Production-induced compaction of the Brent field: An experimental approach
The most attractive option to increase hydrocarbon recovery from the Brent and Statfjord reservoirs (Brent field, North Sea) is a gradual decrease of the reservoir fluid pressure. To provide laboratory data upon which estimates of the resulting reservoir compaction and surface subsidence could be made, the authors performed uniaxial compaction experiments at room temperature and in-situ stress conditions. Experimental observations suggest that the reloading of core samples to in-situ stress conditions closed coring-induced microcracks. Most Brent samples (porosity 6% to 30%) showed a compressibility that was constant with increasing effective stress (i.e., linear compaction) and increased with porosity. There was 30% to 75% strain recovery during unloading and an average permanent shortening of about 0.7%. Some high-porosity (25% to 30%) Brent samples showed a relatively high uniaxial compressibility that increased with stress (nonlinear compaction). Nearly all the statfjord samples showed nonlinear compaction. These inelastic brittle mechanisms, which occur together with elastic deformation of the load-bearing grain framework, seem dominant in high-porosity (Statfjord-type) sandstones and should be incorporated into predictive models of production-induced compaction of quartz-rich reservoir rock.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 250835
- Journal Information:
- SPE Formation Evaluation, Vol. 11, Issue 2; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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