bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Analytical Solution for Predicting Oil Rate Vs. Time in Waterflood Using Various Injection Plans
Authors: Chen Yuting , Ershaghi Iraj
Published: April 2016

This paper introduces a new method and its analytical basis for predicting oil rate vs. time for fields under water flood or water influx. Application to actual waterfloods and water influx cases are included as case studies. Majority of analytical solutions on this subject discussed in the literature have in the past focused on extrapolation of WOR or water cut vs. cumulative production. When it gets to forecast oil rate vs. time, many practitioners have resorted to Arps1 type decline analysis methods. The shortcomings of decline analysis techniques are primarily their lack of honoring the physics of the immiscible displacement processes.

In the application of the proposed method for predicting into the future, assumptions need to be made about the injection rate plans or estimated influx rate based on past histories relating injection or influx to the gross production rates.
Analysis of SEAM Phase I Data and the Related Challenges
Authors: Xue Chenguang , Aminzadeh Fred
Published: April 2016

The salt related traps (sub-salt or slat flank) in the deep water of the Gulf of Mexico (GOM) has a pronounced impact on reservoir exploration and appraisal. It is, therefore, vital to do interpretation and attributes analysis on the seismic data to capture detailed reservoir structure and properties, as that is one of the core goals of the SEAM Phase I Project provided by the SEG. In this paper we will show how using Petrel and OpendTect is one of the keys to achieving that objective.

The strong seismic interpretation tools of OpendTect can help track seismic events and eventually guide us in selecting horizons. Furthermore, the novel approach of using the Supervised Neutral Networks can help us recognize the subsalt zone and faults structure. When the interpretation results, bolstered by additional measured information, are input to Petrel, it can offer the possibility of imaging the subsalt and increasing data analysis for this area.

Some interpretation and analysis results have been generated to represent our targeted area of the GOM. The stratigraphic variation and reservoir properties, as well as the feature of the salt domain, will be detailed in the results. Our analyses have revealed five major horizons in this area, three of which intersect with the salt body. The shape of the salt body is irregular, with a rugged top, and overhangs on both east and west sides. We will continue with confidence towards the end goal of imaging the area, lithology, and to distribute properties that include porosity, density, and fluid saturations (oil, water, and gas). This in turn will help us properly guide the reservoir development in that specific environment.

Our innovative methodology has rewarded us with an efficient way of combining two powerful commercial software programs to perform data analysis and ultimately enable us to image the complex structure of the salt body.
The Lexicon of Recompletion: Empirical Justification for Refrac, Reentry, or Remediation in the Bakken/Three Forks Play
Authors: Gullickson Geoffrey , Ruhle William , Cook Peter F.
Published: April 2016

The horizontal Bakken/Three Forks play of the Williston basin has a long standing history of recompletion dating back to the late 1980s. While rapid evolution of horizontal completion design has allowed expansive Bakken/Three Forks unconventional acreage positions to reach economically viable levels, existing legacy completions have historically been difficult to invigorate to modern productivity expectations. Although recompletion is nothing new to the oil and gas industry, the techniques applied are highly variable and historically may carry disappointing and unpredictable results. As a need for better understanding of principle well development continues to evolve, so do better techniques in legacy well recompletion tactics to enhance both developed and undeveloped assets.

Within the Bakken/Three Forks play, legacy development drilling and completion tactics are vast with significant productivity variances. Industry mindshare often incorrectly groups all recompletion methods into a single category. Differences in technical application, and associated value added per input cost, require subcategorization of recompletions to improve well productivity. A holistic identification process is required to appropriately match the service intensity associated with refracturing, reentry, or remediation to project costs and asset potential.

The focus of this study is to compare and evaluate the production results attained from recompletions in the discrete subcategories of well refracturing, reentry, and remediation. Empirical datasets will be presented to define the project inputs and production value capture associated with each recompletion type. By integrating these workflows, enhanced recompletion design and execution can create value at previously unattainable commodity price levels.

A comprehensive completion and production database of horizontal Bakken/Three Forks wells dating from 1987 to present has been developed to facilitate recompletion selection, design, and predictive production forecasting. Proprietary software that automates production analytics, combined with manual canvassing of over 10,000 wells, has provided an innovative method to cross-examine the Bakken/Three Forks play. By combining a multivariate assessment with probabilistic results, novel recompletion propositions can be successfully matched to project needs.
Steam-Flood Production Optimization Using an Innovative Steam Quality Sensor
Authors: Kerr Robert P. , Medizade Mason M. , Gleason Brian D.
Published: April 2016

