bluuebunny/crossref_metadata_2025 huggingface dataset:
Pengaruh Konsentrasi Rebusan Kelopak Bunga Rossella terhadap pH Saliva Buatan
Authors: Adi Prasetyo , Puspitasari Ambar , I Murni Ukhuwah
Published: November 2016

Saliva adalah sekelompok cairan oral yang kompleks. Salah satu mikroorganisme yang menyebabkan pH saliva menjadi asam adalah Streptococcus mutans. Rebusan kelopak bunga Rossella (Habiscus sabdariffa L) mengandung flavonoid dan antosianin yang dapat mengganggu aktivitas sel dan pertumbuhan Streptococcus mutans. Tujuan penelitian ini mengetahui pengaruh konsentrasi rebusan kelopak bunga Rossella terhadap pH dan absorbansi saliva buatan yang diinduksi Streptococcus mutans secara in vitro. Penelitian ini menggunakan True Experimental Design yaitu Posttest Control Group Design. Konsentrasi yang digunakan dalam penelitian ini adalah 5%, 15%, 25%, dan 35%. Hasil penelitian menunjukkan ada perbedaan nilai pH dan absorbansi saliva buatan yang telah diinduksi Streptococcus mutans dan ditambahkan dengan rebusan kelopak bunga Rossella terhadap kelompok kontrol secara in vitro. Analisa data menggunakan uji Korelasi dan Regresi menunjukkan pengaruh sebesar 99,2% pada pemberian rebusan kelopak bunga Rossella terhadap nilai pH dan absorbansi saliva buatan. Uji One-Way ANOVA menunjukkan nilai signifikansi 0,000 (p< 0,05). Disimpulkan terdapat perbedaan nilai pH dan absorbansi saliva buatan yang signifikan antara kelompok kontrol dan kelompok perlakuan.The Effect of Rossella Flower Petals Stew to Artificial Saliva pH. Saliva is a complex oral fluids. One of the microorganisms that cause the saliva’s pH becomes acid is Streptococcus mutans. Water stew of Rossella flower petals (Habiscus sabdariffa L) contains flavonoids and anthocyanins that interfere metabolism of the cells and growth of Streptococcus mutans. The purpose of this experimental was to know the effect of water stew Rossella flower petals concentration in pH scale and absorbance score of artificial saliva which induced with Streptococcus mutans by in vitro. The method which applied here was True Experimental Design, post test control group design. The concentrations that used in this study were 5%, 15%, 25% and 35%. The results described the differences in pH scale and absorbance score of artificial saliva which induced with Streptococcus mutans between treatment group (added by water stew Rossella petals) and control group. Data analysis using correlation and regression test showed the effect of water stew of Rossella flower petals in pH scale of artificial saliva was 99.2%. The conclusion of this experimental explained the increase of pH scale after added with the water stew of Rossella flower petals, also showed a significant differences of pH scale of artificial saliva between treatment group and control group based on the One-Way ANOVA test, and the water stew of Rossella flower petals was effective to maintain pH scale of artificial saliva approach normal pH scale
The Use of Genre-Based Cycle with L1 Rhetorical Structure in L2 Writing Class: An Exploratory Study
Authors: Chang Tzu-Shan
Published: November 2016

This paper demonstrates the systemic functional approach (SFL) with the L1 rhetorical structure in a genre-based writing class and then examines the effectiveness of this study’s approach in developing Chinese EFL writers’ competence in writing argumentative essays. This EFL writing course follows the SFL approach, the genre-based cycle of teaching and learning, to provide students with repeated opportunities to practice literacy skills gained in previous cycles until they master different genres. The genre-based cycle formed the writing instruction along with the L1 rhetorical structure as a strategy; Chinese EFL sophomores (n = 44) were instructed in this writing class. Qualitative and quantitative data were collected: Interviews and ratings of students’ writing from two raters before and after the instruction. The results presented that most participants had made statistically significant progress in their writing competence, particularly in structuring paper. The incorporation of L1 rhetorical structure into the genre-based cycle offered participants a framework to organize their arguments in L2 writing. When EFL students’ home languages/cultures are treated as the resources within the context of a genre-based cycle, their prior knowledge of L1 rhetorical structure transits to more accurate construction of L2 essays.
STUDI PEMANFAATAN EKSTRAK KUNYIT (Curcuma domestica Valeton) UNTUK PENGENDALIAN PENYAKIT JAMUR AKAR PUTIH PADA TANAMAN KARET
Authors: Kusdiana Alchemi Putri Juliantika , Munir Misbakhul , Suryaningtyas Heru
Published: November 2016

