bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regional In-Situ Stress in Northern Kuwait- Implications for the oil Industry
Authors: Al-Ammar Nada , Hussain Riyasat , Mulyono Rinaldi , Al-Fares Abdulaziz , Al-Kandary Ahmad , Al-Naeimi Reem , Perumalla Satya 
Published: December 2012

Abstract
Role of geomechanics is becoming increasingly important with maturing of conventional reservoirs due to its implications in drilling, completion and production issues. Exploration and development of unconventional reservoirs involve maximizing the reservoir contact and hydraulic fracturing both of which are heavily dependent on geomechanical architecture of the reservoirs and thus require application of geomechanical concepts from the very beginning.
To support the unconventional exploration and conventional reservoir development in Kuwait, country-wide in-situ stress mapping exercise has been carried out in nine fields of Northern Kuwait. Stringent customized quality control measures were put in place to evaluate stress orientation. Cretaceous and sub-Gotnia Salt Jurassic rocks exhibit distinct patterns of stress orientations and magnitudes. While the variations in stress orientation in the Cretaceous rocks are within a small range (N40°E-N50°E) and consistent across major fault systems, the Jurassic formations exhibit high variability (N20°E-N90°E) with anomalous patterns across faults as well as in the vicinity of fracture corridors. Moreover, the overall stress magnitudes were found to be much higher in the strong Jurassic section compared with the relatively less strong Cretaceous strata. During the analysis, it was also observed that several natural fractures in Jurassic reservoirs appear to be critically stressed with evidences of rotation of breakouts.
Using geomechanical models from a specific field, the effects of in-situ stress, pore pressure and rock properties on formations were evaluated in inducing wellbore instability during drilling operations in a tight gas reservoir. It was found that the most favorable orientation for directional drilling is parallel to the maximum horizontal stress (SHmax) within that field.
The geomechanical study provided inputs not only for wellbore stability during drilling, but also regarding the response of natural fractures to in-situ stresses to become hydraulically conductive (permeable) to act as flow conduits. The fracture model of the field shows that the dominant fracture corridor trend in the field is NNE coinciding with present day in-situ maximum principal stress direction.
Implementing Artificial Neural Networks and Support Vector Machines in Stuck Pipe Prediction
Authors: Al-Baiyat Islam , Heinze Lloyd 
Published: December 2012

AbstractStuck pipe has been recognized as one of the most challenging and costly problems in the oil and gas industry. However, this problem can be treated proactively by predicting it before it occurs.The purpose of this study is to implement the two most powerful machine learning methods, Artificial Neural Networks (ANNs) and Support Vector Machines (SVMs), to predict stuck pipe occurrences. Two developed models for ANNs and SVMs with different scenarios were implemented for prediction purposes. The models were designed and constructed by the MATLAB language. The MATLAB built-in functions of ANNs and SVMs, and the MATLAB interface from the library of support vector machines were applied to compare the results. Furthermore, one database that included mud properties, directional characteristics, and drilling parameters has been assembled for training and testing processes. The study involved classifying stuck pipe incidents into two groups - stuck and non-stuck - and also into three subgroups: differentially stuck, mechanically stuck, and non-stuck. This research has also gone through an optimization process which is vital in machine learning techniques to construct the most practical models. This study demonstrated that both ANNs and SVMs are able to predict stuck pipe occurrences with reasonable accuracy, over 85%.The competitive SVM technique is able to generate generally reliable stuck pipe prediction. Besides, it can be found that SVMs are more convenient than ANNs since they need fewer parameters to be optimized. The constructed models generally apply very well in the areas for which they are built, but may not work for other areas. However, they are important especially when it comes to probability measures. Thus, they can be utilized with real-time data and would represent the results on a log viewer.
Evaluation of Micronized Ilmenite as Weighting Material in Water-Based Drilling Fluids for HPHT Applications
Authors: Elkatatny S. M. , Nasr-El-Din H. A. , Al-Bagoury M.. 
Published: December 2012

