Title: Predicting tool for sulphate scale build-up around the wellbore in oilfield

Authors: A.S. Adesina Fadairo, Olugbenga Falode

Addresses: Department of Petroleum Engineering, Covenant University, Km 10, Idiroko Road, Ota, Nigeria. ' Department of Petroleum Engineering, University of Ibadan, Ibadan, Nigeria

Abstract: Formation and deposition of scale in porous media due to extensive use of seawater for oil displacement and pressure maintenance is a problem that results in production decline and loss of billions of dollars to the petroleum industry yearly. A variety of models are presently being used in the oil industry for predicting scaling tendency and average scales precipitation inside the reservoir. These models assumed that all the occurring scale precipitation would cause formation damage near the wellbore region however, only a fraction of the precipitated scales escape through the pore spaces to render havoc to flow in the production string. This paper presents a new model based on existing thermodynamic models for predicting barium and strontium sulphate scale build-up rate around an oil production well during water flooding while accounting only for the fraction resulting into formation damage. The key operational and reservoir parameter which influence the magnitude of impairment by scale deposition are identified through the derivation of an analytical expression for the rate of scale build-up, assuming idealised flow conditions. The model is capable of predicting scale build-up rate and fraction of scale deposited in pore spaces at a particular radial distance from a wellbore during water injection. [Received: June 4, 2009; Accepted: October 10, 2009]

Keywords: modelling; oilfield scale; saturation; wellbore; permeability; porosity; water flooding; scale precipitation; scaling tendency; predictive tool; oil fields; sulphate scale build-up; seawater; petroleum industry; thermodynamics; oil production wells; pore spaces; water injection.

DOI: 10.1504/IJOGCT.2009.030679

International Journal of Oil, Gas and Coal Technology, 2009 Vol.2 No.4, pp.347 - 364

Published online: 30 Dec 2009 *

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