bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanistic Modeling of Clay Swelling in Hydraulic Fractures Network
Authors: Sanaei Alireza , Shakiba Mahmood , Varavei Abdoljalil , Sepehrnoori Kamy 
Published: April 2016

Abstract
Hydraulic fracturing is the most effective technique used in the oil industry for economical production of hydrocarbon from very low permeability reservoirs. Recent experimental studies have indicated a change in hydraulic fractures (HF) conductivity as the result of the interactions between fracturing fluid and shale matrix. Clay swelling is one of the well-known undesirable interactions of this kind. If clay swelling occurs on the surface of hydraulic fractures, it can cause a major damage to the overall performance of the reservoir. Thus, a detailed understanding of clay stability issue is essential for fracturing fluid selection and operation planning.
Clay swelling induced conductivity damage is primarily a function of rock mineralogy, fracturing fluid concentration, and formation brine salinity. Thus, various levels of clay-water interaction are expected in different shale formations. In this study, we present a mechanistic approach to model clay swelling in various rock mineralogies including Barnett (clay-rich), Eagle Ford (Calcite-rich), and Marcellus shales. Subsequently, we investigate the production loss due to clay swelling in a realistic complex hydraulic fracture network. We used UTCOMP_IPhreeqc, a coupled multi-phase reactive- transport simulator developed at The University of Texas at Austin, to comprehensively model this process. Expansion of double diffusive layer was assumed to be the main clay swelling mechanism. Surface complexation and ion exchange reactions were considered to capture the ion diffusion into the double diffusive layer. In each time step of the simulation, the volume expansion of clay materials exposed on the fracture surface was then used to modify the fracture aperture. In order to evaluate the performance of the complex hydraulic fracture network after clay swelling damage, the Embedded Discrete Fracture Model (EDFM) was applied.
The simulation results indicate that the degree of clay swelling varies in different shale formations. Based on the clay content and the mineralogies that were considered in this work, a significant expansion in double diffusive layer was observed for the Barnett shale when fresh water was injected. However, this effect was much lower in Eagle Ford and Marcellus shales. Similarly, the production loss in the hydraulic fracture network was substantial in the Barnett example. The contribution of the fractures far from the producing well in gas production was negligible after clay swelling damage. The pressure depletion profiles clearly showed the adverse impact of conductivity damage on production performance. The presented approach provides the capability to accurately model the clay stability and to approximate its impact on transport properties of hydraulic fractures.
Development and Application of Probabilistic Fluid Property (PVT) Models for Stochastic Black Oil Reservoir Simulation
Authors: Alboudwarej Hussein , Sheffield Jonathan M. 
Published: April 2016

Abstract
Fluid properties are often one of the key uncertainties in reservoir simulation studies. A workflow and guidelines are presented to develop an overall probabilistic forecasting framework, through which likely fluid models are validated, uncertainty ranges are estimated, and probabilistic PVT models are generated for use in stochastic black oil reservoir simulation modeling.
Workflows are provided for two distinct scenarios. For scenarios with a large number of samples from the reservoir or a representative analog fluid property database, standard statistical methodologies are applied to generate probabilistic fluid models. However, in most cases where there are only limited data available, a unique approach is adopted to generate a representative pseudo-database for uncertainty assessment workflows. The pseudo-database is generated based on fluid property correlations that are screened for the conditions of the specific fluid system. The pseudo-database is used to both validate a reliable likely case and to determine ranges to generate probabilistic models. Numerical formulations of probabilistic models are provided.
Application of the workflow is demonstrated for three different cases of fluid property data. For a case based on a large set of PVT measurements, standard deviation of specific fluid properties (FVF, GOR, Viscosity, and Compressibility) is calculated and used in standard statistical methods to calculate P10/P90 cases. In another example, the validity of fluid viscosity data based on an assumed viscosity correlation was investigated, suggesting that fluid viscosity was actually closer to a P20 model as opposed to a P50 (likely case). In another case study, where only limited PVT data were available, a number of screened/filtered fluid property correlations are used to represent available PVT data, and then the input parameters are perturbed to generate a pseudo-database to capture fluid property ranges as well as variation in a field.
Currently, there is a lack of a systematic way to determine uncertainty ranges for fluid properties, as well as validating the most likely case (best case or mid case). The novelty of our framework is in the provision of a consistent workflow to generate probabilistic fluid models that are not based on experiential methods employed in the past.
Uncertainty Reduction in Reservoir Geostatistical Description Using Distributed Temperature Sensing (DTS) Systems Data
Authors: Xu Bohan , Forouzanfar Fahim 
Published: April 2016