Abstract
Barite is the most common weighting material for drilling fluids, which contain several heavy components including lead, cadmium, mercury, and arsenic. Some of these heavy materials can discharge into the sea, which is not allowed especially in the case of oil-based drilling fluid. The supply of barite is geographically limited, with high transportation costs. To overcome the high cost, shortage, and common problems of barite, an alternative weighting material, ilmenite (5 µm), is introduced which is heavier than barite and more stable at high temperature. Also, the micronized ilmenite was introduced to overcome the ECD challenges in some drilling operations at reasonable cost.
Extensive lab work was done in order to: 1) optimize the rheological properties of the drilling fluid, 2) determine the optimum pH that gives stable dispersion, 3) assess the thermal stability, 4) optimize the filtration parameters (filtrate volume and filter cake thickness), and 5) characterize the ilmenite-based filter cake.
Zeta potential results showed that ilmenite was stable when mixed with water at a pH above 7 and it was dispersed and stable when mixed with the drilling fluid components. Drilling fluids have a density range from 100 to 120 pcf and a plastic viscosity of 28–32 cp. No phase separation was observed after hot rolling for 16 hrs at 300°F. The optimized water-based drilling fluid formula had a small filtrate volume (12 cm3) and thin filter cake (0.2 in.) under dynamic conditions. SEM analysis showed that ilmenite filter cake was heterogeneous and contained ilmenite particles in the layer closer to the rock surface. The layer closer to the drilling surface had a mixture of xanthan gum and modified starch, which were used to optimize the rheological properties at 250°F. This study will provide a complete evaluation of the drilling fluids with ilmenite as a weighting material and will help drilling engineers to better design drilling fluids for HPHT wells.
An Integrated and Effective Method for Well Placement Using a Numerical Simulation Model: A North Kuwait Field Case Study
Authors: Abdy Yaser , Amari Mustafa , Sharifzadeh Ahmad , Al-Anzi Ealian , Al-Ansari Muaath 
Published: December 2012

Abstract
The need to develop new tools that allow reservoir engineers to optimize reservoir performance is becoming more demanding by the day. One of the most challenging and influential problems facing reservoir engineers is well placement optimization.
The North Kuwait field (NKF) consists of six fields containing four naturally fractured carbonate formations. The reservoirs are composed of relatively tight limestone and dolomite embedded with anhydrate and shale. The fields are divided into isolated compartments based on fault zones and supported by a combination of different fluid compositions, initial pressures, and estimated free-water levels. Due to natural complexity, tightness, and high drilling costs of wells in the NKF, it is very important to identify the sweet spots and the optimum well locations.
This paper presents two intelligent methods that use dynamic numerical simulation model results and static reservoir properties to identify zones with a high-production potential: reservoir opportunity index (ROI) and simulation opportunity index (SOI). The Petrel* E&P software platform was chosen as the integrated platform to implement the workflow. The fit-for-purpose time dependent 2D maps generated by the Petrel platform facilitated the decision-making process used for locating new wells in the dominant flow system and provided immense support for field-development plans.
The difference between the two methods is insignificant because of reservoir tightness, limited interference, and natural uncertainty on compartmentalization. At this stage, pressure is not a key parameter. As a result, unlike brown fields, less weight was given to simulated pressure, and SOI was used to select the well locations.
The results of this study show that implementing these workflows and obtaining the resulting maps significantly improve the selection process to identify the most productive areas and layers in a field. Also, the optimum numbers of wells using this method obtained in less time and with fewer resources are compared with results using traditional industry approaches.
Integrated Workflow for Small Scale Reservoir Characterization Using Borehole Image, NMR and Core Data
Authors: Al Bloushi Asmaa Faisal , Joshi Deepak , Al Murakhi Haifa Rashed 
Published: December 2012

