bluuebunny/crossref_metadata_2025_split huggingface dataset:
Permeability Limits of Advanced Water Injection Technology in Low Permeability Reservoirs
Authors: Wang Shuai , Tian Ji , Tan Xianhong , Wang Ling , Zhang Shaohui 
Published: October 2016

Abstract
The low permeability reservoir development effects can be effectively improved with the use of advanced water injection technology, which means the water is injected several months before the oil production. Advanced water injection can improve the formation pressure in advance, and establish an effective displacement system. However, with the increase of reservoir permeability, the increasing value of recovery tends to decline in advanced water injection. Therefore, it is necessary to study the permeability limits of advanced water injection.
In this paper, the laboratory experiments of the low permeability natural core from A oilfield were carried out, and the changes of core permeability, pore structure and oil displacement efficiency in advanced water injection were analyzed. Meanwhile, the changes of sweep efficiency and recovery in advanced water injection were figured out with numerical simulation method, and the effect of advanced water injection tested in A oilfield was analyzed.
The results of the laboratory experiments showed that, for the cores of permeability less than 10.0 mD, as the core pressure drops from 19.0 MPa to 17.0 MPa, the permeability declines by 15.0 percentage points. When the pressure is restored, the degree of permeability recovery is 2.0 percentage points. Also, with the pressure increase, the oil displacement efficiency of the core permeability less than 10.0 mD increase 1.2 percentage points, while the oil displacement efficiency of the core permeability above 10.0 mD increase only 0.3 percentage points. The results of numerical simulation showed that, with the use of advanced water injection in the formation of permeability less than 10.0 mD, the sweep efficiency increases by more than 5.0 percentage points and the ultimate recovery increases by more than 0.4 percentage points.
In addition, the effect of advanced water injection tested in A oilfield was much better than that of the conventional water injection oilfield. The daily single well oil production was 1.6 multiple higher than that of the conventional water injection oilfield, and the annual decline rate was 13.0 percentage points lower than that of the conventional water injection oilfield.
Taken together, the permeability limits of advanced water injection is 10.0 mD, and better development effect and higher recovery can be obtained with advanced water injection technology for reservoirs of permeability less than this value.
This paper can provide a reservoir screening criteria for the advanced water injection technology and can guide the further application of this technology in low permeability reservoirs.
Upscaling Technique for High Resolution Coal Bed Methane Reservoir Model
Authors: Sugiarto I. , Mazumder S. , Gan T. 
Published: October 2016

Abstract
Upscaling of a reservoir model is normally conducted when a high resolution model has been generated and it is practically impossible to run the simulation using a high resolution model. Reservoir model upscaling is done in order to have a reasonably coarse model for reservoir history matching and forecasting purposes without losing some of heterogeneity in the reservoir model. A high resolution static coal reservoir model (around 0.1 metre thickness) is generated based on the detailed single coal ply correlation in order to capture complexity and heterogeneity of the coal sediment. A case study is presented in this paper.
Several upscaling methods for reservoir properties such as permeability and gas content were tested and analyzed. The upgridding process on the geocellular model mainly focused on vertical direction in order to identify which ply could be merged into the sub layer level. The next step identifies whether the ply can be merged with neighboring ply individually. The results of the upscaling and upgridding are analyzed using the combination of recovery ratio, simulation running time ratio and cell count ratio plot. Histogram and area map analysis is also used to evaluate the result of the upscaling work.
The expected results of the upscaled model are lower running time, lower cell count and very close recovery value to the high resolution model, while still capturing the heterogeneity. The results of the upscaling exercise for this case are reduction of running time by 72%, reduction of the cell count by 64% and recovery difference of 3%. Some of the plies in one of the layers cannot be merged into a sub layer level which indicates a high degree of heterogeneity. This upscaling technique for the coal reservoir model provides more information about the reservoir characterization methodology for unconventional reservoirs, and coal bed methane reservoirs specifically.
Characterising the Behaviour of Hydraulic Fracturing Fluids via Direct Numerical Simulation
Authors: Leonardi Christopher R. , Regulski Wojciech , McCullough Jon W. , Wang Duo , Mitchell Travis R. , Jones Bruce D. , Williams John R. 
Published: October 2016

