Pavayacu Field, Peru - A Case History for Production Improvement through Reservoir Characterization

Roger Murray, Riaz Ahmad, Radmilo Gregovic, and William Sanchez

The Pavayacu field in the Maranon basin of Peru is a mature oil field with a declining production rate. The field was under consideration for disposal when a 3-D seismic survey and reservoir characterization were conducted. These studies led to a refined understanding of the hydrocarbon distribution, which led to a 10 fold increase in daily production and additional recoverable reserves.

The main reservoir in the Pavayacu field is within fluvial deltaic sands of the Vivian formation. The overall trapping mechanism is controlled by asymmetric anticlinal folding of the reservoir over basement faults. Hydrocarbon distribution and production is greatly influenced by smaller scale reservoir heterogeneities within a seemingly homogenous sand.

Small scale reservoir heterogeneities were successfully resolved through an integrated reservoir characterization process where hydrocarbon pore volumes (HPV) were found to be related to seismic amplitudes derived from the 3-D seismic survey. Additional well locations were successfully selected not only based on the 3-D structural data but also on the HPV distribution. Six wells were drilled based on these analysis resulting in individual flow tests in excess of 4000 BOPD. The one well location based only on the 3-D seismic was not successful. As a result of this study overall field production was increased by an order of magnitude and the field is no longer a candidate for disposal.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California