Abstract

Since the oil discovery at Santa Rita #1 in 1923, the Big Lake Field in Reagan County, Texas, has produced 135 million bbl (21.5 × 10⁶ kl) of oil and 1 billion bbl (159 × 10⁶ kl) of saltwater. Until the early 1960s, the accepted disposal method for saltwater was surface discharge to evaporation ponds north of the field. Approximately 200 million bbl (31.8 × 10⁶ kl) of saltwater was discharged, resulting in 11 mi² (28.5 km²) of barren landscape characterized by saline soils incapable of supporting vegetation.

In 1989, the University of Texas System, the United States Department of Agriculture Soil Conservation Service, and Marathon Oil Company, which acquired Big Lake Field in 1962, initiated an experimental project to reclaim 0.5 mi² (1.2 km²) of affected area to rangeland productivity. An underground drainage system was installed to drain near-surface, salt-saturated perched water. Earthen terraces were constructed to reduce rainfall runoff and increase percolation to facilitate leaching of salts from the surface soil. Salt-saturated groundwater is drained by the system and pumped to injection wells for disposal.

The excellent revegetation that occurred over the test area is encouraging and has shown the need for enhancing the existing system with supplemental water from freshwater wells, application of soil-amending agents, and selective planting of salt-tolerant species.