Abstract
Current design tools used for predicting the placement of proppant in fractures are based on the solution of a simplified conservation equation that is heavily dependent on empirical relationships for particle settling and suspension viscosity. In light of these shortcomings, this paper presents the development of a computational fluid dynamics (CFD) model capable of micromechanical simulation of hydraulic fracturing fluids. The model developed in this research employs the discrete element method (DEM) to represent the proppant for a range of sizes and densities. For the fluid phase, the lattice Boltzmann method (LBM) is utilised in a generalised-Newtonian form. Full hydrodynamic coupling of the LBM and DEM is achieved via an immersed moving boundary condition. The developed model has the ability to simulate Navier-Stokes hydrodynamics, a range of rheological models (e.g. Bingham, power law), thermal effects as well as electromagnetic and electrostatic forces between particles and walls. The model captures the detailed interactions of proppant particles as well as the non-Newtonian rheology of the fracturing fluid in both experimental and fracture geometries. Simulations of small-scale experiments are used to describe suspension rheology as a function of proppant concentration while small-scale fracture models explore the settling and injection of a number of candidate formulations. These results show that the direct numerical simulation (DNS) approach presented in this paper represents a potentially valuable complement to contemporary models which can provide insight on the rheology of new or novel fracturing fluid formulations as well as explore the influence of complex in-situ features on the efficacy of a hydraulic fracture. More detailed knowledge of how proppant is transported from the wellbore to the fracture tip will provide insights that could be used in the optimisation of the hydraulic fracturing process. This is particularly relevant in coal seam gas reservoirs which can include bi-directional fracture networks, non-planar fracture paths, interburden terminations and other leak-off points.
Well Failure Mechanisms and Conceptualisation of Reservoir-Aquifer Failure Pathways
Authors: Wu B. , Doble R. , Turnadge C. , Mallants D. 
Published: October 2016

Abstract
This paper presents a critical review of literature on bore and well failure mechanisms and rates, and conceptualisations of probable reservoir-aquifer failure pathways. The objective was to gain a better understanding about bore and well induced inter-aquifer connectivity and the potential consequences to groundwater resources. This comprehensive review included Australian and international literature on onshore conventional oil and gas wells, water bores, coal seam gas wells and coal exploration bores. Failure mechanisms and rates were discussed for the entire well life cycle. Reservoir-aquifer failure pathways were then conceptualised based on the failure mechanisms and risk analyses considering the likelihood of failure and detection, repair and potential impacts on hydrogeology.
Aquitard and Fault Simulation Approaches for Use in Regional-Scale Assessments of Coal Seam Gas Extraction Impacts
Authors: Turnadge C. , Mallants D. , Peeters L. 
Published: October 2016

Abstract
Low permeability formations (aquitards) and geological faults play a key role in determining the degree of isolation of groundwater resources (aquifers) from hydrocarbon reservoirs. Reliable assessment of the potential risks associated with groundwater extraction and depressurisation for coal seam gas (CSG) development necessitates accurate characterisation of aquitards and faults and incorporation in regional-scale groundwater flow models. We provide an overview of a range of approaches by which aquitards and faults may be represented in such models. A range of approaches that may be used to upscale and spatially interpolate aquitard hydraulic properties for inclusion in regional-scale groundwater flow models was examined. These methods vary in complexity and in the level of data support required. They range from simple analytical averaging approaches and flux-based methods to complex approaches based on geostatistical characterisation and facies reconstruction. Representations of geological faults and associated fracture systems in groundwater flow models include the common use of transmissibility multipliers to represent faults. For the simulation of groundwater flow in fractured porous media, three categories of methods are available, ranging in complexity from equivalent porous media approaches to discrete fracture network models. A review of regional-scale groundwater flow models developed for Australian CSG impact assessments identified that aquitard heterogeneity and geological faults are typically omitted or highly simplified. For aquitards, simplifications typically involve neglecting the spatial heterogeneity of hydraulic properties through the adoption of spatially uniform values. For geological faults and fault networks, a paucity of data currently exists with regards to both fault architecture (e.g. orientation, location, size and frequency) and flow properties of faults.
Revisiting the Ideal Packing Theory with a Novel Particle Size Measurement Approach
Authors: Amer A. , Carter B. , Hudson II E. , Du H. , Judd C. 
Published: October 2016

