Applying complex fracture model and integrated workflow in unconventional reservoirs

Abstract

In this paper we present a comprehensive and yet efficient complex fracture network model that simulates hydraulic fracture networks created during the stimulation treatment and proppant placement. The theoretical framework of overall complex fracture modeling is described. The paper then focuses on two critical components of the model that address hydraulic fracture–natural fracture interaction (the crossing model) and interaction between hydraulic fractures (stress shadowing). The details of the model and its validation against experimental data and other numerical simulations are presented. A field example involving both slick water and crosslinked gel treatment is simulated using the complex fracture model and the results are compared to the microseismic monitoring. Due to the complex fractures generated in stimulation of unconventional reservoirs, proper reservoir characterization is essential to obtain more reliable input to the fracture model and to reduce the uncertainties. Complex fractures also present new challenges for the reservoir simulators to properly model the production through the often partially propped complex fracture networks. To enable efficient development and optimization of the completion strategy and treatment design, the fracture model must be closely integrated in a platform that provides efficient workflow to easily build or leverage available geological and geomechanical models as input to the fracture model, calibrate against microseismic measurement, and link to the reservoir simulator for production simulation. This paper presents the integrated workflow in which the complex fracture model is built and illustrates the design optimization process through an example.