Origin, migration and mixing of oilfield brines: Stable iso- topic evidence from kuqa foreland basin

摘要

87_Sr/86_sr, δD and δ~18O together with chemistry of oilfield brines, were measured from Cambrian to Neogene strata in the Kuqa Foreland Basin, northwest China. The brines have 87_sr/86_Sr ratios ranging from 0.70944 to 0.71716, δD values from -33/100 to -67/100 and δ~18O from -9.0/100 to 3.9/100. The most radiogenic 87Sr brines have relatively heavy δ~18O in the Cambro- Ordo- vician carbonates, ancd are suggested to originate from crystalline basement.