bluuebunny/crossref_metadata_2025 huggingface dataset:
Influencia de los Parámetros Tribológicos en el Coeficiente de Fricción entre Polipropileno y Piel
Authors: Pavón Palacio J.J. , Villarraga Ossa J.A. , Tobon Espinosa D.F.
Published: September 2015

Se adquirieron los datos sobre la topología superficial de Sockets para Amputados Transfermorales utilizando un microscopio de fuerzas atómicas AFM, se caracterizaron las propiedades tribológicas de 12 zonas significativas, a partir de estos datos se crearon superficies virtuales con geometría sinusoidal de 250 μm de área, las cuales fueron empleadas para llevar a cabo una simulación numérica para encontrar cual era la relación entre dichos parámetros y el coeficiente de fricción entre el polipropileno del Socket y la piel. La piel se modeló como un material híper-elástico y el polipropileno como un material elástico lineal, se impuso un desplazamiento inicial de contacto y un desplazamiento tangencial de las probetas para calcular el coeficiente de fricción, adicionalmente, se aplicó una presión a la parte superior de las probetas de polipropileno que simulan las presiones generadas por el calzado de la prótesis y las fuerzas generadas durante la fase de apoyo de la marcha humana. Se encontró que existe una correlación entre los parámetros tribológicos y el coeficiente de fricción, sobre la cual se presentan dos zonas principales, una donde el coeficiente de fricción disminuye a medida que aumentan dichos parámetros, y una segunda zona donde el coeficiente de fricción permanece constante.
The Phenomenon of the Crowd in Russian Psychology: V.K. Sluchevsky's Concept
Authors: Gorbatov D.S.
Published: September 2015

The article describes the concept of the crowd proposed by a Russian lawyer and public figure V.K. Sluchevsky (1893). It focuses on its principal differences from other concepts of this initial period and reveals the moral potential of Sluchevsky's views in psychology. Among the issues that were of particular interest to the author of one of the first concepts of spontaneous groups were the specifics of the crowd as a social association, features of the crowd, factors of its formation, changes in personality of individuals, and problems concerning the prevention and punishment of mass crimes.
Divorce in Russian Sociological and Social Psychological Research on Family Relationships
Authors: Kletsina I.S.
Published: September 2015

The article presents social psychоlogical analysis of publications that focus on divorce situations in official marriages and explore its causes and consequences both for spouses and children. It is argued that the key factor in separation is a socio-psychological phenomenon called 'unconstructive marital relationships'. The partnership model described in the article, on the contrary, may serve as a normative basis contributing to the stabilization of marital relationships. While most publications conceptualize divorce as a collapse and split of family relationship, the article suggests interpreting divorces rather as a transformation stage in spousal and parentchild relationships.
Factors Contributing to the Choice of Ethnic Categorization in Situations of Informational Influence
Authors: Khukhlaev O.E. , Tarasov K.O.
Published: September 2015

The paper focuses on the specifics of mutual impacts of informational influence and personality features of an individual in situations of ethnic categorization. As it was revealed, the subjects that were presented with materials raising the accessibility of ethnic category used ethnicity more often in the process of ethnic categorization. Of all the social psychological parameters employed in the study, only nationalistic attitudes seem to have visible impact on social categorization based on ethnicity. Also, the study found no mutual impacts of information and attitudes towards ethnic categorization. The outcomes suggest that ethnic categorization may well be not just the function of intragroup processes, but also the result of circumstances of the context.
Types of Professional Interactions in Modern Russian Nannies: A Social Psychological Analysis
Authors: Drobysheva T.V. , Romanovskaya M.A.
Published: September 2015

The article describes the concept of the crowd proposed by a Russian lawyer and public The article presents results of a social psychological study of professional interactions in modern Russian nannies. It provides the first ever descriptions of significant interactions between nannies, employers and children. Four types of professional interactions are identified empirically depending on work motivation of nannies. Nannies with an attitude of "the child's older friend" are focused on establishing a close psychological relationship with the child. Their professional interaction with the child can be defined as overprotective. "Nannies-intermediaries" are more aware of their employee status and avoid breaking the psychological distance both with the child and the parents. The choice of interaction strategies in nannies with a "neighbor babysitter" attitude is determined mostly by their desire to gain work experience in their free time. They generally prefer not to establish close relationships with the child. The most professional of all are nannies with an attitude of "servants". They know how to resolve conflicts between children, how to arrange game activities for children, and conform to the requirements set by the parents. However, nannies of this type are more likely to physically suppress the will of the child.
Book review: Diane Ravitch "The death and life of the great American school system". New York: Basic Books , 2010
Authors: Beals K.
Published: September 2015