Many oilfields operators across California and the world use steam as an injection fluid to recover high viscosity heavy oils. The steam injection process is done intermittently in cyclic steam injection and continuously in steam drive or Steam Assisted Gravity Drainage, SAGD, applications. The latent heat of vaporization of steam plays an important role in transferring heat to the oil, water, and reservoir rock and as a result reducing the oil viscosity making the oil trapped by viscosity, capillary and permeability effects, mobile. In cyclic steam injection, since the injection and production takes place in the same well, determining the optimum soak time at which flow back needs to be initiated is very critical, specifically in low permeability reservoirs such as California's diatomite having small well spacing and needing hundreds of short steam cycles. In this case, the overall success depends on ultimate oil recovery at the end of each flow back cycle. Additionally, knowing steam quality on the injection and on the production sides contributes to better heat management and better production practices, improving economics of the steam injection process. In this study, development and laboratory testing of a novel steam quality sensor, a tuning fork densitometer, are presented. This non-nuclear density sensor technology is adaptable to high temperature operation and has high sensitivity, making it ideally suited to measuring the small changes in density that occur due to varying steam quality. The application of this technology for cyclic steam injection, steam drive, and geothermal steam production are discussed. The sensor can be packaged for use down hole and at surface for continuous measurements of steam quality on injection as well as production applications.
Determination of the Stability of Asphaltenes Through Physicochemical Characterization of Asphaltenes
Authors: Prakoso Andreas , Punase Abhishek , Klock Kristina , Rogel Estrella , Ovalles Cesar , Hascakir Berna
Published: April 2016

Significant effort has been dedicated to understand the variables affecting asphaltene precipitation. Based on years of research, it is well known how variables such as temperature and pressure can affect the deposition of asphaltenes. However, much less is understood about the effect that asphaltene characteristics have on the tendency towards precipitation of different crude oils. We characterize extensively a series of n-pentane extracted asphaltenes and construct novel correlations with the stability of their corresponding crude oils.

11 different bitumen and crude oil samples are characterized first with API gravity and viscosity measurements, and thermogravimetric and differential scanning calorimetric analyses (TGA/DSC). The weight percentage of the asphaltenes in bulk samples are determined through n-pentane precipitation. The molecular structure of the asphaltenes is investigated with Fourier Transform InfraRed (FTIR) spectroscopy. Asphaltene stability is measured by ΔPS and by determining the Asphaltene Solubility Profile. The impact of hydrogen deficiency, heteroatom content and solubility distributions on other properties such as viscosity and aggregation behavior is also explored.

It has been observed that there is weak relationship between the asphaltene content and API gravity or viscosity of the bulk samples. The weight percent of the light, intermediate, heavy, solid, and ash fractions of the asphaltenes, defined with TGA/DSC experiments, indicate that the carbon rich solid component of the bulk samples that can decompose over 550 °C, correlate with the weight percent of the asphaltenes in bulk oil. The ash content of the bulk oil, which is mainly composed of heavy metals like sulfur, nickel, and vanadium, is correlated to the amount of asphaltenes precipitated out of the oil. Moreover, FTIR and solubility profile analyses reveals that the polarity of the asphaltene molecules is affected not only by its molecular composition and structure but also by its interactions with other crude oil components.

This study discusses the impact of the physical and chemical properties of crude oils and their asphaltenes on asphaltene precipitation. Several asphaltene deposition mechanisms are developed and validated for 11 different crude oil and bitumen samples with different asphaltene contents, thereby providing important and fundamental insight into asphaltene related problems.
Low Viscosity Cement Slurry for Improved Placement in Narrow Annuli
Authors: Campbell Rianne , Lauper Stephen
Published: April 2016

When cementing wells with small clearance between casing and borehole, or between casing and previous casing, friction pressure becomes a limiting factor in cement placement. The aim of this study was to reduce pressure on these jobs to allow increased rate and more effective cement placement, without compromising slurry integrity or increasing wait-on-cement time. This was achieved through the development of a reduced-density, low-viscosity slurry that maintained many of the same characteristics of the previously-used cement slurries. The particular focus of this project was on coiled-tubing drilling (CTD) production liners, as these well geometries frequently have a very narrow annular gap. In addition, the length of coiled tubing at surface contributes to higher overall pressures than cementing with conventional rigs.

The local slurry previously used on these jobs was a 15.8-lbm/gal (ppg) Class G-blended slurry with gas migration control. With the aim of reducing job pressures, both the density and the viscosity of the slurry were reduced. The density was reduced from 15.8 ppg to 15.3 ppg, while maintaining the gas migration control additives. To ensure that wait-on-cement time was not negatively affected, some of the Class G cement was replaced with microcement to aid in the rapid set of the slurry. Results of initial lab testing were modeled in cement job design software to assess hydraulic results and confirm sufficient displacement efficiency. The lab results from the 15.3-ppg slurry were also compared to those of the 15.8-ppg slurry to ensure there were no reductions in quality. The slurry was then used successfully on several jobs to confirm the pressure reduction, including cementing production liners through coiled tubing (2⅜-in. liner in 3¼-in. open hole), and cementing casing repair tiebacks with conventional rigs (such as 5½-in. casing inside 7-in. casing). Case studies are included.
Measuring Interwell Communication Using the Capacitance Model in Tight Reservoirs
Authors: Mirzayev Mammad , Jensen Jerry L.
Published: April 2016

The Capacitance Model (CM) has been used to analyze flow rates to measure interwell connectivity (IWC). Numerous case studies show the CM can successfully predict production and identify flow paths and barriers in conventional reservoirs. The challenge is to extend the CM to perform as well in tight reservoirs, which includes fields with high well densities. Fields with such large numbers of wells creates the need to perform IWC evaluations over small regions, called windows, to speed computation and preserve the accuracy of estimates. Windowing, however, creates a problem in that wells within the window may be in communication with wells outside the window. The contribution of the outside wells can be significant and affect the IWC estimation. A CM modification is described which has a ‘pseudo well’, decoupling the outside wells from the window and accounting for varying parameters embedded in an estimate in low permeability reservoirs.

