bluuebunny/crossref_metadata_2025 huggingface dataset:
PENINGKATAN KADAR TIMBAL DARAH DAN MUNCULNYA PERILAKU ANTISOSIAL PENGRAJIN KUNINGAN
Authors: Marianti Aditya , Anies Anies , Abdurachim Henna Rya Sunoko
Published: September 2015

Penelitian ini bertujuan mengkaji pengaruh peningkatan kadar timbal (Pb) darah terhadap munculnya perilaku antisosial pada pengrajin kuningan. Disain penelitian  observasional analitik dengan studi cross sectional. Sampel terdiri dari 55 orang pengrajin kuni ngan, dengan kriteria inklusi pria atau wanita, minimal 17 tahun, telah bekerja di industri kuningan minimal 2 tahun, pendidikan minimal pernah SD. Hasil penelitian menunjukkan telah terjadi kontaminasi Pb di lingkungan kerja industri kuningan. Kadar Pb darah pengrajin yang melebihi  nilai ambang batas40µg/dl mencapai 80%. Perilaku antisosial terukur masuk kategori sedang dan rendah. Terdapat hubungan linier antara kadar Pb darah dan perilaku antisosial dengan R2 0,353. Simpulan pajanan kronik Pb di lingku- ngan kerja industri kuningan menyebabkan peningkatan kadar Pb darah pengrajin dan berkontribusi memicu  munculnya perilaku antisosial.

 

This study aimed to examine the effect of increased Blood Lead Levels (BLL) results of the emergence of antisocial behavior in brass craftsmen. The research designs used the analytic observational with cross sectional study. The sample consisted of 55 brass craftsmen, male or female a minimum of 17 years old, has worked in the brass industry at least for 2 years, and at least has a degree in the elementary school level. The results showed that there has been a lead contamination in the environment of brass industry. BLL that exceed the threshold value (40 μg/dl) reached 80%. The antisocial behavior measured was in the category of medium and low. There was a linear relationship between BLL and antisocial behavior with R2 0.353. In conclusion, chronic lead exposure to the brass industry environment led to an increase to blood lead levels BLL  in craftsmen contributed in the appearance of antisocial behavior.
Practice-as-research: An example of the use of action research to link practice and theory in a case of Information Systems strategy development
Authors: Du Toit MJ , Lotriet Hugo
Published: September 2015

The ability to link IS practice to a sound theoretical and scientific basis has been an ongoing endeavour for both IS practitioners

and researchers. This stems from the need of both practitioners and theorists to be able to ensure that the relationship between

practical knowledge and experience gained in the workplace can be grounded in theory with due consideration of the converse

requirement for theory to be based on practice. This paper provides an example of how Action Research (AR) was successfully

applied by a practitioner as method in a South African strategic IS management environment. The paper describes the specifics

of the process that was used and highlights various issues that had to be considered in this specific instance of use of AR as

method.
Synchronisation of fertility with carrying capacity; an investigation using classical and agent based modeling
Authors: Murrell Hugh Crozier , Swart John Henry
Published: September 2015

A generalized Verhulst model subject to seasonal change in both fertility rate and carrying capacity is outlined. Numerical solutions to the Verhulst equations are employed to obtain optimal fertility rate phase shift with respect to carrying capacity. Possible natural selection for a preferred season of conception is investigated using agent based simulations. Both experiments indicate that synchronization of fertility rate to environment carrying capacity is beneficial to species survival.
The integration of computerised accounting in the accounting curriculum as an educational learning curve for students entering the business world
Authors: Papageorgiou Elmarie
Published: September 2015

At universities, educating students on real-life practices is one of the key drivers in a changing academic environment. Academic institutions encourage the study of the learning environment and ensure that appropriate strategies are in place for educating students. A first-year Accounting I student stated the importance of computerised accounting: ‘Computerised accounting is used in the workplace and therefore using it in varsity, grants students a view on how things will be after completion of their respective degrees.’ Accordingly, the purpose of this study was to empirically investigate the perceived acquisition of information technology (IT) knowledge and determine the skills required for students to convert the knowledge gained into actions as a learning curve for accounting students entering the business world. The results indicated that students’ knowledge of Accounting I increased with the integration of computerised Accounting in the Accounting I Curriculum.
Towards Communication and Information Access for Deaf People
Authors: Blake Edwin , Tucker William , Glaser Meryl
Published: September 2015

In tightly circumscribed communication situations an interactive system resident on a mobile device can assist Deaf people with their communication and information needs. The Deaf users considered here use South African Sign Language and information is conveyed by a collection of pre-recorded video clips and images. The system was developed according to our method of community-based co-design. We present several stages of the development as a series of case studies and highlight our experience. The first stage involved ethnographically inspired methods such as cultural probes. In the next stage we co-designed a medical consultation system that was ultimately dropped for technical reasons. A smaller system was developed for pharmaceutical dispensing and successfully implemented and tested. It now awaits deployment in an actual pharmacy. We also developed a preliminary authoring tool to tackle the problem of content generation for interactive computer literacy training. We are also working on another medical health information tool. We intend that a generic authoring tool be able to generate mobile applications for all of these scenarios. These mobile applications bridge communication gaps for Deaf people via accessible and affordable assistive technology.
Intelligent System Design Using Hyper-Heuristics
Authors: Pillay Nelishia
Published: September 2015

