The 1 billion stock tank bbls Schoonebeek oilfield produced 250 million bbls medium gravity waxy oil in the period 1943–1996 from a 20 meter thick sandstone reservoir using nearly 600 vertical wells. In part of the field primary recovery was characterised by early water breakthrough caused by a strong aquifer. In another part of the field limited aquifer support in combination with low GOR led to rapid pressure decline and a subsequent requirement for voidage replacement. Small-scale EOR projects were carried out from 1960 to 1996: hot water flooding; wellbore heating; in-situ combustion; high and low pressure steam drives and soaks. In 1996 exploitation was no longer economic, after which all wells were abandoned and most surface infrastructure was removed.
Today, redevelopment of the part of the field that has limited aquifer support is attractive again by use of up-to-date subsurface and surface technologies.
Detailed reservoir modelling identified steam flooding with a closely spaced pattern of 44 horizontal oil producers and 25 horizontal steam injectors in the bottom part of the reservoir as optimal. This process is called "Gravity Assisted Steam Flooding".
To maximise efficiency, a gas fired Combined Heat-Power plant will generate steam and deliver surplus electricity to the national power grid. Wastewater from a nearby sewage plant will be used to produce boiler feed water. Produced water will be disposed of in depleted gas fields in the area via existing gas evacuation pipelines that are converted to water disposal service. Produced oil will be delivered to a refinery in the region by tying into existing third party infrastructure.
The project will deliver more than 100 million bbls of oil and 120 MW of electrical power. Pending Final Investment Decision planned for end 2007, construction will start in 2008 with the project coming on-stream in 2010.
The Schoonebeek oilfield is located onshore in the northeast of the Netherlands (figure 1). It is part of a complexly faulted anticline that straddles the Dutch-German border. The German oilfields Emlichheim1, Rühlertwist and Rühlermoor are part of the same structure.
Figure 1. Location map of the Schoonebeek oilfield
The main productive formation is the lower cretaceous Bentheim sandstone (KNNSP). This is an unconsolidated, clean, well-sorted strand plain deposit. Table 1 gives an overview of the reservoir parameters and the medium gravity oil properties in the Schoonebeek oilfield.
