bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of Proppant Distribution Effect on Well Performance in Shale Gas Reservoirs
Authors: Yu Wei , Sepehrnoori Kamy 
Published: November 2013

Abstract
The economic viability of shale gas development hinges on uniform proppant distribution and sustaining sufficient fracture conductivity in hydraulic fractures over the lifetime of a well; however, it is very challenging to simultaneously maintain uniform proppant distribution and such conductivity due to proppant settlement, proppant embedment and proppant crushing in shale reservoirs, especially in soft shale formations. It has been reported that the proppant concentration is heavily weighted toward the end clusters, while the initial clusters receiving much less proppant in the same stage. In addition, proppant will settle rapidly in slickwater fracture treatments, forming a proppant bank at the bottom of the fracture, which results in uneven proppant distribution along the fracture height. The effects of the above proppant distribution along with stress-dependent fracture conductivity on ultimate gas recovery are not clearly understood and systematically studied, and have been largely neglected by most fracture modeling work in the literature. Therefore, it is absolutely critical to develop a reservoir-modeling approach that properly examines the relationships between proppant distribution, stress-dependent fracture conductivity and well performance for shale gas reservoirs.
In this paper, numerical reservoir simulation techniques, validated by field production data from Marcellus Shale, are employed to model the proppant distribution and geomechanics effect. A series of reservoir simulations was performed to quantify the impact of uneven proppant distribution between different clusters in the same stage on well performance. The fracture conductivity ratio of 1:1.5:2.5:4 for four clusters within one stage was investigated in this study. The simulations evaluate a range of reservoir permeability from 0.00001 to 0.0001 md. Gas desorption effect is also taken into account. This work enables operators to develop an early understanding of the effects of proppant distribution and geomechanics on shale gas well productivity, and provides insights into fracture conductivity requirements in shale gas reservoirs that can be used to improve hydraulic fracturing treatment design through improved proppant distribution.
Numerical Modeling of Multilateral Junction Stability in the Montney Shale Play
Authors: Li Qiuguo , Hussein Assef Mohamad , Bakhtiari Siamak , Newman Robert , Khosravi Nader , Teichrob Bob 
Published: November 2013

Abstract
While drilling and completing multilateral wells in unconventional shale plays, a major concern is the stability of the junction. If the junction area is to remain open while producing, the stability of the junction is essential until the end of the well life. Due to the complex geometry of the junction, numerical simulations are typically required to understand the stress concentrations and simulate the stability of the junction.
A dual-lateral well was to be drilled and completed in the Montney shale play in Alberta, with the two laterals targeting Middle and Lower Montney, respectively. With the Technical Advancement of Multilaterals (TAML) Level 2 multilateral completion, one lateral would be cased and the other would remain open. Because relatively large drawdown pressures were planned for the well, understanding of the junction stability became an important consideration not only while drilling the lateral, but also while the well was producing.
This paper will present a geomechanical analysis of the multilateral junction stability under two drawdown-pressure conditions, including determination of the mechanical properties and in-situ stresses, numerical simulation of the stress concentrations, and rock deformations at the junction.
Groundwater Considerations of Shale Gas Developments Using Hydraulic Fracturing: Examples, Additional Study and Social Responsibility
Authors: Uwiera-Gartner Michelle 
Published: November 2013

Abstract
Since the mid-1900s, hydraulic fracturing has been used to improve well productivity and gain access to additional resources. For more than a decade, hydraulic fracturing in North America has resulted in the development of significant natural gas resources that would have otherwise been inaccessible.
Recent advances in hydraulic fracturing methods and its access to shale gas resources have prompted public concern about the environmental impacts of using this technology. Concerns about fracking out of the pay zone, the upward migration of methane gas, and contamination of water resources from deeper formation waters, flowback and produced waters, and fracturing fluids are documented. These affect a corporation’s social license to develop unconventional resources.
This manuscript summarizes the potential sources for increased risk to water resources resulting from hydraulic fracturing of shale gas developments. Also provided is a description of some of the hydraulic fracturing operations of natural gas plays that have or believed to have impacted groundwater resources in Western Canada.
A literature review about the groundwater flow systems at the shale gas, unconventional resource plays in Northeast British Columbia is provided. Also summarized is some of the water management strategies used and/or are proposed for shale gas development.
A discussion of social responsibility for exploiting shale gas using hydraulic fracturing is provided. The author indicates that results from continued and additional hydrogeologic investigations should be disclosed in a timely manner as this affects the perception of industry transparency, and can assist with maintaining a social license for resource development.
Uncertainty Analysis of Shale Gas Simulation: Consideration of Basic Petrophysical Properties
Authors: Wu Peng , Aguilera Roberto 
Published: November 2013

