Seismic history matching of fluid fronts using the ensemble kalman filter

Time-lapse seismic data provide information on the dynamics of multiphase reservoir fluid flow in places where no production data from wells are available. This information, in principle, could be used to estimate unknown reservoir properties. However, the amount, resolution, and character of the data have long posed significant challenges for...

Estimation of changes in saturation and pressure from 4D seismic AVO and time-shift analysis

A reliable estimate of reservoir pressure and fluid saturation changes from time-lapse seismic data is difficult to obtain. Existing methods generally suffer from leakage between the estimated parameters. We propose a new method using different combinations of time-lapse seismic attributes based on four equations: two expressing changes in...

Ensemble-based conditioning of reservoir models to seismic data

While 3D seismic has been the basis for geological model building for a long time, time-lapse seismic has primarily been used in a qualitative manner to assist in monitoring reservoir behavior. With the growing acceptance of assisted history matching methods has come an equally rising interest in incorporating 3D or time-lapse seismic data into...

Ensemble-based reservoir characterization using time-lapse seismic waveform data

Assisted history matching methods are beginning to offer the possibility to use 4D seismic data in quantitative ways for reservoir characterization. We use the waveform data without any explicit inversion or interpretation step directly in an ensemble-based assisted history matching scheme with a 3D synthetic reservoir model. For this purpose a...

Sensitivity of time-lapse changes in pressure and saturation to seismic AVO and time-shifts

An inversion scheme that solves for reservoir pressure and fluid saturation changes from time-lapse pre-stack seismic attributes and post-stack seismic time-shifts is presented. It makes use of four equations expressing the changes in zero-offset and gradient reflectivities, compressional and shear waves time-shifts as functions of production...

The value of streamlines based localization in the assimilation of 4D seismic data with the Ensemble Kalman filter

The Ensemble Kalman Filter is a powerful data assimilation algorithm which allows a sequential update of the reservoir states from measurement data. However, results performed on a synthetic 3D model, show that too frequent 4D seismic data may cause an excessive contraction of the ensemble covariance and the filter divergence. A solution to this...

The importance of localization in the assimilation of 4D seismic data in the data assimilation process using the EnKF

The Ensemble Kaiman Filter (EnKF) is considered a fast and efficient algorithm in the data assimilation process to estimate reservoir properties from measured data. 4D seismics is an important source of information for the reservoir monitoring and the improvement of the geological model. The use of low frequencies for deep surface seismic makes...

Synthetic versus real time-lapse seismic data at the Sleipner CO2 injection site

CO2 has been injected into the Utsira Sand at Sleipner since 1996, with more than 9 million tonnes currently in the reservoir. Seismic monitoring surveys to follow the migration of the CO2 in the reservoir have been carried out in 1999, 2001, 2002, 2004 and 2006. The CO2 plume is imaged on the seismic data as a prominent multi-tier feature,...