The current paper is a translation of Katharine Beals' review of the book "The death and life of the great American school system" by Diane Ravich. The article analyses the views on the causes of the inefficiency of the American school system expressed by Ravich, as well as the ways of its improvement suggested by her. A change of stance compared to her previous works is also noted. Translator:  Vinogradova K.N. Original in: Nonpartisan Education Review / Reviews 7(1). Available online: http://www.ncsociology.org/sociationtoday/v111/review1.html
On the Portrait of the Russian Professional Psychological Community: Sparkles of Reality on the Official Tailcoat
Authors: Kondratyev M.Y.
Published: September 2015

The main distinguishing characteristic of SRI GEP is the atmosphere of comeradery, mutual support, youth's admiration for the older generation and respectful, almost touching care for this youth on the part of the "elders". Now for me it is absolutely obvious that maintaining such an atmosphere would have been impossible if the institute had not possess such an astonishingly and professionally top-level group of "elders".
Maximizing Information through Data Driven Analytics in Petrophysical Evaluation of Well Logs
Authors: Jain Vikas , Gzara Kais , Makarychev Gennady , Minh Chanh Cao , Heliot Denis
Published: September 2015

Modern logging data are characterized by abundance and multiple dimensions: spatial, temporal, and physical. Traditional interpretation workflows for logging data are often limited in their scope and flexibility and use only a subset of the data dimensions, either by choice or necessity. Furthermore, the various deterministic or stochastic workflows typically rely on preconceived rock and fluid models. When those a priori models do not fit the data, confusion can ensue, whereas it is obvious that the correct model is buried somewhere in the “big logging data.”

To overcome these limitations, new symbiotic approaches using domain expertise and data analytics (“domain-analytics”) have been developed. Domain experts use those novel approaches to develop data-driven workflows to explore and mine complex logging datasets for latent but interpretable information. Once validated to be idempotent, the expert workflows that respect both the acquired data and domain knowledge can be packaged into new classes of answers products.

In this paper, the novel approaches, along with the examples of new answer products, are presented. These include 1) the automated spatial search for common modes and repeated patterns in the single or multi-well nuclear magnetic resonance (NMR) data, 2) the generation of a data-driven fluid model using time-lapse logging data acquired during multiple passes over the same formation, and 3) the creation of interpretive class-based models using definitive core data that could be propagated to continuous log data for a richer petrophysical interpretation.
Drilling Depleted Sands: Geomechanics, Challenges and Mitigations
Authors: Majidi Reza , Edwards Stephen , Zhang Jianguo , Sant Randall , Last Nigel
Published: September 2015

When hydrocarbons are produced from a subsurface reservoir, pore pressure in the reservoir is reduced. This reduction (termed depletion) causes a redistribution of stress in the reservoir and surrounding rocks, leading to a variety of potential issues such as compaction and subsidence, fault reactivation and other forms of strain localization. It generally also leads to a reduction in the minimum horizontal stress (Sh) and therefore to a potential reduction in the fracture gradient (FG) in the depleted interval. The reduction in FG can be one of the most notable challenges when attempting to drill and complete new wells and is the focus of this paper.

The level of depletion at which the reduced FG becomes an operational issue is a function of the geomechanical properties of the reservoir and surrounding rocks. It is also a function the effectiveness of so called “wellbore strengthening” techniques which aim to locally increase the FG by the addition of an appropriately sized concentration of lost circulation material (LCM). Within BP, reservoirs with depleted sand drilling challenges range from just a few hundred psi of depletion (for example in deep water Angola fields with shallow reservoirs) to several thousand psi (in deeper reservoirs as in the Gulf of Mexico) and in some cases to 10,000 psi or more of depletion in certain High Pressure/High Temperature settings.

Quantifying the FG of the depleted interval and the effectiveness of wellbore strengthening techniques is key to field development planning and safe drilling operations. For a safe and successful development, several issues need to be considered. These include the variation of original (prior to depletion) FG across a field (where experience has shown that traditional 1-D models are inadequate for the complex structures drilled today), the change of FG with depletion (is the “Stress Path” linear and uniform across the field, or is structure and potential stress arching important?), and by how much we can increase the near-wellbore FG using wellbore strengthening techniques such as StressCage.

In this paper, we present an integrated workflow undertaken to mitigate the risks of drilling depleted sands. Field examples are used to demonstrate the utilization of multiple sources of information including drilling data, rock mechanics, and stress analysis, along with the size distribution and concentration of particulate materials in the mud to achieve an optimum solution.
Successful Application of a New Fracturing Fluid with Supramolecular Complex Structure
Authors: Yang Jiang , Cui Weixiang , Duan Yaoyao , Yang Zhanwei , Qiu Xiaohui , Guan Baoshan , Lu Yongjun , Zhai Wen , Liu Ping , Ding Yunhong , Bai Jianwen
Published: September 2015