Determining the most appropriate search method or artificial intelligence technique to solve a problem is not always evident and usually requires implementation of the different approaches to ascertain this. In some instances a single approach may not be sufficient and hybridization of methods may be needed to find a solution. This process can be time consuming. The paper proposes the use of hyper-heuristics as a means of identifying which method or combination of approaches is needed to solve a problem. The research presented forms part of a larger initiative aimed at using hyper-heuristics to develop intelligent hybrid systems. As an initial step in this direction, this paper investigates this for classical artificial intelligence uninformed and informed search methods, namely depth first search, breadth first search, best first search, hill-climbing and the A* algorithm. The hyper-heuristic determines the search or combination of searches to use to solve the problem. An evolutionary algorithm hyper-heuristic is implemented for this purpose and its performance is evaluated in solving the 8-Puzzle, Towers of Hanoi and Blocks World problems. The hyper-heuristic employs a generational evolutionary algorithm which iteratively refines an initial population using tournament selection to select parents, which the mutation and crossover operators are applied to for regeneration. The hyper-heuristic was able to identify a search or combination of searches to produce solutions for the twenty 8-Puzzle, five Towers of Hanoi and five Blocks World problems. Furthermore, admissible solutions were produced for all problem instances.
Assessing Macroscopic Dynamic Permeability Through Pressure and Noise Analysis
Authors: Aslanyan Arthur , Aslanyan Irina , Farakhova Rushaniya
Published: September 2015

One of the common applications of Pressure Transient Analysis and Pressure Pulse Testing is the evaluation of formation permeability that is referred to as dynamic permeability and is then used to calibrate permeability distribution from a geological model before running full-field flow simulations.

In practice, though, the correlation between permeability from pressure tests and that predicted from open-hole logs is often poor and does not provide consistent calibration because of many factors including poor core data, poor porosity-permeability, complex pressure transient responses and others. In many cases, inaccurate dynamic permeability values are due to misinterpretation of flowing thickness.

In this paper, we demonstrate how Spectral Noise Logging can pick the boundaries of actual flow units and enable the accurate determination of effective thickness to substantially improve the correlation between dynamic and open-hole permeabilities.
Modeling and History Matching of a Fractured Reservoir in an Iraqi Oil Field
Authors: Ali Diyar H. , Al-Jawad Mohammed S. , Van Kirk Craig W.
Published: September 2015

In recent years the interest in fractured reservoirs has grown. The awareness has increased analysis of the role played by fractures in petroleum reservoir production and recovery. Since most Iraqi reservoirs are fractured carbonate rocks. Much effort was devoted to well modeling of fractured reservoirs and the impacts on production. However, turning that modeling into field development decisions goes through reservoir simulation. Therefore accurate modeling is required for more viable economic decision. Iraqi mature field being used as our case study. The key point for developing the mature field is approving the reservoir model that going to be used for future predictions. This can be achieved via History Matching. The production of this field is mainly from fractures, and it showed unfavorable decline during the production life from 1952. Thus, well modeling is necessary for developing the field, including history matching.

This study employed a three-dimensional three-phase black-oil dual-porosity model by CMG-Builder/IMEX 2010 simulator using an Iraqi fractured, faulted reservoir model. History matching has been carried out to improve the model which was going to be used in the simulation study. Several modifications were required during the history matching, such as adjusting the vertical fracture permeability, the relative permeability, the aquifer properties, setting fault transmissibility, and the matrix and fracture compressibilities.

The results of the History matching showed excellent agreement between the simulation and the historical profile. Furthermore the recent validated data by history matching have been used for the Iraqi reservoir model by running the CMG/IMEX simulator.
Multi-scale Reservoir Characterisation from Pore Scale to Simulation Scale: Concepts and Workflows
Authors: Curtis Alan A.
Published: September 2015

A consistent framework for reservoir characterisation from the pore scale through to the reservoir simulation scale is presented. Concepts that clarify the characterisation problem are explained and the scales that are of most importance to applied reservoir characterisation are defined. Workflows are presented illustrating how both static and dynamic petrophysical properties may be moved from one scale to the next, and how the similarities and the differences in the procedures at each scale change are considered. Why a multi-scale approach involves more steps than just upscaling, as is often traditionally assumed, is explained and illustrations are given at various scales of what a comprehensive multi-scale approach entails. How the concept of model-prototype similitude can be used to overcome limitations in the characterisation workflow is introduced and then the details of its use to transfer saturation-dependent petrophysical properties to coarser scales are explained.
Developing Performance Estimates of the Heterogeneous Upper Sands of the Greater Burgan Field Using Part Field Models
Authors: Muhammad Y. , Ortegon L. R. , Ibrahim M. N. , Burman K. , Datta K. , Dashti L. , Bond D. J.
Published: September 2015

The Burgan Sand reservoir is the largest and most prolific reservoir in the Greater Burgan field in Kuwait. As development of this reservoir proceeds, greater attention is being paid to the more heterogeneous upper part of the reservoir, the Upper Burgan Sands, which contain significant, multi-billion barrel, resources. A conceptual Field Development Plan was developed to enable an assessment of performance under waterflooding.

