ABSTRACT

While the cost of acquiring 3-D seismic data is greater than 2-D, 3-D seismic can be thought of as an insurance policy with the additional cost being the premiums. An illustration of this analogy is the TEPCO, Inc., Deep Saint Prospect within the Cypress Island Field, located in St. Martin Parish, Louisiana. The prospect was generated using subsurface geology and the available 2-D seismic data; subsequently, 3-D seismic data was acquired prior to drilling. The primary objectives of the play were the Lower Marginulina texana (±13,000 ft), Bolivina mexicana I and Bolivina mexicana III (±15,000 ft). All three objectives drilled out structurally, but were non-commercial.

However, the Miogypsinoides sand at approximately 11,900 ft tested high rates of gas. The Miogyp. pay is expected to yield in excess of 35 billion cubic feet of gas (BCFG) and will make this a commercial project. Utilizing the 3-D seismic data on the prospect, the Miogyp. was quickly mapped with the confidence that small faults were creating the traps. This would not have been possible using the 2-D seismic.

With the completion in the shallower Miogyp. zone, the prospective acreage required for the field shifted approximately 2500 ft north of the original lease block. This necessitated additional leasing to protect the new discovery. The 3-D seismic data refined the maps and ensured that only the appropriate leases were taken, thus saving an investment in both capital and time resources.

In summary, having acquired 3-D seismic data prior to drilling the initial test well facilitated a quick and correct response to the results of the drilling, as opposed to waiting at least twelve (12) months, had the seismic program not been previously shot, processed, and interpreted. The development phase of the prospect began at once, resulting in immediate cash flow.