Abstract
Drilling into production zones requires the use of special fluids with minimal formation damage potential. These fluids typically include a blend of carefully designed bridging particles. The selection of these bridging particles is based on particle size distribution (PSD) and may include other attributes such as acid solubility depending on type of rock and the well completion method. One of the theories that addresses the design of these fluids is the Ideal Packing Theory (IPT).
Two of the most common ways to obtain PSD are laser diffraction (LD) and sieve analysis (SA). Each method has its own bias in measurement. For instance, SA tends to emphasize the second largest dimension of a particle (Kumar et al. 2013) while LD calculates PSD based on the assumption all particles are spheres. Particles in drilling fluids are not all spherical, therefore it was deemed worthwhile to investigate PSD measured by other techniques such dynamic imaging analysis (DIA) which takes in consideration the parameter aspect ratio when generating its PSD.
Sphericity of the bridging particles is a key assumption for the IPT to work. However, the use of dynamic image analysis (DIA) in the field of particle characterization in drilling fluids has led to significant findings. A key finding is that most bridging particles used are neither spherical nor uniform.
This study evaluates whether there are differences in the PSD results for the same sample of bridging particles. The study then examines the effect of using the data from the various PSD techniques on the bridging algorithm thus impacting the fluid sealing ability of porous media represented by ceramic disks.
This study also examines the phenomena of "packing behavior randomness" and its impact on porosity and permeability of blends of bridging particles.
Development of a Novel Sand Retention Cell
Authors: Wu B. , Lupton G. , Barton T. , Denke R. , Wong C. Y. , Feng Y. , Boulanger J. , Choi S. K. 
Published: October 2016

Abstract
Sand screens are widely installed to control unacceptable amount of sand produced from oil and gas wells. Sand retention tests are often used to select optimal sand screen size that minimizes sand production and maximizes hydrocarbon production. However, there is currently no agreed industry standards as to how the tests are conducted and results interpreted. This paper presents development of a novel sand retention cell and the associated experimental procedure with the objective to overcome some of the limitations in the existing sand retention tests. The improvements incorporated into the new sand retention cell and experimental procedure include i) measurements of fluid pressures close to the screen surface and sand pack to allow in-situ measurement of the screen and sand pack permeabilities; ii) delivery of a uniform sand slurry over the entire screen surface that ensures formation of a uniform sand pack over the screen by using a heavy fluid; iii) transparent cell body to allow sand retention and production process to be visually observed and sand pack height to be measured; and iv) sand slurry flow as well as pre-pack sand retention test and assessment for fines migration through gravel pack.
Functional Features of the Pancreas during Chronic Pancreatitis
Authors: Shevchenko B.F. , Babiy A.M. , Tatarchuk O.М. , Makarchuk V.A. , Kudryavtseva V.E. 
Published: October 2016

