Articles | Volume 372
https://doi.org/10.5194/piahs-372-375-2015
https://doi.org/10.5194/piahs-372-375-2015
12 Nov 2015
 | 12 Nov 2015

Inversion of double-difference measurements from optical levelling for the Groningen gas field

P. A. Fokker and K. Van Thienen-Visser

Abstract. Hydrocarbon extraction lead to compaction of the gas reservoir which is visible as subsidence on the surface. Subsidence measurements can therefore be used to better estimate reservoir parameters. Total subsidence is derived from the result of the measurement of height differences between optical benchmarks. The procedure from optical height difference measurements to absolute subsidence is an inversion, and the result is often used as an input for consequent inversions on the reservoir. We have used the difference measurements directly to invert for compaction of the Groningen gas reservoir in the Netherlands. We have used a linear inversion exercise to update an already existing reservoir compaction model of the field. This procedure yielded areas of increased and decreased levels of compaction compared to the existing compaction model in agreement with observed discrepancies in porosity and aquifer activity.

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Short summary
Hydrocarbon extraction lead to compaction of the gas reservoir which is visible as subsidence on the surface. We have used surface height difference measurements to quantify compaction of the Groningen gas reservoir in the Netherlands. This procedure yielded areas of increased and decreased levels of compaction compared to the existing compaction model in agreement with observed discrepancies in porosity and aquifer activity.