Treatment of Salt Affected Soil in the Oil Field

Abstract

Abstract Soils, drill cuttings and other solid wastes which are exposed to high levels of salt through spillage from drilling and producing operations, pipe line breaks or leaks, become saturated with sodium. Although the EPA and the industry have demonstrated that the vast majority of such wastes are non-hazardous, in actuality, they have an adverse impact on the fertility of the soil. The degree of salt saturation is influenced by the soil mineralogy. Many native soils containing high montmorillonitic clays have the capacity of adsorbing sodium species in their crystal structure. Sodium adsorbed montmorillonitic clays being dispersed affect the physical structure of soil and, in turn, adversely influences its permeability. High salt content of soil also has a profound influence on its osmotic pressure. Consequently, it has a detrimental influence on the health of the commercial crops or native vegetation. The physical structure of the soil can be chemically modified, allowing improved drainage of undesirable salt species. To store its physical structure and to make it permeable, the industry has practiced cationic amendment of sodium contaminated soil. Traditionally used gypsum, being sparsely soluble in water is unable to provide a readily available source of cationic species for amendment. A carefully designed product containing readily available cationic source along with other nutrients for the growth of vegetation has been highly successful. Field results from various geographical locations with different soil composition and degree of contamination showing rapid reductions in the sodium contents and, in turn, also having a dramatic effect on the restoration of vegetation are discussed in this paper.