A new fracturing fluid based on supramolecular complex of associative polymer and wormlike micelle was developed and applied in a gas well in China. The crosslink complex gel was based on weak physical attractive force such as van der waals, hydrogen bonding and electrostatic interaction between associative polymer and wormlike micelle. The fluid contained much less surfactant than that of conventional viscoelastic surfactant. The associative polymer is used at less than 0.25% by weight. The gel is reversible, and has 50% lower formation damage than that of conventional guar. The mixture of the two fluids synergistically enhances the viscosity ten times more than individually combined. The viscosity of fluid can maintain at the test temperature and suspend proppant up under static condition. The dynamic proppant transport test in flow tube also showed good proppant suspension ability. The fluid was simple to prepare with less additives, and formed gel instantly upon mixing in the field. The gel can be completely broken with no residue by an internal breaker. Field application of the new fracturing fluid in a gas well of Sulige basin in China showed the enhancement of gas production over 100%. The fracture height is also well controlled. The fluid also has 20% lower friction pressure than that of guar fluid. Hence, the supramolecular complex gel provides a new fracturing fluid system with less formation damage for fracturing operation.
Assessing Diverse Variables and Technologies and Their Impact on Sustained Gas Production in Carbonate Reservoirs – Field Examples
Authors: Rahim Zillur , Al-Anazi Hamoud , Al-Kanaan Adnan , Kayumov Rifat , Al-Jalal Ziad
Published: September 2015

Using well performance as the primary determining factor, a systematic study and evaluation was conducted on numerous vertical and horizontal wells drilled in the high-pressure/high temperature heterogeneous carbonate reservoirs to assess effectiveness of stimulation treatments and benefits of using novel technologies. Numerous variables analyzed to determine impact on production include well type, wellbore length, drilling azimuth, number of stimulation stages per well, chemistry and volumes of treatment fluids, pumping rates and pressures, fracture dimensions (half-length and width), and applied drawdown. A comprehensive database for stimulated wells was created that included reservoir parameters, completion data, minifrac and main stimulation treatment parameters (fluid types, volumes, rates and pressures), computed fracture geometry, and normalized well performance data. The variables were grouped and arranged according to their similarities and impact on well productivity. Correlations were drawn using the Pearson correlation coefficient to compute upward and downward data trend, ensure use of good quality data, and discard few nonaligned data. Numerous, very useful plots are constructed and presented that show the different trends of the variables evaluated and how they affect the productivity index (PI) of a well.

Results have been drawn based on completion parameters, design and execution variables, treatment evaluation results, and well production. The results demonstrate the importance of real-time application of geomechanics to achieve borehole stability and drilling laterals toward the minimum in-situ stress σmin) direction to achieve sustained post-treatment gas rates. Trends also highlight improved well performance with the increase in stimulation stage count and maintaining isolation between producing intervals. The influence of different fluid types and their volume on post-fracturing productivity was analyzed. Normalized PI was used to assess optimum pump rates and pressures. Some important conclusions were made regarding targeted etched fracture half-length and width. The analyses identified the key post-fracturing production drivers in the gas reservoirs and their impact on long-term well performance.
Walking the Walk – Industry Support of Natural Resource High School Education
Authors: Tobin John , Todd Jennifer
Published: September 2015

Until recently the Energy Industry has only passively supported high school education in the natural resource field. At the same time this industry continually expresses concerns over its future work force and the public's appreciation of the role energy plays in our daily lives.

This paper discusses two examples where the industry is truly “walking-the-walk” with programs aimed at stimulating interest and preparing high school students for college and eventual careers in the industry. The Energy Institute Magnet High School in Houston is an example of an existing effort that came into existence in the fall of 2013 with the enthusiastic support of the industry. The other example that will be discussed is an embryonic effort in Colorado that is trying to capture similar support.

These education models and their support by the industry can be applied nationally. This will require not only similar enthusiastic support, but also a real effort to get the hundreds of existing educational programs to work together. Only through such collaboration can this overall goal be achieved.
Innovative Process for Formation Damage Removal in Sandstone Reservoir Based on Real-Time Downhole Monitoring: A Malaysia Case History
Authors: Riyanto Latief , Musa Mohd Nizar , Deris Nurul Asyikin , Yaakub Mohd Yuzmanizei , Ghazali Rohaizat , Hamidon Zahaezuani Rafiq , Wijoseno Danny Aryo , Jenie John Rizal , Parapat Arthur , Kasim Mohamed Heikal
Published: September 2015

Many retrograde condensate gas wells in field A, located offshore Malaysia, are underperforming or even idle because of calcium carbonate scale deposition and near-wellbore condensate banking. Previous treatments were performed without any adjustment of fluid placement across the multiple fractured zones due to the lack of technology enabling real-time downhole monitoring. Fluids could, therefore, be lost into depleted or high-water-cut intervals, leading to suboptimal treatment.

Distributed temperature sensing (DTS) technology through optical fiber installed inside coiled tubing strings mitigates the risks related to blind acid pumping. The technology makes it possible in real time to monitor and adjust fluid placement and diversion efficiency to squeeze acid into target zones and maximize the treatment success.

