Validation of Analytical Model for Tracer Flow within the Naturally Fractured Reservoir by the Use of Sensitivity Analysis on the Numerical Model

Naturally Fractured Reservoirs (NFRs), containing an important part of hydrocarbon resources, demand more practical models of reservoir fluid flow. Also they have low recovery, high water cut, and generally low performance which present unique challenges. Core sampling, well logging, well testing, seismic surveying, and outcrop data have been used to develop fractures models with limitations. Often well tests as one of the reliable methods for characterization cannot capture the dual medium signature of NFRs. Tracer test may be a possible option for the company to characterize the dual medium behavior of such reservoirs, and in particular determine fracture porosity and/or matrix block size. Tracer test is a developing tool to match reservoir models with tracer breakthrough and tracer concentration history.To investigate the application of tracer test in fractured reservoirs, this study begins with a literature review on modeling of the fluid flow and mechanisms of flow in a fractured dual media. One of the most recent analytical model is discussed. The innovation is the use of derivative curve of concentration history for a better matching of most impacting parameters. Besides block size distribution of the matrix observed to be independent of the peak for concentration derivative curve.The objective of this project is the analysis and comparison of the semi-analytical model to result from simulations with a numerical model. The reservoir simulator, Eclipse, is used to simulate tracer injection and production in a phenomenological model. Sensitivity analysis of the tracer production curve based on the numerical model gives the contribution of different parameters. Sensitivity analysis is carried out by the use of EST as a reliable software. Fracture porosity is seen to be the main determining parameter for tracer break-through time. One of the main focuses of this study is the investigation into the effect of the rock matrix block size on the concentration history and its derivative.

Validation of Analytical Model for Tracer Flow within the Naturally Fractured Reservoir by the Use of Sensitivity Analysis on the Numerical Model Keywords:

Tracer Test , Naturally Fractured Reservoirs , Reservoir Characteristics , Modeling , Sensitivity Analysis