Simultaneous Hydraulic Fracturing of Adjacent Horizontal Wells in the Woodford Shale

Abstract

Hydraulic fracturing of horizontal wells in shale gas reservoirs is now an established, commercially successful technique. The evolution of the completion technique has reached the point that numerous stimulation stages through multiple perforation clusters in wellbores with some form of annular isolation is now an accepted practice. The objective is to place multiple closely spaced hydraulic fractures. This has proven to be a viable development strategy for many shale reservoirs in North America. To further enhance the recovery factor in these ultra low permeability reservoirs simultaneously hydraulically fracturing of adjacent wellbore is increasingly being tested. Most of the time this is performed in horizontal wellbores paralleling each other. The goal is to create hydraulic fractures more closely spaced than can be achieved from a single wellbore. When real time microseismic monitoring of the stimulation treatments is incorporated changes can be made "On-the-Fly" to improve the effective stimulated reservoir volume. Continental Resources has employed simultaneous hydraulic fracturing as a development strategy for their Woodford Shale acreage in the Arkoma Basin of Eastern Oklahoma. To monitor the effectiveness of the stimulations geophones have been deployed into horizontal wellbores to record microseismic events when offsetting vertical wellbores are unavailable. Cased hole sonic logs have also been run to quantify cement bond quality, estimate stress variation along the lateral, and to pick optimum perforating points. This paper reviews the methodology employed in the completion design and process. The impact of the simultaneous stimulations and geologic structure on the fracture geometry are shown as well as the impact on well productivity.

A review on hydraulic fracturing of unconventional reservoir

“…Also the real time change along the near wellbore can change the hydraulic fracture direction and affect the production greatly [3,9,90]. The differences in far-field principal stress can alter the direction of hydraulic fractures and also determine whether there is a main fracture or there are many secondary fractures, as well as the shape of fracture has also been constrained [23,88]. But Abass et al [2] pointed out that the near wellbore stress field can control the hydraulic fracturing in its early stage, and once the fracture extended into the original stress field, its propagation will be controlled by the original stress field.…”

“…Stages of hydraulic fracturing process will be performed on a single well or on multiple wells, moreover, simultaneous and sequential fracking has been adopted to lead the orientation of hydraulic fracture [13,85]. Previous hydraulic fractures impacts on later fracking work and simultaneous fracking will influence each other by reforming the stress field and transfiguring the formation [46,64,88]. Different spacing will lead to different stress condition which can prevent/enhance secondary hydraulic fractures [88].…”

“…Previous hydraulic fractures impacts on later fracking work and simultaneous fracking will influence each other by reforming the stress field and transfiguring the formation [46,64,88]. Different spacing will lead to different stress condition which can prevent/enhance secondary hydraulic fractures [88]. Moreover, contact area between hydraulic fracture and rock matrix has been enlarged by increase the fracture complexity or networking [59,66].…”

Adaptive Finite Element‐Discrete Element Analysis for Microseismic Modelling of Hydraulic Fracture Propagation of Perforation in Horizontal Well considering Pre‐Existing Fractures

“…Microseismic and nondestructive testing methods have been used to investigate the hydrofracturing crack morphologies [18][19][20][21][22]. The laboratory experiments show that the dip angle affects crossing behaviours between hydraulic and pre-existing fractures to form the complex fracture networks [23]. Some other techniques, that is, microseismic measurements, mine-back experiments, and surface tiltmeter, also have been effectively applied [24][25][26][27][28].…”

Modeling Simultaneous Multiple Fracturing Using the Combined Finite-Discrete Element Method

“…A great number of attempts have been made to simultaneously fracture multiple adjacent horizontal wells to generate complex fracture networks. Although field practices have yielded a significantly improvement from simul-frac over stand-along wells [5], microseismic data [6], and numerical simulations [3,[7][8][9][10][11][12] also show a complex fracturing network produced by simulfrac, the reasons for simul-frac success are still not clear.…”