bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of gemtuzumab ozogamycin combined with conventional chemotherapy in patients with acute myeloid leukemia
Authors: Perini Guilherme Fleury , Santos Fabio Pires de Souza , Esteves Iracema , Nascimento Claudia Mac-Donald Bley do , Rodrigues Morgani , Assis Reijane Alves de , Helman Ricardo , Kutner Jose Mauro , Ribeiro Andreza Alice Feitosa , Hamerschlak Nelson
Published: September 2015

Objective: To analyze the outcome of patients treated with gemtuzumab ozogamycin combined with conventional therapy treated at Hospital Israelita Albert Einstein. Methods: 14 patients who had high risk features (secondary leukemia, unfavorable cytogenetics, and refractory disease) were treated with gemtuzumab ozogamycin combined with conventional therapy and their outcome was analysed by reviewing their medical records. Results: Overall response rate was 58%, with 43% achieving complete response, with a median follow-up of 11 months, event-free survival was 3 months. Eleven patients died, 6 of them due to refractory acute myeloid leukemia. Only four patients presented with grade 3 to 4 toxicities and only one patient had sinusoidal obstruction syndrome after bone marrow transplant. Conclusion: gemtuzumab ozogamycin combined with chemotherapy is a feasible treatment regimen in acute myeloid leukemia patients. However, further studies are necessary to clarify which subgroup of patients may beneft from this treatment.
A new spectrophotometric method to detect residual amounts of peroxide after reprocessing hemodialysis filters
Authors: Oliveira Moacir de , Dalboni Maria Aparecida , Iizuka Ilson Jorge , Manfredi Silvia Regina , Guimarães Nadia Karina , Andreoli Maria Claudia Cruz , Matos Ana Cristina Carvalho , Batista Marcelo Costa , Santos Bento Fortunato Cardoso , Cendoroglo Neto Miguel
Published: September 2015

ABSTRACT Objective: Reuse of hemodialysis filters is a standard practice and the sterilizing chemical most often employed is peracetic acid. Before starting the dialysis session, filters and lines are checked for residual levels of peracetic acid by means of a non-quantitative colorimetric test that is visually interpreted. The objective of this study was to investigate a new quantitative spectrophotometric test for detection of peracetic acid residues. Methods: Peracetic acid solutions were prepared in concentrations ranging from 0.01 to 10 ppm. A reagent (potassium-titanium oxide + sulfuric acid) was added to each sample in proportions varying from 0.08 to 2.00 drops/mL of solution. Optical densities were determined in a spectrophotometer using a 405-nm filter and subjected to visual qualitative test by different observers. Results: A relation between peroxide concentrations and respective optical densities was observed and it was linear with R2 > 0.90 for all reagent/substrate proportions. The peak optical densities were obtained with the reagent/substrate ratio of 0.33 drops/mL, which was later standardized for all further experiments. Both qualitative and quantitative tests yielded a specificity of 100%. The quantitative test was more sensitive than the qualitative test and resulted in higher positive and negative predictive values. There was a difference between observers in the qualitative test and some samples with significant amounts of peroxide were not detected. Conclusion: A quantitative spectrophotometric test may improve detection of residues of peracetic acid when compared to the standard visual qualitative test. This innovation may contribute to the development of safer standards for reuse of hemodialysis filters.
Hodgkin's disease and pregnancy: case series and proposal for treatment protocol
Authors: Kassab Carolina , Perini Guilherme Fleury , Bollmann Patrícia Weinschenker , Kerbauy Fabio Rodrigues , Hamerschlak Nelson
Published: September 2015

The peak frequency of Hodgkin's disease convergesmatches with women of reproductive fertility age. Currently, this disease is the fourth more diagnosed neoplasia during pregnancy. In addition, there is no consensus in the literature on how to treat pregnant women because of the risks of chemotherapy for mothers and for fetuses. We report three cases of pregnant women with Hodgkin's disease. A review of the literature was made aiming to suggest a protocol to treat these patients.
Overall Description of Wind Power
Authors: Trejos–Grisales Luz , Guarnizo–Lemus Cristian , Serna Sergio
Published: September 2015

This paper presents a general overview of the main characteristics of the wind power systems, also considerations about the simulation models andthe most used Maximum Power Point Tracker (MPPT) techniques are made. Some simulation results are shown and conclusions about the workare given.
On the 100th Anniversary of the Southern Federal University. Social Psychology at the Southern Federal University (RSU): Stages of Development and Research Directions
Authors: Labunskaya V.A.
Published: September 2015

