Steven R. Clawson¹, Hai-Zui Meng¹

(1) iReservoir.com, Greenwood Village, CO

ABSTRACT: Seismic acoustic impedance inversion in reservoir characterization

Seismic amplitude data inverted to acoustic impedance (AI) rock properties is used as a constraint in geostatistical interpolation of the well log data when building a reservoir model of porosity for the reservoir. Application to the public domain dataset at Boonsville Gas Field, North Central Texas will be used to show the procedure. This public domain dataset includes 5.5 square miles of good quality 3D seismic data, 38 wells with digital log data and production data. The reservoir interval is about 1300 feet of interbedded sandstones and shales of the Bend Conglomerate Group of the Pennsylvanian aged Atoka Fm.

The workflow is generally comprised of 1) Seismic to well log calibration. 2) Low frequency background acoustic impedance model from the well log data. 3) Inversion of seismic amplitudes to impedance model. 4) Depth conversion of seismic AI property data. 5) Geostatistical integration of well log properties of gamma ray, resistivity and porosity together with the seismic derived AI.

While the seismic AI data improves the interwell modeling of the reservoir, utilizing all the well control also improves the seismic inversion. There is synergy in integrating both these seismic and well log data. Consideration of the different scales of resolution between the seismic and well log data is adapted in the workflow. Integration of all the available data over the different scales of information is important in building the most accurate representation of the reservoir. The reservoir model can then be used to make better business decisions for reservoir management.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado