LOWRY, PHILIP, HUNG V. TRAN, and CHARLES W. BEIERLE, ARCO, Plano, TX

ABSTRACT: Application of Computer-Assisted Well Log Correlation to Understanding Reservoir Architecture in the Ranger Zone of the Long Beach Unit, California

Unique workstation software developed by ARCO is being used to zone over 1000 ft of section in more than 1200 wells in the Ranger zone of the Long Beach Unit. The Ranger zone is dominated by 100-200-ft thick, laterally offset lobate sand bodies deposited in a deep marine setting. Several of the major sand bodies extend beyond the unit boundaries and are bounded above and below by shales up to 30 ft thick. These major sand bodies consist, in turn, of smaller lobate and elongate sand bodies bounded above and below by 5-10-ft thick shales. Delineation of these small-scale sand bodies is critical to determining fluid flow pathways in the reservoir and potential bypassed oil.

The reservoir zonation workstation system permits rapid correlation and visualization of sand body and barrier geometries on cross sections, fence diagrams, and 3-D perspectives. Electrofacies maps can be generated rapidly. Finally, formation tops and net-thickness maps can be created and exported to third-party mapping and cross-section software for further analysis and display. The application of this software has dramatically increased the efficiency of a daunting zonation task. Also, results from the reservoir description project provide an excellent insight on sand body architecture of turbidite reservoirs and quantitative data on the dimensions and geometry of these sand bodies.

As exploitation of major domestic fields becomes increasingly more important, development geologists will be called upon to apply such workstation systems to make the most efficient use of diverse and abundant geological, petrophysical, and engineering data to create integrated descriptions for reservoir management.

AAPG Search and Discovery Article #90992©1993 AAPG Pacific Section Meeting, Long Beach, California, May 5-7, 1993.