Aim of study: to identify functional status of pancreas in patients with chronic pancreatitis depending on the stage of fibrotic transformation and activity of parenchymal inflammation. Materials and methods. The preoperative laboratory results and the data of morphological study performed on biopsies obtained during surgery in 88 patients with complications of chronic pancreatitis (CP) were compared. According to morphological study of pancreatic biopsies, the early pancreatic parenchymal fibrosis (I–II degree) has been diagnosed in 31 cases (35.2 %), late fibrosis (III–IV degree) — in 57 (64.8 %) cases. Results. Active parenchymal inflammation at early and late stages of pancreatic fibrosis are associated with changes in pancreatic secretion and intracellular activation of pancreatic enzymes, leading to autodigestion and release of these enzymes from acinar cells into the blood, which has been confirmed by an increase of trypsin and amylase activity in blood compared with inactive inflammation. At late stages of fibrosis reduction of fecal elastase‑1 (161.7 ± 4.8) mg/g was observed in 73.9 % of patients. Reverse correlation has been found between fibrotic transformation of pancreatic parenchyma and the level of fecal elastase‑1 (r = –0.46; p = 0.05), i.e. progressing fibrotic transformation of pancreas leads to reduced exocrine function. Correlation analysis showed that the progression of fibrotic transformation violates carbohydrate metabolism — a direct correlation with glycosylated hemoglobin (r = 0.496; p = 0.05), namely, the endocrine secretion deficiency. Novelty in science. The pancreas functioning was studied depending on the inflammation activity and stage of fibrosis transformation of its parenchyma at chronic pancreatitis. The active inflammation of the pancreas was found to be accompanied by significant activation of pancreatic enzymes (significant increase in blood amylase and trypsin activity), which causes the progression of fibrotic transformation of pancreas in CP. Conclusions. Progression of fibrotic transformation of the pancreatic parenchyma in CP leads to deterioration of the exocrine pancreatic function, as defined by a decrease in the level of fecal elastase‑1 in case of late fibrosis of the pancreas and to the deterioration of endocrine pancreatic function, as manifested by impaired fasting glucose metabolism both at early and late stages of fibrosis, the development of pancreatogenic type II diabetes at the early stages of pancreatic fibrotic transformation, insulin resistance and type I diabetes at later stages of pancreatic fibrotic transformation.
Kompensasi Pengurangan Subsidi Bahan Bakar Minyak Melalui Insentif Fiskal Pemerintah Pusat kepada Pemerintah Daerah
Authors: Kurniawan Dwi Ardianta , Wismadi Arif , Adji Artidiatun 
Published: October 2016

Subsidi Bahan Bakar Minyak di Indonesia meningkat secara tajam dalam beberapa tahun terakhir dengan rata-rata peningkatan sebesar 18,29% per tahun dalam periode 2006 – 2013. Besaran subsidi mengambil porsi antara 22% hingga 39,7% terhadap APBN pada periode tersebut. Tingginya besaran subsidi tersebut menimbulkan beban berat pada anggaran pemerintah pusat. Salah satu upaya untuk mengurangi beban pemerintah adalah dengan mengurangi jumlah subsidi yang diberikan. Pengurangan subsidi tersebut harus dikembalikan kepada masyarakat dalam bentuk yang lebih produktif, salah satunya dalam bentuk insentif fiscal pemerintah pusat kepada pemerintah daerah.
Mekanisme pemberian insentif kepada pemerintah daerah dapat dilakukan dengan mempertimbangkan kebijakan dan program yang dijalankan oleh pemerintah daerah untuk mengurangi konsumsi BBM. Metode perhitungan besaran insentif dapat dilakukan dengan beberapa skenario dengan mempertimbangkan penghematan anggaran pemerintah karena pengurangan subsidi dan perubahan Dead Weight Loss (DWL) sebagai kerugian yang timbul karena alokasi anggaran yang tidak tepat.
Hasil perhitungan besaran insentif fiskal berdasarkan skenario harga BBM memperlihatkan adanya perbedaan cukup signifikan antara skenario 1 yang berbasis besaran subsidi yang dikeluarkan pemerintah, dengan skenario 3 yang berbasis pada besaran DWL. Alternatifnya, dapat diperhitungkan besaran insentif berdasarkan proporsi pengurangan DWL dibandingkan penghematan anggaran. Hasil perhitungan berdasarkan skenario ini memperlihatkan besaran insentif antara Rp1,2 tilyun (pada harga bensin Rp7.100) hingga Rp3,3 trilyun (pada harga bensin Rp9.500 atau subsidi dicabut). Sementara pada solar, besarannya antara Rp1,08 trilyun (pada harga solar Rp7.100) hingga Rp2,97 trilyun (pada harga solar Rp9.500 atau subsidi dicabut). Besaran ini relatif moderat dan dapat menjadi acuan dalam pemberian insentif kepada daerah.
Progression of Interstitial Fibrosis during the First Year after Deceased Donor Kidney Transplantation among Patients with and without Delayed Graft Function
Authors: Heilman Raymond L. , Smith Maxwell L. , Smith Byron H. , Qaqish Ibrahim , Khamash Hasan , Singer Andrew L. , Kaplan Bruce , Reddy Kunam S. 
Published: October 2016

Background and objectives
Delayed graft function is a form of AKI resulting from ischemia-reperfusion injury. Our aim was to study the effect of delayed graft function on the progression of interstitial fibrosis after deceased donor kidney transplantation.

