bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flowback Fracture Closure: A Key Factor for Estimating Effective Pore-Volume
Authors: Ezulike D. O. , Adefidipe O. A. , Fu Y. , Dehghanpour H. , Virues C. J. , Bearinger D. , Hawkes R. V. , Jones R. Steve 
Published: September 2015

Abstract
The importance of evaluating well productivity after hydraulic fracturing can not be overemphasized. This has necessitated the improvement in the quality of rate and pressure measurements during flowback of multistage fractured wells. Similarly, there has been corresponding improvements in the ability of existing transient models to interpret multiphase flowback data. However, the complexity of these models introduces high uncertainty in the estimates of resulting parameters such as fracture pore-volume, half-length and permeability. This paper proposes a two-phase tank model for reducing parameter uncertainty and estimating fracture pore-volume independent of fracture geometry.
This study starts by using rate-normalized pressure plots to observe changes in fluid flow mechanisms from multistage fractured wells. The fracture “pressure supercharge” observations form the basis for developing the proposed two-phase tank model. This model is a linear relationship between rate normalized pressure and time, useful for interpreting flowback data in wells which show pseudo steady-state behavior (unit slope on log-log rate normalized-pressure plots). The linear relationship is implemented on a simple monte-carlo spreadsheet. This is then used to estimate and conduct uncertainty analysis on effective fracture pore-volume, using probabilistic distributions of average fracture compressibility, and gas/water saturations respectively. Also, the proposed model investigates the contributions of various drive mechanisms during flowback including fracture closure, gas expansion and water depletion.
Application of the proposed tank model to flowback data from fifteen shale gas and tight oil wells estimates the effective fracture pore-volume and initial average gas saturation in the active fracture network. The results show that fracture pore-volume is most sensitive to fracture closure compared to gas expansion and water depletion, making fracture closure the primary drive mechanism during early flowback periods. Also, the initial average gas saturation for all wells is less than twenty percent. The parameters estimated from the proposed model could be used as input guides for more complex studies (such as discrete fracture network modeling and transient flowback simulation). This reduces the number of unknown parameters and uncertainty in output results from complex models.
Advances in Understanding Wettability of Tight Oil Formations
Authors: Habibi Ali , Binazadeh Mojtaba , Dehghanpour Hassan , Bryan Donald , Uswak Gordon 
Published: September 2015

Abstract
This paper presents comprehensive rock-fluid experiments, using reservoir rock and fluids, to investigate wetting affinity of the Montney (MT) tight oil play located in the Western Canadian Sedimentary Basin. Wettability characterization is essential for selecting optimum fracturing and treatment fluids by completion engineers and for selecting appropriate relative permeability and capillary pressure curves by reservoir engineers. Application of the conventional techniques for wettability evaluation of tight rocks is challenging primarily due to their extremely low permeability and complex pore structure. The objective of this paper is to develop an alternative laboratory protocol for evaluating the wettability of tight oil rocks reliably.
First, we conducted systematic spontaneous imbibition tests on fresh core samples from two different wells drilled in the MT formation. We measured air/brine, air/oil, and brine/oil contact angle for all samples. We used the end pieces of the samples to conduct SEM and elemental mapping (EDS) analysis. Finally, we investigated the spontaneous imbibition of brine (or oil) into the samples partly saturated with oil (or brine). Both oil and brine spontaneously imbibe into the fresh samples, composed of quartz, carbonates (dolomite/calcite), clay minerals, feldspars, and organic matter. The results indicate that the effective pore network exhibits a mixed-wet behavior. Moreover, brine spontaneously imbibes into and forces the oil out of the oil-saturated samples, while oil cannot imbibe into the brine-saturated samples. This indicates that in the presence of both oil and brine, the rock affinity to brine is higher than that to oil.
The First Master in Geothermal Engineering Offered by a Petroleum Engineering School: Curriculum Challenges and Opportunities
Authors: Falcone Gioia , Pawellek Claudia , Teodoriu Catalin 
Published: September 2015