Due to the complexity of the Upper Burgan Sands and the very large areal extent of the Greater Burgan field, it was considered impractical to model the reservoir in appropriate detail in the full field simulation model. An alternative modeling approach was adopted. This involved developing a number of part field geological models which were subsequently used to develop high resolution dynamic simulation models.

This paper describes the challenges of choosing an appropriate range of part field models that capture variation in geological characteristics and of hydrocarbon properties, conditioning these models to available dynamic data and accounting for the historical production.

Particular attention is paid to three problems. First, to rank the models in terms of key features that would be expected to govern reservoir performance. These included internal heterogeneity, average reservoir quality, connectivity to the underlying Middle Burgan Sands and variation in fluid properties. Second, to assign the selected models to represent different parts of the reservoir. Third, to ensure that historical performance, including water influx inferred from surveillance data, is accounted for in predicting future performance.

The estimates were determined by a hybrid formulation, combining an analytic and simulation approach, suited for rapid computations and multi-scenario generation. Simulation results of water-cut versus recovery have been integrated with standard analytic expressions for fully developed pattern waterfloods. Scenarios investigated include the determination of ultimate recovery, a phased out recovery according to production and sweep of lower intervals, sensitivities to drilling rate, and a waterflooding scheme prioritized on area production potential.

Based on the results from the part field models, performance estimates of the Upper Burgan Sands reservoir have been made. Volumes forecasts and associated well numbers have been predicted.

A new reservoir simulation and analytical formulation has been developed to enable rapid predictions of waterflood scenarios. The hybrid formulation has proved to be significantly faster, resulting in a much quicker turnaround time compared to a traditional simulation study.
Case study: Implementation of Waterflooding in Unconsolidated Thin Heterogeneous and Viscous Oil Sands in Romania. Integrated Approach
Authors: Chirkov Maxim , Gonzalez Jose
Published: September 2015

This paper presents the implementation of pattern water flood in a very complex field in Romania. It's a multilayer formation with thin 2-5 m highly permeable (up to 2 Darcy) unconsolidated sands and unknown fluid contacts. Additionally high mobility ratio (around 50) and unfavourable rock wettability complicate the water flooding process. Project considered different injection schemes like peripheral, line drive and pattern. Integrated approach includes depositional environment analysis, 3D seismic interpretation, acquisition of complex log to investigate current oil saturation, field injectivity tests, pilot water injection and intensive surveillance plan. Water injection is part of field redevelopment plan and will increase recovery factor by 7.3%.
Multi-Scale Rock Analysis for Improved Characterization of Complex Carbonates
Authors: Dernaika Moustafa , Uddin Yasir Naseer , Koronfol Safouh , Al Jallad Osama , Sinclair Gary , Hanamura Yasuaki , Horaguchi Keishi
Published: September 2015

The evaluation of carbonate reservoirs is a complex task because of the inherent heterogeneities that occur at all length scales. Rock properties may be defined differently at different scales and this introduces a challenge in capturing heterogeneity in a single rock volume. Heterogeneities at smaller length scales must be upscaled into larger scale volumes to better predict reservoir performance. The objective in this study is to define carbonate rock types at multiple scales and then upscale those rock types and associated properties to the whole core level.

Representative core plugs were selected in a heterogeneous reservoir interval based on statistical distribution of litho-types in the core. The litho-types were described by porosity and mineralogy variations along the core length using advanced dual energy XCT imaging. Plug-scale rock types were defined on the basis of petrophysical data and geological facies. High-resolution micro to nano XCT images were integrated in the rock typing scheme. Those rock types were upscaled to the whole core level by linking the core litho-types to the plug data.

The core litho-types (porosity and mineralogy) gave good representation of the whole core heterogeneity and were reliable for selecting representative samples. This allowed establishing the link between plugs and whole cores and hence upscaling rock type information to the whole core scale. The high-resolution digital images emphasized the different pore geometries in the samples and improved the definition of the rock types. Accurate porosity and permeability logs were derived along the core length and gave very good match with the plug data. Multi-scale porosity-permeability trends were investigated and found to have direct impact on the determination of upscaled permeability log at the whole core level.

