RIASSUNTO
Abstract
This paper discusses progressive construction and operational techniques which can be employed to minimize impacts from drilling operations in sensitive wetland environments. Some of the techniques to be discussed include:
- Use of previously impacted wetlands for access routes;
- Modified culvert design and placement criteria;
- Specialized secondary and tertiary spill containment systems;
- Closed-loop and containerized mud system;
- ""Environmentally friendly"" substitutes for hydraulic fluids and lubricating compounds;
- Integrated waste minimization practices; and
- Innovative restoration alternatives.
Natural resource trustees have come to expect the use of such techniques when permitting access to custodial wetland areas. While some of these innovations add to the overall cost of the project, others may actually reduce total project cost. Combined with careful planning, these techniques can provide improvement in environmental protection at little incremental cost.
Introduction
The quest for oil and gas reserves continues to take exploration and production companies, both large and small, into sensitive environmental areas. As industry strives to minimize the impacts to these areas and meet increasingly strict regulatory requirements, new environmentally sensitive techniques are being developed and applied.
In early 1993, Vastar Resources, Inc. (Vastar), made the decision to pursue an exploration prospect, known as Black Bayou, located in the heart of the Sabine National Wildlife Refuge. The refuge was established in 1937 and covers approximately 125,000 acres in southwest Louisiana (See Figure 1). As the largest wildlife refuge in the Gulf Coast region, the Sabine National Wildlife Refuge is a major wintering ground for migratory waterfowl in both the Central and Mississippi flyways, as well as a permanent home for over 250 species of birds, alligators, marsh mammals, and estuarine dependent marine species.
For the first Black Bayou exploratory well to be drilled in 1993, permits had to be obtained in record time. Furthermore, drilling operations and associated wetlands mitigation had to be completed in a seven-month window, prior to the return of migratory birds to the area. Working together, Vastar and U. S. Fish & Wildlife Service (USFWS) personnel at the refuge developed a plan that would allow drilling to take place within the prescribed time constraints, while minimizing environmental impacts.
Several innovative techniques used during the project are now regarded by the USFWS as the standard for similar drilling projects in the refuge and have been described as state-of-the-art technologies for environmentally-sound wetlands drilling operations. The incorporation of these additional environmental safeguards on the Black Bayou project did not have a significant impact on project schedule or cost, as the first exploratory well was drilled on time and under budget. A second well was drilled in 1994 using similar techniques. For the two projects combined, the incremental cost associated with these environmental-related project enhancements was $228,000, or approximately 2.6% of the total project cost.
Project Considerations
Access Routes. The coastal wetlands in the Sabine National Wildlife Refuge represent a unique and valuable ecosystem.
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