Abstract
The Middle Minagish Oolite Formation is 450 to 550 feet thick interval of porous limestone reservoir, composed of peloidal/skeletal grainstones with lesser amount of packstone, oolitic grainstone, wackstone and mudstone in Umm Gudair field, West Kuwait. It is characterized by small scale reservoir heterogeneity, primarily related to the depositional as well as diagenetic features. Capturing reservoir properties in micro scale and its spatial variation needs special attention in this reservoir due to its inherent anisotropy. Reservoir properties will depend on the level that we are analyzing on reservoir (millimeter to meter scale). Here we used Electrical Borehole Image (EBI) and Nuclear Magnetic Resonance (NMR) to capture small scale feature of Umm Gudair carbonate reservoir and compared them with core data In present work, reservoir properties (including texture, facies, porosity and permeability) interpreted by the EBI shows good match with NMR driven properties and core data. Textural changes in image logs also match well with pore size distribution from NMR logs. Further highly porous zones which are considered either due to primary porosity or vugs match with larger pores of NMR logs and these corroborates with also core derived porosity. A good match has been observed between EBI, NMR and cored derived porosity. Permeability calculations have also been made and compared with core data. A detail workflow has been developed here to interpret reservoir properties on un-cored wells, where only low vertical resolution data is available. This technique is quite useful to identify the characters and mode of origin highly porous zones in reservoir section which are generally not identifiable by low resolution standard logs. This workflow will allow us to interpret the heterogeneity at high resolution level in un-cored wells, as results are validated with integration of EBI, NMR and core data.
Unique Process and Tool Provides Better Acid Stimulation and Better Production Results
Authors: Al-Saqabi Mishari , Gazi Naz , Vishwanath Chimmalgi , Al Bahrani Hasan , Turkey Naween , Abdul-Razaq Eman , Al-Zankawi Omran , Bouland Ali , Surjaatmadja Jim B. , Al Hamad Abdulla M. , Brand Shannon 
Published: December 2012

Abstract
There are many ways to stimulate an unlined openhole horizontal well using acid. The simplest way is to just pump acid into the well (i.e., bullhead) without placement control. However, this can often be ineffective. Although still used, such approaches can create massive enlargements at the entry point or high injectivity area, thus causing ineffective treatments and re-entry issues. Wellbore collapse often follows. The use of coiled tubing (CT) as a "pin-point" delivery method is therefore preferred. Using CT allows dispersal of the acid either uniformly or intermittently along the lateral, as desired. CT also allows acid washing to be performed, which is another common process that can improve stimulation without much additional expense to the operator. Using a jetting tool with many jets, acid can be sprayed onto the wellbore wall, and the active agitation caused by the acid-wash process increases the chemical reactivity of the acid at the desired locations.
Another beneficial approach of using CT is the hydrajet assisted acid fracturing (HJAAF) method. With focused jetting of acid at much higher pressures, the process initiates microfractures in the wellbore walls. When etched with acid, this approach effectively bypasses near-wellbore (NWB) damage much deeper than common washes, thus providing much better results. Further modification of the process by exerting high annular pressures offers the capability of delivering medium to large fractures.
This paper discusses two HJAAF processes uniquely combined into one process used in two large horizontal wells. Because of the large dimension of the inner diameter (ID) of the wells combined with the small production tubing the tool must pass through, the implementation had to be further improved by using a unique jetting mechanism, which positioned the jet nozzles closer to the target. Actual results of such stimulations are presented.
Real-Time Estimation of Well Drainage Parameters
Authors: Al-Kadem Mohammad S. , Al-Khelaiwi Faisal T. , Al-Amri Meshal A. 
Published: December 2012

Abstract
The well drainage pressure and radius are key parameters of real-time well and reservoir performance optimization, well test design and new wells' location identification. Currently, the primary method of estimating the well drainage radius is buildup tests and their subsequent well test analysis. Such buildup tests are conducted using wireline-run quartz gauges for an extended well shut-in period resulting in deferred production and risky operations.
A calculation method for predicting well/reservoir drainage pressure and radius is proposed based on single-downhole pressure gauge, flowing well parameters and PVT data. The proposed method uses a simple approach and applies established well testing equations on the flowing pressure and rates of a well to estimate its drainage parameters. This method of estimation is therefore not only desirable, but also necessary to eliminate shutting-in producing wells for extended periods; in addition to avoiding the cost and risk associated with the wireline operations. The results of this calculation method has been confirmed against measured downhole, shut-in pressure using wireline run gauges as well as dual gauge completed wells in addition to estimated well parameters from buildup tests.
This paper covers the procedure of the real-time estimation of the well/reservoir drainage pressure and radius in addition to an error estimation method between the measured and calculated parameters. Furthermore, the paper shows the value, applicability and validity of this technique through multiple examples.
Research on Auditor Professional Skepticism: Literature Synthesis and Opportunities for Future Research
Authors: Hurtt R. Kathy , Brown-Liburd Helen , Earley Christine E. , Krishnamoorthy Ganesh 
Published: December 2012