Penyakit jamur akar putih (JAP) yang disebabkan oleh cendawan Rigidoporus microporus (Sw.) Overeem masih menjadi penyakit penting dan merugikan pada perkebunan karet Indonesia hingga saat ini. Upaya pengendalian JAP secara biologi terus dilakukan untuk melengkapi cara lain yang telah ada (kimia dan kultur teknis) agar diperoleh hasil yang lebih efisien dan efektif. Studi pendahuluan pemanfaatan bahan tanaman antagonis telah memberikan capaian yang prospektif. Diperolehnya ekstrak tanaman antagonis kunyit (C. domestica) yang efektif untuk pengendalian JAP. Penelitian ini dilakukan dengan tujuan untuk mengetahui efektifitas, persistensi, dan fitotoksisitas bahan nabati tersebut yang diekstrasi menggunakan berbagai bahan pelarut dan dibuat dalam berbagai bentuk formula. Hasil penelitian yang dilakukan di laboratorium dan rumah kaca Balai Penelitian Sembawa menunjukkan bahwa pada kondisi laboratorium ekstrak kunyit efektif menekan perkembangan cendawan R. microporus sebesar 43,25% s.d. 65,13% terhadap kontrol. Pada kondisi rumah kaca diperoleh hasil bahwa formula ekstrak kunyit 20 EC + pelarut n-hexane dapat menurunkan intensitas serangan penyakit JAP sebesar 20,80%. Semua jenis formula yang diuji tidak toksik terhadap tanaman karet dan memiliki persistensi yang baik sampai empat hari setelah aplikasi formula ke media tanam (tanah) dalam polibeg.
Opportunities for Fluorocarbons Interior Coating Technology in ASP Flooding EOR: Evaluation of Corrosion Protection and Drag Reduction
Authors: Wang Zhihua , Lin Xinyu , Zhang Lei , Zhong Huiying , Fan Meng , Yu Tianyu
Published: November 2016

Alkali/surfactant/polymer (ASP) flooding technology has become an important way to enhance the oil recovery and improve the recoverable reserves in Daqing Oilfield. However, the problems of corrosion that surface facilities encounter with still remain very challenging in ASP flooding production, especially in the strong base (NaOH) fields. In this paper, the situation of corrosion in the ASP flooding surface system in Daqing Oilfield is surveyed, and several measures of anticorrosion operated in production are demonstrated. A program about coating the production facilities with fluorocarbons is proposed. The performance of the coating is tested, the nature of alkali and surfactant resistance is evaluated, and its mechanism of anticorrosion is explained. The drag reduction advantage of fluorocarbons interior coating is confirmed by conducting a series of comparison experiments. The procedure of the coating is optimized and validated with the actual operational data from a known ASP flooding pilot area in Daqing Oilfield.

The surveys indicate that serious corrosion occurs in ASP solutions preparation tanks, injection system, gathering and disposal facilities of produced liquid. The defects such as bulging, damaging and falling away, appear frequently in the epoxy coatings which stand for the most traditional measure. There are many high-energy C-F bonds in fluorocarbon paint, and the corrosion resistance and self-cleaning of the coating with low surface energy are excellent after the film-forming. The performance parameters of adhesion, flexibility and impact strength determine that the coatings can resist chemical erosion and osmosis diffusion of alkali and surfactant solutions in different degrees. By reference to the uncoated and the epoxy coating flowlines, the drag reduction rate of ASP flooding produced liquid in fluorocarbon coating flowlines achieve 52.75% and 31.64% respectively in the same flow condition, and the effects impacted by temperature are negligible. Furthermore, the practice in strong base (NaOH) ASP flooding pilot area obtains satisfactory with the advisable procedure. This paper emphasizes the extension of fluorocarbon coating technology is promising in addressing the operational problems and the coating failures. The case study is beneficial to design another pattern-flood pilot and accelerate further application of ASP flooding.
Use of Advanced Mud Gas Chromatography for Reservoir Quality Prediction While Drilling
Authors: Dashti Jalal , Al-Awadi Mashari , Al-Ajmi Bader , Rao Sudhakar , Shoeibi Ahmad , Estarabadi Javad , Ferroni Gionata , Nadiminti Avataram
Published: November 2016

While drilling through a reservoir, a lot of valuable information can be obtained from mud logging to support formation evaluation. Field data will help wellsite geologists, petrophysicist and reservoir engineers to predict reservoir quality, fluid contacts and reservoir permeability based on formation gases detected while drilling. This study discusses some examples from exploratory wells that have recently been drilled in Kuwait. Gas readings were recorded while drilling through deep Jurassic formations to evaluate hydrocarbon content using Advanced Gas Chromatography. The primary components of the system utilized are: a constant volume gas extractor, a gas sample flow control system, and a high resolution chromatographic system. To interpret the findings Gas readings are monitored by a complex system which provides real-time continuous measurements of the concentration of formation gases from very light components such as methane, to heavy components such as C6, C7 and C8 hydrocarbon species, comprising n-hexane, n-heptane, n-octane, benzene and toluene. Formation gas is considered as the first indication of a reservoir's fluid characterization and reflects the extent of the productivity of the well. Geochemical ratios and equations can enhance the interpretation of field data and give the first indication of zones of interest that need further evaluation.