The first worldwide implementation of sandstone matrix acidizing using the DTS technology was performed on a well completed with four perforated and propped fractured zones. The main treatment fluid was designed to remove both types of formation damage: organic acid would attack the scale and alcohol would eliminate the condensate banking. The first challenge was the cleanout of hard carbonate scale from the wellbore, which was performed with a bottomhole assembly composed of a high-pressure rotating jetting tool and a real-time fiber-optic tension-compression sub enabling the coiled tubing unit operator to maximize the slack-off on scale and facilitate its removal. The second challenge was the depleted upper perforated and propped fracture interval detected by the DTS. If diversion was inefficient, all fluids would get lost into the upper zone. A diverter fluid system formulated with degradable fiber blended into viscoelastic-surfactant-based fluid was optimized based on expected downhole conditions, and two stages were successively squeezed into the highly permeable (130-Darcy) depleted upper interval before getting a good signature on the DTS surveys showing that this zone was temporarily plugged and that the main treatment fluid would be squeezed into the lower target zones.

The post-treatment gas production was double what was expected. A memory production logging tool was run after the job. This confirmed the crossflow to the upper depleted zone during shut-in and showed 86% gas production from the two bottom intervals, which demonstrates the effectiveness of both the innovative stimulation process with DTS and the diversion with degradable fiber.
Fracture Gradient Prediction Using the Viscous Relaxation Model and Its Relation to Out-of-Zone Microseismicity
Authors: Yang Yi , Sone Hiroki , Zoback Mark. D.
Published: September 2015

During hydraulic fracture stimulation of the Middle Bakken Formation, many out-of-zone microseismic events are observed in the Mission Canyon Formation located ~ 800 ft above the Middle Bakken. These microseismic events follow an abnormal sequence, where the events are first located ~800 ft above the perforation location, followed by subsequent events moving downwards towards to the perforation location along an interpreted fault. We predict frac gradient variation in the vertical depth direction to investigate its relation to the unusual microseismicity. Using laboratory observed time-dependent behavior of rocks from the study field, we apply the viscous relaxation model to predict horizontal differential stress accumulation from geophysical logs. We further calculate two horizontal stress magnitude profiles from knowledge of the tectonic faulting constraint within the reservoir. The predicted least principal stress magnitude indicates that the Upper and Lower Bakken Formations are acting as weak frac barriers during hydraulic fracture stimulation in the Middle Bakken, while the Lodgepole and the Three Forks Formations above and below the Bakken Formation are not frac barriers. To compare the predicted stress values with the depth at which the out-of-zone seismicity occurs, we calculate the pore pressure perturbation (ΔP) required to cause slip along well-oriented fractures and faults as a function of depth. We find that the calculated ΔP values match the microseismicity sequence: that is, the events occur first at depths that require the smallest values of pore pressure perturbation, and events of later stages are located at depths that require a much higher pressure perturbation. The stress profile calculated using a modified Eaton model does not capture the characters of the microseismicity. The calculated stress and ΔP profiles indicate that the out-of-zone microseismic events are related to a combined contribution from preexisting fault and the lack of frac barrier above the Bakken Formation, while the abnormal sequence of these events are caused by variations of the stress state within the formations.
Analytical Model to Estimate the Directional Tendency of Point and Push-the-Bit BHAs
Authors: Zhang Yuan , Samuel Robello
Published: September 2015

Over the past few decades, drilling engineers have developed two types of rotary-steerable systems (RSS) as directional drilling tools: push-the-bit and point-the-bit bottomhole assemblies (BHAs). Some eccentric components are used in these RSS BHAs to control the drilling direction. For these RSS, side forces on bits are important factors that change drilling direction. However, because of the complex structure of BHA and wellbore environments, there is not a good analytical industry model currently available, so experience-based methods are commonly used to estimate BHA tendencies.

In this paper, an analytical method is proposed to calculate side force on the bit and the dog leg severity (DLS) of a wellbore to help predict the drilling direction. In this method, a drillstring is taken as a continuous beam, which is supported by components installed on the string. Side forces and bend angles induced by the eccentric component are solved with the continuous beam theory. After force analysis is completed, drilling engineers can use new equations proposed in this paper to calculate the DLS of the wellbore.
Automated Workflow for Real-Time Management in a Large Carbonate Field
Authors: ALNakhli Maithem M. , AlMousa Talal S. , Al-Nuaim Ahmad , Dallag Mohammed
Published: September 2015

Managing an oil and gas reservoir requires the integration and analysis of several data elements, including reservoir, well, and production data from multiple sources. Quick and efficient access to this data will allow engineers to concentrate their efforts on the important tasks of analysis and decision making, to improve reservoir and field performance.