Abstract
Uncertainties in basic petrophysical parameters in shale gas reservoirs are discussed in this paper. These parameters include porosity, permeability, gas adsorption, water saturation and TOC. Current available methods to evaluate shale gas petrophysical properties are summarized. These methods include core laboratory measurements and well logs. Sources of uncertainty in these measurements are discussed.
Uncertainty analysis using commercial simulation software was performed to understand how these uncertainties influence reservoir simulation results and predictions. Sensitivity and uncertainty studies in this paper are based on typical ranges of shale gas properties extracted from published evaluation reports or open data. Results from this study will help guide the focus of future research and technology development for shale gas reservoirs.
Assessment of Eagle Ford Shale Oil and Gas Resources
Authors: Gong Xinglai , Tian Yao , McVay Duane A. , Ayers Walter B. , Lee W. John 
Published: November 2013

Abstract
The Eagle Ford play in south Texas is currently one of the hottest plays in the United States. In 2012, the average Eagle Ford rig count (269 rigs) was 15% of the total US rig count. Assessment of Eagle Ford oil and gas resources and their associated uncertainties in the early stages is critical for optimal development. The objective of our research was to assess Eagle Ford shale oil and gas reserves, contingent resources, and prospective resources.
Probabilistic decline curves using Markov Chain Monte Carlo (MCMC) were used to forecast reserves and resources. The Eagle Ford play from the Sligo Shelf Margin to the San Marcos Arch was divided into 8 different production regions based on geology, fluid type, and well performance. We used the Duong model switching to the Arps model with b = 0.3 at the minimum decline rate to model the linear flow to boundary-dominated flow behavior often observed in shale plays. Cumulative production after 20 years predicted from Monte Carlo simulation combined with reservoir simulation was used as prior information in the Bayesian decline-curve methodology. Probabilistic type decline curves for oil and gas were then generated for all production regions. Individual-well reserves and resources estimates were aggregated probabilistically within each production region and arithmetically between production regions.
The total oil reserves and resources range from a P90 of 5.3 to P10 of 28.7 billion barrels of oil (BBO), with a P50 of 11.7 BBO; the total gas reserves and resources range from a P90 of 53.4 to P10 of 313.5 trillion cubic feet (TCF), with a P50 of 121.7 TCF. These reserves and resources estimates are much higher than the U.S. Energy Information Administration’s 2011 recoverable resource estimates of 3.35 BBO and 21 TCF. The results of this study provide a critical update of the reserves and resources estimates and their associated uncertainties for the Eagle Ford shale formation of South Texas.
Evaluation of Time-Rate Performance of Shale Wells using the Transient Hyperbolic Relation
Authors: Fulford D. S. , Blasingame T. A. 
Published: November 2013

Abstract
In this work we present the “Transient Hyperbolic” relation for the analysis and interpretation of time-rate performance data from wells in shale gas/liquids-rich shale plays. This model assumes a transient “b(t)” function which has constant early-time and constant late-time values, with an exponentially decaying transition function. This “b(t)” function is derived from the Gompertz logistic function.
Our goal in developing this formulation is to represent the early-time (or clean-up) portion of the production profile (often a hyperbolic function), the transition to the terminal hyperbolic behavior, and finally, the terminal hyperbolic behavior — where the terminal hyperbolic is usually representative of the “non-interfering” vertical fractures in a multi-fractured horizontal well (MFHW). We could further modify this relation to have a terminal exponential decline (thought to represent the performance of the stimulated-reservoir-volume (or SRV)), but that is not a primary purpose of this work — our primary purpose is to demonstrate the “Transient Hyperbolic” nature of the flow behavior from a multi-fractured horizontal well in a shale gas/liquids-rich shale play.
The technical contributions of this work are: Development of the “Transient Hyperbolic” time-rate relation — this relation includes an early AND a late-time hyperbolic behavior, as well as a logistic transition function.Application of the “Transient Hyperbolic” time-rate relation to modeling completion heterogeneity in a MFHW by a superposition of divisions that have differing durations of linear flow.Application of the “Transient Hyperbolic” time-rate relation to several field cases — specifically: tight gas, shale gas, and “liquids-rich” shale cases.
Geomechanics Mechanisms in Microseismicity Generation Near Natural Fractures Induced by Hydraulic Fracturing
Authors: Han Y. , Hampton J. , Li G. , Warpinski N. R. , Mayerhofer M. J. 
Published: November 2013

