Response to an Induced Flow/Pressure Transient During Well Fracturing

Hydraulic fracturing of oil and gas wells is often needed to increase well production. The fluid pumping schedule is designed to control the fracture growth in length, width and height. This paper investigates the potential for using the fracture fluid acoustic properties to measure, on-line, the length of the fracture and or reduce the enormous pumping power required. This preliminary study shows that most induced flow or pressure transients are critically damped inside the fracture. Pulses with pressure rising or dropping faster man the time required for the wave to travel the length of the fracture, behave differently. Those pulses excite the natural frequency of the fracture, which is about 10 Hertz for a 100 ft. (30 m) long fracture. If the fracture natural frequency can be detected at the surface, it provides an on-line insight into the length of the fracture created.