The paper presents an advanced and quick tool for representative sample selection and statistical core characterization in heterogeneous reservoirs. The identified rock types at multiple scales provided new insights into carbonate heterogeneity and gave upscaling options for rock types and petrophysical data. The upscaled rock types at the whole core level enhance the prediction of dynamic imbibition data along the reservoir column for improved reservoir performance.
Regional Stress Rotation in Arabia; Implications for Hydrocarbon E&P in Abu Dhabi, UAE
Authors: Sirat Manhal
Published: September 2015

The main objective is to unravel the development of the fracture system within the hydrocarbon fields in the Onshore of Abu Dhabi, where an alternative understanding of the fracture system development in association with the counterclockwise rotation of the regional causative stress throughout the geologic time is introduced in this paper.

Manifestation of the tectonic history of Arabia in the UAE is demonstrated by both folding represented by gentle and open folds comprising most of Abu Dhabi's hydrocarbon structural traps and a brittle deformation represented by a fracture system comprising long en echelon seismic faults and several joint and vein sets. The most dominant, tens of kilometers long seismic faults in the Cretaceous rocks of Abu Dhabi are the N75W and N45W oriented faults, which have been considered so far as conjugate strike-slip faults. It is argued here whether these two seismic fault sets, which appear in many instances as conjugate sets, have been really developed coevally by a single tectonic event when the SHmax was approximately at 120°? The current understanding that these faults are strike-slip faults despite the absence of extensive horizontal displacements along them as shown on different time-slices is also discussed. Seismic attribute analysis and interpretation, outcrop analogs and fracture description from logs and FMIs reveal that this fracture system might have been developed in a more complicated manner than reported in different publications.

It is proposed here that the N75W seismic faults have been developed first as tensile fractures shortly prior to folding when SHmax oriented approximately at 120°. The N45W seismic faults have been developed at a later stage possibly as splay faults by reactivation/ branching from the preexisting N75W when the SHmax was approximately oriented E-W. This has occurred by a continuous counterclockwise rotation of the causative SHmax stress from Cretaceous to present. A periodic strike-slip movement along deep-seated basement faults could also have developed many structural features in the sedimentary cover including several hydrocarbon fields in the Onshore of Abu Dhabi.

The implications of the drift of the causative stress with geologic time from ∼120° to E-W, NE-SW and finally to NNE-SSW include its effect in reactivating the preexisting fracture system, tilting folds, and control fluid charge and movement within Abu Dhabi petroleum system. The significance of the results is the impact on exploration, production and field development plans. In the exploration of the new plays, both leads with their fractures can be predicted once the direction of the paleo-causative stress can be defined. In production and filed development planning, predicting the fracture system would help better production with appropriate well placement.
Borehole Breakout Modeling and Stress Profiling Using Anisotropic Mechanical Properties: Case Study in a Tight Basement and Overlying Formation
Authors: Moronkeji Dee , Cazeneuve Eduardo , Franquet Javier , Sandia Marianella Rojas , Velo Diego
Published: September 2015

Optimizing the drilling and completion phases of a typical oil or gas wellbore requires geomechanical analysis to characterize the in-situ stresses. Stress profiles and lateral tectonic stresses can be determined and calibrated through MicroFrac testing and by modeling borehole breakouts observed in borehole image logs.

Several wells in the Campamento 1 field (the first field in the Neuquén Basin) were drilled with the tight basement formation in the Neuquén province in Argentina as the primary target. These wells were evaluated to estimate the stress profile using anisotropic mechanical properties and to identify suitable intervals to fracture. There are several tests and analyses that can typically be used to calibrate horizontal stresses. These tests and analyses include leak-off test (LOT), extended leak-off test (XLOT), minifrac test, step-rate-injection test (SRT), MicroFrac test, core strain measurement (Anelastic Strain Recovery, ASR), analysis of borehole breakouts and induced fractures from specific image logs.

The objective of this paper is to show the use of borehole breakouts and hydraulically induced fracture initiation and closure pressures to calibrate the magnitude of the horizontal stresses in a vertical well. Breakouts are typically more visible in an acoustic image log and are expected to occur in formations with lower strength and/or lower internal friction coefficient but sometimes they occur in intervals with high strength and stiffness sustaining high horizontal tectonic stresses.

Examples are shown in the Campamento 1 field wells with borehole breakouts and minifrac data used in constraining the magnitude of the lateral tectonic strains. The horizontal stress profiles obtained from these vertical wellbores provide valuable information for predicting hydraulic fracture geometry, propagation and containment for subsequent reservoir stimulation jobs. Two vertical wells where coupled calibration with minifrac data and breakout modeling were done are presented to show how this calibration is achieved and how it helps to constrain the magnitude of the horizontal stresses in a vertical well.

