/80385-MS.
McCartney, R. A. and Rein, E. 2005. Formation Waters of the Norwegian Continental Shelf. Presented at Tekna 16th International Oil Field Chemistry Symposium, Geilo, Norway, 13–16 March.
McCartney, R. A., Eriksen, S. Hj., Ramstad, K. et al. 2013. Investigation of the Use of Scale Risk Parameters To Predict Failure of Downhole Safety Valves on the Gullfaks Field. Presented at the 24th International Oil Field Chemistry Symposium, Geilo, Norway, 17–20 March.
McCartney, R. A., Aarrestad, H. D., Lien, S. K. et al. 2015. Reactive Transport Modelling of Mud Filtrate Invasion During Drilling and Application to Mud Contamination Corrections on Formation Water Analyses. Presented at the Tekna Oil Field Chemistry Symposium, Geilo, Norway, 22–25 March.
Pedenaud, P., Hurtevent, C., and Baraka-Lokmane, S. 2012. Industrial Experience in Sea Water Desulfation. Presented at the SPE International Conference on Oilfield Scale, Aberdeen, 30–31 May. SPE-155123-MS. http://dx.doi.org/10.2118/155123-MS.
Petroleum Safety Authority Norway. 2015. Regulations Relating to Conducting Petroleum Activities, Chapter XI Emissions and Discharges to the External Environment, Section 60b Discharge of Oily Displacement Water. Norway, 18 December. http://www.psa.no/activities/category399.html#_Toc438209903.
Ramstad, K., Tydal, T., Askvik, K. M. et al. 2005. Predicting Carbonate Scale in Oil Producers From High-Temperature Reservoirs. SPE J. 10 (4): 363–373. SPE-87430-PA. http://dx.doi.org/10.2118/87430-PA.
Ramstad, K., Rohde, H. C., Dalland, A. et al. 2012. Flow Assurance in Complex Topside Processes With Subsea Tie-ins and Multiple Fluid Systems. Presented at the SPE International Conference on Oilfield Scale, Aberdeen, 30–31 May. SPE-155036-MS. http://dx.doi.org/10.2118/155036-MS.
Ramstad, K., McCartney, R. A., Aarrestad, H. D. et al. 2016. The Johan Sverdrup Field – Origin of Sulphate-Rich Formation Water and Impact on Scale Management Strategy. Presented at the SPE International Oilfield Scale Conference and Exhibition, Aberdeen, 11–12 May. SPE-179895-MS. http://dx.doi.org/10.2118/179895-MS.
Simpson, C. M., Graham, G. M., Collins, I. R. et al. 2005. Sulfate Removal for Barium Sulfate Scale Mitigation – Kinetics vs. Thermodynamic Controls in Mildly Oversaturated Conditions. Presented at the SPE International Symposium on Oilfield Scale, Aberdeen, 11–12 May. SPE-95082-MS. http://dx.doi.org/10.2118/95082-MS.
Smith, A. L. 2010. NORM: The Lessons to be Learned, New Challenges and Innovative Thinking with Decommisioning and Radioactive Waste. Presented at the SPE International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production, Rio de Janeiro, 12–14 April. SPE-125661-MS. http://dx.doi.org/10.2118/125661-MS.
Stewart-Liddon, C., Goodwin, N. J., Graham, G. M. et al. 2014. Qualification of Chemicals/Chemical Injection Systems for Downhole Continuous Chemical Injection. Presented at the SPE International Oilfield Scale Conference and Exhibition, Aberdeen, 14–15 May. SPE-169782-MS. http://dx.doi.org/10.2118/169782-MS.
Tjomsland, T., Sæten, J. O., Vikane, O. et al. 2008. Veslefrikk Scale Control Strategy and Economic Implications: Revisited 7 Years Later—Did We Improve? Presented at the SPE International Oilfield Scale Conference, Aberdeen, 28–29 May. SPE-114086-MS. http://dx.doi.org/10.2118/114086-MS.