Early Time Flowback Tracer Test for Stimulated Crystalline-Georeservoir of Multiple Parallel Fracture Characterization

Abstract

Stimulated georeservoir needs to deal with the fracture properties of which, most of them are estimated from geological inherent knowledge, hydraulic test and geophysical methods except transport effective parameters such as fracture aperture and effective porosity. Single-well tracer injection-flowback based ‘early time’ tracer signal provides a relatively small duration and efficient test method to estimate those transport effective parameters, that is relevant not only for EGS of sedimentary formation but also other stimulated geo-reservoirs (e.g. HDR or oil/gas reservoirs). The application that described in early-time flowback tracer test study article has not exhaustively demonstrated its complete range of uses for stimulated georeservoir. Sorptive tracer either on proppant or on a matrix that used for stimulated fracture characterization has raised the question about the range of sorptive tracer to produce for an effective tracer test that is very important to know beforehand conducting such a field experiment. This study accounts the full array of sorptive tracers for different candidate georeservoir and at the same time a guideline for candidate tracer in relation to georeservoir properties proposed. For the purposes of the present study, a lower sorptive tracer than its minimum necessary was suggested, assuming a sensitivity improvement factor (ratio between sorptive tracer signal changes to conservative tracer signals changes, s/c) approximately equal to √ (1 + 0.7× sorption coefficient, κ). One needs to note that the higher the tracer's retardation, the lower is its fracture invasion, and consequently a poorer capability for characterizing the fracture as a whole. In principle, this could be compensated by increasing the chaser volume (i.e., by injecting sorptive tracers earlier than conservative tracers).