In 2007, the Barnett Shale in the Fort Worth basin of Texas produced 1.1 trillion cubic feet (Tcf) gas and ranked second in U.S gas production. Despite its importance, controls on Barnett Shale gas well performance are poorly understood. Regional and vertical variations of reservoir properties and their effects on well performances have not been assessed. Therefore, we conducted a study of Barnett Shale stratigraphy, petrophysics, and production, and we integrated these results to clarify the controls on well performance. Barnett Shale ranges from 50 to 1,100 ft thick; we divided the formation into 4 reservoir units that are significant to engineering decisions. All but Reservoir Unit 1 (the lower reservoir unit) are commonly perforated in gas wells. Reservoir Unit 1 appears to be clay-rich shale and ranges from 10 to 80 ft thick. Reservoir Unit 2 is laminated, siliceous mudstone and marly carbonate zone, 20 to 300 ft thick. Reservoir Unit 3 is composed of multiple, stacked, thin (~15-30 ft thick), upward coarsening sequences of brittle carbonate and siliceous units interbedded with ductile shales; thickness ranges from 0 to 500 ft. Reservoir Unit 4, the upper Barnett Shale is composed dominantly of shale interbedded with upward coarsening, laterally persistent, brittle/ductile sequences ranging from 0 to 100 ft thick. Gas production rates vary directly with Barnett Shale thermal maturity and structural setting. For the following five production regions that encompass most of the producing wells, Peak Monthly gas production from horizontal wells decreases as follows: Tier 1 (median production 60 MMcf) to Core Area to Parker County to Tier 2 West to Oil Zone-Montague County (median production 10 MMcf). The Peak Monthly oil production from horizontal wells is in the inverse order of gas production; median Peak Monthly oil production is 3,000 bbl in the Oil Zone-Montague County and zero in Tier 1. Generally, horizontal wells produce approximately twice as much oil and gas as vertical wells.This research clarifies regional variations of reservoir and geologic properties of the Barnett Shale. Result of these studies should assist operators with optimization of development strategies and gas recovery from the Barnett Shale.

The goal of the present work is to improve shale reservoir stimulation treatment by using ultra light weight proppants in fracturing fluids. Slickwater has become the most popular fracturing fluid for fracturing shales in recent times because it creates long and skinny fractures and it is relatively cheap. The problem with slickwater is the high rate of settling of common proppants, e.g. sand, which results in propped fractures which are much smaller than the original fractures. Use of gels can help in proppant transport but introduce large formation damage by blocking pores in nano-darcy shales. Gel trapping in the proppant pack causes reduction in permeability of the proppant pack. The light weight proppants which can easily be transported by slickwater and at the same time be able to provide enough fracture conductivity may solve this problem. Three ultra light weight proppants (ULW1, ULW2, and ULW3) have been studied. The mechanical properties of the proppant packs as well as single proppants have been measured. Conductivity of proppant packs has been determined as a function of proppant concentration and confining stress at an average Barnett shale temperature of 95oC. The crush strengths of all the three proppant packs are higher than typical stresses encountered (e.g., Barnett). ULW1 and ULW2 are highly deformable and do not produce many fines. ULW3 has a higher Young’s modulus and produces fines. Conventionally, the proppant conductivity decreases with decreasing proppant concentration and increasing confining stress. But in cases of ULWs, for a partial monolayer, conductivity can be as large as that of a thick proppant pack. The settling velocity is the lowest for ULW1, intermediate for ULW2 and the highest for ULW3. This work contributes new mechanical, conductivity, and settling data on three ultra light weight proppants. Application of light weight proppants in stimulation treatments in shale reservoirs can lead to large propped fractures, which can improve the productivity of fractured shale reservoirs. / text

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Iowa, 1978. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 370-386).

Thesis (Ph. D.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

This thesis investigates the utilization of hydrodynamic models as tools for assessing factors impacting water quality in the Ross Barnett Reservoir. The primary focus is development of a hydrodynamic model that provides transport information to subsequent application of a water quality model. Environmental Fluid Dynamics Code (EFDC) is a complex, dynamic, multi-dimensional computer model used to simulate hydrology in water bodies. The secondary focus is on data acquisition and manipulation methods for completing the hydrodynamic modeling. Monitoring was completed to create modern bathymetry of Ross Barnett Reservoir to provide accurate model cell grid representation. Temperature and dissolved oxygen profile monitoring occurred to provide data for model output comparison. The EFDC model successfully predicted lake stratification and subsequent mixing based on changes in observed meteorological conditions.

Horizontal drilling and hydraulic fracture stimulation have enabled the economic development of unconventional resource plays. An average horizontal well in the Barnett Shale requires 3 to 4 million gallons of fresh water, 90% of which is used for hydraulic fracture stimulation. While the water consumption of Barnett Shale operations is less than 1% of total Region C consumption, extended drought conditions and competing demands for water resources are placing pressure on operators to reduce terminal water consumption. Strategies which reduce water requirements associated hydraulic fracture stimulation without compromising the efficiency and cost of energy production are essential in developing a comprehensive policy on energy-water management. Recycling and reuse technologies were evaluated on the basis of performance, cost, and capacity to treat reclaimed flowback water and oilfield brine. Recycling flowback fluids for future hydraulic fracture applications is the most practical repurposing of oilfield waste. The low TDS content of flowback derived from water-based fracs permits multiple treatment options. Mobile thermal distillation technology has emerged as the prevailing technique for recycling flowback water, yielding maximum water savings and reduced operating costs. The estimated cost of recycling flowback water by thermal distillation is $3.35/bbl. Compared to the current cost of disposal, recycling provides an opportunity to minimize waste and reduce the fresh water requirements of hydraulic fracture stimulation at an incremental cost. The stewardship role of the Texas Legislature is to protect the water resources of the state and to facilitate the Regional Water Planning Process, ensuring future water needs are met. The support and participation of the Legislature and other planning entities is critical in advancing the energy-water nexus. As operators pursue innovative water management practices to reduce terminal water consumption in the oilfield, the Barnett Shale positions itself as a model for sustainable water use in the development of unconventional shale resources. The cost of recycling and reuse technology limits the participation of small and mid-size operators who possess the greatest market share of the Barnett Shale. Funding for research and implementation of water-conscious strategies such as shared recycling facilities, CO2 capture and storage, and pipeline infrastructure would create multi-user opportunities to promote conservation and reduce net consumption of fresh water supplies. Through the integration of technology and policy, terminal water consumption in the Barnett Shale can be greatly diminished. / text