Design, setting, participants, & measurements
Our study is a retrospective study of all patients transplanted at our center between July of 2003 and September of 2014 using a kidney from a deceased donor. The primary outcome was the progression of interstitial fibrosis on serial protocol biopsies done during the first year post-transplant. We analyzed the distribution of the change in the Banff interstitial fibrosis (ci) score between the delayed graft function and nondelayed graft function groups for all of the paired biopsies done at time 0 and 12 months post-transplant (Δfibrosis). We also performed a linear mixed model analyzing the difference in the slopes for the progression of mean Banff ci score for all of the biopsies done at time 0 and 1, 4, and 12 months post-transplant.

Results
There were 343 (36.7%) in the delayed graft function group and 591 in the control group. The biopsy rates for the delayed graft function and nondelayed graft function groups at time 0 were 65.3% (n=224) and 67.0% (n=396), respectively, and at 12 months, they were 64.4% (n=221) and 68.4% (n=404), respectively. Paired biopsies were available for 155 in the delayed graft function group and 283 in the control group. In a risk-adjusted model, Banff ci score >0 on the time 0 biopsy had a higher odds of delayed graft function (odds ratio, 1.70; 95% confidence interval, 1.03 to 2.82). The distribution of the Δfibrosis between 0 and 12 months was similar in delayed graft function and control groups (P=0.91). The slopes representing the progression of fibrosis were also similar between the groups (P=0.66).

Conclusions
Donor-derived fibrosis may increase the odds of delayed graft function; however, delayed graft function does not seem to increase the progression of fibrosis during the first year after transplantation.
Qualidade de silagens de milho para gado leiteiro produzidas na Região Sul do Brasil quanto às micotoxinas
Authors: Marcelina Bottoni Horn  , Luchtenberg Rafael , Assunção Maria Amélia , Santos Silvio Alexandre , Scussel Vildes Maria 
Published: October 2016

Silage corn (Zea mays L.) quality was evaluated from January 2010 to December 2012 for the presence of field (fumonisins-FBs and zearalenone-ZON) and storage (aflatoxins-AFLs) mycotoxins, supplied to dairy cattle in the Southern Brazil. A total analysis of 1,006, 1,077 and 1,080 for FBs, ZON and AFLs were performed by the immunoenzymatic (ELISA) methodology with LOQ of 500, 25 and 5 µg/kg, respectively. From the data obtained it was observed that there was contamination in different samples, the levels varied and so the toxin evaluated throughout the period of the year. Although, not much difference among the states that comprise the region (temperate climate) under study, was detected. The toxin produced by Fusarium graminearum, ZON, was present ranging from 28.2 to 1538 µg/kg indicating a large variability between levels (standard deviation-SD & relative standard deviation-RSD% of 131 & 65.4%) regardless of the origin of the sample or trial period. There is no ZON limit established in Brazil for feed. Out of these samples, 75.5% were above the maximum tolerable (LMT) established in Uruguay (200 µg/kg) for cereals for animal feed, although the country does not specify for silage. The FBs were the toxins that had the lowest percentage of contaminated samples (11.4 to 34.4%) between the years of study, with the year 2011 presenting the highest levels yet, all below LMT U.S.A. (30,000 µg / kg) and 7.3% above the limit set by Switzerland (1,000 µg / kg). There are no limits set for FBs in Brazil feed. Regarding AFLs, the percentage of samples contaminated with levels higher than the Brazilian LMT (Ministry of Agriculture - 50 µg/kg) was 11.6% (125) of the total of 1080 tested silages. The levels varied among the positives samples with 9.7% (46-97), 11.3% (31-125.8) and 14.5% (48-105.4) for the states of PR, RS and SC, respectively. Although the levels detected for FBs were low, AFLs and ZON were higher, being some above the LMT of different countries. Therefore there is the need for agricultural practices adequacy in the production of silage for dairy cattle through several stages (harvesting / milling plant / fermentation / compression & silo type / size & closure) as well as its constant monitoring in order to avoid or minimize any economic losses. This is the first work reporting toxins of temperate climate in silage.