Abstract
Renewables are seen as the future source of energy to meet the world’s growing demand, with geothermal resources offering a constant and independent supply. Trained staff will be needed to ensure successful implementation of ever more geothermal energy projects to help lower the dependency on energy imports and to develop a broader base in the future energy mix.
The exploitation of geothermal resources faces many of the technical and commercial challenges that are encountered in oil and gas exploration and production, as well as analogous issues of social acceptance and environmental impact. Hence, it is logical to create more synergy between these two energy sectors and enhance the technology transfer, beginning with university education.
A 2-year Master of Science (MS) in Geothermal Engineering, fully taught in English, has been developed at the Institute of Petroleum Engineering of Clausthal University of Technology (CUT), Germany. It is the first dedicated MS of its kind offered by a Petroleum Engineering school. Following its accreditation, classes began in earnest in October 2014.
A number of courses are offered in common with the MS in Petroleum Engineering at CUT to encourage graduates to acquire the broadest skill set they can, and so improve their global marketability and career prospects. Sharing classes also offers a unique, more balanced view of the global energy panorama.
This paper describes the process of assessing the need for this new MS program and the potential market acceptance of a “geothermal engineer” professional profile. It then discusses the implementation of the lessons learnt from Petroleum Engineering curricula to build a geothermal program focused on the full project cycle, from exploration to production, with the associated challenges and opportunities ahead.
It is hoped that other Petroleum Engineering departments in the world will follow CUT’s lead by expanding their curriculum offerings to include Geothermal Engineering.
Modernizing Petroleum Engineering Education: A New Global Online Petroleum Engineering University Serving all Universities
Authors: Aggour T.. , Donohue T.. , Donohue D. A. 
Published: September 2015

Abstract
This paper presents an initiative to establish an online petroleum engineering educational resource that provides electronic learning to universities to enhance the learning experience of students and address many of the challenges and ambitions of petroleum engineering programs worldwide.
In recent years there has been much discussion of the difficulty in recruiting quality petroleum engineering faculty. A confluence of industry and demographic circumstances has resulted in petroleum engineering programs with very high enrollment levels and excessive student-faculty ratios, leading to a diminished learning experience for students.
The way today's students process information is fundamentally different from previous generations, yet in most cases academia continues to teach them as they always have. Progressive universities are striving to adapt their models to the changing learning styles of their student bodies, while trying to leverage technology as best as possible.
To address these issues, an online resource is being established that will allow students from different universities to access electronic learning that will complement the instructor-led training that currently exists. Electronic learning is well suited to academic learning, where the focus is on fundamental theory and concepts in addition to the basic application of these concepts.
This paper provides details on how this resource has been developed and how it will be implemented. A significant portion of undergraduate petroleum engineering education can be covered by innovative electronic learning, allowing faculty to focus on problem-solving while spending fewer hours in the classroom. By soliciting corporate support from industry to support the centralized resource, individual universities will have cost-effective access to a resource that will enhance the educational process by catering to the learning styles of this generation, alleviate some of the challenges faced due to faculty shortages, and progress petroleum engineering university learning farther into the modern digital era.
Description of the Results of Experiments on Developed Miscibility With Nonequilibrium Gas/Oil Gravity Drainage
Authors: Zobeidi K.. , Fassihi M. R. , Rasaei M. R. 
Published: September 2015