Abstract
Economic success producing oil/gas from low-permeability shale often relies on pre-existing natural fractures (NFs) to be activated or connected by hydraulic fracturing (HF) stimulation. In practice, the reactivated natural fracture network is often identified using the microseismicity (MS) monitored during the stimulation. However, the fundamental mechanisms of MS generation and focal mechanisms inferred from geophysical analysis near hydraulic fractures are not currently well understood (e.g., it is not clear whether the MS observed in the field can be mainly attributed to local shear slip along natural fractures when leakoff occurs and/or induced by stress changes as a result of HF propagation or fluid leakoff). The exact slippage area and amount of slip displacement generating the microseimic event are not well understood either, thus requiring a “bridge” between geomechanics and geophysics. To bridge this gap, a set of experiments will be performed in a geomechanics laboratory to observe whether, when, where, and how the acoustic emission (AE) events are generated under various scenarios. The experiments are designed under the guidance of fracture flow-discrete element method (DEM), coupling geomechanical simulations. In this paper, the reliability and accuracy of the fracture flow-DEM coupling approach is validated through solving a few fundamental problems and comparing the numerical simulation results with the corresponding analytical solutions. The coupling approach is then applied to simulate and optimize two fundamental laboratory experiments. The simulations indicate that, despite the difference in the magnitude, the local slip along natural fractures could be induced by both fluid leakoff and stress changes.
New Multi-Zone Stimulation Method Reduces Water Requirements and Operational Costs in the Spearfish Formation
Authors: Olson Keith , Al-Ssalmani Zeyad , Dunlop Tyson , McNeil Fraser 
Published: November 2013

Abstract
Advanced Multi-Stage completion methods are game changers for oil and gas companies, turning previously uneconomic formations into attractive investments. The challenge in the Spearfish formation is generating and propagating the size of fracture required to maximize oil recovery, while avoiding penetration into an underlying water zone.
In the Spearfish formation the typical completion methods use pre-installed burst ports or pre-perforated zones, where each are isolated using a straddle system and then treated individually. These methods have shown to be especially effective; however, complications with burst ports not opening or not being properly located downhole have resulted in significant downtime and additional cost. Pre-perforated intervals have resulted in difficulty achieving breakdown and have also shown more communication issues to other zones. Additionally, these methods fix the depths at which treatments can be placed before the job begins, resulting in missed pay if unplanned events occur.
This paper introduces a new coil tubing deployed system which uses Hydrajet Assisted Fracturing (HJAF) technology to lower treatment pressures and optimize fracture extension in the zone of interest. This process offers a low-risk, operationally flexible, and efficient multi-stage stimulation method designed to reduce the time between stages and minimize the total fluid pumped into the reservoir. Also included is a detailed case history in the Spearfish that demonstrates how this process can maximize return on investment (ROI) for the operator.
Promoting Environmental Protection while Boosting Shale Gas Development in China
Authors: Yuan Jiehui , Luo Dongkun , Feng Lianyong 
Published: November 2013

Abstract
Shale gas, due to its clean-burning and efficient nature, is becoming an increasingly popular and important alternative energy resource. Boosting shale gas development will gradually play a significant role in effectively improving energy structure, increasing living standards and quality, promoting energy conservation and emission reduction in China. This can provide a crucial guarantee for China to implement economic transformation strategy, developing low-carbon economy and green economy. Simultaneously, numerous concerns have been currently raised about the potentially adverse environmental impacts of shale gas development. Accordingly, reducing the possibly negative environmental impacts as much as possible in order to decrease the resistance of shale gas development is the key issue which urgently needs to be addressed.
This paper conducts the study by means such as literature review, field investigation, conference communication, and presents some solutions and measures in terms of technologies and practices, HSE management, government regulation, and others, to prevent the potential negative environmental impacts of shale gas development in China. Alleviating the potential negative environmental impacts to a certain extent with rational use of these methods and measures proposed can conduce to develop shale gas resources by an environmentally friendly and sustainable way. Then, it would adde more impetus for shale gas development in China to continue to move forward.
Compared with the previous common practices of resources development by "treatment after pollution", this paper focuses on intensifying environmental protection efforts while accelerating shale gas development. To enhance environmental protection when promoting shale gas development will not only help shale gas development to play a greater role in environmental protection, but also can promote China’s shale gas industry healthy and sustainable development. This study can provide good references for related government departments and enterprises which are engaged in shale gas development to develop appropriate decision-making correspondingly. That will be conducive to achieve the harmonious development of shale gas development and environmental protection.
Intensive Production Enhancement of a Low-Permeability Oil Reservoir
Authors: Li Dongmei , Dalamarinis Panagiotis , Economides Michael J. 
Published: November 2013

