Modelling of Non-Aqueous and Aqueous Scale Inhibitor Squeeze Treatments

Abstract

fax 01-972-952-9435. AbstractThe most common method for preventing downhole scale formation is by applying a scale inhibitor squeeze treatment. In this process, a scale inhibitor solution is injected down a producer well into the near wellbore formation. Commonly, these scale inhibitor treatments are injected as aqueous solutions. However, there are certain situations where an aqueous based treatment is not desirable, such as where relative permeability effects, water blocking, fluid lifting, chemical penetration or hydrate formation are of major concern.This paper presents the results of a modelling sensitivity study comparing non-aqueous and aqueous scale inhibitor squeeze treatments. The model described can simulate the effect on the treatment life of treatment solubility in the oil and water phases, treatment strategy, adsorption properties (from the water and oleic phases), viscosity effects and wellbore friction. Of particular interest is the relationship between inhibitor solubility in the carrier and in situ phases, and the choice of phase for the overflush fluid. The relationship can have a very pronounced impact on inhibitor penetration and squeeze lifetimes.The sensitivity study is carried out using purpose written software for scale treatments. The code is a two-phase flow, multi-component, multi-layer, radial or linear mathematical model capable of simulating both aqueous and non-aqueous squeeze treatments. The model considers the immiscible displacement of oil and water phases along with inhibitor transport in both phases and mass transfer between phases. It is capable of modelling kinetic and equilibrium adsorption and desorption from either phase. The model has been validated by comparison with analytical solutions, standard conventional single-phase squeeze calculations and multiphase reservoir simulation calculations 5 . An example twophase calculation of a specific field treatment is included, and the results are compared with the field return profiles.

Functional scale inhibitor nanoparticle capsule delivery vehicles for oilfield mineral scale control

“…4 The objective of the preush treatment is to replace the uids inside tubing and also to clean up formation surfaces. 4,29,30 Transport experiment (TE) #1 and #2 are purposely designed to examine the impact of ionic strength of preush solution on SINC transport. TE #1 and #2 were carried out at the same physiochemical conditions including ow rate, temperature, sandstone grain size, back pressure, except the ionic strength of the preush solution.…”

Modeling a Series of Nonaqueous Field-Scale Inhibitor Squeeze Treatments in the Heidrun Field

“…This behavior is a result of the effect of the kinetic adsorption process on the SI transport and retention. The combination of water overflush and the kinetic effects increases the penetration of the SI deep in the reservoir where the SI is spread out over a greater distance from the wellbore at lower concentrations (Hong and Shuler 1988;Vazquez et al 2007Vazquez et al , 2009. Normally a greater SI exposure to the rock surface leads to a longer squeeze lifetime, but it could have a negative effect in a more-complex system such as in Well A where the combination of overflush and kinetic effect may have undesirable consequences.…”

“…Finally, a sensitivity study on the effect of the overflush on the squeeze lifetime was carried out for treatment optimization. The modeling and optimization calculations were conducted using a near-wellbore two-phase model specially designed for simulating squeeze treatments (Sorbie et al 1991;Vazquez et al 2006Vazquez et al , 2007Vazquez et al , 2009Zhang and Sorbie, 1997).…”

Modelling a Series of Non-Aqueous Field Scale Inhibitor Squeeze Treatments in the Heidrun field

“…This behaviour is a result of the effect of kinetic adsorption process on the SI transport and retention. The combination of water overflush and kinetic effects increases the penetration of the SI deep in the reservoir, where the SI is spread out over a greater distance from the well bore at lower concentrations (Hong and Shuler, 1988;Vazquez et al, 2007Vazquez et al, , 2009. Although, normally a greater SI exposure to the rock surface leads to a longer squeeze lifetime, it could have a negative effect in a more complex system such as in well A, where the combination of overflush and kinetic effect may have undesirable effects.…”

“…Finally, a sensitivity study on the effect of the overflush on the squeeze lifetime was carried out for treatment optimization. The modelling and optimization calculations were done using a near wellbore two-phase model, specially designed for simulating squeeze treatments (Sorbie et al, 1991;Vazquez, et al, 2006Vazquez, et al, , 2007Vazquez, et al, , 2009Zhang and Sorbie, 1997).…”