Abstract
Slickwater hydraulic fracturing is becoming a prevalent approach to economically recovering shale hydrocarbon. It is very important to understand the proppant’s transport behavior during slickwater hydraulic fracturing treatment for effective creation of a desired propped fracture geometry. The currently available models are either oversimplified or have been performed at limited length scales to avoid high computational requirements. Another limitation is that the currently available hydraulic fracturing simulators are developed using only single-sized proppant particles. Motivated by this, in this work, a computationally efficient, three-dimensional, multiphase particle-in-cell (MP-PIC) model was employed to simulate the multi-size proppant transport in a field-scale geometry using the Eulerian–Lagrangian framework. Instead of tracking each particle, groups of particles (called parcels) are tracked, which allows one to simulate the proppant transport in field-scale geometries at an affordable computational cost. Then, we found from our sensitivity study that pumping schedules significantly affect propped fracture surface area and average fracture conductivity, thereby influencing shale gas production. Motivated by these results, we propose an optimization framework using the MP-PIC model to design the multi-size proppant pumping schedule that maximizes shale gas production from unconventional reservoirs for given fracturing resources.
Highlights
Hydraulic fracturing is a well stimulation technique to enhance shale gas production from unconventional reservoirs in the petroleum industry [1,2,3]
Our results indicated that pumping schedules significantly affect propped fracture surface area (PFSA) and average fracture conductivity (AFC), and thereby the cumulative shale gas production volume from unconventional reservoirs
The first model is a multi-variable output error state-space (MOESP)-based reduced-order model (ROM) that describes the relationships between the manipulated input variables and the output variables (i.e., PFSA and AFC) of the multiphase particle-in-cell (MP-PIC) model
Summary
Hydraulic fracturing is a well stimulation technique to enhance shale gas production from unconventional reservoirs in the petroleum industry [1,2,3]. In CFD-DEM models, each individual particle is treated separately, and the velocity and position of every particle are calculated by integrating the forces acting on them over time While this approach is effective in capturing proppant transport at relatively small scales, it is difficult to apply this method to field-scale simulations because of its extremely high requirement of computation power. It is very important to achieve desired PFSA and AFC values by manipulating the pumping schedule (i.e., fracturing fluid flow rate, proppant concentration, and proppant size injected at the wellbore) In this regard, we use a MP-PIC model within an optimization framework to compute the optimal multi-size proppant pumping schedule that maximizes shale gas production from unconventional reservoirs for given fracturing resources (i.e., proppant amount, etc.).
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call