The results show how observed borehole breakouts and fracture pressures can help in constraining the magnitude of the lateral tectonic strains. These are important parameters in estimating the horizontal stress profile in the target reservoir and the stress contrast over the sub-adjacent and supra-adjacent formations.
Value of Multiple Production Measurements and Water Front Tracking in Closed-Loop Reservoir Management
Authors: Barros E. G. , Leeuwenburgh O. , Hof P. M. , Jansen J. D.
Published: September 2015

This paper extends previous work on value of information (VOI) assessment in closed-loop reservoir management (CLRM) to estimate the added value of performing multiple measurements along the producing life of the reservoir. The new procedure is based on the workflow from our previous paper which allows to quantify the VOI of a single observation under geological uncertainty. Here we show that, by modifying that workflow slightly, it is possible to assess the value of a series of measurements without a prohibitive increase in computational costs. The approach is illustrated with two cases based on a simple water flooding problem in a two-dimensional five-spot reservoir: the first one, in which we assess the value of a series of production measurements, and the second one, in which we estimate the additional value of water front positions tracked by an interpreted time-lapse seismic survey. We believe that our proposed workflow is a complete methodology to estimate the VOI in a CLRM context because we take into account that the production strategy is updated periodically after new information has been assimilated in the models. However, future work will be required to reduce the computational load to allow for the application of the workflow to real field cases.
Automatic Well Completions and Reservoir Grid Data Quality Assurance for Reservoir Simulation Models
Authors: Al-Zahrani Tariq , Al-Mulla Muath , Al-Nuaim Mohammed
Published: September 2015

Reservoir simulation engineers have to go through an intense and time consuming process to manually quality check large amounts of data which consist of wells, logs and completion events for more than 50 years of history. It is fundamental that data used in building reservoir simulation models is quality controlled and cross-checked to eliminate inconsistencies during the history match process.

This new implemented method will give an overview of the simulation data quality workflow design and outline the development of a state of the art software package that guides engineers through the quality checking process as the first stage of simulation model construction.

We have developed a workflow software package that covers most of the data required for building simulation models. The preparation and validation of data is conducted using tailored automated workflows that guide engineers through the quality control steps in a streamlined manner. At every step, specific data is reviewed and validated based on some well-developed quality check (QC) criteria. In case of any inconsistencies, the software issues relevant error and warning messages and recommends possible remedial solutions or actions.

This tool eliminates tedious manual nonformal effort and results in high-quality simulation models checked and verified through formal and automated workflows, therefore. The new workflow/software reduces the checking process from weeks to days or hours and hence minimizes the overall time to perform history matching.
Exploring the Upside Potential of Ras El Ush - A Mature Producing Field, its Challenges and Solutions
Authors: Patnaik Golak , Abhishek Karmesh , Naser Khafagy Abdel , Attia Wael , Walia Samir K. , Abd-Allah Mohammed
Published: September 2015

The Gulf of Suez is characterized by intensive normal faulting related to rifting of the Red Sea. The Ras El Ush (REU) field displays the same pattern. The field itself is bound on its eastern margin by large NW-SE oriented normal faults dipping NE (towards the Red Sea) and has dip closure to the west. However the nature of the northern and southern boundaries is unclear and they could be limited either by fault or dip terminations.

The REU field has been producing since 1996 from the Nubia and Matulla formations and it currently has around a 26% recovery factor. Nubia and Matulla are isolated from the bottom water aquifer by tarmat layer that acts as a barrier. The field therefore exhibits depletion drive with a sharp pressure decline initially then a secondary gas cab expansion drive.

The objective is to optimize pressure maintenance in the developed blocks either by using Gas Injection or Water Interjection and to evaluate the upside potential using an integrated reservoir management study approach and leveraging advance tools, technologies and best practices.

Since the structure contains dipping beds (up to ~50 deg) and faults, the conventional seismic does not help in interpreting reservoir units and dipping faults. Some of the vertical faults can be picked from seismic. In this case, it's critical to quantify the structural uncertainty due to lateral movement of faults and vertical movement of horizons, particularly near the oil water contact.
Upscaled Pseudo-porosity Extracted from Impedance Volume Can Effectively Predict Gas Fingering in a Dynamic Model – a Gas Injection Case Study
Authors: Namdarian Fatemeh , Taghanaki Morteza Aghababaee , Hashemi Abolfazl
Published: September 2015

Gas injection in an unsaturated carbonate reservoir which is located in south-west of Iran started in 2009, and based on the original dynamic model the gas breakthrough would not have happened earlier than 2017. However, the gas oil ratio (GOR) in some wells increased rapidly before the anticipated time; also the real field data shows different behaviors of gas breakthrough in different wells.