In 2015 the Southern Federal University celebrates its centennial anniversary. The University is the largest research and education center of the Russian south, and its history dates back to 1915 when the Imperial University of Warsaw was moved to Rostov-on-Don. The paper focuses on various factors that have contributed to the development of social psychology at the SFU (former RSU) over the period of 45 years, from the establishment of the Department of General and Social Psychology in 1971 to the emergence of the Department of Social Psychology in 1999 that is still active nowadays. Special attention is drawn to the analysis of the general context in which social psychology has been developing. The paper traces the origins of scholarly activities carried out at the Department of Social Psychology and provides a description of research areas covered by the staff of the Faculty of Psychology. The paper concludes that a distinctive feature of the Department is that each researcher provides academic courses and training in the field of his/her research activities and practice.
The persistence of populations facing climate shifts and harvest
Authors: Fuller Emma , Brush Eleanor , Pinsky Malin L.
Published: September 2015

Many species are expected to shift their geographic distribution as climates change, and yet climate change is only one of a suite of stressors that species face. Species that might, in theory, be able to shift rapidly enough to keep up with climate velocity (the rate and direction that isotherms move across the landscape) may not in actuality be able to do so when facing the cumulative impacts of multiple stressors. Despite empirical reports of substantial interactions between climate change and other stressors, we often lack a mechanistic understanding of these interactions. Here, we developed and analyzed a spatial population dynamics model to explore the cumulative impacts of climate with another dominant stressor in the ocean and on land: harvest. We found that critical rates of climate velocity and harvest depend on the growth rate and dispersal kernel of the population, as well as the magnitude of the other stressor. This allowed us to identify conditions under which harvesting and climate velocity can together drive populations extinct even when neither stressor would do so in isolation. Except in these extreme cases, we also found that the interaction between the declines in biomass caused by climate velocity and harvest is approximately additive. Finally, we have shown that threshold harvest rules can be effective management tools to mitigate the interaction between the two stressors, while protected areas can either help or hinder, depending on how harvesters reallocate their effort. We also have parameterized the model for black rockfish (Sebastes melanops) to demonstrate the model's broad applicability.
Theory of Petroleum Engineering Education: Big Bounce, Big Crunch, or Big Freeze?
Authors: Plaksina Tatyana , Gildin Eduardo
Published: September 2015

Historically petroleum engineering departments have been the primary suppliers of engineering human resources to the oil and gas industry. Similar to the operators and service companies, the universities are sensitive to changes in demand. Though the asset of the petroleum engineering academia is not barrels of crude oil and cubic feet of gas, it is future professionals of different degrees (bachelor's, master's, and doctorate). In the last several years in response to rapid increase in hydrocarbon prices and unconventional production, we observed a hiring surge in the industry and subsequent agitation among engineering freshmen to choose petroleum engineering as their major. As a result, this short-lived high demand for petroleum engineering graduates created tremendous pressure on the departments causing them to expand their educational capacities. In some cases that led to doubling of the number of undergraduates in the program. Simultaneously, such dramatic expansion of the student body created a growing demand for professors. According to the most conservative estimates, there is an obvious shortage of professors of all ranks. This demand for the specialized engineering professionals occurs on the foreground of the domestic shortage of the general engineering professionals as indicated by the Labor Department.
Consistent Entry-Hole Diameter Perforating Charge Reduces Completion Pressure and Increases Proppant Placement
Authors: Rasmuson Craig D. , Walden Joel T. , Smith Charles H. , Pinkett John
Published: September 2015

To help reduce entry-hole diameter variation and eliminate the risk of using centralizing rings, a family of perforating charges was developed with the objective to maintain consistent hole size, regardless of the clearance distance between the charges and the casing. This paper demonstrates that this family of charges makes the stimulation behavior, specifically the treating pressures and rates, more consistent and predictable.

Consistent entry-hole diameter charges and an industry standard premium charge were run in two horizontal wells for comparison. The fluid systems of the two wells varied, so only stage-to-stage comparisons within the same well were used for analysis. Comparison of breakdown and treating pressures and overall proppant placed in each stage demonstrated that consistent hole-size charges yielded better results. Breakdown pressures were reduced by 10%; treating pressures were reduced by 3%, and the amount of proppant placed in the formation increased by approximately 4,640 lbm/stage using consistent hole-size charges.

The design of horizontal completions includes multiple inputs and variables that can make it difficult to determine completion fluid and proppant behavior during stimulation, particularly the entry-hole diameter created by explosive perforating charges. In horizontal wells, perforating charges are near the bottom of the casing, causing energy directed outward from the charges through the casing, cement, and formation to be inconsistent. Generally, charges lying on the bottom of the casing create larger, deeper holes. However, energy is lost from the charges facing upward because the perforating jets must first pass through a larger fluid gap before penetrating the casing. This inconsistency in hole size causes significant variation in formation breakdown and treating pressure between stimulation intervals, affecting the amount of fluid and proppant placed in the formation, influencing overall well productivity. Attempts to centralize a perforating gun in the wellbore have been made, reducing variability of perforating charge standoff from the casing. This introduces additional risk of becoming stuck or unintentionally pumping the guns off the wireline. Therefore, a perforating charge capable of delivering consistent entry holes is essential.