Abstract
Downhole temperature measurements provide valuable data for characterizing the flow between the reservoir and wellbore, which in turn is a function of the individual reservoir layer properties. In this paper we investigate the use of downhole temperature profile data, provided from Distributed Temperature Sensing (DTS) systems, as a cost effective and robust alternative to other common approaches, such as using data from production logging tools, for estimating the formation properties and production profile along the wellbore. Previous applications of history matching techniques using downhole temperature profile data have been mostly limited to simple reservoirs, and the quality of their results were unacceptable for more complex cases. In this work, we present the evaluation and application of temperature profile data from DTS systems for the purpose of uncertainty reduction in the reservoir description. We focus on the characterization of multi-layer multi-phase reservoir cases with a high degree of vertical heterogeneity. First, using the principles of information theory we investigate the information content of the temperature profile data regarding various reservoir properties. By computing the mutual information between the reservoir parameters and the temperature profile data, the reservoir properties with higher influence on the reservoir and wellbore temperature profile data are identified. The associated uncertainty in these reservoir properties can be reduced by assimilating the downhole temperature profile data. Through these analysis, we also present an estimation for the expected reduction of uncertainty in the reservoir properties by assimilating the temperature data. Then, we apply the Ensemble Smoother with Multiple Data Assimilation (ES-MDA) algorithm to estimate the reservoir properties selected based on our previous analysis. The set of observed data contains the wellbore temperature profile, the temperature profile of the reservoir adjacent to the wellbore, and the flowing bottomhole pressure (BHP) of the well at a reference depth. We investigate the performance of the history matching algorithm using various combinations of these observed data for estimating the properties of a synthetic layered reservoir. Additionally, the implementation of a doubly stochastic model is also investigated to account for possible uncertainties in the prior mean of the reservoir properties. Our results show that the downhole temperature profile data contain significant amount of information about the permeability and porosity of the reservoir layers. Moreover, the use of temperature profile data within the ES-MDA history matching algorithm is able to provide a good estimation of these properties and significantly reduce the uncertainty in the reservoir description.
Characterization of the Lithological Profile at the Point Arguello Field Using the Hurst Coefficient
Authors: Qi Qianru , Rebolledo Leilani C. , Ershaghi Iraj 
Published: April 2016

Abstract
Very prominent sections of the Monterey Formation in terms of fracture content and productivity are the intervals that exhibit intense fracturing caused by diagenetic, de-watering or tectonic effects. In this paper, we examined the auto correlated nature of intervals that contain various stages of biogenic silica diagenesis. Because of combination of diagenetic processes and mixing with detrital materials, one may expect a chaotic geologic environment. Our focus was to examine the nature of lithology signals from well logs and ascertain the existence of long-range dependence and persistency.
Recorded gamma ray and neutron logs vs. depth, were used to examine the autocorrelation of sequential appearance of highly cherty intervals. Estimation of the Hurst coefficient as a measure of autocorrelation of the log readings vs. depth was also verified by Power Spectrum Density plots. We examined intervals detected from the mud logs with high concentration of glassy cherts and porcelanites. Our analysis detects a persistency in the lithology data in the intervals significantly affected by the silica diagenesis.
Flow of Gases in Organic Nanocapillary Pores of Shale: A Boundary-Driven Molecular Simulation Study
Authors: Kazemi Mohammad , Takbiri-Borujeni Ali 
Published: April 2016

Abstract
Modeling of gases flow in organic nanopores of shale is associated with complexities due to ultratight pores and adsorption capacity of the kerogen. The pore sizes in organic nanopores are small such that the mean free path of gas molecules become comparable to the characteristic length of the system. The objective of this work is to fulfill the need for the investigation of flow of different gases with unlike adsorption characteristics and examining the contribution of the adsorbed phase to total mass flux. In this study, adsorption and transport of three different gases, argon, methane, and neon, are investigated by performing the dual control volume grand canonical molecular dynamics (DCV-GCMD) simulation in identical setups of carbon nanocapillarys. The simulations are performed for two capillaries of of 2 and 4 nm in diameter for a wide range of pressures and pressure gradients. The velocity, density, and molecular fluxes of these gases are computed and compared with each other. Based on the MD simulation results, as the pressure of the system increases, the number of gas molecules adsorbing to the nanocapillary walls increases to reach a state of full single-layer coverage. Normalized velocity profiles with average gas velocities show that for all gases in both nanocapillary diameters, flow profiles are plug shaped. Furthermore, it is found that the Knudsen diffusion model underestimates the molecular fluxes in carbon nanocapillaries by one order of magnitude. This underestimation is shown to be a function of excess adsorption amount and it is not a strong function of the pore size or the pore pressure.
Revisiting Lisburne, a New Approach to a Mature Fractured Carbonate
Authors: Michie J. J. , Siks A. , Sauve M. A. , Wages D. B. 
Published: April 2016