This paper presents an overview of the implementation of an automated workflow designed to support the management of a Saudi Arabian reservoir, by integrating real-time production data with other data elements. The workflow and techniques used require specialized engineering processes to fully understand the reservoir behavior and associated parameters to identify wells with anomalous behavior1.

Among the solutions provided in this workflow is a system for real-time data retrieval, visualization, and analysis of reservoir production performance. This is achieved by linking dynamic surveillance processes with real-time data, and allowing data to be provided in real-time at the engineer's desktop. To provide a coherent explanation of the production behavior, multiple analysis processes and tools were used. These included a workover candidate selection system, decline curve analysis, and heterogeneity index analysis.

The workflow also included mapping and quality control tools to flag out data outliers. In addition, alarm systems were included to alert the engineer when sudden changes in reservoir performance occur in the field. The implementation of this workflow has resulted in considerable time savings, with pertinent data being automatically updated and used in the analysis, as opposed to manual processing, leading to improved efficiency in field management practices. The workflow has been deployed as an application of the Intelligent Field concept in a carbonate field in Saudi Aramco.
Sustainable Flow Back and Produced Water Treatment Using A Next Generation ElectroOxidation Reactor
Authors: Fraim Mike , Jakhete Sanjeev
Published: September 2015

Advances in electronics and materials technology have enabled fundamental changes in electro-oxidization reactor designs, significantly improving their performance, safety, and enabling dramatic treating cost reductions. Theoretical basis and field results are presented demonstrating in-situ generation of multiple oxidants using simply electricity and produced water without addition of hazardous reagents or oilfield chemicals. These oxidants are shown to be extremely effective biocides for bacteria disinfection, electrochemical precipitation is shown to reduce the scaling tendencies of the treated water for fracture treatment and water recycle or water injection. Creation of the ferrate ion on the anode side of the electrode surface inactivates the current borate ion concentration in the treated water so that it will not flash cross-link the added polymer for the hydraulic fracture treatment.
Estimation of Fracture Volume Between Well Pairs Using Deuterium Tracer
Authors: Leong Y. , de Iongh J. E. , Bähring S. , Tuxen A. K. , Nielsen T. B.
Published: September 2015

Short-circuit connections between injectors and producers resulting from induced or natural fractures in tight chalk reservoirs can divert the injection water resulting in poor sweep efficiency and early water breakthrough in producers. The overall impact is a significant reduction in oil recovery. Curing of these connections can be achieved through the application of a chemical conformance treatment aimed at plugging off the fracture and shutting the connected zone. Knowing the volume of the fracture is essential for such a conformance treatment, since it determines the amount of conformance chemical that should be injected. If too little material is pumped, the fracture will not be effectively closed, and if too much material is pumped, there is a risk of contaminating the connected well. However, the fracture volume estimation can be challenging due to the uncertainty of the fracture geometry.

Deuterium tracers offer a simple, quick and environmentally friendly method to estimate the volume of the fracture. The method was successfully employed on an injector/producer pair with a known fracture connection in the Danish North Sea. A deuterium tracer was selectively injected at a constant rate via coil tubing (CT) into the connected zone in the injector, and the producer was sampled from the wellhead. With the exception of the fracture volume, all other volumes (and therefore transit times) within the deuterium tracer injection path are known. Based on the deuterium's arrival time, the fracture transit time and therefore volume can be calculated.

The use of heavy water (D2O) as a chemical tracer allows DTI to conduct the tracer operation with real-time offshore analysis of the tracer breakthrough. The results obtained were subsequently applied to adjust the injection time and volume of the cement during the operation to cement the fracture.
Successful Case History of Drilling Through Major Loss Zone Using MPD/PMCD Techniques on a Santos Basin Well
Authors: Tomita R. A. , Schnitzler E. , Destri J. F. , Da Silva P. H. , Brasiliense N. R. , Fernandes A. A. , Gozzi D. S. , Da Silva T. Pinheiro , Kozlov A.
Published: September 2015

The development of the production phase of pre-Salt fields in Santos Basin have been facing many challenges, one of them is the occurrence of massive fluid losses during drilling, completion and evaluation operations. One possible solution to drill in this scenario is the usage of the Managed Pressure Drilling (MPD) techniques to minimize fluid loss and, in cases of massive losses, the use of the Mud Cap Drilling technique.

This paper presents a case study of the drilling operations on a Santos Basin well that had major losses while using conventional drilling technique hence unable to reach all objectives. The well was successfully reentered using MPD/PMCD to successfully reach target reservoir and the details of the solution to reentry using MPD/PMCD and its successful results is presented

It is described the use of MPD variants including the first use of PMCD on a DP rig on an offshore well in Santos Basin. MPD/PMCD proved an enabling technology when reentering a reservoir with major losses and absent drilling window. Design, execution and results of successful operations are covered.
Sand Control Screen Erosion: Prediction and Avoidance
Authors: Procyk Alex , Gou Xinjun , Marti Srinagesh K. , Burton Robert C , Knefel Markus , Dreschers Daniel , Wiegmann Andreas , Cheng Liping , Glatt Erik
Published: September 2015

Erosion of sand control screens in oil and gas wells can lead to catastrophic completion failures, substantial production losses and damage to downstream facilities. Screen erosion can be caused by a number of completion design and environmental factors. However, the dominant failure mechanism is production of small solids through the screen openings, leading to development of localized high-velocity hot spots in the screen filter media and subsequent failure of the media.

