Abstract: West Delta Block 107 Field: Hidden under a Mudflow

KUHNEN, CARL W.
Walter Oil & Gas Corporation, Houston, TX

West Delta Block 107 Field, located eight mi seaward of the Southwest Pass of the Mississippi River in 235 ft of water, contains approximately 18 million barrels of oil (MMBO) and 70 billion cubic ft of gas (BCFG) (recoverable) in nineteen Pliocene sands. Hydrocarbons are trapped in a three-way structural closure downthrown to a large down-to-the-southeast growth fault.

Walter Oil & Gas Corporation discovered the field in 1993 with its OCS-G 8736 No. 1 well, located within a large active mudflow lobe that has caused major difficulties in seismic and drilling exploration over the years. Due to effects of the mudflow, pre1983 2D seismic data did not adequately define the amplitude response or the structure of the prospect. Only after 1988 3D seismic data was reprocessed with refraction statics corrections by Shell Offshore, Inc. in 1993 was it possible to interpret structure and amplitude correctly enough to discover the field. A 1996 3D survey has further improved data quality and has refined our understanding of the field.

The field has been developed by seven wells. Five of those wells were drilled from a conventional platform site (West Delta 106 "A" platform) outside of the mudflow and two mi west of the field. The two other wells (including the discovery well) are active subsea completions. Field production rate since February 1995 has averaged 7200 barrels of oil and 17 million cubic ft of gas daily. The Block 107 Field was nearly found in 1968 by a Humble well and in 1983 by a McMoran well, each of which missed the main accumulation by less than 200 ft horizontally.

AAPG Search and Discovery Article #90932©1998 GCAGS/GCS-SEPM Meeting, Corpus Christi, Texas