This paper discusses a comparison of two distinct perforating charges fired in the same well in contrast to previous studies conducted with the charges fired in different wells. This comparison reduces the amount of uncontrollable variables and demonstrates the improved economics of an asset using a consistent hole-size charge.
Fuzzynistic Models for Multiphase Flow Pattern Identification
Authors: Popa Florentina , Dursun Serkan , Houchens Brent
Published: September 2015

This paper presents an innovative method for the identification of multiphase flow patterns and the estimation of pressure drop. This method uses a data-driven classification model based on a fuzzy inference system (FIS). The paper discusses the specific problem of two-phase, gas-liquid regime identification and pressure drop prediction for pipe flow and demonstrates the ability of the fuzzy-mechanistic (fuzzynistic) model to accurately identify the flow regime. In addition, the fuzzynistic model is computationally efficient, and can help to provide real-time monitoring and control of production and pipeline equipment. The fuzzynistic model is demonstrated for two-phase, gas-liquid pipe flow over a wide range of superficial velocities and pipe inclination angles. Seven flow regimes are identified.

Historically, regime predictions for multiphase flows have been based on either empirical maps created from experimental observations or on mechanistic models, which consider the physical mechanisms that cause variations of fluid phase distribution. Both have disadvantages in that they are either tied to limited experimental data or are prone to discontinuities at the regime transitions, or both. An innovative contribution of the fuzzynistic method is that it classifies flow patterns with associated weights. These flow patterns allow the aggregation of pressure drop functions of classified flow patterns to help estimate the corresponding pressure drop automatically across flow regime transitions. Flow regime maps generated using the fuzzy logic approach accurately mimic those generated by mechanistic models, but have “fuzzy” transitions between regimes because of the partial degree of membership to adjacent and neighboring regimes. Thus, along the flow path, partial degrees of membership to adjacent and neighboring flow regimes are assigned to account for the pressure drop prediction at the regime transitions. Furthermore, because the fuzzynistic method is computationally efficient, it could be used for real-time monitoring and control of equipment in wells, pipelines, and downstream processing.
Restimulation Design Considerations and Case Studies of Haynesville Shale
Authors: Melcher Joseph , Persac Stephen , Whitsett Andrew
Published: September 2015

This paper discusses a method for, and case histories of, using an environmentally acceptable, self-removing particulate diverter that has proven to be successful in the refracturing efforts of horizontal unconventional reservoirs. This method is typically chosen for its low cost, self-assembly, self-removal, and ease of addition into treatment. An outline of the evolution of restimulation design, typical procedures, and candidate selection strategies is provided. The ability to add reservoir contact, restore conductivity, and remediate blockage makes this technique desirable.

Different strategies can be applied when using this product and are typically customized to the particular candidate well selected for the refracturing treatment. The treatment design is also often customized to the particular candidate well; however, key components of the design are outlined. Candidate wells for refracturing typically fall into one or more categories: Understimulation occurred in the original completion.Production damaging mechanisms are present.A low investment lease retention strategy is required.A pressure-sink mitigation strategy is necessary for infill completions.

A typical procedure will consist of casing inspection, wellbore cleanout, addition of perforations, and flowback considerations.

In this study, different Haynesville shale refracturing treatments and results are compared. The evolution of treatment designs, such as carrier fluid, fluid volume, proppant volume, and diverting methodology, are explained. The results and the theory behind these changes are outlined, along with the economic viability of refracturing treatments. Pre/post-treatment estimated ultimate recovery (EUR) calculations are compared, along with treatment pressure trend analysis. The EUR uplift from the refracturing treatments is used to show the economic viability.

Although performing secondary stimulation treatments is not uncommon, the industry's focus on improving production decline curves has led to a surging interest in refracturing horizontal unconventional reservoirs. Decline rates in unconventional reservoirs tend to be more rapid compared to conventional reservoirs because of their ultralow permeability, limited reservoir contact, and original completion strategy. Restimulation of these reservoirs enables the recovery of hydrocarbons trapped by these restrictions.
Slickwater Proppant Transport in Complex Fractures: New Experimental Findings & Scalable Correlation
Authors: Alotaibi Msalli A. , Miskimins Jennifer L.
Published: September 2015

Slickwater hydraulic fracturing is an important technology that has enabled the oil and gas industry to economically develop enormous unconventional resources. Despite its great success, this technology faces challenges, especially with proppant transport in complex fractures. Very limited work exists in literature about slickwater proppant flow in subsidiary fractures or predictive correlations to estimate settled proppant dune heights.