Abstract
Hydraulic fracturing, which has had a long and well established place in petroleum production engineering, especially in the mature areas of North America, has emerged recently with equally large role to play in China. Tight reservoirs including shale gas have promoted Chinese fracturing activities to ever higher levels. Western design and execution techniques have been adopted and modified.
We present field examples for the Shun 9, a low-permeability oil reservoir (permeability ranges from 0.001 to 0.1 md) in North-Western China for which horizontal wells with multiple fractures appear to be the only choice for some credible production. The physical optimization in this work is done with the Unified Fracture Design (UFD), partitioning the well length and employing a large number of fractures. Design of each fracture is treated separately with an allocated drainage area allowing different aspects ratios in each iteration of design.
The UFD approach is augmented by a net present value (NPV) calculation allowing for the critical economic optimization. In past work NPV has been a decisive element in the optimization process, because it utilizes operational costs and hydrocarbon production to evaluate reservoirs which are candidates for exploitation strategies. The number of fractures per well, their spacing and the size of the fractures are the results of this optimization. Actual treatment variables are presented, including all injection variables, fluid and proppant properties.
Based on post-treatment well performance, the entire project presented here is marginal when considering economics e.g., the best is a 5-year NPV of $5 million for a horizontal well with four-transverse fractures. A comprehensive approach is required for this reservoir, optimizing well architecture and costs. What we present in this paper is the procedure to achieve the best physical optimization, followed by the proof of economic viability through the NPV calculation.
Application of Dual-String Production and Produced Water Re-Injection Technology into Underlying Bed: Gremikhinskoe Field Case Study
Authors: Vershinin S.. 
Published: November 2013

Abstract
Injection of produced water through production wells into underlying horizon is an advanced technique of formation water disposal, without lifting water on the surface. The effectiveness of this method lays in considerable economy of energy and material resources at well production, preparation of commercial oil, prevention of corrosion, depreciation and scale precipitation due to reduction of ineffective pumping of the produced fluid. This technology is also effective because helps to solve the problem of inefficient development of the reservoirs with low reservoir pressure. Forecasted economic potential at implementation of Commingled Production and Injection Technology in five wells will count more than 100 MRb per year, and this is not taking into account the need to drill additional network of wells to maintain reservoir pressure, because both production and injection is carried out within a single wellbore.
The Innovative Approach to Use of Emulsion Drilling Fluid – Reversible Inverted Drilling Fluid
Authors: Popov S. G. , Natsepnskaya A. M. , Okromelidze G. V. , Garshina O. V. , Khvotscin P. A. , Grebneva F. N. , Nekrasova I. L. 
Published: November 2013

Abstract
A new type of emulsion drilling muds is developed, i.e. reversible invertible drilling mud (RIDM). RIDM is capable to change an emulsion type on a reciprocal (eversible) basis affected by a vatiety of chemical inverters; thus it can change its processing behavior from OBM to water–base solution and vice versa. The topic of discussion is methods and approaches used for transition oil-in-water emulsion into inverted (water-in-oil) emulsion and vise versa. Application of RIDM technical process is described. Process characteristics of RIDM are specified. Changes in emulsion microstructure during phase inversion are investigated. Performance analysis of RIDM application in field conditions is given.
Construction of the mutually orthogonal extraordinary supersquares
Authors: Ghiu Cristian , Ghiu Iulia 
Published: November 2013

Abstract
Our purpose is to determine the complete set of mutually orthogonal squares of order d, which are not necessary Latin. In this article, we introduce the concept of supersquare of order d, which is defined with the help of its generating subgroup in $$\mathbb{F}_d \times \mathbb{F}_d$$. We present a method of construction of the mutually orthogonal supersquares. Further, we investigate the orthogonality of extraordinary supersquares, a special family of squares, whose generating subgroups are extraordinary. The extraordinary subgroups in $$\mathbb{F}_d \times \mathbb{F}_d$$ are of great importance in the field of quantum information processing, especially for the study of mutually unbiased bases. We determine the most general complete sets of mutually orthogonal extraordinary supersquares of order 4, which consist in the so-called Type I and Type II. The well-known case of d − 1 mutually orthogonal Latin squares is only a special case, namely Type I.
Estimating the adsorption energy of element 113 on a gold surface
Authors: Rusakov Alexander , Demidov Yuriy , Zaitsevskii Andréi 
Published: November 2013

Abstract
We report first-principle based studies of element 113 (E113) interactions with gold aimed primarily at estimating the adsorption energy in thermochromatographic experiments. The electronic structure of E113-Aun systems was treated within the accurate shape-consistent small core relativistic pseudopotential framework at the level of non-collinear relativistic density functional theory (RDFT) with specially optimised Gaussian basis sets. We used gold clusters with up to 58 atoms to simulate the adsorption site on the stable Au(111) surface. Stabilization of the E113-Aun binding energy and the net Bader charge of E113 and the neighboring Au atoms with respect to n indicated the cluster size used was appropriate. The resulting adsorption energy estimates lie within the 1.0–1.2 eV range, substantially lower than previously reported values.