The present study applies evolutionary and resource-based firm theories to three of the most prominent U.S. shale gas basins – the Barnett, Fayetteville, and Haynesville plays. Rather than broadly considering a host of factors that enabled what has often been labelled a shale gas revolution, an evolutionary approach recognizes the internal agents that have long been in place, but were triggered by technical and economic developments. As geologic understanding, along with innovation and competitive environments, evolves in each play so too does the entire shale gas industry. Building upon the Bureau of Economic Geology shale gas study funded by the Sloan Foundation, this study offers data-driven analyses to test theories of industrial evolution as applied to shale gas plays. Each of the three focus plays has undergone introductory and growth phases as well as a maturation phase in which there is an evident shakeout of operators. Industries are theorized to enter decline phases, yet none of the plays here have definitively declined. Certain economic signals, however, indicate that a decline is imminent, albeit variable in timing and pace. Conceptualizing the entire shale gas industry as an amalgamation of individual and evolving plays correctly describes how the industry is able to rejuvenate its growth trajectory through investment in emerging plays. Although heterogeneous geology, engineering capabilities, and economic environment, particularly natural gas prices, complicate the economics of shale gas extraction, an evolutionary approach proves to be a useful tool in describing the historical development of individual plays as well as the entire shale industry. Importantly, this application sheds light on the future development of valuable shale resources. / text

Master of Visual Arts / The title Normal What refers to a group of paintings that emerged from my Masters of Visual Arts 2004/05 studio project. Individual paintings are chronological self portrait reflecting upon my own experiences and those in the wider community who at some point in their lives have had to endure the struggles, and negative stigma that is so often attached to those who have become marginalised and detached from mainstream society. People found in this category include the disabled, homeless, unemployed, and those with addiction problems. Each painting bears a close connection with techniques associated with abstract expressionist painting. This radiates through the vast expanse of drips, stains and explosions which appear to suffocate the paintings delicate monochrome surface. Strong references to Kristeva’s theory on Abjection arrive through the aggressive and violent outbursts of paint that evoke an atmosphere of symbolic horror, personal dysfunction and social oppression. This emerges out of the shadows and private spaces of the painting’s domestic interior. Deep emotional, psychological, sociological sensitivities are raised throughout my studio practice. Combined with a series of unresolved tensions, and questions surrounding normality run deep a consequence of society’s push for normality are being felt most acutely by those effected by this form of sociology. The ideas raised through my studio project had a profound influence on the research being conducted for the dissertation. Kristeva’s theory on Abjection, along side the practices of Eva Hesse, Barnett Newman, Agnes Martin emerged from a group of highly emotional abstract paintings. This strengthened the connection between the studio project and the dissertation. Aimed at deepening a personal understanding an commitment to researching the subject of normality and how it could be successfully articulated through a visual narrative.

Today everyone seems to agree that ultra-low permeability and shale reservoirs have become the potentials to transform North America's oil and gas industry to a new phase. Unfortunately, transient flow is of long duration (perhaps life of the well) in ultra-low permeability reservoirs, and traditional decline curve analysis (DCA) models can lead to significantly over-optimistic production forecasts without additional safeguards. Stretched Exponential decline model (SEDM) gives considerably more stabilized production forecast than traditional DCA models and in this work it is shown that it produces unchanging EUR forecasts after only two-three years of production data are available in selected reservoirs, notably the Barnett Shale. For an individual well, the SEDM model parameters, can be determined by the method of least squares in various ways, but the inherent nonlinear character of the least squares problem cannot be bypassed. To assure a unique solution to the parameter estimation problem, this work suggests a physics-based regularization approach, based on critical velocity concept. Applied to selected Barnett Shale gas wells, the suggested method leads to reliable and consistent EURs. To further understand the interaction of the different fracture properties on reservoir response and production decline curve behavior, a series of Discrete Fracture Network (DFN) simulations were performed. Results show that at least a 3-layer model is required to reproduce the decline behavior as captured in the published SEDM parameters for Barnett Shale. Further, DFN modeling implies a large number of parameters like fracture density and fracture length are in such a way that their effect can be compensated by the other one. The results of DFN modeling of several Barnett Shale horizontal wells, with numerous fracture stages, showed a very good agreement with the estimated SEDM model for the same wells. Estimation of P90 reserves that meet SEC criteria is required by law for all companies that raise capital in the United States. Estimation of P50 and P10 reserves that meet SPE/WPC/AAPG/SPEE Petroleum Resources Management System (PRMS) criteria is important for internal resource inventories for most companies. In this work a systematic methodology was developed to quantify the range of uncertainty in production forecast using SEDM. This methodology can be used as a probabilistic tool to quantify P90, P50, and P10 reserves and hence might provide one possible way to satisfy the various legal and technical-society-suggested criteria.