This paper provides a scalable correlation to predict dune height across a wide range of flow rates and proppant concentrations. A unique feature about this correlation is its inclusion of the friction effect, as roughness was introduced to the fracture slot walls. 30/70 mesh brown sand was used to conduct the slot flow experiments and build the correlation. This paper also spotlights the proppant transport mechanism during proppant dune development. Understanding this mechanism reveals key information about the horizontal and vertical settled proppant size distribution. In addition, experimental results are presented to answer the debatable question whether slickwater can transport proppant into tertiary fractures or not. In fact, the data shows that proppant in slickwater is not only capable of "turning the corner" but also developing high dune levels exceeding 96% of the tertiary fracture slot heights.
Reducing Costs and Optimizing Drilling and Completion Efficiencies in Unconventional Plays Using Completion Diagnostics
Authors: Senters C. W. , Warren M. N. , Squires C. L. , Woodroof R. A. , Leonard R. S.
Published: September 2015

Horizontal drilling and hydraulic fracturing techniques continue to drive the profitable development of previously uneconomical reservoirs. In many basins across the world, economic exploration and production activities are a prerequisite for developing these unconventional reservoir projects, as well as vertically-drilled conventional reservoir projects. The specific examples in this paper are located in the Anadarko Basin and Appalachian Basin.

Completion diagnostics are being employed to validate the drilling and completion optimization of wells across all of the major unconventional plays in North America. This paper focuses on three specific projects in which the diagnostics implemented in horizontal completion programs led to significant cost reductions and efficiency gains. All of the wells in the discussed projects utilized at least one type of completion diagnostics to implement cost savings or optimize drilling and completion practices.

Eliminating unnecessary wellbore interventions reduces costs and lowers operational risks. In order to justify the need for a wellbore intervention, completion diagnostics are applied during the stimulation treatment. The first case history in this paper reviews data that support the decision to reduce costs by not milling out completion hardware, as well as supporting the expenditure for a wellbore intervention when data indicate flow obstructions along the lateral.

The second case history illustrates the evaluation of completion methods ranging from different openhole systems to a cemented plug and perf completion that had a failed cement job. The post treatment diagnostic data are illustrated with actions taken to further optimize the drilling and completion practices in the future.

The third and final case history is an interwell communication study that uses fluid tracers to evaluate potential areas of acreage that could be left unaccessed. Interwell communication is evaluated for toe-to-toe communication to determine if the area between toes in adjacent pad completions is sufficiently accessed.
Furthering the Capabilities of Coiled Tubing Production Logging in Horizontal and Highly Deviated Wells: The Advent of Reservoir Saturation Logging in Southern Mexico
Authors: Bueno O. Jimenez , Nava A. F. , Leyva H. Hernandez , Ortega C. A. , Ramondenc P. , Fonseca S. Hassig , Fernandes R. A. , Rodriguez F. L.
Published: September 2015

A new solution to reservoir saturation logging in highly deviated and horizontal wells leverages a light system using coiled tubing (CT) equipped with fiber optics to overcome reach limitations and provide real-time acquisition of downhole reservoir information. The advantages of the methodology in terms of technical capabilities and efficiency have been demonstrated in wells in Mexico where acquisition of once-inaccessible logging information opened new avenues in the production management of the area.

The conveyance of logging tools via wireline cable or wired CT presents significant reach and pumping limitations in highly deviated or horizontal wells. The combination of a recent downhole module development and the use of lighter CT package equipped with fiber optics addresses these conveyance and operating challenges. The optical telemetry link supports real-time logging without the need for wireline surface equipment, and the new downhole module provides power to a wide range of logging tools, including the power-demanding reservoir saturation tools.

The lighter system overcomes weight limitations, and logging can be performed in any type of well profile. The new module significantly increases the voltage output from the downhole source to the logging toolstring, thus enabling the use of power-demanding components that were previously unusable with CT systems. It also extends the downhole operating logging time for traditional production logging tools by up to six times over that of previous methods. As the production of mature fields in Southern Mexico is gradually decreasing and water has become an increasing issue, operators in the area are currently performing major workover operations to rejuvenate the fields. This novel approach enabled acquisition of reservoir saturation data in several wells in which this information could not be acquired previously because of reach limitations. The newly acquired data enabled identification of bypassed hydrocarbons in those wells. With this information, the operator could selectively shut off the water-producing zones while opening new hydrocarbon-bearing ones, thus significantly reducing water production and prolonging the life of the wells.

The introduction of the innovative methodology not only significantly broadens the range of logging interventions that can be performed, it also enables accessing reservoir data that, in some cases, have been inaccessible for a long time, and which can be key to the optimization of production management of entire fields.
Rapid Data Integration and Analysis for Upstream Oil and Gas Applications
Authors: Cheung Chung Ming , Goyal Palash , Harris Greg , Patri Om , Srivastava Ajitesh , Zhang Yinuo , Panangadan Anand , Chelmis Charalampos , McKee Randall , Theron Mo , Nemeth Tamas , Prasanna Viktor K.
Published: September 2015