The current work discusses a detailed screen erosion study conducted to evaluate screen flow parameters leading to erosion and to provide safe operating guidelines for wells completed using cased hole perforated frac-pack (CHFP) and cased hole perforated gravel-packed (CHGP) completions with premium wire-mesh sand control screens.

The erosion study consisted of both experimental work to determine erosion damage in screen samples and computational fluid dynamic (CFD) simulations to help visualize particle flow paths through the metal-mesh sand control media and determine local flow velocities and erosion-induced wear patterns.

The experimental erosion tests and CFD modeling were performed on a specific screen configuration used in a number of subsea gas wells subject to high velocity flow conditions and associated high screen erosion potential. An empirical erosion model was then developed to translate short-term, high-velocity laboratory test results into field erosion predictions and well flow guidelines to minimize erosion potential.

This paper presents results of the experimental work and associated CFD modeling as well as completion flow guidelines developed for field operation of subsea gas wells.
Engineered Shale Completions Based On Common Drilling Data
Authors: Logan W. D.
Published: September 2015

Current best practices in North America's shale basins deliver inconsistent production results because of a lack of reservoir understanding along the lateral. Reservoir data is difficult and expensive to obtain in horizontal sections; therefore, most completions are designed geometrically, with little or no concern for reservoir heterogeneity. This leads to dramatic variability in productivity between neighboring wells, often described as the statistical nature of the play.

In this study, we demonstrate a reliable, cost effective methodology that empowers shale operators with reservoir data on every well. This technique will enable operators to engineer their designs by using reservoir data on every completion, resulting in significant productivity improvement without any significant increased cost or inconvenience.

This methodology leverages commonly available drilling measurements (rate of penetration, weight on bit, rotational speed, hole diameter, flow rate, differential pressure and standpipe pressure) and mud motor parameters (Kn, Tmax, ΔPmax) to derive Mechanical Specific Energy (MSE), using well established algorithms. The MSE parameter is then shown to be a good proxy for Unconfined Compressive Strength, a valuable reservoir parameter commonly used in frac designs. The MSE drives a facies-based answer product that enables the operator to position perforation clusters so that they breakdown at a common treating pressure, resulting in uniform fracture treatment within each frac stage.

To date the technique has been applied successfully on over 60 wells. It is validated through comparison to openhole wireline logs and by comparing productivity to offsetting wells. The technique is shown to be superior to similar attempts done by using openhole wireline logs and production data confirms its accuracy and reliability. This study demonstrates that drilling data can be effectively used to derive reservoir parameters that lead to completion designs that produce superior production results.

This methodology is the first application of drilling data to derive reservoir parameters that are then used to engineer a completion design. The significance of this development cannot be overstated, since it provides shale operators with the guidance they need to intelligently engineer their completions. The end result is significant productivity increases without any associated cost or inconvenience.
Integrated Injection Modeling
Authors: Izgec Bulent
Published: September 2015

The success of a waterflood is mainly determined by the performance of injector wells. This work outlines a simple three-stage integrated workflow for optimizing injector well performance.

In the first stage of workflow, matrix injection, fracture propagation, and plugging periods are identified with advanced Hall plots. In the second stage, field reported pressures are matched with a full field thermal/ geomechanical simulator. The final stage consists of duplicating the characteristic advanced Hall plot patterns with the history matched simulation model. At this stage, the previously history matched model is further fine-tuned to duplicate the characteristic advanced Hall plot patterns that were generated with field data.

Once complete, this fine-tuned model helps us understand the changes in fracture gradient caused by depletion and cooling, the extent and direction of the fracture and the impact of water quality on the overall performance.
Progressive Royalty Framework for Oil and Gas Development Strategy: Lessons from Nigeria
Authors: Echendu Joseph C. , Iledare Omowunmi O.
Published: September 2015

Royalty is a mechanism by which mineral owners – usually host government – obtain upfront revenue as soon as production begins from a petroleum lease or block. It can be received in cash or in kind and represents a part of front-loaded cost of doing business; it is tax deductible in oil and gas tax calculations. Economic rents extracted through royalty payments are usually not based on profits. This dampens the progressiveness of a fiscal regime and would normally have effects on investments and resource development economics.