Dedicated flowmeter sensors (Coriolis) utilized to evaluate formation fractures while drilling. The Delta Flow trend versus time is characteristic of the type of losses and consequently of the downhole fractures.

Geochemical ratios are plotted against depth and lithology to determine fluid type, contacts, fractures and dolomitization. For this purpose Well-Site Geochemical Package services, including X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) workflow at rig site was also applied in of the wells. The analysis is based on measuring major and minor chemical mineralogy and elements of the drilled cuttings. This has helped in better quantitative assessment of different facies such as limestone, dolomite, shale etc., and providing a better control on geological model update while drilling the well.

To take advantage of the field data, advanced mudlogging data are plotted on a depth log, which can be easily integrated with other data (post well data).
Transient IPR for Fractured Horizontal Wells in Niobrara Formation
Authors: Yuan Bin , Moghanloo Rouzbeh Ghanbarnezhad , Zheng Da
Published: November 2016

The dominate flow regime for multistage fractured wells in unconventional shale reservoirs is transient flow regime. Understanding the interplay between flow rates and the flowing pressures for different fracturing schemes and completions is critical knowledge required for production optimization. The well production can be optimized by adjusting the flowing bottom-hole pressure. The Inflow Performance Relationships (IPR) are based on the premise of pseudo-steady state flow regime that is inherently not applicable to transient flow; thus, this paper introduces a new empirical IPR model obtained by integrating a series of piece-wised pseudo-steady state flow regimes that occur as the drainage volume expands. The average reservoir pressure calculated within the dynamical drainage volume (DDV) at any given time is used to derive an IPR model.

A computer code is developed to evaluate the evolution of DDV using the macroscopic material balance equation. Fluid and rock compressibilities are the only production mechanism. The computer code is used for ten wells in the Niobrara shale oil play. The size of the DDV, associated average reservoir pressure, and transient productivity index are calculated. This newly derived empirical IPR is capable of predicting production performance

In practice, this paper provides an insight to understand the long-term transient flow regime and its impact on productivity of wells in shale plays. The method does not require comprehensive inputs, and can be used to optimize the design of multistage fractured wells.
Enhanced Oil Recovery After Polymer Flooding by Wettability Alteration to Gas Wetness
Authors: Cheng Changhui , Li Kewen , Liu Changwei , Jia Lin
Published: November 2016

Polymer flooding, as one of the EOR (Enhanced Oil Recovery) methods, has been adopted in many oilfileds in China and some other countries. Over 50% oil remains undeveloped in oil reservoirs after polymer flooding. It has been a great challenge to find approaches to further enhancing oil recovery when polymer flooding is over. In this study, a new method was proposed to increase oil production using gas flooding with wettability alteration to gas-wetness when polymer flooding has been completed. The rock wettability was altered from liquid- to gas-wetness during gas flooding. An artificial oil reservoir was constructed and many numerical simulations have been conducted to test the effect of wettability alteration on the oil recovery in reservoirs developed by water flooding and followed by polymer flooding. Production data from different scenarios, water flooding, polymer flooding after water flooding, gas flooding with and without wettability alteration after polymer flooding, were calculated using numerical simulation. The results demonstrate that the wettability alteration to gas-wetness after polymer flooding can significantly enhance oil recovery and reduce water cut effectively. Also studied were the combined effects of wettability alteration and reservoir permeability on oil recovery.
Getting the Best Out of Online Acoustic Sand Monitoring System: A Practical Method for Quantitative Interpretation
Authors: Gupta A. , Kamat D. , Borhan N. , Madon B. , Ahmad Z. , Farouqi A. , Zulkapli M
Published: November 2016