The 3D Geocellular grid obtained from 3D seismic cubes was applied to dynamic model, and by making the size of the cells smaller, the heterogeneity was identified as the most important factor in modeling and monitoring the gas movement from the injected wells towards the production wells. Based on the new upscaling, two dynamic models were constructed. The original model had 267,000 grid cells and the new ones have 1,120,000 and 2,400,000 grid cells respectively. Running the new models illustrated the gas breakout from some wells mostly through one layer of the reservoir. Since effective porosity was estimated by collocated cokrigging of well data with seismic porosity, vuggy porosity distribution in this layer is correctly predicted, given that a karstic volume has been detected in some part of the reservoir which its boundary has been defined by seismic data and the cross-plots of neutron porosity with acoustic impedence validate the reliability of this karstic zone. The results show various types of vuggy porosity that mostly governs the productivity of the wells in this reservoir.

As a result of this study, both dynamic and static models modified based on pseudo-porosity derived from seismic cubes as the best known distributed heterogeneity in this field to predict the gas movement in the reservoir. Based on this modeling, new maximum efficient rates were defined for wells and field development strategy was reconsidered.
Tapping Marginal Resource into Reality: A Case Study in Economically Developing a Low Resistivity Deep Thin Pay Reservoir, Tarim Basin West China
Authors: Li Ning , Li Qiang , Yang Pei , Zhou Bo , Liu Ruiying , Guo Xinyong , Wen Zhang , Xia Guofeng , Lin Xin , Kok Jeffrey , Yen Han Shim , Wang Yong , Liu Yanmei , Wu Bohong , Wang Xiongfei , Sun Qigang , Geng Gan
Published: September 2015

The study area is a marginal oilfield with tilted oil-water-contact. The target reservoir is located more than 5000m deep with an oil column of merely 1m. The primary challenge is to accurately land the well in this thin interval without penetrating the water zone. Faced with complex lithology in a low resistivity pay zone, formation evaluation poses obvious complications. Steering the production lateral within the thin oil column, while performing real-time reservoir evaluation, is the key to succeed economic objectives.

A combined while-drilling technology, including multi-layer bed-mapping and multi-function Logging-While-Drilling (LWD) tools were employed to address these challenges and by the end of 2014, the pilot project had successfully placed the lateral within the target zone, securing an in zone Key-Performance-Indicator (KPI) ratio of over 90% despite encountering lateral heterogeneity. By achieving this KPI, the drilling cycle was shortend by almost one-third. The authors believe that the fit-for-purpose solution can be applied in similar blocks to achieve repeated success.
Reservoir Monitoring Using Streaming Potential; Is the Thermoelectric Correction Necessary?
Authors: Jaafar M. Z. , Ahmed T. , Sulaiman W. R. , Ismail A. R.
Published: September 2015

Wellbore streaming current and their applicability in the location of subsurface sand bodies were discovered in 1931 and the usefulness of this measurement has persisted to the present day. Through the endeavor of many researchers, knowledge and understanding of streaming potential (SP) have slowly evolved from the original mere recognition of its existence to its present-day quantitative use in many applications such as Enhanced Oil Recovery (EOR), water flooding, intelligent wells, etc. The spontaneous potential acts to maintain overall electroneutrality when a separation of electrical charge occurs in response to gradients in pressure (Electrokinetic), chemical composition (Electrochemical), or temperature (Thermoelectric). In spite of it being discovered 70 years ago, unfortunately little work has been done to find measurable value especially for thermoelectric coupling coefficient. Many researchers attempt to generate a universal model for SP. They attributes the limitations (if any) of their model to the scarce availability of accurate estimation for coupling coefficient. This study measures the value of thermoelectric coupling coefficient for five rock samples saturated with 0.01M (NaCl) saline brine. The study takes account of temperature dependant electrode effect. The result shows value of 0.2 mV/K, which is in a good match with most of the published data. It was also found that there is no strong correlation between the thermoelectric coupling coefficient and porosity. The measured thermoelectric values are considered insignificantly small compared to the electrokinetic effect in the system.
Developing A Two-scale Fracture Model And Its Application For Drilling Strategy In A Fractured Carbonate Reservoir
Authors: Changrong Bian , Wang Yi , Feng Xingqiang , Zhang Yu , Li Zhihua , Shen Feng
Published: September 2015

In this study, we present an integrated approach to develop a two-scale fracture model for the Ordovician carbonate fractured reservoir in the Yubei area. The objective of this study is to provide new insights into the impact of fractures on oil production and to recommend drilling strategy. Fractures are characterized by using log data, 3D seismic attribute, borehole image logs and reservoir production data. Image logs illustrate that the dominant reservoir fractures trending in the NE direction parallel to the present-day maximum horizontal compressive stress and are consistent with the major fault system. The electrofacies generated with conventional logs are calibrated into different fracture units by using borehole image logs and reservoir dynamic data. The dynamic behavior of the complex matrix and fracture system is characterized for fracture units at wells. For layer bound diffuse fractures, the fracture properties are modeled statistically set by set with borehole image logs, fracture seismic facies volume representing degree of the fracturation and seismic geometric attribute. Fracture lineaments at the corridor scale are extracted directly from edge-enhanced seismic attribute. Fracture lineaments are cleaned and meshed to define their topology relationships to construct a comprehensive DFN (Discrete Fracture Network) model. Fracture networks are characterized deterministically, which constitute a unique fracture model on the reservoir scale. DFN model provides a geological representation how these fractures are spatially organized in the subsurface and how they may enhance or inhibit fluid flow. The final fracture model honored the two scale fracture models. Grid-cell permeability properties are derived from the two-scale fracture model. Based on the dynamic behavior of fracture units, fracture properties are calibrated against the dynamic data. Our results show that NE orientated fractures are open and conductive. The high productivity zones are characterized by high permeability located in the vicinity of faults. Enhanced oil recovery operations could be optimized using production wells oriented at high angles to NE orientated fractures.
Determination of Effective Matrix and Fracture Compressibilities from Production Data and Material Balance
Authors: Ham J. M. , Moreno A. , Villasana J. C. , Herrera R. Perez , Rodney C. A.
Published: September 2015

