This study was designed to add quantitative solutions to the problem of undesirable hydraulic communication which results in active fluid flow between productive horizons. Transfer of novel geochemical methods, based on effective, economic, and environmentally acceptable isotopic techniques for identification of leaking hydrocarbon reservoirs, is a major objective of this study. The effectiveness of a continuous trap's seal depends on an equilibrium between the capillary forces holding formation water in pore spaces of the seal and the buoyancy forces of the oil and gas column in a system. Therefore, some seals may leak selectively at changing pressure and temperature conditions with respect to different fluid phases (oil, gas, and water). A break in continuity of confining layers will promote relatively fast interreservoir migration of fluids. It may intensify in reservoirs subjected to high pressures during implementation of secondary and tertiary processes of recovery. Such fluid flow should result in identifiable chemical, isotopic, and often thermal anomalies in the area of an open flow path. Quantitative hydrodynamic reservoir modeling based on geochemical/isotopic and other evidence of fluid migration in a system require, however, more systematic methodological study. Such a study is being recommended in addition to a field demonstration of the method in a selected oil/gas reservoir where geochemical and production anomalies have been documented. 62 refs., 7 figs., 2 tabs.