Sand Management in the current oil industry trend is one of the important aspects for operators. Managing sand, be it downhole or at surface depending on economic analysis provides an optimised production with proper risk mitigation. Just like for proper hydrocarbon optimisation, accurate monitoring tools such as well test that uses separator or multiphase flow meters are being used and are evolved. Similarly, sand production monitoring is one of the key components during sand management production. Without a proper and reasonably accurate monitoring of sand being produced, it is not possible to manage. With the advent of various techniques of sand monitoring evolved in the last few decades, the industry is moving further on how to improve the new methods of monitoring or utilising the current techniques more effectively. The industry is still struggling to make significant improvements or find new methods of monitoring or more effective application of the current techniques. analogy between sand management and hydrocarbon production and the significance of the same in sand management.
Application of Spectral Decomposition and Seismic Inversion for the Determination of Reservoir Architecture and Connectivity for Coal Seam Gas Field Development
Authors: Ahmad Mirza Naseer , Tyson Stephen
Published: November 2016

Coal seam gas (CSG) is naturally occurring methane found in coal seams. Fractures act as the major channel for the gas to flow and play a significant role in evaluating the practicability of the CSG exploitation. Prediction of the subsurface coal seams and the distribution of the fractures within the coal seams is a challenge. This study attempted to predict coal distribution by applying spectral decomposition and post-stack seismic inversion on a data set of the Surat Basin, Queensland, Australia. Semblance and curvature attributes were computed to determine fracture distribution within the coal seams.

According to the rock physics analysis, based on well data, coal beds had a low p-impedance as compared to surrounding lithologies. A model-based P-impedance inversion was executed to create a P-impedance volume. Extracted horizon slices successfully highlighted coal seams at different levels. Blind test for the P-impedance prediction at a well location revealed a reasonable match for coal prediction. High frequency (from 40~60 Hz) spectra delineated thin coal beds. Semblance and curvature predicted zones of high fracture density within various stratigraphic levels. The high density of fractures is along faults.

This study successfully demonstrated the prediction of coal seams and fracture distribution by using seismic inversion spectral decomposition and seismic attributes. Hence, these techniques can be used for the field development of coal seam gas.
Oxygen-Free Sliding – CO2 Corrosion Test Rig for Evaluating the Performance of Corrosion Inhibitors for Steel Tubings
Authors: Trausmuth Andreas , Rodriguez Ripoll Manel , Totolin Vladimir , Badisch Ewald , Zehethofer Gerald , Vogl Thomas
Published: November 2016

CO2 corrosion combined with sliding wear plays a significant role in limiting the lifetime of tubings in oil exploration industry. These phenomena often lead to material damage and ultimately to tubing failure. However, the combined effect of CO2 corrosion with mechanical wear at elevated pressure and temperature under anoxic conditions is seldom considered in laboratory tests. In this work, a novel testing system able to perform CO2 tribocorrosion tests under realistic testing conditions is presented. Furthermore, the test rig is characterized for having a floating cell, which allows monitoring the corrosion potential throughout the experiment and evaluate the performance of corrosion inhibitor (CI) packages. The final goal is to investigate the behaviour of corrosion inhibitors during sliding-CO2 corrosion of low-alloyed carbon steel tubings. The results show that, besides surface degradation, the CI significantly influence the friction behavior of tubings. As a consequence, the mechanisms of surface degradation are different than those obtained under inert conditions, thus highlighting the need to evaluate prospective tubing materials under close-to-reality conditions.
Numerical Simulation Analysis on Degassing Structure Optimisation of a Gas-Liquid-Solid Three-Phase Separation Hydrocyclone Based on the Orthogonal Method
Authors: Zhao Wenjun , Zhao Lixin , Xu Baorui , Zhao Yu , Jiang Minghu
Published: November 2016

The composition of oilfield produced fluid (OFPF) is introduced, and the necessity of degassing and desanding of OFPF are illustrated. Two main degassing and desanding methods, gravitational method and hydrocyclone separation method, are respectively introduced. The latter attracts much attention due to its small occupation area and high separation efficiency. Classification and respective characteristics of solid-liquid hydrocyclone and gas-liquid hydrocyclone are described. The state-of-the-art of gas-liquid-solid three-phase hydrocyclone are briefly introduced. A new gas-liquid-solid three-phase hydrocyclone was designed based on the thought of connecting an inner-cone gas-liquid hydrocyclone with a conventional solid-liquid hydrocyclone in series by spiral flow channels. Based on the orthogonal method, influencing degree and rules of geometric parameters on the gas separation efficiency are studied using a computational fluid dynamics software FLUENT, and geometric parameters are preliminarily optimized. Study shows that degassing cone angle and gas phase overflow pipe stretch length have more significantly impact on gas-phase separation efficiency. The results provide some reference for the structure optimization of the three-phase hydrocyclone for gas phase separation.
Geomechanical Evaluation for Previously Fractured Unconsolidated Formation in Microscopic Numerical Modeling
Authors: Li Wenjing , Wu Rui
Published: November 2016

