Abstract

Fracture potential of a formation is governed by its ability to create high quality/extensive fracture networks that can remain open during production and maintain conductivity. In permeability challenged reservoirs, overall success of the hydraulic fracture operation is measured by this fracture conductivity. Different techniques have been used to increase fracture conductivity by employing a variety of proppant placement strategies. One strategy is to involve alternating (i.e. pulsed) stages of proppant-containing fluids and proppant-free fluids to form heterogeneously distributed proppant clusters and highly conductive flow channels in between each cluster. If engineered accurately, proppant clusters can withstand closure stresses (reducing embedment or crush risk), and result in longer effective fracture length(s) with improved conductivity.

While there are a number of approaches to modify or adjust treatment schedules to optimize clustered proppant placement, many of these suffer from a consideration of only one or two aspects of a fracturing operation. There is a need for a physics based integrated methodology which couples advanced flow and geomechanical models (with production analysis) to optimize engineering design and proppant placement. In this study, clustered proppant design optimization is demonstrated within the framework of an integrated geomechanics-flow-reservoir workflow. The workflow combines quick look analysis (i.e. candidate screening) with advanced computational models (i.e. geomechanical, flow and reservoir models). Candidate screening process utilizes response surface(s) to asses fracture closure risk for multiple well(s) or formation(s). Following the screening procedure, computational fluid dynamics (CFD) flow analysis, geomechanical and reservoir modelling are performed on specific well(s). These results are then used to (i) adjust treatment schedule, perforation geometry, pulse frequency, flow rate, drawdown, (ii) optimize proppant cluster transport/configuration within fractures, and (iii) quantify conductivity & production uplift from multiple scenarios. The formulated workflow indicates that clustered proppant placement design can be optimized, proppant configuration/transport can be customized and operational parameters can be adjusted to maximize production.

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