We tested the new model with numerical simulation cases. The CM accuracy (ie simulated vs CM-predicted production rates) is very high (R2> 0.98) for both cases with balanced injection/production and those with local imbalances. The errors (RMSE) of the modified CM-predicted production rates are one-half the unmodified CM errors..

In the Cardium East Pembina field, we used the modified CM to analyze several areas having differing amounts of conglomerate and hydraulically fractured wells. IWC evaluations included areas with wells which were fractured after several years of production and we could therefore compare the pre-fracture IWC with the post-fracture IWC values. The IWC results clearly show elevated connectivities reflecting the presence of conglomerate. The model also captures differences between pre- and post-fracturing connectivities. The direction of the largest IWC change agrees with the expected maximum stress (fracture) direction (NE-SW) in the Western Canada Sedimentary Basin. The matches to measured production are very good, 0.76 < R2 < 0.95.

With the new method, we do not need to include all nearby wells in the window and it tolerates the changes in an estimate accounting for the storage effect and long production well shut-in periods during analysis (tshut-in > 12 months). Due to the windowing capability, the method also enables us to make local IWC evaluations accurately in large tight reservoirs where injectors might have a similar injection profile. The field data illustrate the method's utility and insights it brings.
A Non-Damaging Friction Reducing Agent for Slick-Water Fracturing
Authors: Ibrahim Ahmed F. , Nasr-El-Din Hisham A. , Rabie Ahmed , Lin Genyao , Zhou Jian , Qu Qi
Published: April 2016

Friction reducers (FRs) are crucial components in any slickwater fracturing fluid. Revising the previous literature showed that the majority of research focused on evaluating the friction-reduction performance of these chemicals. Another important aspect, which a few studies addressed, is the potential damage friction reducers can cause, especially to low-permeability formations.

Friction reducers are polymeric in nature (typically polyacrylamide); therefore, they can either filter out onto the surface of the formation or penetrate deeply to plug the pores. Breaking these polymers at temperatures lower than 200°F remains a challenge. This work evaluates a non-damaging and breakable friction reducer that can be a replacement for liner gel with enhanced proppant-carrying capacity.

Friction-reduction performance, proppant settling, breakability, and coreflood experiments were conducted to investigate the new friction reducer (FR1) in terms of friction-reduction, breakability, and the potential damage it might cause to tight sandstone cores at 150°F. The results of the new friction reducers were compared against two conventional friction reducers; one polyacrylamide-based (FR2), and one guar-based (FR3). Different breakers were used to examine the breakability performance; ammonium persulfate (APS), sodium persulfate (SPS), hydrogen peroxide (H2O2), and sodium bromate (SB).

The friction reduction of the new chemical was always higher than 65% in both fresh water and 2 wt% KCl. The presence of calcium chloride did not affect the friction-reduction performance, compared to performance reduction in the cases of FR2 and FR3. The presence of 1 gpt of different types of breakers did not affect the friction-reduction performance, even for stronger breaker (friction-reduction performance was 67% with APS breaker comparing to 68.5 % with no breaker). The new friction reducer is easily breakable in the three tested breakers: ammonium persulfate, sodium persulfate, and hydrogen peroxide. Among the three, ammonium persulfate was the most efficient breaker. Static and dynamic proppant settling tests indicated a superior performance of FR1 compared to the other conventional friction reducer (FR2). Coreflood experiments showed that the new friction reducer FR1 did not result in any formation damage with APS breaker at low KCl concentration (5 wt%) and high KCl concentration (20 wt%). A 9% formation damage was observed at weaker breaker (SB), comparing to 47 and 41.5% damage when the other two conventional friction reducers FR2 and FR3 were tested, respectively. The proposed friction reducer has higher friction-reduction performance and better proppant-carrying capacity with no formation damage compared to the conventional friction reducers.
Conductor-Soil Interaction in Wellhead Motion (WHM) of Platform Wells
Authors: Sathuvalli U. B. , Suryanarayana P. V.
Published: April 2016

During production in prolific high temperature (HT) platform wells, the forces exerted by the inner strings can cause noticeable Wellhead Motion (WHM). The thermal forces created by the inner strings are balanced by the conductor (structural casing), and finally by the friction between the conductor and the formation. Depending on the shear stress profile at the conductor-soil interface, the point of fixity (POF) of the structural casing may lie below the mudline (ML), and gross motion in the subterranean section of the conductor can occur. When the shut-in well cools back to the undisturbed state, the thermal forces disappear. Due to the anisotropic nature of the frictional forces, the wellhead does not always return to its original position, and a fraction of the overall wellhead (WH) displacement is locked in at the mudline. This phenomenon recurs during subsequent production and shut-in cycles and it can lead to ratcheting. Ratcheting becomes a critical issue when the net thermal force on the wellhead is an appreciable fraction (or exceeds) the pullout capacity of the pile.

