Date of Award

2013

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Geology

First Advisor

R.D. LeFever

Abstract

Unconventional hydrocarbon reservoirs have proved to be challenging in terms of reservoir characterization, predicting production potential, estimating ultimate recovery, and optimizing hydraulic fracture stimulations. The methods by which these resources are extracted use progressive, or unconventional, technologies. Today, through the use of hydraulic fracturing and horizontal drilling, extraordinary amounts of oil and natural gas from deep shale formations across the United States and around the world are being safely produced.

Performing a hydraulic fracture design requires modeling of fracture propagation and tracking the fluid front in the created fracture. In this dissertation, the roles of all effective parameters and properties on the design and performance of hydraulic fracturing in the Bakken Formation, Williston Basin, are examined.

To accomplish the above objectives, this dissertation is divided into four major sections that include: 1) basic principles of geology, lithology, and reservoir aspects of the Bakken Formation, 2) the fundamental concepts of hydraulic fracturing, 3) technology aspects are integrated into one cohesive unit to model and optimize the entire hydraulic fracture treatments, and 4) a comprehensive approach to the uncertainty assessment of the complex numerical simulations is described.

In this research by integrating reservoir and hydraulic fracture simulations, a robust workflow was used to evaluate several combinations of fracturing materials (i.e. fluids and proppants) and well/fracture parameters (i.e. lateral length, fracture spacing, and fracture half-length) to identify the best candidate(s) for well stimulation planning. Using an automated history matching procedure, the reservoir properties of the Bakken Formation were estimated that can be used in future reservoir simulation projects.

The fully 3D/FEM* fracture simulation showed that a fracturing treatment with injecting slickwater as the pad followed by crosslinked gel together with ceramic or resin-coated sand would guarantee that most proppants would stay within the Bakken Formation. The results from this research also suggest that in a Bakken well with a long lateral length (e.g. 10,000 ft), a fracturing strategy that leads to a relatively high fracture half-length (e.g. 1000 ft) with a high number of fractures (36 or more) would return an efficient balance between the operating charges, fracture treatment costs, drilling expenses, and the benefits earned from the incremental oil production. The pump schedule developed for the optimal fracture treatment, obtained from the fully 3D fracture modeling, would also guarantee fracture confinement within the Bakken Formation.

Included in

Geology Commons

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