Incorporating EM Inversion into Reservoir Monitoring

Incorporating EM Inversion into Reservoir Monitoring

Wirianto, M.
Mulder, W.A.
Slob, E.C.

Civil Engineering and Geosciences

Geoscience & Engineering

2012-06-04

In the application of controlled source electromagnetics for reservoir monitoring on land, the timelapse signal measured with a surface-to-surface acquisition can reveal the lateral extent on the surface of resistivity changes at depth in a hydrocarbon reservoir under production. However, a direct interpretation of the time-lapse signal may generally be difficult and biased. We investigated if non-linear inversion can use time-lapse responses to characterize the subsurface resistivity changes. We examined two different strategies, using a full non-linear inversion algorithm as the interpretation tool: inverting the reference and monitor data independently or in sequence. In the second case, the inversion result of the reference data set serves as an initial guess for the inversion of the monitor data set. Numerical examples show that independent inversion of the data sets can provide an estimate of the depth and lateral extent of the resistivity changes. The second strategy of sequential inversion produces less satisfactory results. We illustrate the independent inversion approach for an example with large survey repeatability errors are large and another one with a complex overburden.

http://resolver.tudelft.nl/uuid:8f7143b0-2e63-474d-8eb7-a58dd180cb66

978-90-73834-27-9

74th EAGE Conference & Exhibition incorporating SPE EUROPEC 2012, Copenhagen, Denmark, 4-7 June 2012

Institutional Repository

conference paper

(c) 2012 The Author(s)