Current models to assess WHM regard the inner casings as elastic springs that are attached between the wellhead and the POF. The conductor-soil interaction or the casing-cement interaction below the POF are traditionally addressed by a finite element analyses (FEA). In this paper we discuss the importance of the anchoring shear stress at the conductor-soil interface and provide methods to assess its orders of magnitude. We present solutions to frequently encountered problems in operational and design situations where sections of casing below the assumed TOC come loose or when the subterranean motion of the conductor is appreciable. These solutions can be used in lieu of FEA. By coupling the results of this model with the t-z response of pile driven conductors (as per API RP 2GEO), we present semi-analytical models that are applicable in a wide variety of wellhead loading situations.
Pseudo Density Log Generation Using Artificial Neural Network
Authors: Long Wennan , Chai Di , Aminzadeh Fred
Published: April 2016

Reservoir characterization is often a demanding and complicated task due to the nonlinear and heterogeneous physical properties of the subsurface environment. Those issues can be overcome accurately and efficiently by the use of computer-based intelligence methods such as Neural Network, Fuzzy Logic and Genetic Algorithm. This paper will describe how one integrates a comprehensive methodology of data mining techniques and artificial neural network (ANN) in reservoir petrophysics properties prediction and regeneration. Density log, which acts as a powerful tool in petrophysical properties indication, is often run over just a small portion of the well due to economic considerations, the borehole environment or operation difficulties. Furthermore, missing log data is common for old wells, and wells drilled by other companies. Working towards a resolution to these challenges, we will demonstrate successfully constructed automatic system which includes well logging data preprocessing, data mining technologies and ANN prediction. Based on one field case study, this methodology was proficient and stable in pseudo-density log generation.
Analytical Modeling of Flow in Highly Disordered, Fractured Nano-Porous Reservoirs
Authors: Albinali Ali , Ozkan Erdal
Published: April 2016

Conventional porous-medium-flow models are not suitable for naturally fractured, nano-porous reservoirs where the conditions of the continuum assumption do not hold. Due to the abrupt pore-scale variations and severe contrast between matrix and fracture characteristics, the velocity fields over nano-porous unconventional reservoirs display sharp discontinuities and irregular fluctuations. These heterogeneous velocity fields cannot be represented by Darcy's Law, which relates fluid velocity to an instantaneous, local pressure-gradient. An alternative approach is to use anomalous diffusion over a highly heterogeneous velocity field. This paper considers transient, single-phase production from a fractured horizontal well in an unconventional reservoir and uses anomalous diffusion to represent flow in the naturally fractured region between hydraulic fractures. The anomalous-diffusion model combines a time-fractional flux law and classical mass balance to describe sub-diffusive flow in natural fractures, in matrix, or both. The solution of the model is obtained within the framework of fractional calculus. Comparison with established and published solutions shows excellent agreement. Sensitivity analyses indicate that the proposed model can be used to describe a wider range of flow heterogeneity without need for the intrinsic details of the matrix and natural fracture properties.
Girouxville East Montney Waterflood
Authors: Pyo David , Pyo Ken , James Erin , Alwast Norbert
Published: April 2016

This paper presents the design, current status and future expansion plan of the waterflood scheme in the Girouxville East Lower Triassic Montney reservoir, which is located about 350km north-west of the city of Edmonton, Alberta, Canada (Figure 1). The Girouxville East Montney reservoir is a structural trap and is composed of predominantly marine interbedded shales, siltstones and dolomitic sandstones. The reservoir produces 30 – 32 °API crude oil and is a saturated hydrocarbon system with an up-dip gas cap and a down-dip water zone with unusually long oil-water and gas-oil transition zones. The reservoir was initially developed in the early 1990's with vertical wells targeting the up-dip gas cap. Over the last 4 years the down dip oil leg has been targeted and developed exclusively with horizontal drilling technology coupled with multi-stage hydraulic fracturing. This technology has been instrumental to improve well productivity and oil reserves. However, oil recovery under primary depletion still has been low, often less than 5% of original oil-in-place (OOIP), due in large part to local pressure depletion caused by large reservoir withdrawals including formation water and gas. This sets the stage for improved oil recovery via waterflood.

A small water injection pilot was initiated in October 2013 with a single water injector to alleviate reservoir pressure depletion in the local area. The results were encouraging, and the project has been expanded to a larger scale waterflood scheme in 2015, which currently consists of 6 horizontal producers and 4 horizontal water injectors. A 388 ha (1½ sections) waterflood expansion was designed based on comprehensive geological and engineering evaluations. A detailed geomodel was created with available core data, well petrophysical analyses, horizontal well geologic descriptions and seismic data in the area; the Montney formation was subdivided into 4 coarsening-upward cycles, with 6 facies identified within. Dynamic reservoir simulation was initiated by importing data from the geomodel. Reservoir and well properties were fine-tuned with a high-quality history. Multiple forecast scenarios were run to determine an optimal waterflood recovery scheme.