Abstract
This paper is a review of new well design and completion technologies utilized in the 2015 Lisburne drilling program in context of the historical development, most of which occurred in the 1985-1991 timeframe. The scope includes a comparative review of the new well program and design, as well as preliminary results. Lisburne is a low recovery, complex fractured carbonate field. Since the 1980s, attempts have been made to make the field more productive, including waterflooding and limited infill drilling. In 2015, the working interest owners of the field elected to employ well technologies that have matured since the initial field development. A U-shaped well design, with a swellpacker sliding sleeve completion, and a multi-stage acid and hydraulic fracture stimulation was utilized in the 2015 program, while the majority of the 1985-1991 historical development was with vertical wells with acid stimulations. Initial results show an approximate 10 times improvement in productivity index (PI) compared to the average well, access of multiple drainage intervals, and ability to successfully execute multistage acid and hydraulic fracture stimulations.
Optimization of Wellbore Strengthening Treatment in Permeable Formations
Authors: Razavi Omid , Vajargah Ali Karimi , van Oort Eric , Aldin Munir , Govindarajan Sudarshan 
Published: April 2016

Abstract
Wellbore Strengthening (WBS) is an enabling technology to simplify casing designs, prevent costly lost circulation events, and complete wells with a narrow drilling margin. Given its effectiveness to help drill today's challenging wells economically, WBS has become a routine part of the drilling fluid design and the well construction process in general. However, the drilling industry still lacks a general model to optimally exploit WBS for various formation types and fluid systems.
In this paper, we have conducted a systematic investigation of the major parameters which affect WBS treatment in permeable formations. Large-scale fracturing experiments were conducted on two rock types with significantly different permeability and stiffness: Berea sandstone (stiff - moderately permeable) and Castlegate sandstone (weak - highly permeable). Several fluid injection cycles were carried out on each rock sample to characterize the Fracture Initiation Pressure (FIP) and Fracture Propagation Pressure (FPP). Further, we investigated the effect of Lost Circulation Material (LCM) - which are used for WBS purposes - on the FIP and the FPP. Also, we studied the effects of the concentration and the Particle Size Distribution (PSD) of LCM blends, the confining pressure, the stiffness and the permeability of rock samples.
The experimental results confirmed that the FIP is mainly a function of rock tensile strength and stress concentration around the borehole, and not affected by the presence of LCM. The FPP, however, can be significantly enhanced by adding LCM to drilling fluids. Further, FPP enhancement is largely independent of the rock stiffness. We also found that a minimum concentration of LCM is necessary for effective WBS. However, no significant additional enhancement in the strengthening benefits was observed for concentrations above a certain upper threshold. In addition, our results showed that a higher LCM concentration is required for effective WBS in formations with a lower permeability (i.e. tighter formations). PSD dominates the strengthening benefits of an LCM blend and, for both tested rock types, LCM blends with a broad bimodal PSD provide superior strengthening benefits compared to those with a unimodal PSD.
In this paper, we introduce design guidelines to maximize the attainable strengthening benefits of LCM blends. The findings of this paper are relevant to improve the construction of (ultra-) deep-water wells with a narrow drilling margin through systematic optimization of WBS treatments and minimization of non-productive time.
Static and Dynamic Comparison of Equation of State Solid Model and PC-SAFT for Modeling Asphaltene Phase Behavior
Authors: Abouie Ali , Rezaveisi Mohsen , Mohebbinia Saeedeh , Sepehrnoori Kamy 
Published: April 2016

Abstract
Asphaltene deposition is known to be one of the major problems in oil fields. Asphaltene precipitation and deposition from the reservoir fluid can block pore throats or change the formation wettability in the reservoir. Furthermore, asphaltene precipitation and deposition result in partial to total plugging in the wellbore. Recent studies have shown that PC-SAFT EOS is a more appropriate and comprehensive thermodynamic model for simulation of asphaltene precipitation. The main objective of this paper is to implement PC-SAFT EOS into a compositional wellbore simulator to model asphaltene precipitation. Flocculation and deposition models are also integrated with the thermodynamic model to simulate the dynamics of asphaltene deposition along the wellbore. In addition, the capabilities of PC-SAFT and common-used Peng-Robinson equation of state are compared through fluid characterization to reproduce experimental precipitation data.
The simulation results indicate asphaltene deposition profile and consequent decline in production rate. It is shown that the profile of asphaltene deposition is mostly governed by the precipitation condition and the deposition rate. Moreover, prediction capability of cubic equation of state is shown to give approximately similar results if additional precipitation data is available (e.g. lower onset pressure and maximum amount of precipitation). The prediction results of the developed tool are highly crucial to monitor the well performance, optimize the operating conditions of the field, and propose the remediation technique.
3-D Reconstruction of Porous Media From a 2-D Section and Comparisons of Transport and Elastic Properties
Authors: Naraghi Morteza Elahi , Spikes Kyle , Srinivasan Sanjay 
Published: April 2016

