ABSTRACT:

Hydraulically stimulating dense reservoirs to extract

O

il and

G

as (O&G) will remain the preferred technology in shale resource development. Fluid is injected into a well and as the pressure increases, the rock mass fractures, leaving residual increased fluid conductivity along the stimulated natural fractures, increasing formation permeability so that slow diffusive O&G escape from tiny pores can take place at commercially interesting rates. The

H

ydraulic

F

racturing (HF) design process is a complex mechanical interaction analysis based on the

G

eology of the rocks and the

G

eometry of the HF fractures or stimulated volume - G&G interactions. Stress is the primary control (work minimization) and if the fracture size (height) is large, or if fracturing is taking place in multi-layered strata with lateral stress inhomogeneity, the geometry of the stimulated zone for a HF stage - height, length, and spatially averaged aperture changes - is impacted by the initial and induced stress profile. This paper attempts to somewhat clarify the outcomes for a single fracture stimulation in a homogeneous 2D elastic medium with non-uniform stresses at the boundaries.

H

ydraulic

F

racture

S

timulation (HFS) is the most effective technique to extract

O

il and

G

as (O&G) from low-permeability formations. Similar to all other stimulation techniques, the goal of HFS is to increase the reservoir permeability, connect natural and induced fractures and ultimately, increase the productivity of the reservoir to enhance O&G profitability (Daneshy, 2010).

H

ydraulic

F

racturing (HF) is a multi-disciplinary process (Taleghani , 2015), and is acclaimed as the most effective reservoir-scale stimulation technique. To attain economical production rates from tight strata such as milliDarcy range sandstones to microDarcy range shale oil and shale gas (Al-Kanaan, 2014), HF is applied along long horizontal wells in stages. A full well stimulation may cost one to two million dollars per well, more for exceptional cases (high pressures, large volumes, complex treatment schedules, many stages). The design and operational processes involved in HF are complex and include hydraulic, mechanical, geomechanical and logistics aspects, requiring a comprehensive workflow. HF design must address geomechanical (in-situ state) and production aspects (experience) in advance, and for optimization, it is also necessary to monitor and evaluate the success of the HFS (Cantagliari , 2010). Furthermore, preliminary workflows for HFS can be enhanced by including other concerns and recommendations arising from environmental, economic, social, and related issues (Oyarhossein & Dusseault, 2016).

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