New Potential Tracer Compounds for Inter-well SOR Determination - Stability at Reservoir Conditions

摘要

The number of mature oil fields increases worldwide with recovery factors of 20% - 40%. Further exploration of the known oil resources requires thorough understanding of the reservoir. Partitioning inter-well tracer test (PITT) is a promising method to determine residual oil saturation in the reservoir's swept volumes, thus contributing for its understanding. PITTs identify EOR targets, evaluate EOR operations and the efficiency of volumetric sweep between wells. PITTs are rare in the oil industry, partly due to the scarce number of compounds qualified for such application. A PITT tracer must be thermally, chemically, and biologically stable, have constant and reversible phase partitioning and be unique at reservoir conditions. It should also be analyzable in ppb/ppt concentrations, and available in considerable quantities at acceptable cost. In this paper, the stability studies conducted with 15 PITT tracer candidates are presented. They were tested for thermal, chemical and biological stability under temperatures of 25 °C - 150 °C and pH 5.5 -8.0. Their interaction with sandstone, limestone and kaolinite was also investigated. Six compounds were found to possess suitable characteristics for this application and another five compounds show interesting properties to retrieve other information from the reservoir, such as temperature or geochemical data.