Within half a year most offsetting oil producers have shown positive response to water injection with an increase in total fluid and gradual decrease in the producing gas-oil ratio (GOR). The oil rate decline has slowed down significantly with anticipated incremental oil recovery of 5 – 7% OOIP over the primary depletion. Further expansion has been identified in the oil-leg of the surrounding sections. The waterflood design will focus on down-dip injection to maintain more gravity stable injection water fronts along the field oil-water contacts for optimum pressure support and oil displacement.
Relative Viscosity of Hydraulic Fracturing Fluids Containing Nanoparticles
Authors: Fakoya M. F. , Shah S. N.
Published: April 2016

The concept of relative viscosity is widely used in literature for describing the rheological behavior of Newtonian and non-Newtonian fluids containing particles. Generally, nanoparticles are used at low concentrations; but Einstein equation hardly predicts the suspension viscosity values. Similarly, equations developed for high particle concentrations hardly made the predictions too. This paper presents the inability of Einstein and Krieger-Dougherty equations in predicting the relative viscosity of surfactant-based fluids (SBF), polymeric fluids, and SBF-polymeric fluid blends.

Concentrations of 5% and 33 lb/Mgal guar were used for the laboratory preparation of SBF and polymeric fluids respectively, and both fluids contained 4% potassium chloride (KCl). Also, the mixture of SBF and polymeric fluids in the ratios of 3:1 (vol.) and 1:3 (vol.) resulted into Blend-A and Blend-B fluids respectively. The addition of 20 nm silica nanoparticles, at concentrations of 0.058, 0.24, and 0.4% wt., to the clean fluids generated the nano-fluids. Rheological data were gathered with Bohlin CS-50 rheometer within a temperature range of 75 to 175 °F.

Silica nanoparticle concentrations of 0.058, 0.24, and 0.4% wt. were converted to 0.0083, 0.034, and 0.055 solid volume fractions respectively. Relative viscosity values could not be predicted using Einstein and Krieger-Dougherty equations. The nano-fluids display both increase and decrease in suspension viscosity; furthermore, their suspension viscosities were dependent on the solids volume fraction, temperature, and shear rate (9 to 1026 sec−1.). Lastly, relative viscosity correlations (that covered the whole range of values for which the experiments were conducted), previously developed by the authors, were included for complementary purpose. The correlations predict the viscosity of nano-suspensions as a function of solid volume fraction, temperature, and shear rate.

This work provides an insight into the behavior of suspension at nano-scale level. The prediction of viscosity of nano-suspensions depends on more than one parameter. Moreover, this study will facilitate the field application of these novel hydraulic fracturing fluids.
Possible Misinterpretations in Well Test Analysis Due to Unfiltered Tidal Signal
Authors: Gowtham T , Rouzbeh G. Moghanloo , Vamsi Krishna B , Srikanth P
Published: April 2016

This paper presents the most common misinterpretations in pressure transient analysis owing to unfiltered tidal signal in well test data. Pressure transient analysis gives reservoir engineers an idea about permeability, different components of skin, reservoir model, as well as reservoir geometry. While collecting downhole pressure data, the reservoir engineer is mainly concerned about pressure changes due to fluid flow in porous media. However, the downhole pressure data is affected by a few unavoidable natural phenomena. One of such natural phenomena is the tidal effect in offshore wells and on-land wells near to the shore. Most of the times tidal signals are filtered with the help of pressure recorded by sub-sea pressure gauges and maritime tide tables. However, when those data are not available, or in case of SRO (surface read-out) without provision for filtering tidal signal, build-up data is analyzed without filtering tidal signals.

This paper discusses how tides with different time and amplitudes effect the interpretation of build-up tests having various QBμkh values. [GR1] Tidal signals that have different amplitudes and time periods were superimposed on pure build-up pressure of infinite acting radial model data, and an interpretation of results were compared.

Our results suggest that the early time region of the pressure build-up is not significantly affected by the tidal signal because of the steep increase in pressure. If the build-up test is continued for a significantly long time, even after pressure stabilization (not practical), tidal signals could be identified on a log-log plot by inverted U shape patterns. However, in the case of build-up studies, which are not sufficiently continued, it is likely that geneous infinite acting reservoirs are interpteted as parallel fault, U shaped fault or closed boundary models.