Summary
This paper describes the results of several experiments that were carried out to investigate the block-to-block interaction in fractured limestone reservoirs for both gas/oil and solvent/oil systems by use of carbonate cores. The focus of this research was to understand gravity drainage, reinfiltration, and mixing in fractured systems with a set of laboratory experiments. The designed setup included three kinds of models (i.e., a transparent rectangular box filled with a glass-bead pack and two cylindrical models with single and stacked carbonate blocks inside to cover all important cases in this area); then, several factors are defined to correlate the results of glass-bead-pack model with the two other kinds of models. Also, the survey of the experiments and the properties of the fluids used takes a relatively wide range of the applicable laboratory experiments to provide a better understanding of the mentioned mechanisms. In general, this paper can be very revealing to other researchers in the field because it provides some experimental data for future theoretical and simulation studies.
Analytical and Experimental Investigations of Gas-Flow Regimes in Shales Considering the Influence of Mean Effective Stress
Authors: Moghadam Alireza A. , Chalaturnyk Rick 
Published: September 2015

Summary
Flow conditions determine the flow regimes governing gas flow in porous media. Slip-flow regime commonly occurs in laboratory gas-permeability measurements, and one must consider the physics of that when finding the absolute permeability of a sample. Accurate permeability estimates are paramount for production forecasts, financial planning, and recovery estimation. Slip flow is present in low-permeability rocks, both in the laboratory environment and at reservoir conditions. Gas flow through the matrix lies under the slip-flow regime for the majority of low-permeability-reservoir production scenarios, and accurate prediction of pressure and production rate requires a good understanding of the flow regime. In this paper, an analytical study is conducted on the dominant flow regimes under typical shale-gas reservoir conditions. A flow-regime map is produced with respect to gas pressure and matrix permeability. Steady-state gas-permeability experiments are conducted on three shale samples. An analytical model is used to match the experimental results that could explain the order-of-magnitude difference between the permeabilities of gas and liquid in shales. Experimental results are combined with further tests available in the literature to inform a discussion of the model's parameters. The results improve the accuracy of gas-flow modeling and of absolute-permeability estimates from laboratory tests. Similar tests performed at various mean effective stresses investigate the influence of mean effective stress on flow regime and apparent permeability. The results indicate that flow regime is a function of mean effective stress, and that the apparent permeability of shale rocks is a function of both flow regime and mean effective stress.
Simulation and Testing of the Hydraulic Performance of the Sliding Vane Pump
Authors: Zhao Yanlong , Wang Zhiming , Xue Liang , Zhang Lixin , Hao Zhongxian 
Published: September 2015

Summary
A new all-metal sliding-vane pump (SVP) and matching lift system were developed as an alternative to the low efficiency and poor high-temperature performance of conventional artificial-lift systems. Numerical simulation and laboratory tests were used to conduct a comparative study of the hydraulic performance of the pump. The effects of pump-lifting-pressure difference and rotational speed on pump rate and efficiency were studied. The test results showed that, if the rotation speed is fixed, the pump rate and efficiency will decrease with an increase in required pressure difference. With a constant pressure difference, the flow rate can be controlled by varying the pump speed.
On the basis of computational fluid dynamics (CFD) and finite-element-method (FEM) numerical simulation, a numerical model of the SVP was created. The pressure and fluid-flow distribution in the vane pump were determined under zero pump-pressure-difference condition, which helped realize the working principles of the pump. The simulation results agreed well with the test results, thus validating the reliability of the numerical models in this paper.
The MSE Ratio: The New Diagnostic Tool to Optimize Drilling Performance in Real-Time for Under-Reaming Operations
Authors: Abbott Andrew 
Published: September 2015