The increasingly large number of sensors and instruments in the oil and gas industry, along with novel means of communication in the enterprise has led to a corresponding increase in the volume of data that is recorded in various information repositories. The variety of information sources is also expanding: from traditional relational databases to time series data, social network communications, collections of unsorted text reports, and linked data available on the Web. Enabling end-to-end optimization considering these diverse types of information requires creating semantic links between them. Though integration of data across silo-ed databases has been recognized as a problem for a long time, it has proven to be difficult to accomplish due to the complexity of the data arrangement within databases, scarcity of metadata that describe the content, lack of a direct mapping between related entities across databases, and the several types of data represented within a database. In addition, there are large amounts of unstructured text data such as text entries in databases and document repositories. These contain valuable information on processes from the field but there is currently no method to convert this raw data to useable information. The Center for Interactive Smart Oilfield Technologies (CiSoft) is a USC-Chevron Center of Excellence for Research and Academic Training on Smart Oilfield Technologies. We describe the Integrated Optimization project at CiSoft which has the goal of developing a framework for automated linking of heterogeneous data sources and analysis of the integrated data in the context of upstream applications.
Permeability, Skin and Inflow Profile Estimation From Production Logging Tool Temperature Traces
Authors: App Jeff
Published: September 2015

Temperatures traces from multiple rates are used to estimate the production inflow profile and layer permeability and skin using a transient coupled reservoir/wellbore model. Production Logging Tool (PLT) temperature traces from two rates show heating of approximately 6–11 °F above the geothermal due to Joule-Thomson expansion of the reservoir oil. Production is single phase oil from a high pressure oil reservoir. Nonlinear regression was used to automatically adjust the layer permeability and skin values until the observation temperature traces from both rates were matched. History matching the temperature data provides a quantitative estimate of the skin and permeability within each contributing layer; this cannot be obtained from conventional pressure transient analysis which unless for highly specialized cases provides only a single value of permeability and skin. The production inflow profile is then constructed using the history matched layer permeability and skin values. In addition to the wellbore temperature profiles, temperature and pressure profiles within the reservoir will be shown which illustrate the relative impact of the reservoir permeability and skin on the wellbore temperature responses. Information on the coupled reservoir/wellbore model and the optimizer will be provided.
FLNG vs ‘Subsea-To-Beach’: A Study on the Critical Factors Governing Concept Selection in Deepwater Gas Field Developments
Authors: Beltrami Francesco , Olugbode Funmi , Subramanian Kartik , Barrero Alejandro
Published: September 2015

The objectives of this study are: (a) The investigation of the main technical factors affecting the preliminary design and cost estimation of a ‘Subsea-to-Beach’ subsea production system (SPS) and, indirectly, of a floating LNG (FLNG) offshore development; (b) The identification of the ‘key’ factors, seen as the real differentiators in the comparison between ‘Subsea-to-Beach’ and FLNG; and (c) how these ‘key’ factors relate to other decision factors (for example, economics, risks, and technology readiness).

The four (4) steps followed in this study can be summarized as follows: (a) Review of historical ‘Subsea-to-Beach’ developments associated to LNG production; (b) Definition of the study cases, including preliminary design and cost estimation (by means of a proprietary cost estimating tool); (c) Presentation of the cost estimates and discussion of the technical factors that affect them in the most relevant way; and (d) Discussion of the key differentiating factors with respect to areas of applicability for ‘Subsea-to-Beach’ and FLNG (where one of the two alternatives works best).
Offshore Membrane Deaeration as a Replacement for Vacuum Tower Deaeration - A Comparative Study
Authors: Van Pelt Stephen , Churman Holly
Published: September 2015

A membrane deaeration pilot study undertaken on seawater from an onshore seawater intake, successfully demonstrated removal of dissolved oxygen to less than 10 parts per billion without the use of chemical oxygen scavenger. To assess the commercial viability of adapting membrane deaeration technology to offshore oil and gas applications, a comparative evaluation of size, weight, capital cost, and operating cost for membrane deaeration versus conventional vacuum tower deaeration was performed.

The comparative evaluation considered membrane and vacuum tower deaeration technologies across a range of injection flow rates, from 30,000 – 250,000 barrels per day. Multidisciplinary engineering and design was conducted for each technology at specific injection flow rates within this range. Detailed 3D models, material take-offs, and weight reports were produced for each design. The capital cost study was prepared, with the goal to estimate direct field cost for installation of each technology. These costs were derived using quotes from vendors and installed cost norms for similar offshore installations. Operating costs were developed using quotes for consumables and estimations for power cost.

The comparative evaluation indicated that selection of membrane deaeration technology over conventional vacuum towers resulted in the following offshore facilities impacts: 60 – 70% dry and operating weight savings across the entire range of injection flow rates studied.30 – 60% total size savings, with increased savings at elevated injection flow rates.10% footprint savings from 125,000 – 250,000 barrels per day. The footprint of membrane deaeration is larger at small flow rates.

Selection of membrane deaeration technology over conventional vacuum towers results in the following offshore economic impacts: 10 – 15% direct field cost savings from 30,000 – 125,000 barrels per day. Direct field cost savings between 5 – 10% from 125,000 – 250,000 barrels per day, as economies of scale of vacuum towers begin to take effect.50 – 60% annual operating cost savings across the entire range of injection flow rates studied, based partially on an assumed cost per kilowatt-hour for offshore power generation.