A new method is proposed to estimate the matrix and fracture’s effective compressibilities by using the material balance equation (MBE) and production data. Assuming the behavior of naturally fractured reservoir (NFR), accordingly to the pressure tests analysis, it is then possible to replace the effective compressibilities into a MBE of double porosity to determine original oil from both systems.

Due to the lack of information from cores and the problem that implies acquiring it, this method represents a useful alternative for analytical models. Generally, it is complicated to determine representative values of fracture compressibilities for the entire reservoir; especially when this is very heterogeneous. The calculated compressibility of the matrix and fractures can be compared with formation compressibility correlations when there are no core analysis or pressure tests available.

This is an innovative method to obtain reliable compressibilities for the analysis of material balance of double porosity (MBDP). In addition, with this method it is also possible to obtain the original ratio of the volume stored in the fractures to the total volume in the reservoir; which is a crucial factor in the determination of the final oil recovery.
Strategy for Calibrating a Field-Scale Numerical Simulation Study for the Implementation of a Chemical Enhanced Oil Recovery Pilot Using Core Flooding and Pre-Pilot Experiments
Authors: Bozorgzadeh M. , Stofferis M. M. , Yznaga R. Angulo , Cubillos H. , Caro E. Yuste , Montes J. , Gallego P. Alonso , Rodriguez R. , Fernandez P. Romero , Blin N. , Prieto C. A.
Published: September 2015

Chemical Enhanced Oil Recovery (CEOR) in a multi-layered reservoir environment with moderate to strong natural water-drive is a complex process with associated risks and uncertainties. Reservoir simulation is one of the most important tools available to predict behavior under chemical flooding conditions and to study sensitivities aimed to a cost-effective CEOR process implementation. Key to the success of a reliable reservoir simulation is the application of a de-risking process and the acquisition of important calibration data, such as laboratory core-flood data and field-scale pilot experiments.

A CEOR pilot is currently undertaken in the Caracara Sur (CCS) field (Llanos Basin, Colombia) which has an unfavorable mobility ratio and very low water salinity. However challenges exist, such as strong water drive (no water injection experience), high temperature and a complex geological nature (up to 15 reservoir layers that made up of multiple isolated distributary channels). A detailed reservoir simulation model was built to study full field implementation of CEOR in Caracara Sur. The model was calibrated with laboratory tests data, residual oil saturations from Single Well CEOR ASP Well Tracer Test Pilots, injectivity tests and breakthrough times from inter-well tracer tests.

The paper discusses the approaches taken for full field modeling of Caracara Sur using commercial software and describes how the data collected from alkaline/surfactant/polymer (ASP) core flooding were up scaled and used in pilot sector modeling and for designing tracer back flow tests (TBFT) and single well tracer tests (SWTT) before and after ASP flooding. The TBFT and SWTT results in a pilot injection well, in the middle of three producers, confirmed the absence of aquifer drift, which was also predicted by pilot sector modeling. The paper explains how the obtained results from the tracer tests (residual oil saturations, breakthrough times) and well injectivity were used to calibrate the full field numerical model for reliable prediction of the effectiveness of the ASP flooding.
Modelling Reservoir Depletion Processes to Obtain Representative Oil Formation Volume Factors
Authors: Liu Lulu , Williams John M.
Published: September 2015

This research investigates the way laboratory oil formation volume factors (FVF or Bo) from differential liberation (DL) and flash separation tests are used by engineers to represent real reservoir production processes. A survey about Bo was performed among industry professionals. The work proposes standardisation in these approaches, including a way of adjusting laboratory DL data to represent a true differential process and a new technique for obtaining composite Bo data from combined DL and separator tests. Finally, 3-D reservoir black-oil and compositional models were developed to calculate Bo and explore which phase behaviour processes ECLIPSE 100 and ECLIPSE 300 are mimicking.