Several possible misinterpretations owing to the presence of diurnal and semi diurnal tidal signals in build-up data are listed in this paper. It has to be ensured that pressure transient data is free of tidal signal before concluding any boundary presence. Unfilterd tidal signals in the pressure transient data may lead to interpretation of unrealastic boundaries. The outcome of this research will help reservoir engineers avoid misinterpreting pressure transient data.
Cointerpretation of Distributed Acoustic and Temperature Sensing for Improved Smart Well Inflow Profiling
Authors: Bukhamsin Ahmed , Horne Roland
Published: April 2016

Current advances in the well completion technology have allowed for more complex smart well instrumentations with marginal additional cost. As an example, optical fibers can be run along horizontal wells to provide acoustic and temperature data that are distributed both in time and space. With such data at our disposal, an immediate evaluation of the well response is possible as changes in the reservoir or well occur. Most current work in distributed measurements looks at Distributed Acoustic Sensing (DAS) or Distributed Temperature Sensing (DTS) data individually, which limits our inferences about the multiphase flow problem. The objective of this work was to look at the two pieces of data together and determine what improvements can be achieved in multiphase flow problems compared to the conventional methods of looking at each DAS and DTS alone.

The study began by evaluating the performance of DAS in analyzing two-phase flow; a process which begins by extracting the speed of sound within the fluid medium from the acoustic signal, then obtaining the phase fraction combination that obtains this speed of sound reading. Another procedure is explained to obtain similar results from DTS measurements. In this case, however, the in-situ phase fractions are correlated to the Joule-Thomson effect as reservoir fluids enters the wellbore. As both these procedures are limited to one- and two-phase flow applications, we extended the solution to work in three-phase flow problems by combining information from DAS and DTS.

The flow profiling procedure was applied to two smart wells in the Middle East. Flowrates from different segments of the well were calculated and results were in close agreement with a surface flowmeter for most sections of the well. In cases where both DAS and DTS were not available for the same well, a commercial compositional and thermal reservoir simulator was used to generate synthetic examples. By applying the developed procedure, we found that cointerpretation of DAS and DTS data yields accurate in-situ three-phase fractions for all ranges of water cuts and gas volume fraction. In comparison, analyzing DAS or DTS individually is usually not sufficient to fully determine a three-phase flow problem.
Nanotechnology Improves Wellbore Strengthening and Minimizes Differential Sticking Problems in Highly Depleted Formations
Authors: Al-Haj Hussain , Al-Ajmi Abdullah , Gohain Ashis Kumar , Al-Rushoud AbdulAziz , Khatib Faiz Ismail , Soliman Ahmed Hussein , Al-Mujalhem Manayer , Fathallah Mohamed Omar , Ibrahim Ahmed Samir
Published: April 2016

It is a challenge to drill in highly deviated or horizontal holes with high differential pressures. Wellbore instability, differential sticking and mud loss are frequently encountered problems while drilling slanted wells in Kuwait across shale and sand series. Drilling became more challenging with considerable non-productive time. Therefore, it is necessary to identify a fluids solution when other options with casing zone isolation are not viable. Traditionally, oil-based mud (OBM) was used while drilling these formations with limited success.

A customized fluid system was designed to overcome the issue of high overburden pressure in shale and sand series formations targeting effective bridging, minimizing pore pressure transmission, and strengthening the wellbore. A nano-size deformable synthetic polymer, along with sized calcium carbonate and graphite, was identified to effectively plug the pore throats and minimize fluid invasion, which was confirmed by particle plugging tests.

A well section was identified to comingle the highly depleted and pressurized formations. This was the first attempt on a high-angle well with development drilling operations in Kuwait and was performed to facilitate the successful drilling of the reservoir. Traditional OBM was converted to a customized fluid system using a nano-size polymer and sized bridging additives based on proprietary software selection and a series of laboratory tests. Drilling and logging were successfully performed for the first time in the commingled section without incident. There was no wellbore instability or differential sticking tendencies, less torque and drag, as well as enhanced wellbore cleaning in the high-angle sections.

This paper also presents some successful applications of the nano-size deformable polymer in OBM to drill highly depleted formations in HTHP wells managing up to 3500 psi overbalalnce across highly permeable formations.
Saproxylic Beetle Biodiversity in Golf Course Habitats
Authors: Powell Gareth S. , Shukle John T. , Richmond Douglas S. , Holland Jeffrey D.
Published: April 2016

Saproxylic beetles are a diverse group of insects that use deadwood as food or habitat at some stage of their life. While a few species of saproxylic beetles are considered to be pests, the majority of species perform important ecological roles such as decomposition, nutrient recycling, pollination in the mobile adult form, or act as food sources for other organisms. Their diversity and variable responses make them good biological indicators. Promoting biodiversity in managed areas, such as golf courses, may be relatively easy by creating saproxylic habitat. We examined the influence on saproxylic beetle communities of habitat type, log type, and distance from a fairway. Sentinel logs were provided for colonization for one season, and emergence was monitored over the following 2 years. We found that beetle species richness increased with log volume but did not change with distance from the fairway playing surface. Our findings suggest that although species richness may be low compared with that in less fragmented habitats, a diverse assortment of saproxylic beetles can be supported in golf course wooded habitats. This may be accomplished by leaving fallen trees in place when they do not pose a hazard or interfere with play. In particular, the provision of large woody debris that is more difficult to remove may maximize the benefit to superintendents and the saproxylic beetle community. Findings also support the idea that golf courses containing woody patches may increase habitat connectivity for these insects, and possibly other organisms, in otherwise highly fragmented urban areas.
Solubilization of Polycyclic Aromatic Hydrocarbons by Single and Binary Mixed Rhamnolipid–Sophorolipid Biosurfactants
Authors: Song Dandan , Liang Shengkang , Yan Lele , Shang Yujun , Wang Xiuli
Published: April 2016