This paper presents a progressive royalty framework and investigates the impacts of the various kinds of royalty schemes on oil and gas development economics. The conducts and performances of fixed, jumping and/or sliding royalty schemes are evaluated. Further, the paper reviews the different sliding scale specifications in fiscal systems and recommends the optimal boundary to ensure efficiency and effectiveness. The proposed royalty scheme recommended in the Inter Agency Team (IAT) memorandum on the 2008 Petroleum Industry Bill of Nigeria (PIB 2008), which was tied to terrain, geology and value forms the basis for the royalty design and modeling analysis evaluated in this paper.

Logarithmic sliding scale royalty scheme is generally perceived to perform better than other schemes but our analysis shows that terrain and geology matter a lot. This implies that if the royalty scheme is tied to geology, then marginal field operators would prefer the linearly sliding scale mechanism to logarithmic scale. Flexibility to switch from one scheme to the other offers incremental fiscal regime progressiveness in the quest for efficient, effective, equitable, and ethical energy resource development.

The paper recommends the use of sliding scale royalty scheme as a progressive bidding parameter and subsequent rent extraction instrument. The uncertainty in oil prices and its plummeting trend – plausibly discouraging exploration and exploitation of the not-easy-to-find hydrocarbons – requires progressive royalty schemes to create an equitable performance outcomes for all stakeholders in the emerging new petroleum era.
Wellbore Stability of Deviated Wells in Depleted Reservoir
Authors: Li Xiaorong , Gray K. E.
Published: September 2015

Reservoir depletion alters formation pressure, far-field in-situ stresses, and stresses around the wellbore. All of these factors influence collapse and fracture gradients, and therefore the drilling mud weight window. For deviated wells in depleted reservoirs, this situation is even more complicated due to the effect of well inclination and azimuth on the mud weight window. Analytical model results are presented in this paper for mud weight window calculations, considering formation pressure depletion, initial in-situ stress ratio (SHmax/Shmin), well inclination and azimuth.

In-situ stresses change due to reservoir depletion are first determined from poroelastic theory, assuming the reservoir experiences vertical deformation, but no deformation in the lateral directions. Next, far-field in-situ stresses after depletion are transformed to a deviated wellbore with arbitrary well inclination and azimuth. Then, utilizing the Mohr-Coulomb shear failure criterion and tensile strength failure criterion, collapse and fracture gradients are calculated for various ratios of initial horizontal stress, degree of depletion, wellbore inclination, and azimuth. Finally, the sensitivities of collapse and fracture gradients relative to these factors are compared and discussed. The most problematic situation is to drill highly deviated or horizontal wells in reservoirs with large depletion along the maximum horizontal stress direction. In this case, fracture gradient can reach extremely low levels, resulting in very narrow drilling window and very small margin for mud weight adjustment. Drilling along or near the direction of minimum horizontal stress is preferred. An interesting finding in this study is that fracture gradient does not always decrease for deviated wells, which is contrary to common understanding that fracture gradient always decreases as the pore pressure gradient declines.
Self-Suspending Proppant Transport Technology Increases Stimulated Reservoir Volume and Reduces Proppant Pack and Formation Damage
Authors: Goldstein Brian , VanZeeland Alan
Published: September 2015

Self-suspending proppant technology, a hydrogel polymer wrapped around a sand or ceramic substrate, resists settling in a low-viscosity fluid to uniformly distribute proppant throughout the fracture. The fluid remains in-zone to increase the stimulated reservoir volume. With this new technology, oil and gas production increases.

This technology eliminates compromises the industry has faced for decades. Because proppant falls out of the fluid before reaching the fracture tip, engineers have had to increase fluid viscosity and/or pumping rates, in addition to decreasing proppant mesh size or proppant density. These compromises increase completions cost and reduce conductivity.

With self-suspending proppant technology, fluid sweeps are eliminated because proppant maintains efficient transport characteristics and forms a higher, more uniform settled bed height compared with proppant transported by conventional gel or slickwater fluid systems. Pumping time is reduced because of the higher capacity to carry proppant compared with slickwater. Fewer fluid additives are required because less fluid volume is needed.

In addition to better proppant transport, this technology reduces proppant pack and formation damage. After breaking the polymer system and during fluid flowback, little to no residue remains. Further, according to test results from an independent laboratory, this new technology does not damage the proppant pack and formation with fluid additives, resulting in maximum regain conductivity and retained permeability. Typical frac fluid additives that support proppant transport can damage proppant pack conductivity and formation permeability by as much as 70% and 60%, respectively (Bilden, Fletcher, Montgomery, Guillory, and Allen 1995).

Two field trials show how the application of self-suspending proppant technology can increase stimulated reservoir volume and increase well production. In a Mississippian Lime liquids-rich play, self-suspending-proppant-coated 20/40 Northern White sand increased 18-month cumulative BOE 45% compared with the uncoated 20/40 Northern White sand in the offset's conventional slickwater design.

In an Escondido formation gas play, an operator compared a 46% self-suspending proppant tail-in with a simplified slickwater design. The technology boosted 60-day gas production by more than 55% while decreasing pumping time and water consumption with fewer fluid additives.