This study accounts for parameters which have not been addressed in previous literature to date: Costs related to the installation of each deaeration technology on offshore topsidesImpacts on the entire topsides process due to selection of each deaeration technology (i.e., injection booster pumps, chemical injection facilities, etc.)
New Fast and Accurate 3D Micro Computed Tomography Technology for Digital Core Analysis
Authors: Katsevich A. , Frenkel M. , Feser M. , Huang Z. , Andrew M. , Case T. , Gu A. , Thompson W.
Published: September 2015

Micro Computed Tomography (micro-CT) of cores is an emerging technology that yields vital information about key rock and fluid properties at pore-scale resolution. Micro-CT imaging results presented to date are encouraging and indicate that this technology has the potential to revolutionize petrophysical analysis and reservoir engineering. The application of micro-CT in petroleum engineering requires reconstructed scan data to be of high and uniform image quality to enable reliable analysis during subsequent segmentation and numerical modeling. This is achievable in existing micro-CT systems using standard circular scan trajectories with non-exact filtered backprojection (FBP) reconstruction, but requires small cone angles to keep cone beam artifacts below detectable limits.

We describe the implementation and results of adapting an exact helical FBP reconstruction algorithm (the so-called “Katsevich Algorithm” or KFBP) and data acquisition scheme on a high-performance micro-CT system normally running in circular scan trajectory mode. Side-by-side comparisons of stitched circular scan trajectories with continuous helical scan trajectories on simulated and real rock core data show the throughput advantage of this modality for applications relevant for the petroleum industry keeping equivalent image quality to low cone angle circular scans. The analytical exact helical reconstruction can be performed in quasi-real time leading to instantaneous results. Simulated and experimental results indicate that an imaging throughput improvement of 2-5 times can be achieved employing KFBP-based exact helical reconstruction compared to the standard circle scan trajectory when imaging whole rock cores/plugs that are significantly longer than their diameter.
The New Reality of Hydraulic Fracturing: Treating Produced Water is Cheaper than Using Fresh
Authors: Barnes Christopher M. , Marshall Ryan , Mason John , Skodack Dave , DeFosse Grant , Smith Daniel G. , Foreman Scooter , Hanna Ty , Cecchini Michael
Published: September 2015

Simple, cheap, and reliable treatment of produced water will transform the economics and viability of unconventional plays. Produced water recycle not only creates options to minimize fresh water usage; in local areas it can take tens of thousands of water hauling trucks off the road and significantly reduce salt water disposal.

This is no pipe dream. A novel process based on a step-change in the application of chlorine dioxide chemistry has been proven to work and consistently generate frac-compatible fluid at several company facilities in Texas. The solution is an inline system that simplifies the operation, optimizes chemical consumption, and enables continuous on-the-fly treatment. Case studies over multiple years and greater than 18 million barrels used at the field level show that produced water is being recycled for less than half the equivalent cost of using fresh water.
Refracs- Diagnostics Provide a Second Chance to Get it Right
Authors: Leonard R. S. , Moore C. P. , Woodroof R. A. , Senters C. W.
Published: September 2015

The surge in unconventional completions over the last 10 years has created a substantial accumulation of previously hydraulically fractured wells that are candidates for hydraulic refracturing (refracs). As new plays are developed over time, refracs offer the opportunity to apply improved stimulation techniques to optimize well performance.

Maximizing new fracture network development is a key to successful re-stimulation of existing unconventional wells. Completion diagnostics are a valuable tool in determining the most cost-effective stimulation and completion parameters, part of the refrac optimization process. All of the major unconventional basins have seen significant design changes over time. Refracs allow the operator to capitalize on this continuous improvement in stimulation design. They also provide an excellent opportunity to add incremental production.

The dataset contains over 65 wells that were re-stimulated during the last 10 years. Stimulation and production information will be provided along with suggested refrac techniques. Several diagnostic case histories for Barnett Shale and Marcellus Shale wells will illustrate various successful approaches to the re-stimulation process. The data will be used to address observed diagnostic metrics.

Key parameters and diagnostic metrics will be defined and utilized for the candidate selection process, refracturing design, and post-refrac evaluation. This is the first macroscopic study of its kind where diagnostic and completion metrics are compared with performance metrics. The focus of this study is to compare the various captured metrics with the incremental estimated ultimate recovery (EUR) percentage gains from the refracs. Additionally, post-refrac production rates will be compared with the existing maximum monthly production. The results of this study should continue to be an excellent tool for further optimization in re-stimulation across North America.
Diagnosis And Characterization Of Cross Flow Behind Casing From Transient-Pressure Tests
Authors: Anisur Rahman N. M. , Bin Akresh S. A. , Al-Thawad F. M.
Published: September 2015

A reservoir system with two neighboring layers, the tested and the adjacent layers being separated by impermeable strata, is considered. Fluid may still migrate from the adjacent layer to the tested layer if the zonal isolation behind casing is compromised or flow channels exist in the vicinity. A method is presented to diagnose the fluid contribution to the tested layer from the adjacent layer, and to quantify the transient rate of cross flow by utilizing the transient-pressure data.

