A Practical Method of Predicting Calcium Carbonate Scale Formation in Well Completions
- Syed Hamid (Halliburton) | Orlando De Jesús (Consultant) | Carlos Jacinto (Petrobras) | Ronaldo Izetti (Petrobras) | Hardy Pinto (Petrobras) | Enrique Droguett (University of Maryland) | Christopher Edwards (Halliburton) | Juanita Cassidy (Halliburton) | Haoyue Zhang (Halliburton) | Pete Dagenais (Halliburton) | Marcelo A. P. Batocchio (Welltec)
- Document ID
- Society of Petroleum Engineers
- SPE Production & Operations
- Publication Date
- February 2016
- Document Type
- Journal Paper
- 1 - 11
- 2016.Society of Petroleum Engineers
- interval control valve, presalt well, intelligent well completion, rate of scale formation, prediction of tool performance
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- 671 since 2007
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Scale formation in downhole tubular-flow passages can cause partial to complete plugging that will affect production or injection rates adversely. In an intelligent-well completion in which the interval-control-valve (ICV) opening must be changed to control flow rate, the completion will become ineffective if plugging of clearances prevents valve actuation. To mitigate these problems, a method to predict the potential rate of scale formation under realistic conditions has been developed.
This empirical method allows prediction of tool performance under scale-forming conditions for downhole applications, and uses chemical data and flow fields generated by computational-fluid-dynamics (CFD) models for downhole tools. Chemical data are obtained from laboratory tests on coupons by use of brines matching the chemistry of connate fluids. Tests were conducted in a high-pressure, corrosion-resistant vessel over a range of high pressures (100 to 10,000 psi) and high temperatures (75 to 150°C) to simulate downhole well conditions. Two test sets were conducted, each with fluid at rest and with an impeller generating low velocity in the reaction vessel, ranging from 4 hours to 4 days, with scaling rates determined from coupon-weight gain. Concentrations in the range of 50 to 125% of the typical connate-fluid concentration were used.
The weight-gain data obtained from the coupon tests and from a tube-plugging test were used to develop an empirical model for scale-growth rate at a given point on a solid surface with pressure, pressure gradient, temperature, fluid velocity, and brine concentration as independent variables. Artificial-intelligence methodology was used to develop this model, which can be used to predict scale-growth rate for any arbitrary geometry. By use of the internal geometry of any tool to be modeled, a CFD model is prepared and the pressure, fluid velocity, and pressure-gradient data are generated for the entire internal solid surface of the tool for a given flow rate through the tool. These data are fed into the empirical model to calculate the scale-growth rate, which is integrated to obtain scale thickness at each point of the internal solid boundary. To verify accuracy, scale formation in a 4.5-in. ICV was predicted at high-pressure, high-temperature conditions at a low flow rate. Laboratory tests on the valve matched the model predictions well enough, which enabled Petrobras to design a better completion and fluid-handling system for a presalt well.
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Boak, L. S., Al-Mahrouqi, H., Mackay, E. J. et al. 2005. What Level of Sulphate Reduction Is Required to Eliminate the Need for Scale Inhibitor Squeezing? Presented at the SPE International Symposium on Oilfield Scale, Aberdeen, 11–12 May. SPE-95089-MS. http://dx.doi.org/10.2118/95089-MS.
Boak, L. S. and Sorbie, K. S. 2006. The Kinetics of Sulphate Deposition in Seeded and Unseeded Tests. Presented at the SPE International Oilfield Scale Symposium, Aberdeen, 30 May–1 June. SPE-100513-MS. http://dx.doi.org/10.2118/100513-MS.
Haarberg, T., Selm, I., Granbakken, D. B. et al. 1992. Scale Formation in Reservoir and Production Equipment During Oil Recovery: An Equilibrium Model. SPE Prod Eng 7 (1): 75–84. SPE-19449-PA. http://dx.doi.org/10.2118/19449-PA.
Kan, A. T., Wu, X., Fu, G. et al. 2005. Validation of Scale Prediction Algorithms at Oilfield Conditions. Presented at the SPE International Symposium on Oilfield Chemistry, The Woodlands, Texas, USA, 2–4 February. SPE-93264-MS. http://dx.doi.org/10.2118/93264-MS.
MathWorks. 2010. MATLAB R2010b. Natick, Massachusetts: The Mathworks, Inc.
Nancollas, G. H., White, W., Tsai, F. et al. 1979. The Kinetics and Mechanism of Formation of Calcium Sulfate Scale Minerals—the Influence of Inhibitors. Corrosion 35 (7): 304–308. http://dx.doi.org/10.5006/0010-9312-35.7.304.
Oddo, J. E. and Tomson, M. B. 1982. Simplified Calculation of CaCO3 Saturation at High Temperatures and Pressures in Brine Solutions. J Pet Technol 34 (7): 1583–1590. SPE-10352-PA. http://dx.doi.org/10.2118/10352-PA.
Oddo, J. E. and Tomson, M. B. 1994. Why Scale Forms and How to Predict It. SPE Prod & Fac 9 (1): 47–54. SPE-21710-PA. http://dx.doi.org/10.2118/21710-PA.
Østvold, T. and Randhol, P. 2001. Kinetics of CaCO3 Scale Formation. The Influence of Temperature, Supersaturation and Ionic Composition. Presented at the International Symposium on Oilfield Scale, Aberdeen, 30–31 January. SPE-68302-MS. http://dx.doi.org/10.2118/68302-MS.
Stiff, H. A., Jr. and Davis, L. E. 1952. A Method for Predicting the Tendency of Oil Field Waters to Deposit Calcium Carbonate. J Pet Technol 4 (9): 213–216. SPE-952213-G. http://dx.doi.org/10.2118/952213-G.
Straub, F. G. 1932. Solubility of Calcium Sulfate and Calcium Carbonate at Temperatures between 182° and 316°C. Ind Eng Chem 24 (8): 914–917. http://dx.doi.org/10.1021/ie50272a019.
Yeboah, Y. D., Somuah, S. K., and Saeed, M. R. 1993. A New and Reliable Model for Predicting Oilfield Scale Formation. Presented at the SPE International Symposium on Oilfield Chemistry, New Orleans, 2–5 March. SPE-25166-MS. http://dx.doi.org/10.2118/25166-MS.