Analysis of Pressure Interference During Fracture Injection Tests and Stimulation Treatments

Abstract

Summary Hydraulic fracturing in tight rocks is a prime strategy in unconventional resources. A key parameter to determine the success of a Frac job is the Stimulated Reservoir Volume (SRV), a volume of a network of induced hydraulic fractures and natural fractures. Due to the low-permeable, micro fracture dense nature of tight carbonate shale, induced fractures can continue propagating in natural fractures, bypassing a large volume of unstimulated rock. Natural fractures have a variety of effects on hydraulic fracturing, including the stimulated fracture pattern, leak off, and the transport of proppants, etc. because some natural fractures may be reactivated or crossed during the propagation of hydraulic fracture. Therefore, adequate well spacing is essential to maximize SRV with the lowest number of wells drilled. Pressure monitoring a stimulation treatment from adjacent wells in the same formation and other layers can be utilized to estimate fracture propagation behavior and SRV extension. This allows for optimum well placements and intervention operations scheduling. Pressure monitoring was done using downhole measuring gauges (DHMG) and surface gauges to monitor the pressure response during several fracturing operations, such as Diagnostic Fracture Injection Tests (DFIT) and hydraulic stimulation treatments. The gauges can be installed with direct communication with the rock (open perfs) and in sealed wellbores. Multiple horizontal wells at different spacing with toe sections in communication with the rock are used to measure the pressure response from a stimulation treatment in an adjacent well. The monitoring wells are landed in the same layer and other formations to test the fracture propagation path.