MINOR ELEMNTS IN OIL - FIELD WATERS

The minor element composition of 823 oil-field water samples from the United States and Canada has been determined spectrochemically. In these samples the determined concentrations have a wide range but commonly are: K and Sr, 100 + p.p.m.; Al, B, Ba, Fe, Li, and Si, 1 - 100 p.p.m.; Cr, Cu, Mn, Ni, Sn, Ti, and Zr, p.p.b. (most waters); and Be, Co, Pb, V, W, and Zn, p.p.b. (some waters). When differences in total dissolved solid contents are eliminated (by calculation), Cr, Li, Mn, Si, and Sr are commonly more than twice as abundant as in present sea water; Cu, K, Ni, and Sn are commonly less than half as abundant. Si content appears to vary between areas, between formations in the same area, and inversely with total solids content in the same formation. Relationships in the variation of other minor elements is more difficult to establish, partly because the minor elements, if actually present, were below our detection limits and partly because our spectrochemical method was not of high precision. Extensive changes in pH of many waters occurred between collection and analysis. Because of this and changes that may occur between subsurface and surface, quantitative interpretation of geochemical relationships between water and rock composition will be difficult. © 1969.