Reservoir Study Of Southeast Pecan Island Geopressured Water Sands
Authors: Bassiouni Z.A. , Bernard W.J. , Welsh J.H. 
Published: December 2007

The detailed technical evaluation of the Southeast Pecan Island geopressure aquifer prospect is described. The quantitative evaluation was based on detailed geology consisting of structural, isophachous, and cross-sectional maps of the geopressured zone. Pressure, water salinity, porosity, and permeability data were obtained porosity, and permeability data were obtained from well logs.

The gathered information was used to choose a location for a proposed exploratory well.

The evaluation of this prospect can serve as a guide for future analysis of other geopressured prospects.

Introduction

Sixty-three potential areas of interest for the geopressure energy resource were found in a preliminary geologic study of southern Louisiana. preliminary geologic study of southern Louisiana. The geographic area of the study included all southern Louisiana (south of Baton Rouge) including the State-owned offshore area.

At present, the sixty-three potential areas of interest are being ranked, and the most promising prospects are being mapped and studied promising prospects are being mapped and studied in much greater detail. A preliminary ranking indicates that the better prospects tend to lie in the western half of the study area. The prospects in the eastern half of the study area prospects in the eastern half of the study area were down-graded primarily because of poorer sand development, but it is entirely possible that several of these prospects will be attractive upon closer inspection.

Detailed geologic studies have been started on five prospects. A suitable site for a geopressured test well will be selected within each of these prospects. It is hoped that a test well will be started at one of these sites before the end of the year.

At present, the Southeast Pecan Island area appears to be a promising prospect. This area is identified on Figure 1 together with the other four prospects.

The Southeast Pecan Island Prospect is located in the extreme southern portion of Vermilion Parish, Louisiana, being approximately 25 miles south-southwest of Abbeville, and approximately 6 miles southeast of Pecan Island, Figure 2. The prospect is surrounded by the Pecan Island Field to the northwest, Vermilion Block 16 Field to the south-west, and Fresh Water Bayou Field to the north. It is separated from these fields by large regional faults.

The primary source of data used in the detailed evaluation of the prospect was electric well logs obtained from the files of the Louisiana Office of Conservation. Logs from forty-six wells drilled in the area were available. Core data, water analyses and production test results were available from a limited number of these wells.

The evaluation techniques used are basically those used by the oil and gas industry. However, because of the nature of the problem and the limited data available, the evaluation methodology is noteworthy. Also, this methodology can serve as a guide for future analysis of other geopressured prospects. The following aquifer properties are prospects. The following aquifer properties are important and have been evaluated:Areal extent,depth,thickness,temperature,pressure,porosity,salinity,permeability, pressure,porosity,salinity,permeability, anddissolved natural gas content.

GENERAL GEOLOGY

Geopressured zones in Louisiana are known to occur in Tertiary sediments in the southern part of the State. This Middle and Lower Miocene trend ranges in width from 50 to 70 miles northward of the Louisiana coastline.