Fracture closure modes during flowback from hydraulic fractures

Abstract

SummaryFlowback analysis recently has been considered as a potential tool for assessing induced fractures through corresponding pressure analyses and rate transient analysis. In this paper, we study fracture closure mechanisms during the flowback of fracturing fluid after hydraulic fracturing treatments. Although it is known that flowback can be significantly affected by the geometry of the fractures and closure stress, there has not been any effort to understand the problem from the geomechanical point of view; rather, available studies assume that a fracture closes uniformly with constant fracture compressibility. The coupled geomechanics and fluid flow model presented in this paper help to elucidate how geostresses may affect fracturing fluid recovery under different conditions. We perform a scaling analysis to formulate the occurrence of different fracture closure modes and then use numerical analyses to verify our scaling parameters. The factors governing the flowback process include the mechanical and petrophysical properties of the rock as well as preexisting discontinuities such as natural fractures. Three different closure modes for fracture networks are described and numerically verified. The occurrence of each mode can dramatically affect fracturing fluid recovery. The role of fluid leakoff into the formation, fractures conductivity, and drawdown strategy are examined for each fracture closure scenario.

Transient Pressure Performance Analysis of Hydraulically Fractured Horizontal Well in Tight Oil Reservoir

“…In future works, the fracture network will be verified in the tight oil reservoir by microseism or fiber optic testing, and the discrete fracture model (DFM) or the embedded discrete fracture model (EDFM) will be employed to treat the fracture network when meaningful field data can be obtained [41,42]. In addition, after hydraulic fracturing, the fracturing liquid cannot flow back totally; hence, in the early flow period, the fluid flow should be a two-phase flow, which would affect the transient pressure performance in new models [43,44].…”

Complex Fracture Closure Pressure Analysis During Shut-in: A Numerical Study

“…Hydraulic fracturing is a well stimulation technology that is effective in increasing hydrocarbon production in unconventional reservoirs such as shale gas, coal-bed methane, and tight sandstone (Montgomery and Smith, 2010; Dahi Taleghani et al, 2020; Wang et al, 2020b). A large volume of viscous fluid is continuously injected into such a formation to promote hydraulic fracture propagation, which occurs at a depth of several thousand metres and accordingly cannot be directly observed.…”

Experimental Investigation of the Growth Law of Multi-Fracture during Temporary Plugging Fracturing within a Stage of Multi-Cluster in a Horizontal Well

“…Unconventional reservoirs such as shale have extremely low permeability. The function of hydraulic fractures will be undermined (e.g., fracture closure) after a long-term production, which will lead to a decline in oil and gas production [1,2]. Correspondingly, it is difficult to achieve the economic and efficient development of shale oil and gas resources.…”