Abstract
The Mechanical Specific Energy Ratio (MSER) is a correlation that optimizes drilling performance when used as a real-time trending tool. This paper specifically addresses its use in under-reaming operations of deep water wells. Mechanical Specific Energy is an equation combining multiple drilling parameters to determine overall efficiency, but it does not explicitly identify the location of various inefficiencies. The MSE Ratio solves this problem. Through a simple ratio of the MSE surface values to the MSE downhole values, the locus of inefficiency is more easily identified.
In deepwater operations, the bit or the under-reamer often causes inefficiency, and the MSE Ratio helps to diagnose the trouble area. An increase in the values returned by the MSE Ratio indicates under-reamer inefficiency, while a decrease in the returned values indicates drillbit inefficiency. By pinpointing the zone of the problem, system inefficiencies can be better predicted, avoided, and mitigated. The information contained in this paper outlines the original study that was completed to analyze the MSE Ratio and the conclusions of that study. All data was taken from a deepwater well drilled by Statoil in the Gulf of Mexico (GOM) during the summer months of 2014.
The MSE Ratio can be used to accurately locate areas of inefficiency on the drillstring so performance may be optimized, it was both developed and proven in field trial, and it can be used in both real-time and for post-analysis. Further field studies should be conducted to refine the use of the Mechanical Specific Energy Ratio in drilling operations and to determine other trend-line signatures of the data.
Extension of the Gray Correlation To Inclination Angles
Authors: Oyewole Adeoluwa 
Published: September 2015

Abstract
Proper design of gas wells requires accurate estimation of pressure profile. This task is usually carried out by integrating mechanistic models and correlations along the well trajectory. Gray (1975) correlation is widely used for gas wells where the liquid fraction is usually low. This correlation has been generated by extending the single phase gas equation to the two-phase flow case. The effect of the liquid in the frictional pressure gradient has been considered by a pseudo roughness. Also, a correlation for the holdup was proposed by Gray (1975). Unfortunately, these two correlation did not consider the effect of the deviation angle which became critical with the recent increment of horizontal well drilling. This paper aims to include the deviation angle effect on Gray (1975) correlation. Gas-liquid experimental data from horizontal to vertical has been considered for the calibration. The considered experimental data (Guner, 2012; Alsaadi, 2013) includes pressure drop and liquid holdup for a 3-in ID pipe. The calibration has been carried out through the inclusions of new dimensionless numbers. Comparison between the original and modified Gray correlation are also presented.
New Artificial Lift Design For Sidetracks Operations
Authors: Zaytsev Anton , Kirichenko Anastasia 
Published: September 2015

Abstract
A prolonged period of low oil prices (2014 – present) is known to affect the economies of oil-exporting country as well as the technologies applied in industry. Meanwhile it's becoming more important to use up-to-date highly cost-effective technologies for conventional field development to keep oil production rate fixed. Well stock analysis based on open-source data demonstrates in this paper and represents considerable quantity of idle, or uneconomical, wells in Russian Federation. Thus, they make up about 14% of the total number of production wells. Marginal wells, or wells with low flow rates, are considered to be the most subjected to be ‘uneconomical’.
Sidetracking as a stimulation of marginal well production seems like the most effective method to boost the production rate of mature oil field. But most of artificial-lift technologies aren't cost effective in sidetrack applications for some reasons. Review of up-to-date artificial-lift technologies used for sidetrack application is also presented in this paper.
The author designed new kind of equipment permitting operating inside sidetracks-rodless reciprocating electric submersible hydraulic pump unit. It consists of electric submersible motor, protector, and specially designed both transmission to transform mechanical energy into hydraulic and double-acting hydraulic pump. The key unit elements are reviewed in this paper. So, double-acting hydraulic pump is composed of two hydraulic cylinders (actuator) and two piston pump, connected with each other by valve box where suction and discharge valves are placed. Transmission representing by hydraulic fluid tank, power pump and sleeve valve is to drive hydraulic pump and also provide reciprocating pistons moving. Specially designed equipment meets all the sidetrack operation requirements.
Forecasting Production Performance in Reservoir-Network Coupled Systems with Asphaltene Modeling
Authors: Valbuena Ernesto 
Published: September 2015