During transient tests on the tested layer, the cross flow from the adjacent layer has to be accounted for to ascertain reasonable characterization of the tested layer. A new analytical solution for a two-layer system with cross flow behind casing has been employed to understand the effects of cross flow on the transient behavior in the tested layer. Matching of type curves with measured pressures helps diagnose the presence of cross flow behind casing and estimate parameters. The cross-flow rate as a function of time is also estimated by quantifying the hydraulic conductivity of the compromised zonal isolation.

This study shows that the magnitude of the hydraulic conductivity of the compromised zonal isolation or flow channels has a strong effect on the rate of cross flow with the flow capacities of individual layers. There is an upper limit of the conductivity of the zonal isolation beyond which the cross-flow rate is limited by the layer flow capacities. For a given two-layer system, the cross-flow rate increases with time for a constant rate drawdown in the tested layer due to the increasing pressure differential across the compromised zonal isolation. The test duration is another important aspect which lets the cross-flow rate reach a critical value to be detected in the log-log plot of the pressure derivative. This means that a long transient test is likely to be affected substantially by the cross flow behind casing.

Field examples with build-up test data are presented to illustrate the methodology. These show that ignoring the flow behind casing may lead to an over-estimated flow capacity of the tested reservoir layer. Matching of the transient-test data also provides estimates of the conductivity of the zonal isolation, which leads to computing the transient cross-flow rates.
Reconciling Log-Derived Water Saturation and Saturation-Height Function Results through Resistivity Modeling, Core-Log Integration and Image Log Data: A Case Study from Deepwater Gulf of Mexico
Authors: Miranda Javier , Rabinovich Michael , Hamman Jeffry , Mousavi Maryam
Published: September 2015

Saturation Height Functions (SHF) have a key role in reservoir description and in quantifying oil in place. The function(s) must compare well with other sources of water saturation (Sw) when available, such as core measurements and well-log interpretations. We have reconciled the different Sw sources through a reliable SHF function based on the Brooks-Corey model with parameters optimised for Thunder Horse (TH) Field. The function is used to populate oil volumes in the 3-D static and dynamic models.

Thunder Horse is one of the largest deep-water fields in Gulf of Mexico and is operated by BP, with ExxonMobil as a co-owner. TH is divided in two trapping structures: TH North (THN) and TH South (THS). The field has multiple Miocene turbidite reservoirs commonly grouped in units known as the Pink, Brown, and Peach. Thunder Horse is fortunate to have Dean-Stark (D-S) and well-log data sets that detail the Sw changes at and above the oil-water contact (OWC). We developed a continuous log-derived Sw after appropriate model calibration with D-S measurements. Subsequently, we applied the Brooks-Corey SHF model with parameters defined for each rock type in TH area based on an iterative regression to the log-interpreted Sw following a workflow we developed.

This case study illustrates methods and results of reconciling saturations determined from a number of techniques and validation of the outcomes with independent borehole and direct measurements from core. Two cases where differences were observed are addressed by combining resistivity modeling and borehole images with core-log integration.

A comparison of binary vs. continuous net-to-gross (NTG) on Hydrocarbon Pore Volume, based on SHF and log-derived Sw, proved the volume impact is not significant for the highest NTG TH Pink reservoirs. However, the deliverable provides significant value through a consistent and defendable linked saturation and net-to-gross suitable for use in reservoir modelling.
Investigation of Wettability and Fluid Distribution in Organic-rich Mudrocks using NMR Two-Phase Simulation
Authors: Chi Lu , Heidari Zoya , Garcia Artur Posenato
Published: September 2015

Interpretation of NMR relaxometry in organic-rich mudrocks still remains a challenge for petrophysicists. A reliable numerical simulation of NMR response in these rocks helps in better understanding of the NMR relaxometry data and the corresponding petrophysical properties (e.g., the wettability and fluid distribution in the pore space). The hydrocarbon-wetting or mixed-wetting characteristics of organic-rich mudrocks have significant impacts on hydrocarbon recovery from the rocks, but quantification of wettability using conventional well-log interpretation methods remains a conundrum. The objectives of this paper are (a) to introduce a NMR two-phase simulation method to model the NMR responses in organic-rich mudrocks and (b) to investigate the effects of wettability alteration and fluid distribution on NMR relaxometry using numerical simulations.