Abstract
High resolution, 3-D micro-structure images of rocks can be used to compute the transport and elastic properties of those samples using a digital rock physics approach. Those properties are complex functions of the pore size distribution, geometry and morphology, which necessitates the use of accurate 3-D volumes. Because of the limited availability of 3-D micro-structure images of rocks, several attempts to construct 3-D images from 2-D ones have been made.
In this study, we propose a new stochastic method to reconstruct a 3-D image of the rock using only a 2-D section of the imaged rock sample. Our method is based on a simple observation that the pores are gradually deformed from one section to the next one. Therefore, the first step is to generate multiple independent realizations by performing Multiple-Point Statistics (MPS) based stochastic simulations. These simulations represent independent 2-D scans through the rock volume. Next, a succession of images is generated spanning two adjacent independent sections. These images consist of gradually morphed features from one section to those in the next independent section. Juxtaposing these 2-D images results in the reconstructed 3-D image.
We calculate the spatial connectivity in the 3rd direction and confirmed that the proposed method can retrieve the connectivity in the 3rd direction accurately. We also compute transport and elastic properties from the reconstructed image and from the original image to verify that this method reproduces the appropriate spatial statistics and pore size distribution, geometry and morphology. We also compare the numerical results with laboratory measurements performed on the sample. The results obtained using the reconstructed image reveal that the numerically calculated properties are similar to the measured values. We compare the mismatch of transport and elastic properties with the original measurements with that of the previous reconstruction algorithm. These comparisons show that the proposed simulation method has the same accuracy as previous ones. However, the proposed method is much more computationally efficient than the other algorithms, mainly due to the faster MPS algorithm and the fact that the simulation is being done only for the independent layers instead of all the layers.
The proposed methodology is an accurate method to reconstruct a 3-D representative sample of a rock given only one 2-D thin section. The algorithm is computationally efficient and faster than the previously introduced algorithm, and can easily be used to characterize samples for which 3-D images are difficult to obtain in terms of both time and expenses.
Wind Erosion of Cropland in the Northwestern Tarim Basin
Authors: Zheng Zehao , Sharratt Brenton , Feng Gary , Li Xinhu , Pi Huawei 
Published: April 2016

Core Ideas
The Tarim Basin is a major source of windblown dust in Asia and China.
No studies have previously documented wind erosion from cropland in Tarim Basin.
Wind erosion was measured from an irrigated cotton field and red date orchard.
Wind erosion from cropland is lower than from China's deserts.
Management practices must be developed to control wind erosion in Tarim Basin.
The Aksu region within the Tarim Basin is a major source of windblown dust in China due to the arid climate and vast areas under intensive irrigated crop production. Despite the importance of crop production to human subsistence and the local economy, little is known about the amount of soil eroded by wind from agricultural lands in the region. Passive aeolian sediment collectors were used to measure soil loss from an irrigated cotton (Gossypium spp.) field and red date (Ziziphus jujuba Mill.) orchard in the Aksu Oasis during high wind events in 2012 and 2013. Mass of sediment trapped by the collectors was best described as a power function of height above the surface in the cotton field and red date orchard. Soil loss from the cotton field ranged from 0 to 142 g m−2, whereas soil loss from the red date orchard ranged from 0 to 71 g m−2 for single‐ or multiple‐day high wind events. Total soil loss from the cotton field and red date orchard, for the high wind events observed in this study, was 130 and 96 g m−2, respectively, in 2012 and 305 and 165 g m−2, respectively, in 2013. Soil loss was similar to that reported from agricultural lands in other regions of the world. Although soil loss is relatively small compared with the Gobi Desert in China, poor air quality in the Tarim Basin necessitates identifying crop and soil management practices for reducing windblown dust and conserving the soil resource.
The Portrayal of Indonesian Image in 2007 Kompas Selected Short Stories: Social Problems, Criticisms and Hopes
Authors: Akun Akun 
Published: April 2016

Article aimed at exploring social problems reflected in 15 selected short stories printed in Kompas during 2007 both explicitly and implicitly. Specifically, this research is focused on the mapping of dominant social problems raised by the short stories, the social criticisms strongly voiced by the authors and the hopes of a better situation implicitly reflected in these interesting short stories. This study applies the Defamiliarization Effect promoted by Bertolt Brecht and Negative Dialectics or Negative Knowledge by Theodor Adorno, specifically in analyzing the literary works as a criticism tool. The result of the research shows that phenomena of social problems current lately in Indonesian context like identity, poverty, corruption, religious tensions, moral degradation, politics dirtiness, minority group problems, social security, natural disasters and the like are clearly seen and teased in these writings.