The effect of fluid injection rate on hydraulic fracturing of limestone rocks: an experimental study

Hydraulic fracturing based on the use of guar gum water-base fluid with appropriate viscosity has been recognized as a viable solution for extracting oil and natural gas from the reservoir due to its unique benefits such as low cost and proppant carrying capacity. However, the lack of knowledge of reservoirs fractures has challenged field applications. Therefore, the purpose of this study was to investigate the effect of fluid injection rate on fracture pressure and geometry of fractures. To achieve this goal, a series of hydraulic fracturing experiments were performed on limestone rock samples using a guar gum water- base fluid. To investigate the effect of fluid injection rate, CT scan technology was also used to describe the geometric parameters of the fracture. The results of experiments show that with increasing fluid flow rate injected from 1 to 6 ml/min, breakdown pressure and fracture opening increase. As the volume of consumed fluid increases the breakdown time decreases. The findings of this study reveal that low guar gum-flow rates can create a better inter- connected fracture network than higher flow rates.