Abstract
This manuscript presents the development and implementation of a new integrated reservoir-network compositional simulator for analysis of asphaltene precipitation within tubing and production pipelines. The need for integrated models for flow assurance analysis in assets with high potential of asphaltene precipitation is demonstrated for the following scenarios: i) natural depletion, ii) downhole asphaltene inhibitor injection, and iii) artificial gas-lift system.
Fully-implicit compositional formulation forms the basis for reservoir and network simulators. Implementation of a tightly-coupled solution allows assessing mutual interaction between subsurface and surface components. Compositional delumping from reservoir to network fluid characterizations enables accurate modeling of complex thermodynamic phase behavior for asphaltene precipitation. The Peng-Robinson equation of state with volume translation models phase equilibria in coupled solution and asphaltene precipitation in network pipelines. Asphaltene accretion to internal pipe walls is estimated with a mechanistic transport model to forecast reduction of flow area and its impact on production performance.
Solid precipitation and deposition in the production system have a negative impact on production rates, pressure management, and field operations. Results show increased thickness of asphaltene deposits in time, reaching up to 50% diameter reduction after a few months of production for the cases evaluated. Pipeline diameter increase at wellhead promoted asphaltene formation, caused by fluid velocity reduction. Bottomhole injection of asphaltene inhibitor reduced formation of solid deposits by 90%. Artificial gas-lift systems influence deposition profiles due to fluid compositional changes and velocity in the wellbore column.
Field Development Planning - A Key Towards Success in Rich Gas Condensate Reservoirs
Authors: Shoaib Muhammad 
Published: September 2015

Abstract
Phase behavior of a highly rich gas condensate reservoir, especially near critical one, is very difficult to predict. Presence of compositional gradient in these reservoirs further adds to the complexity. In these circumstances, it is very important that precise and detailed field development planning should be done in early phase of reservoir life (preferably before starting commercial production).
A compositional simulation model of rich gas-condensate reservoir is built and a representative fluid model based on Equation of State (EOS) is used for predicting phase behavior of a hydrocarbon reservoir which is a dynamic event. For pressure maintenance feasibility, comparison was performed between no gas injection, partial pressure maintenance and full pressure maintenance. Different sensitivities were performed to come up with an optimum case on the basis of NPV and IRR value from detailed economic analysis. To check for the presence of compositional gradient, compositional data was analyzed for different wells at different depths (at least two required). After establishing compositional gradient, different sensitivities were performed regarding location of wells to maximize recovery and improve economics.
Without pressure maintenance, high gas-oil ratio is produced from reservoir due to loss of valuable condensate in near wellbore region along with reduced gas recoveries. If compositional gradient is not recognized in rich gas-condensate reservoir and wells are drilled at shallow depths avoiding rich gas or oil rim at larger depths then it will ultimately lead to reduced oil recoveries.
On the basis of simulation results and economics, it is recommended to perform pressure maintenance to avoid dropout of heavier ends in reservoir especially in case of rich gas condensate reservoir. Along with that, it is better to produce from deeper wells in presence of compositional gradient and use shallow wells for dry gas injection (pressure maintenance).
Inhibitory effect of schizophyllan on rat glioma cells
Authors: Zhou Bin , Fu Qiang , Song Sha-Sha , Zheng Hong-Li , Wei Yu-Zhen 
Published: September 2015

<p class="Abstract">The aim of this study was to examine the anticancer effects of schizophyllan (a -D-glucan) against the growth of rat CNS-1 glioma cells and preliminarily assess its effect on inducing apoptosis and blocking cell cycle. In order to evaluate its inhibitory effect, firstly MTT assay was conducted followed by annexin V/propidium iodide double staining or propidium iodide single staining, apoptosis and cell cycle using flow cytometry. All the experiments were carried in a dose- and time-dependent manner. Experimental results showed that treatment of 40 and 60 mg/L schizophyllan significantly increa-sed the apoptotic rate and blocked the cell cycle. In addition, increase in the proportion of cells in G0/G1 phase and decrease in the proportion of S-phase cells were also observed. Overall experimental studies suggest that schizo-phyllan can significantly inhibit the growth of rat CNS-1 glioma cells, in vitro and induced apoptosis and blocked the cell cycle.</p><p> </p>