Employing Live Subsurface Measurements to Support Supervised and Autonomous Intelligent Decision-Making While Fracturing

Abstract Historically, real-time changes during fracturing treatments have primarily been limited to avoiding or controlling screenouts using only the guidance of surface treating pressure. In this paper, a workflow is introduced that utilizes live surface-based measurements of perforation friction, perforation efficiency, and Uniformity Index to support intelligent decision-making based on subsurface data during a fracture stage. The study describes how frac fluid and proppant can be reallocated from a poor-performing stage with runaway fractures into a stage with high Uniformity Index that will have a better distributed fracture network and ultimately be a better producer. High-frequency transducers tied in on surface capture any rapid rate change that occurs during a fracture treatment. Acoustic friction analysis principles are used to uniquely separate pipe and perf friction components of the induced tube wave. Perf efficiency, Uniformity Index, perf diameter, pipe friction curves and other calculations are then displayed on a live dashboard that is consulted in real-time to assist frac decision makers. Rate changes were planned on each stage during pad, midway through the stage, and at stage end prior to full shutdown. Any additional unplanned drops including pump kickouts were also analyzed to understand how the subsurface measurements were evolving through the stage. A data acquisition system was installed along with the high frequency transducer to gather the pumping stream. The real-time friction analysis system is comprised of a rate drop detection and friction analysis module. It operates by continuously receiving pumping pressure and rate delivered by the completions platform. Upon detection of a rate change event, perforation efficiency and UI are computed, and the results are used for real-time evaluations. A decision tree was implemented to guide the next steps in a stage pending the current UI. If UI falls below a certain level at the stage midpoint, the decision is made to redistribute the remaining volume to a subsequent stage. This is an improvement on the previous process of simply cutting stages short due to adverse treating pressure conditions. Subsurface conditions may not reveal themselves in surface treating pressure alone and require additional technology like acoustic friction analysis to understand. Real-time decision making while fracturing is a relatively undeveloped field, historically driven by basic pumping data. Live subsurface measurements enabled by acoustic friction analysis allow completions engineers and onsite consultants to either boost stage performance or prevent wasted capital on suboptimal stages.