Laboratory Modeling of hydraulic fracturing

Hydraulic fracturing has two major applications: 1. determining the in-situ stress state of a site; 2. increasing the productivity of oil wells by propagating the existing fractures at the site. Hydraulic fracturing is used in the oil industry in order to increase the index of production and processing in wells whose efficiency has been dropped due to long-term harvest or the rocks around the well are low permeable.In this study, the Hoek triaxial cell was adapted for a laboratory modeling of hydraulic fracturing. The specimens under study are in the shape of thick-walled hollow cylinders with an external diameter of 54.7 mm, an internal diameter of 12 mm, and a height of 108 mm. These specimens were taken from the carbonate rocks of the Bangestan reservoir, located in the southwest of Iran. By using the cell, the hydraulic fracturing experiment can be modeled in the laboratory before being conducted at the site, so that a suitable pump can be selected. In all the experiments, the fractures are created with a vertical (along the sample axis) or near-vertical orientation. Borehole breakdown pressure increases with an increase in lateral stress but does not change much with a change in vertical stress.