SUMMARY
Both researchers (e.g., Nelson 2009) and regulators (e.g., the PCAOB) have emphasized the importance of exercising the appropriate level of professional skepticism when conducting an audit. However, professional skepticism remains a hard concept to define and measure. In addition, it is often difficult to determine if a lack of skepticism is the primary cause of audit deficiencies and if so, what factors led to the lack of skepticism. The purpose of this paper is threefold: (1) extend the work of Nelson (2009) by synthesizing research related to auditors' professional skepticism to identify antecedents to both skeptical judgment and skeptical action, (2) identify areas where research is lacking on a particular dimension and suggest avenues for future research, and (3) discuss the implications of research findings for regulators and auditing professionals. We adopt two foundational aspects of the framework introduced in the seminal paper by Nelson (2009), which proposes that lack of skepticism can either be the result of a failure in problem recognition (lack of skeptical judgment) or a failure to act on a problem recognized (lack of skeptical action). We organize research studies into four categories of antecedents: studies relating to auditor characteristics, evidence characteristics, client characteristics, and environmental characteristics. We find that while research studies provide insights into both the antecedents to skeptical judgments and actions, the majority of research efforts to date have focused on the antecedents to skeptical judgments and on auditor characteristics in particular. Research findings have implications for practice, but in order to understand how skeptical judgment translates into skeptical action, additional research on skeptical action will need to be conducted.
Effects of insertion angle and implant thread type on the fracture properties of orthodontic mini-implants during insertion
Authors: Cho Il-Sik , Kim Tae-Woo , Ahn Sug-Joon , Yang Il-Hyung , Baek Seung-Hak 
Published: December 2012

ABSTRACTObjective:To determine the effects of insertion angle (IA) and thread type on the fracture properties of orthodontic mini-implants (OMIs) during insertion.Materials and Methods:A total of 100 OMIs (self-drilling cylindrical; 11 mm in length) were allocated into 10 groups according to thread type (dual or single) and IA (0°, 8°, 13°, 18°, and 23°) (n  =  10 per group). The OMIs were placed into artificial materials simulating human tissues: two-layer bone blocks (Sawbones), root (polymethylmethacrylate stick), and periodontal ligament (Imprint-II Garant light-body). Maximum insertion torque (MIT), total insertion energy (TIE), and peak time (PT) were measured and analyzed statistically.Results:There were significant differences in MIT, TIE, and PT among the different IAs and threads (all P &lt; .001). When IA increased, MIT increased in both thread groups. However, TIE and PT did not show significant differences among 0°, 8°, and 13° IAs in the dual-thread group or 8°, 13°, and 18° IAs in the single-thread group. The dual-thread groups showed higher MIT at all IAs, higher TIE at 0° and 23° IAs, and longer PT at a 23° IA than the single-thread groups. In the 0°, 8°, and 13° IA groups, none of the OMIs fractured or became deformed. However, in the 18° IA group, all the OMIs were fractured or deformed. Dual-thread OMIs showed more fracturing than deformation compared to single-thread OMIs (P &lt; .01). In the 23° IA group, all OMIs penetrated the artificial root without fracturing and deformation.Conclusions:When OMIs contact artificial root at a critical contact angle, the deformation or fracture of OMIs can occur at lower MIT values than those of penetration.
Determination of the Age and Growth of Glossogobius Giuris (Hamilton-Buchanan, 1822) Using Sectioned Otolith
Authors: Ahmed Md Sagir , Latifa Gulshan Ara 
Published: December 2012

