Abstract

A number of EOR technologies were introduced in Norway while the oil price was high in the late 80's and early 90's. As the oil price is going up again and the time to benefit from new methods is getting shorter in the maturing giants, an EOR revival is a matter of urgency.

Low salinity water injection (LSWI), Link Polymer Solution, Bright Water, polymer, Na-silicate and a combination of LSWI with some of the other methods have now been tested at laboratory conditions and their mechanisms are better understood. Approximately ten pilots have been decided for the next few years and, given success, field implementation is planned by 2014 and later.

Some challenges offshore are (i) the long distance between wells with related long times between injection and increased production, (ii) the need for reliable prognoses based on poorly history matched models and immature simulation techniques, (iii) requests for highest possible production conflict with drilling wells dedicated to prove new EOR techniques and (iv) the need to see EOR based changes in drainage strategy together with a well strategy.

In addition, oil companies have been very successful in reducing the use of chemicals with possibly environmentally questionable consequences. There is then resistance to increase their use, even if the probability of chemical spill is drastically reduced and oil production increases and water production is cut down. The solutions are monitoring of chemicals in produced water and high regularity reinjection of produced water.

Technical, economical and environmental aspects of basing a field wide decision in a one well pilot for LSWI and considering Bright Water as one-well-at-a-time consideration will be discussed in detail for the Heidrun field.

Introduction

One out of every four barrels in place is recovered on average worldwide. In Norway, the current prediction for ultimate recovery is closer to two out of every four barrels in place. We will briefly discuss the reasons for this discrepancy in the first chapter of this paper, together with the contributions of improved (IOR) and enhanced (EOR) oil recovery to the higher figure. Many definitions of both terms exist, and we will refer to EOR as a range of processes which seek to improve hydrocarbon recovery with injection methods which are more advanced than water or methane injection alone. IOR includes an even broader spectrum of measures to improve recovery, from four-dimensional (4-D) seismic to digital oil field technologies.

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