Modeling the Influence of Pressure Depletion in Fracture Propagation and Quantifying the Impact of Asymmetric Fracture Wings in Ultimate Recovery

Mata, Domingo; Cherian, Bilu Verghis; Gonzales, Veronica; Han, Hongxue

doi:10.2118/169003-ms

Cited by 8 publications

(2 citation statements)

References 5 publications

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“…These ЉsinksЉ become preferential for subsequent hydraulic fracture propagation. As such, the degree of and proximity to depleted zones must be quantified to account for asymmetrical fracture propagation for subsequent infill wells (Han et al 2014;Mata et al (2014).…”

Section: Importance Of Geomechanicsmentioning

confidence: 99%

Eight-Plus Years of Hydraulic Fracturing in the Williston Basin: What Have We Learned?

Srinivasan

Krishnamurthy

Williams

et al. 2016

Day 3 Thu, February 11, 2016

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Since the inception of the oil boom in North Dakota, the Williston basin has witnessed a tremendous growth in horizontal drilling and completion activity primarily targeting the Bakken and Three Forks formations. Although the activity in the basin is maturing in terms of our understanding rock quality and completion quality, there is a wide variation of these indices within the basin from one field to another. Some of these variations are clearly noticeable in parameters such as thicknesses of the shale barriers, pore pressure gradients, reservoir permeabilities, porosities and stress gradients. The combined impact of these parameters has a huge impact on key decisions including, but not limited to, completion methodologies, types of proppants and fluids used for completion, number of fracturing stages in the lateral, number of perforation clusters per stage, and well spacing. This paper discusses the evolution of stimulation strategies and completion practices in the Williston basin since 2009. Operators have experimented with cemented and uncemented laterals; sliding sleeves and plug-and-perf completions; lateral lengths ranging from 5,000 to 10,000 ft; perforation clusters ranging from one to six per stage; crosslinked, hybrid, and slickwater fluid systems; proppants ranging from sand to ceramic, etc. The consequent impacts of these variations on well completion pressure responses and long-term production have been mixed. As part of the work covered in this paper, the differences between various completion methodologies and their impact on the stimulation strategies have been discussed in a chronological order.Although there is no single optimized design for the entire basin, experimentation of multiple methods and technical interpretation of various fracture and production models have provided us with a strong foundation to narrow down our practices to the most successful and repeatable ones across all the fields in the Bakken and Three Forks formations. The paper also covers how real-field measurements such as diagnostic fracture injection tests (DFITs), microseismic data, radioactive or chemical tracers, bottomhole pressure gauges, and interference experiments combined with log measurements such as magnetic resonance, acoustic logs, and elemental spectroscopy can provide us with a strong base for building and calibrating reservoir models that are reliable and reasonable.The paper covers technical differences between sliding sleeves and plug-and-perf completions; differences between crosslinked, slickwater, and hybrid designs and their impact on fracture geometries; effect of using different proppant types; and ways to optimize the number of fracturing stages and proppant and fluid volumes. As part of the study, the importance of geomechanics in understanding planar versus complex fracture geometries is discussed to close the loop with reservoir simulation models.

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Section: Importance Of Geomechanicsmentioning

confidence: 99%

Eight-Plus Years of Hydraulic Fracturing in the Williston Basin: What Have We Learned?

Srinivasan

Krishnamurthy

Williams

et al. 2016

Day 3 Thu, February 11, 2016

View full text Add to dashboard Cite

show abstract

“…Such interference from nearby wells is of increasing importance in densely drilled unconventional reservoirs where hydraulic fracturing is common. It was recently demonstrated that hydraulic fracture asymmetry will affect well productivity as well as overall hydrocarbon recovery of the area (Mata et al 2014).…”

Section: Introductionmentioning

confidence: 99%

In-Situ and Induced Stresses in the Development of Unconventional Resources

Han

Mata

Gonzales

2014

Day 3 Thu, October 02, 2014

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Multistage hydraulic fracture stimulation of horizontal wells often results in asymmetric hydraulic fractures, which are suboptimal for draining reservoirs. Field observations suggest that hydraulic fractures grow further than expected toward, and sometimes up to and beyond, adjacent producing wells. Such interference from nearby wells is of increasing importance in densely drilled unconventional reservoirs, where hydraulic fracturing is common. Eventually, the underlying mechanism needs to be factored into well spacing plans and hydraulic fracture treatment designs, which can either mitigate the undesired consequences of the nonvirgin conditions, or take advantage of them.An integrated approach has been developed to quantify depletion-induced stresses. In this approach, a three-dimensional (3D) Mechanical Earth Model (MEM) is constructed using the finite-element method to initialize the in-situ stresses. Coupled simulation between the dynamic reservoir model and the geomechanical model is used to quantify stress variation, induced by pressure depletion of the parent well. The altered stress profile is then used as input to a hydraulic fracture design.The methodology has been applied to an unconventional resource play in the Williston Basin in North America. In this example, three adjacent horizontal wells were hydraulically fractured and put on production sequentially within four years. The analysis indicated that the minimum horizontal stress decreased in the area between a newly drilled well and the nearby producing well; whereas the area on the opposite side of the new well showed no obvious stress variations. Formations above and below the depletion zone experienced an increase of minimum horizontal stress as a balance effect of the finiteelement calculation. Fracture modeling using the depletion-induced stresses showed that the effective half-length of the fracture directed toward the depleted well can extend up to two times the length of the hydaulic fracture in the opposite direction.

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