(184q) Modeling and Control of Proppant Distribution of Multi-Stage Hydraulic Fracturing in Horizontal Wells

In shale rock formations, multiple hydraulic fracturing treatments with slick water (i.e. a low-viscosity fluid) are generally used to stimulate the recovery of natural gas and oil. The slick water can create massive hydraulic fractures, but it is inefficient at suspending proppant due to the low-viscosity, resulting in the creation of significant proppant bed at the bottom of the fracture, which will influence the subsequent proppant transport mechanism inside the fracture. Currently available hydraulic fracture simulators mainly focused on simulating simultaneously propagating multiple fractures considering stress shadow effects without considering this proppant transport phenomena [1, 2]. As of now, the simulation of proppant transport has mainly focused on simple fracture geometry, i.e. a single, planar fracture [3, 4]. Even though some efforts have been made to simulate the proppant transport using the Eulerian-Eulerian method [5], dense proppant transport and proppant bed formation were not considered. Recently, the Eulerian-Lagrangian method was used to model particle movement [6]. However, the approach is highly computationally expensive to be incorporated into simultaneously propagating multiple fractures model. Motivated by these considerations, the proposed research will first address the development of a new high-fidelity model to describe the fracture propagation by explicitly accounting for stress shadow effects as well as proppant transport to fluid conductivity.

The hydrocarbon production through these simultaneously propagating multiple fracture networks is strongly dependent on the proppant distribution within the fractures, because they will create conductive channels through which natural oil and gas can be easily transported. Therefore, the proppant distribution at the end of pumping in simultaneously propagating multiple fractures must be regulated by developing model-based pumping schedules. In this work, utilizing the new high-fidelity model, we will focus on introducing a new model-based control algorithm to compute online pumping schedules that compensate for stress shadow effects; the computed pumping schedule will be able to generate uniform proppant distribution in simultaneously propagating multiple fractures.

References:

[1] Wu, K., & Olson, J. E. (2015). Simultaneous multifracture treatments: fully coupled fluid flow and fracture mechanics for horizontal wells. SPE journal, 20(02), 337-346.

[2] Peirce, A., & Detournay, E. (2008). An implicit level set method for modeling hydraulically driven fractures. Computer Methods in Applied Mechanics and Engineering, 197(33-40), 2858-2885.

[3] Siddhamshetty, P., Yang, S., & Kwon, J. S. I. (2017). Modeling of hydraulic fracturing and designing of online pumping schedules to achieve uniform proppant concentration in conventional oil reservoirs. Computers & Chemical Engineering. URL: https://doi.org/10.1016/j.compchemeng.2017.10.032.

[4] Siddhamshetty, P., Kwon, J. S. I., Liu, S., & Valkó, P. P. (2017). Feedback control of proppant bank heights during hydraulic fracturing for enhanced productivity in shale formations. AIChE Journal, 64(05), 1638-1650.

[5] Liu, Y. (2006). Settling and hydrodynamics retardation of proppants in hydraulic fractures. The University of Texas at Austin, Ph.D. thesis.

[6] Wu, C., Yi, S., & Sharma, M.M. (2017). Proppant distribution among multiple perforation clusters in a horizontal wellbore. Presented at SPE Hydraulic Fracturing Technology Conference and Exhibition, The Woodlands, Texas, USA.