ABSTRACT

The West Delta 117 field is an intensely faulted graben structure with numerous stacked pay sands trapped against east-west trending faults. In early 1995, the production from this field was in steep decline and the field was projected to become uneconomic by 1997. In an attempt to identify new drill opportunities and reverse the production decline, a 6-month project was undertaken to reinterpret ten horizons within a 914.4 m (3000 ft.) interval in the deeper lower Pliocene section using a more efficient workflow, including 3-dimensional (3-D) earth modeling technology. Interpretation of the complexly faulted structure was aided by combining a number of vendor and proprietary software packages into an improved integrated workflow. Using this workflow, a detailed geologic model that incorporated fault-to-fault relationships and fault-horizon intersections was developed. This model, based on 3-D seismic interpretation and validated by visualization software, was used as the framework to build detailed computer generated structure maps, isopachs, and cross sections. The interpretation was used to design a strategic delineation well which was drilled in 1996 targeting multiple objectives. The well not only proved up new reserves, but also defined a new geologic feature into which three additional wells are planned to be drilled. The use of 3-D modeling technology has played a critical role in revitalizing this 35 year-old field.