This paper shows laboratory Bo data are commonly misunderstood by engineers, and recommends greater awareness and better education. A novel analysis of laboratory DL studies demonstrates that these can seriously overestimate true differential processes. The work tests and discusses the feasibility of using 3D compositional simulation models to derive more realistic Bo values for the combined reservoir and production process. A procedure has been written based on the findings of this work to help petroleum and PVT engineers to standardise the reporting and proper use of laboratory Bo measurements.
Innovative PDC Bit Design Increases Drilling Efficiency in Egypt’s Notoriously Difficult Western Desert Deep Lithology Column
Authors: Farouk H.. , Elwekeel W.. , Shokry A. E. , Ibrahim A.. , Sherif M.. , Elsherif O. H. , Aguib K.. , Bits Smith
Published: September 2015

Efficiently drilling the deep lithology column with PDC bits in Egypt’s Western Desert (WD) has been extremely challenging. The formations—Alam El Buwaib, Masajid, Zahra, and Safa—contain a volatile mixture of highly interbedded sandstone, siltstone, and shale that have damaged PDC bits, especially at depths of 12,500 ft and greater. In addition to the demanding drilling requirements, operators are pursuing multiple targets per well for better cost optimization. Finally, a tight control on target drilling days has required more efficient and consistent drilling solutions. In addition, the array of different drive types and BHAs used in the area have all suffered and exhibited the same symptoms: high stick/slip, high shock and vibration, failure of MLWD tools, RSS, or positive displacement motor (PDM), and premature tripping for bit changeout.

To solve the issues, several 8½-in PDC bits were developed that feature a central conical diamond element (CDE). The bit designs feature an abbreviated cutting structure profile at the bit center that generates a rock column that stabilizes the bit. The rock column is constantly being destroyed with axial force as opposed to traditional shear, resulting in lower torque magnitude and fluctuations. The reduction in torque fluctuations increases the bit’s potential to solve a combination of vibration issues. The new-style bits were scheduled to be field tested in different wells and runs in Egypt’s Western Desert applications, including with classical rotary BHAs, with different RSS/PDM types in a variety of directional well profiles, at different depths, and in different fields. This robust field campaign was performed with the intent of proving and providing a consistent solution and grounds for a paradigm shift of how PDC bits need to be constructed.

The results of the multifield campaign delivered low levels of torque and torque fluctuations; enhanced bit durability, frequently replacing two bits or more; low vibration levels; a significant increase in cuttings size, thereby enhancing surface formation identification; and high dogleg capability and smooth directional response. The bits also increased footage and overall ROP due to preserving the cutting structure, producing a performance step change and achieving consistent lower cost per foot across the WD field.

The field test campaign results in Western Desert spans over 60 runs conducted over a 12-month period. A close monitoring of the performance improvement has been tracked where the runs are rated against offsets. The rating is in terms of overall run performance, footage improvement, ROP increase, cutting structure condition, and overall dull grade. The new bits set over 30 new benchmarks.
Detailed Mineralogy and Organic Carbon Detection Through Casing Using Pulsed Neutron Technology - A Case Study in a Carbonate Formation (KY)
Authors: Mendez Freddy E. , Siddiqui Aamir , Hanif Amer , Longo John , McGlynn Ian , Gade Sandeep , Blood David R.
Published: September 2015

Spectral analysis of natural and stimulated gamma rays is a well-established open-hole technology that enables accurate mineral characterization and petrophysical evaluation of conventional and unconventional reservoirs. The determination of detailed mineralogy in the cased-hole environment, however, has been a challenge because of the significantly increased uncertainties caused by the additional attenuation and contribution effects of casing and cement that are observed in the gamma ray spectra. The acquired spectral gamma ray data is processed with proprietary algorithms that are based on a combination of lab experiments and modeled tool response standards. The resulting elemental composition, corrected for the cased-hole environment, is further processed in an expert interpretation system to determine lithology and detailed mineralogy of the target formation. Candidates for this technology include older and newly cased wells where lithology and detailed mineralogy from open-hole logs are not available.

This work discusses some aspects of the corrections needed for an accurate quantification of chemical elements from measurements through casing. The impact of casing collars and presence of cement on the spectral data are also discussed. Finally, we report a case study that uses this technology and illustrates a successful mineral characterization of a complex reservoir rock in the United States. Results show good agreement with an x-ray difraction (XRD) analysis of ditch cuttings. The resulting logs were productively used by the operator to understand the siliciclastic influx as well as the distribution of carbonates in the Big Lime formation. The results also show the ability of the methodology to identify organic carbon directly from measurements of the inelastic spectrum in the cased-hole environment.

The application of pulsed neutron technology (PNT) in cased holes has, so far, been limited to basic lithology identification. This methodology expands the applicability of the PNT, previously mostly confined to open-hole cases, to the cased-hole environment and enables operators to take full advantage of the valuable information contained in high-resolution inelastic, capture and natural spectra. This enables characterization of hydrocarbon-bearing formations to a level of detail previously possible only from open-hole data.