Where Fairfield Proposes Gulf Coast Group Shoot
A Houston geophysical contractor is organizing an exploratory 3D group shoot in the Gulf Coast transition zone of South Louisiana.
If formed as proposed by Fairfield Industries Inc., the multiyear program will serve as the basis for a campaign believed to be the largest, contiguous, onshore, 3D seismic survey in the U.S.
Operators in the Gulf of Mexico recently have drilled a series of large oil and gas discoveries in exploration programs based on 3D seismic data. Because it is relatively inexpensive to generate, marine 3D data cover much, if not all, of the U.S. gulf.
Many of the formations newly productive offshore extend inland beyond Louisiana's coastline. However, operators have not yet achieved comparable exploration successes onshore, largely because of the high cost of collecting land 3D data. Various issuesaccess, permitting, leasing, and environmental protection, for exampleadd to the cost and complexity of organizing onshore 3D shoots.
As a result, present onshore 3D seismic coverage in South Louisiana's Gulf Coast transition zone consists mostly of proprietary company data of various parameters, quality, and age.
Fairfield in its proposed group shoot plans to set data acquisition parameters to image geological objectives chosen by the group, as well as to tie the 3D land data to nonexclusive Fairfield marine 3D data. Correlating group data with offshore data aims to allow participants more effective pursuit of offshore plays across the beach.
Regional potential
Fairfield believes its plan for a comprehensive, regional 3D survey by a group of big operators is the most cost effective way to unlock the region's oil and gas potential.
The company aims to finish forming the group and have the necessary agreements in place in time to begin permitting by yearend. Crews would begin acquiring field data about mid-1996.
Fairfield estimates the total cost of the proposed survey at more than $50 million. Each group member would have exclusive use of the data for 12 months and receive a share of late sale proceeds to help offset costs.
Part of Fairfield's proposed compensation package is to include an overriding royalty on any successful wells drilled based on the data.
Fairfield proposes to form a closed group of three or four large operators to fund the survey. It estimates about 3 crew years would be needed to complete data acquisition.
In all, the group shoot would cover about 1,400 sq miles onshore. Group members would determine the sequence in which onshore areas would be surveyed.
If four companies join the survey group, each could expect to spend about $3.5 million on the shoot in 1996, $7 million in 1997, and $3.5 million in 1998.
Survey characteristics
Fairfield transition zone crews would collect 3D data across South Louisiana within a 5-15 mile wide swath from the beach inland. Individual surveys would cover 50 sq miles or more at surface to attain the needed migration apertures and ensure full fold data.
When geometry and binning differences preclude a prestack merger of land and marine data sets, Fairfield would regrid and phase match the offshore data stack to fit onshore data and migrate the blended data as a single unit.
All onshore survey areas eventually would be connected, based on land accessibility.
Fairfield would dedicate a fully equipped 3D transition zone seismic crew to the project. Instrumentation would be based on a telemetric, 1,800 channel, 24 bit data acquisition system.
The company would deploy six or eight receiver lines and acquire data with a crossed array technique. It would maintain far trace offset of at least 19,800 ft, with fold levels ranging from 24 to 32.
Energy sources are to be dynamite on land and air guns in the transition zone's shallow water. Based on projected survey parameters, by working year-round, Fairfield's crew should be able to generate about 40 sq miles/ month of 3D seismic data.