Biosurfactants are promising additives for surfactant enhanced remediation (SER) technologies due to their low toxicity and high biodegradability. To develop green and efficient additives for SER, the aqueous solubility enhancements of polycyclic aromatic hydrocarbons (PAHs; naphthalene, phenanthrene, and pyrene) by rhamnolipid (RL) and sophorolipid (SL) biosurfactants were investigated in single and binary mixed systems. The solubilization capacities were quantified in terms of the solubility enhancement factor, molar solubilization ratio (MSR), and micelle‐water partition coefficient (Km). Rughbin's model was applied to evaluate the interaction parameters (β) in the mixed RL–SL micelles. The solubility of the PAHs increased linearly with the glycolipid concentration above the critical micelle concentration (CMC) in both single and mixed systems. Binary RL–SL mixtures exhibited greater solubilization than individual glycolipids. At a SL molar fraction of 0.7 to 0.8, the solubilization capacity was the greatest, and the MSR and Km reached their maximum values, and β values became positive. These results suggest that the two biosurfactants act synergistically to increase the solubility of the PAHs. The solubilization capacity of the RL–SL mixtures increased with increasing temperature and decreased with increasing salinity. The aqueous solubility of phenanthrene reached a maximum value at pH of 5.5. Moreover, the mixed RL–SL systems exhibited a strong ability to solubilize PAHs, even in the presence of heavy metal ions. These mixed biosurfactant systems have the potential to improve the performance of SER technologies using biosurfactants to solubilize hydrophobic organic contaminants by decreasing the applied biosurfactant concentration, which reduces the costs of remediation.

Core Ideas

Micellization behaviors of rhamnolipid–sophorolipid systems (RL–SL) were investigated.

Mixed RL–SL systems generally enhanced the water solubility of PAHs.

Mixed biosurfactant systems might be used for surfactant‐enhanced PAH remediation.
Aeration‐Induced Changes in Temperature and Nitrogen Dynamics in a Dimictic Lake
Authors: Holmroos Heidi , Horppila Jukka , Laakso Sanna , Niemistö Juha , Hietanen Susanna
Published: April 2016

Low levels of oxygen (O2) in the hypolimnion layer of lakes are harmful to benthic animals and fish; they may also adversely affect nutrient cycles. Artificial aeration is often used in lake management to counteract these problems, but the effects of aeration on nitrogen (N) cycling are not known. We studied the effects of hypolimnetic aeration on N dynamics and temperature in a eutrophic lake by comparing continuous and pulsed aeration with a nonaerated station. Aeration decreased the accumulation of NH4+–N deep in the lake (20–33 m) by supplying O2 for nitrification, which in turn provided substrate for denitrification and promoted N removal. Aeration also increased the temperature in the hypolimnion. Denitrification rate was highest in the nonaerated deep areas (average, 7.62 mg N m−2 d−1) due to very high rates during spring turnover of the water column, demonstrating that natural turnover provides O2 for nitrification. During stratification, denitrification was highest at the continuously aerated station (4.06 mg N m−2 d−1) and lowest at the nonaerated station (3.02 mg N m−2 d−1). At the periodically aerated station, aeration pauses did not restrict the increase in temperature but resulted in accumulation of NH4+–N and decreased the contribution of denitrification as a nitrate reduction process. Our findings demonstrate that hypolimnetic aeration can substantially affect N cycling in lakes and that the effect depends on the aeration strategy. Because N is one of the main nutrients controlling eutrophication, the effects of aeration methods on N removal should be considered as part of strategies to manage water quality in lakes.

Core Ideas

Continuous hypolimnetic aeration prevented NH4+ accumulation in a lake at 20–33 m depth.

Continuous aeration promoted denitrification by enabling nitrification.

Periodical aeration did not restrict temperature changes, but NH4+ was accumulated.

Denitrification rate decreased during aeration pauses.

Benthic N removal in a lake can be enhanced via hypolimnetic aeration.
Effect of a Biological Additive on Nitrogen Losses from Pig Slurry during Storage
Authors: Provolo Giorgio , Finzi Alberto , Perazzolo Francesca , Mattachini Gabriele , Riva Elisabetta
Published: April 2016

Additives applied to animal manure slurries can affect the chemical composition and the biological processes of slurries during storage, with possible improvement of their management and reduction of environmental problems. Some new formulations are marketed claiming a nitrogen (N) removal effect due to denitrification, with the consequence of a reduced N content in the manure after storage. This study evaluated the effects of one of these commercial additives (BACTYcomplex) on slurry characteristics and N losses at a commercial piggery. The additive was applied to four different sectors of the piggery, each with an independent under‐floor slurry pit; four other sectors served as controls without treatment. Pits were emptied every 4 wk, and the manure was analyzed for total and ammonia‐N and total and volatile solids. Slurry samples from the last month of the on‐farm assessment were removed and stored thermostatically in vessels external to the piggery. A subsample of slurry that was treated with the additive at the piggery was treated with an additional dose of additive at the beginning of long‐term storage. The additive did not change the composition of the slurry during in‐house storage (4 wk duration). During the 155 d of external thermostatic storage, the total solids content of treated slurry was reduced by 18% compared with control slurry, but the N content and composition of treated slurry was unaffected. The additive had a positive effect in accelerating the stabilization of the slurry but did not modify N losses.