The freshwater gobi, Glossogobius giuris (Hamilton-Buchanan, 1822) (Gobiidae: Perciformes) is an important freshwater fish species in Bangladesh. The age and growth of this species, collected from the river Titas, Brahmanbaria, were studied with transverse sections of otoliths. The otoliths opaque zones that are formed every year were the annual rings. The growth of this species was rapid during the first two years, reaching 18.5 cm in total length. Most of the specimens were 1-2 years old and accounted for 90% in total. The maximum age recorded was five years with 19.5 cm in total length. The von Bertalanffy growth parameters L? and K for this species were 19.58 cm and 1.36/year, respectively. The study indicated that the age and growth of G. giuris can be determined using its sectioned otolith. DOI: http://dx.doi.org/10.3329/bjz.v40i1.12889 Bangladesh J. Zool. 40(1): 13-19, 2012
Studies on the Protozoan Parasites of Hilsa Shad, Tenualosa Ilisha in Bangladesh
Authors: Bhuiyan Aminul Islam , Momen Mahfuza 
Published: December 2012

Present investigation was conducted to study the protozoan parasites of hilsa shad, Tenualosa ilisha collected from Aricha Ghat, Dhaka. Thirty fishes were observed. Fishes were collected during months of August 2010 and September 2010. A total of 1099 individuals of protozoan parasite of eight genera/species were recorded during the present study. These parasites were found on body surface, gills and gall bladder of the fish. Jirovecia piscicola had the highest prevalence (53.33%) while Coccomyxa baleswarensis had the lowest prevalence (26.67%) of infection. Most of the host individuals had double (43%) and single (40%) species infection. Only a few (10%) host had triple species infection. No fish had more than three species of parasite at a time. Glugea sp. dominated over all other parasites. J. piscicola, Zschokkella ilishae and Ceratomyxa hilsae had almost similar abundance while C. baleswarensis had the lowest (5.64%) abundance. Abundance of Sphaeromyxa dighae, Myxobolus sp. and Kudoa sp. were comparatively low ranging from 9.36% to 17.35%. DOI: http://dx.doi.org/10.3329/bjz.v40i1.12892 Bangladesh J. Zool. 40(1): 33-41, 2012
The Current Status of Indigenous Freshwater Fishes in Jordan
Authors: Mir Sayeeda , Hamidan Nasht 
Published: December 2012

Considerable changes were revealed in the indigenous freshwater fish fauna during a field survey of six years from 2006 to 2008. Most of them are endangered and one endemic species, Aphanius sirhani, is under the threat of extinction. Four other species, Garra rufa, G. ghorensis, Nemacheilus insignis and Aphanius dispar richardsoni are also endangered. Misuse of the limited water resources, intensification of agriculture, overexploitation of fishing and the introduction of exotic species are considered to be major threats to Jordans freshwater fish fauna. DOI: http://dx.doi.org/10.3329/bjz.v40i1.12895 Bangladesh J. Zool. 40(1): 59-67, 2012
Efficacy of Monosodium Glutamate in the Australian Blowfly, Lucilia Cuprina Wiedmann (Diptera : Calliphoridae)
Authors: Begum M , Kabir M A , Khan H R , Rahman M F 
Published: December 2012

Efficacy of monosodium glutamate (MSG) was studied in the Australian blowfly, Lucilia cuprina at six different doses, viz. 0.5, 1, 2, 3, 5 and 10 g, and the results were compared with the control. The effects of MSG were observed on the mortality, width and histology of Malpighian tubules (MTs) of the fly. The highest (100%) and lowest (16.67%) mortalities of the flies were recorded at 10g and 0.5g doses, respectively. Average widths of the MTs of flies in treatment (5g dose) and control were 48.62 ?m and 58.85 ?m, respectively. Histological observations through the cross section of the MTs showed the constriction at 0.5g and 5g doses. DOI: http://dx.doi.org/10.3329/bjz.v40i1.12896 Bangladesh J. Zool. 40(1): 69-75, 2012