We simultaneously simulate the NMR responses from both water and hydrocarbon phases in organic-rich mudrocks using a random-walk algorithm. The main input to this two-phase NMR simulator is a digital rock matrix reconstructed from 3D pore-scale images of organic-rich mudrock samples, including water, inorganic grains, hydrocarbon, and kerogen. The pore-scale digital images are obtained from FIB-SEM (Focused Ion Beam Scanning Electron Microscope) images. The output of the NMR simulator is the NMR transverse magnetization decay in the rock matrix. The NMR T2 distribution is estimated by inversion of the simulated magnetization decay using a curvature smoothing method. We also separate the individual T2 distribution peaks from different pores and compare them against the combined T2 distribution to demonstrate the reliability of the simulation results.

We successfully simulated NMR T2 distribution in synthetic and actual organic-rich mudrock samples. We also showed that the alteration of wettability and fluid distribution within the organic-rich mudrock matrix have a measurable impact on NMR T2 distribution. The introduced simulation method enables further developments on interpretation of NMR measurements in organic-rich mudrocks, which has been challenging in laboratory experiments. The outcomes of this paper can improve the understanding of the parameters affecting NMR relaxometry in organic-rich mudrocks. They also potentially enhance the interpretation of NMR borehole measurements for real-time assessment of porosity, pore-size distribution, and wettability.
Constant GOR as an Infinite Acting Effect in Reservoirs Producing Below (Dew/Bubble) Saturation Pressure
Authors: Zhang Miao , Ayala Luis F.
Published: September 2015

In recent years, constant producing gas-oil-ratio (GOR) trends have been repeatedly observed in many unconventional oil and gas reservoirs. This effect can last many years, even after the depleting system is believed to have crossed its saturation pressure. In this study, we corroborate that constant GOR could indeed be expected in depleting reservoir systems exhibiting early-transient infinite-acting flow under constant bottomhole pressure (BHP) production constraint for both linear and radial flow geometries. This effect had been shown to be present in infinite-acting linear systems by previous authors; but this study shows how this GOR trend and value can be fully predicted prior to availability of production data. Focusing on liquid-rich gas systems, we start with the applicable multiphase governing flow equations and provide semi analytical and rigorous solutions. Similarity theory is applied to transform the resulting system of equations and achieve the multiphase solution. The results show that a constant GOR effect could be maintained as long as the flow regime remains infinite-acting, which is a typical condition to be found in unconventional systems. Also, it is found that, in both linear and radial multiphase systems, this constant or stabilized GOR is shown to be present regardless of condensate phase mobility at sandface conditions.
Logging Services: Towards the 3D Measurement of Formation Properties in High-Resolution with a Continuous Depth of Investigation
Authors: Walker Kristoffer , Granville John , Kainer Gary , Cheng Arthur
Published: September 2015

The Xaminer Sonic is a new wireline acoustic logging tool that represents the culmination of 4 years of computer modeling, engineering, lab testing, field surveys, and data analysis from fast and slow formations. Spanning a total of 52 ft, the tool includes a 6-ft-long array of 13 rings of eight azimuthally separated receivers located every 6 in. along the axis. There are a total of 104 individual receivers, each a piezoelectric hydrophone with a precisely matched response from 300 to 25,000 Hz. Four monopole piezoelectric sources and two orthogonal dipole shaker sources are located at different offsets to and different sides of the receiver array, permitting an advanced, multi-scale, 3-D interrogation of the formation's elastic properties with a continuous depth of investigation. These sources transmit a modally pure, full spectrum of acoustic energy into the formation using minimum phase and chirp drive pulses. Substantial modeling and engineering efforts have produced a tool structure design that mitigates the effects of the tool and enables broadband measurement of formation compressional, Stoneley, and flexural wave dispersion. By virtue of this unique tool design, load-bearing axial stresses are automatically transferred from the weaker inner tube to the stronger outer structure when hostile logging loads are encountered, thereby reducing the risk of tool loss or damage. All recordings are saved in high fidelity to tool memory, permitting full decomposition and analysis in post processing. Examples of waveforms, dispersion curves, sonic logs, and anisotropy measurements are presented to demonstrate the quality of the acoustic recordings.
Study on the Behaviours of Settled Heavier Phase in Two Phase Flows in Pipelines
Authors: Koguna Aminu J. , Yeung Hoi , Lao Liyun
Published: September 2015

Pipelines transfer production fluids from the well head to the platform and from the platform to process facilities. Water, sand or liquids like condensate could settle at the bottom of pipelines especially at low flow velocities and this has implication for flow assurance. During shutdown the settled heavy liquid (e.g. water), could result in corrosion in pipelines, while following restart stages the settled water could form a water plug that could damage equipment, while settled sand could also form a blockage that needs to be dispersed into the flowing fluid. This study looked at cases of low water cut in oil flows and, low sand concentrations in water flows. Conductive film thickness probes were used to obtain oil and water interface height and the water film velocities in water in oil flows.

Similarly values for the sand in water, sand layer profiles and sand dune velocities were investigated respectively. Comparisons are made between two cases in order to gain better understanding of the dispersal process of low loading heavier phase in two phase flows.