Core Ideas

A new biological additive with denitrification enhancement capability was tested.

The additive increased the total solids reduction during 6 mo storage of the slurry.

The total and ammonia‐N losses were not affected by the additive.

The additive promoted stabilization of slurry but did not reduce N content.
Analisis Metode Belajar Kosa Kata
Authors: Robihim Robihim
Published: April 2016

Many jobs fields needed foreign language skills, such as Japanese. To comprehend the Japanese text, people must understand Japanese characters like Hiragana, Katakana, and Kanji because three of them were always used in Japanese text. Learning Hiragana and Katakana usually were taught in elementary level then secondary and high levels have more Kanji usages. Learning Japanese kanji meant learning vocabulary too. But, learning kanji had to be continuos and routine, because kanji had more than one meanings. Kanji did not only one meaning. So, we should know the meaning of the interrelated other kanji writing. To make easy in reading to read Japanese texts, certainly we should know kanji characters and the meanings.
Aspek Semantik dan Pragmatik dalam Penerjemahan
Authors: Pelawi Bena Yusuf
Published: April 2016

Research deployed translation issues, mainly concerning from semantic and pragmatic aspects. Discussion was started by stating the importance of linguistic aspects comprehended and applied by a translator, such as grammar, phonology, morphology, syntax, semantics, pragmatics, sociolinguistics, and psycholinguistics. Research presented six meaning problems in translation, those related to lexical meaning, grammatical meaning, contextual meaning or situational meaning, textual meaning, socio-cultural meaning, and idiomatic meaning. It can be concluded that the ability to apply linguistic aspect both from the source and targeted languages take important role to produce a good translation.
Analisis Kesalahan Penggunaan Hyoogen “temo ii” Dalam Bahasa Jepang Pada Mahasiswa Upi Bandung
Authors: Juangsih Juju , Aneros Noviyanti
Published: April 2016

This research will study the use of “temo ii” of 31 students seventh semester in UPI. This study uses analysis descriptive method by collecting data from students to take 20 questions. It can be concluded that the understanding of the use of “temo ii” of students show good scores about 53,39 % at average. There are three students who get 14 points (70%) which is the highest score. On the otherhand there is one student who gets 5 points (25%) which is the lowest score. Although the result shows they are above average, but some students still missuse the word “temo ii”. Moreover, they think the word “boleh” in Indonesia can be replaced by “temo ii”. However, the word “boleh” can not usualy be defined by “temo ii”.
The Dynamic Identity: Analysis Of Gender Identity In Breakfast On Pluto By Patrick Mccabe
Authors: Ayuningtyas Paramita
Published: April 2016

Article focused on gender identity in Breakfast on Pluto by Patrick McCabe. By using Stuart Hall’s concept of identity, the analysis showed that gender identity had the potential to be deconstructed, as shown by the identity transformation done by Patrick Braden. Positioning by other people and his own body happened to be barriers for his identity transformation. However, those barriers basically could not stop Patrick’s transformation to be a woman. Patrick had its own strategies in changing his gender identity, which were gender deconstruction, body decoration, and language. It can be concluded that Breakfast on Pluto offers a discourse of identity that is dynamic. Identity is a becoming process that will happen endlessly in human’s life.
The Condition Of Mandarin Language Learning In Indonesia
Authors: Shenglin Zhang , Ying Yi
Published: April 2016

The condition of Mandarin language learning in Indonesia was still a main issue for Mandarin lecturers and researchers in China and Indonesia. To find out the clear condition, a research having a combination of qualitative and quantitative methods was done, in which questionairs were distributed and interviews with Mandarin students, lecturers, and experts were conducted. Respondents were selected by random sampling. After data analysis, a conclusion which indicates a general condition and some problems in the process of teaching and learning Mandarin, as well as the use of learning materials can be presented. The research results show that at present, the Mandarin learners are still dominated by the descendants of Tionghoa, even though learners coming from non-Tionghoa’s descendants are getting increase; learners’ motivation in studying Mandarin is closely related with the self-identity as Tionghoa’s descendants and the job’s demands; Mandarin language still belongs to the second language in Indonesia and has not able to replace the domination of English; the insufficiency of lecturers and learning materials in the past have significantly provided, but this condition has not solved the problems, especially which concerns to the improvement of the quality of learners and local learning materials.