Imperial College London

Dr Craig Smalley

Faculty of EngineeringDepartment of Earth Science & Engineering

Visiting Professor







Royal School of MinesSouth Kensington Campus






BibTex format

author = {Smalley, PC and Collins, I},
pages = {300--308},
title = {Precipitation and dissolution of minerals durina waterfloodina of a North Sea Oil Field},
year = {2006}

RIS format (EndNote, RefMan)

AB - A long-term study of produced water chemistry from a North Sea field was used to investigate the mechanisms of water mixing and water-rock interaction in the reservoir. Seawater flooding has continued throughout much of the production life. Detailed repeated sampling of the produced water was undertaken and has produced an extensive dataset, yielding information on water chemistry variations in space and time. The dataset documents both fluid mixing in the field and the physical, chemical and thermodynamic response of the system to the injection of seawater. Analysis of the data establishes the nature of the controls on the composition of the scale-prone formation water, and enables an in-depth look at the fluid-rock interactions occurring in the reservoir during a waterflood. Changes in produced-water chloride concentration through time reflect changing proportions of injected seawater and formation-water, revealing differing patterns of injected-water breakthrough over the field. However, parallel changes in the concentrations of less conservative fluid components provide evidence of fluid-mineral interactions that occurred in the reservoir on the timescale of the waterflood. For example, calcium is enriched in the produced fluid relative to a linear mixture of original formation-water and seawater, while magnesium is depleted, probably reflecting dolomitisation of calcite and growth of clay. Barium and sulphate are strongly depleted due to precipitation of barite. However, mass balance highlights an additional sink for sulphate, possibly reduction to sulphide. Excess silica present in the produced fluid is ascribed to dissolution of silicate phases in the reservoir. Concentrations demonstrate that the produced water is always close to quartz saturation at reservoir temperature, irrespective of the proportion of seawater produced.Analysis of produced water chemistry provides insights into the inner workings of the reservoir system during a waterflood. Study of ind
AU - Smalley,PC
AU - Collins,I
EP - 308
PY - 2006///
SP - 300
TI - Precipitation and dissolution of minerals durina waterfloodina of a North Sea Oil Field
ER -