The shear-resistant polymer ensures greater drainage by traveling farther in a thin fluid for a substantially increased propped fracture area. A clean polymer break leaves the proppant pack and formation without fluid damage so hydrocarbons can flow freely.
A Real Options Approach to the Gas Blowdown Decision
Authors: Thomas Philip , Bratvold Reidar B.
Published: September 2015

Many oil fields have gas caps or associated gas. The common approach for these fields is to continue to produce oil, whilst re-injecting any gas produced, for as long as it is profitable, and then produce gas. This approach is motivated by the belief that it will maximize the oil reserves and thus maximize the overall value of the field.

In this paper we show why maximizing the length of profitable oil production does not necessarily create the most value. The analysis also provides guidance and insight on operating decisions that would not be obtained through a more conventional approach.

In this paper we show how a real options valuation approach can be used to determine the optimal blowdown decision. The approach we take is to re-inject gas to maintain oil production only until the time it is more financially valuable to produce gas and thus blow-down pressure support for oil production. To model price uncertainty we use correlated two-factor price processes. We also consider, uncertainties in oil and gas reserves and production as well as in transition costs. The model is solved using the Least-Squares Monte Carlo simulation approach. We use a material balance simulator, which is embedded into the underlying model, to represent the oil and gas production.

We illustrate how the approach can be used to identify optimal blowdown time, and thus maximize value, for a North Sea based oil field with associated gas.

Our results indicate that the value-maximizing blowdown time is different than would be computed using traditional net present value. Furthermore, the approach we take in this paper yields a decision-policy “map” that indicates the optimal choice given the state of oil prices, gas prices, production rates, costs, and remaining reserves in any given year.

The results presented here are relevant and applicable to oil and oil/gas fields across the world. Calculating the optimal blowdown time is not straightforward as it is a function of the underlying uncertainties such as oil and gas prices, their co-variation, oil and gas reserves and production, blowdown costs, and technology improvements, and its calculation is not trivial. However, ignoring these uncertainties leads to sub-optimal blowdown decisions, resulting in significant value losses.
A Framework for Transparency in Drilling Mechanics and Dynamics Measurements
Authors: Macpherson John D. , Paul Pastusek , Behounek Michael , Harmer Richard
Published: September 2015

The use of real-time mechanics and dynamics measurements has expanded and evolved significantly in the last thirty years, enabling the safe and reliable drilling of complex wells. Unfortunately, these measurements are poorly defined, which inhibits straightforward analysis and hinders development of models, simulators and automation applications. Adoption of open measurement guidelines will provide the transparency required to improve the value of existing measurements and accelerate the development and adoption of enhanced applications and automation.

Mechanics and dynamics measurements currently can be processed and transmitted from downhole in near real-time and then merged with other surface measurements. Optimization of the drilling process uses these combined measurements for monitoring, advising and control, thereby delivering a quality borehole as planned, in a safe and reliable fashion. Processing includes real-time filtering, mathematical modeling, and simulation, which are significant parts of any systems approach.

There are currently multiple methods used to quantify downhole and surface vibrations, displacements, and forces. Tools use dissimilar sensor and processing configurations, so they yield significantly different data. Regrettably, these different measurements are given the same name, and published descriptions often do not include the details required to understand and properly utilize the data. Examples of key information include sensor characteristics, sensor arrangement, bandwidth, and signal processing. Guidelines are suggested to resolve this state of confusion, including: terminology describing each drilling mechanics and dynamics sensor, configuration, and measurement; and metadata describing how a data value is derived, filtered, processed, transmitted and stored.

This paper examines and defines drilling mechanics and dynamics measurements. It recommends measurement practices and good processing techniques of these measurements, with examples, and presents a recommended open measurement framework. Adoption of this framework will resolve the current state of confusion and uncertainty, enable all parties to develop monitoring, advising and control applications that use these data, and help lower well costs and improve borehole quality.
Two Dimensional Monte-Carlo Simulation Method of Risk Assessment for Strategic Asset Investment Decision Making
Authors: LI D. , Chang P. , YANG X. , SUN Z. , JIN F. , YIN Y.
Published: September 2015

Because systematic and project specific risks exist during the project feasibility phase, the variability and uncertainty of these risks included in economic modeling improve the estimation of an assets NPV or IRR. For strategic investment decision making, parameters are defined with uncertainties and variability's. Examples of these type of parameters include raw material and product prices, Capital and Operating Expenses (CAPEX and OPEX), inflation index, interest and exchange rates. The purpose for gathering these data is to simulate the probability distributions of NPV or IRR using two-dimensional Monte Carlo Simulation. Sensitivity analysis, economic limit analysis and stress analysis are applied to optimize the final results for decision makers. This paper uses a case study to demonstrate the validity and effectiveness of a proposed method for project strategic investment decision making.