Experimental Study of Proppant Transport Using 3d-Printed Rough Fracture Surfaces

3D printing is a type of additive manufacturing technology that allows for digital 3D models to be made into physical objects out of a wide range of thermoplastics, resins, and occasionally metals. In previous years, 3D printing models at high-resolution suitable for oil and gas research was either time consuming, cost-prohibitive, or limited to a small model build volume. However, the rapid advancement in resin 3D printing technology recently has allowed for a significant increase in production speeds and model size at little cost. In this study, we utilized 3D printed rough-wall fracture panels in a large-scaled proppant transport apparatus to evaluate the feasibility of repeatable and realistic experimental investigation by the 3D printing technology. Understanding proppant transport in hydraulically created fractures helps to answer the questions about proppant distribution, resultant fracture conductivity, effectiveness of fracture fluid and additives, and all leads to fracture treatment efficiency. In the past, lab experiments showed that fracture topography plays an important role on fracture conductivity, and the characteristics of fracture surfaces have been grouped as random distribution, channel, wavy and ledge (step-change). These surface features can be described by geostatistical parameters. For large-scale proppant transport, the realistic surfaces are difficult to create, and thus most studies have used smooth-surfaced parallel acrylic panels for the fracture walls. Stereolithography (SLA) resin 3D printers produce a physical model by using an ultraviolet light source to selectively illuminate and cure a photopolymer onto a travelling build platform. The physical models are based on a computer-generated surface with controlled statistical definition. We have successfully printed panels to build a 4ft X 2ft main fracture with a smaller fracture intersecting orthogonally. The panels are carefully printed with transparent resin to allow for video recording. Initial tests showed the mechanical integrity of printed fractures and proppant transport results. This paper describes the detailed procedure of generating fractures by 3D printing, experimental setup and the test results of proppant transport.