Traditionally, hydraulic fracturing is considered as an effective stimulating method for unconventional reservoirs with extremely low permeabilities. For poorly consolidated sandstone formations in Gulf of Mexico, East China, West Africa, etc., hydraulic fracturing is used for control or solution of sand production and formation damage more than just creating conductivity. However, it is difficult to analyze the rock mechanisms after stimulation due to the consequences of weakening of proppant overtime and changing of fracture tortuosity, etc. Stress distribution in the formation has been altered with the propagation of fractures, which make the situation more complex. For simulation of solid rock, applied by Discrete Element Method (DEM), a dynamic numerical model approached by PFC 2D Modeling is used to evaluate geomechanical properties and predict the potential formation damage. DEM is also coupled with Pipeline Network Approximation (PNA) for solid-fluid interaction. In this paper, fracture initiation and propagation, anisotropic stress boundary effect, contact forces between particles, and change of stress are investigated in microscopic system. Results demonstrate that the shear cracking mode should not be neglected in the formation of low strength and high permeability. The simulation results from PFC modeling are in agreement with the conventional numerical simulation methods. This study provides an alternative method of understanding the fracture micro-mechanism for poorly-consolidated formations, which could be applied into design and optimization of hydraulic treatment.
MPD Closed Loop Cementing in High-Pressure, High-Temperature Wells in Vietnam
Authors: Singh Harpreet Kaur Dalgit , Quoc Bao Ta , Yong Tan Chai , Nguyen Vi Pham , Wittry Alan E. , Malpas Peter , Beaugeois Aldric , Huu Nhieu Nguyen
Published: November 2016

Managed Pressure Drilling (MPD) technology has effectively proven that it can overcome the operational obstacles encountered when drilling difficult and challenging wells. MPD has helped many operating companies reach target depth by accurately managing the annular pressure profile of the wells in which it is deployed. However, well construction operations do not stop when target depth is reached. The well still has to be cased, cemented, and completed in order to produce and returns the initial spend on these investments.

In high-pressure, high-temperature (HPHT) well conditions where very narrow margins between the pore and fracture pressures are prevalent, conventional cementing operations become a complicated task. The tendency of inducing losses is very common, specifically during running of casing or liners, which is then further aggravated during the displacement of the cement slurry.

This was the case in one of the HPHT wells in Vietnam where losses were encountered during previous liner running operations. This situation led the operating company to decide to utilize MPD technology to improve, enhance and optimize the cementing operation. Pre-modeling to determine the correct parameters and the utilization of MPD technology allowed the mud weight to be reduced while managing equivalent circulating density (ECD) through the application of surface backpressure (SBP) to stay within the limits of the well. The application of MPD closed loop cementing on this HPHT well proved effective and provided correct parameters to successfully complete the cementing operations.

This paper will discuss the application of MPD closed loop cementing on this HPHT well in Vietnam. Specifically, it will examine the following: (1) reasons and concepts associated with MPD closed loop cementing; (2) MPD closed loop cementing pre-planning and engineering; (3) MPD closed loop cementing execution; (4) MPD closed loop cementing challenges; and (5) lessons learned and best practices.

The paper will also detail how the MPD closed loop cementing technique can be further refined and improved to be able to address other pertinent concerns experienced by other HPHT operations in Vietnam, thereby realizing the full potential and impact that the technology can help bring about in terms of drillability, efficiency, and above all safety.
The Survey for Prevention of Work-Related Musculoskeletal Disorders Among Workers Performing Manual Material Handling Work
Authors: Thongpradit A. , Dusadi-Isariyavong A. , Jongpaiboonkit A. , Kim J. , Jalayondeja W. , Mekhora K. , Jalayondeja C. , Bhuanantanondh P. , Upiriyasakul R.
Published: November 2016

Manual Material Handling (MMH) activities (i.e. lifting, lowering, pushing, pulling, and carrying) pose the risk of injury to the musculoskeletal system of the workers. The injuries may lead to decreased work performance, and increased errors, absenteeism and health care cost. Therefore, it is necessary to know whether the workers of one of the Oil and Gas Company in Thailand are facing with the injury problem and to find the solutions for preventing those injuries.

The procedure of the solution is walk-through survey of hazards and risks of Work-Related Musculoskeletal Disorders (WMSDs) among the workers (both onshore and offshore platforms) whose works involved in MMH tasks and providing the recommendation and followed up by Medical and Occupational Health team of the Company together with the physical therapists from one of the famous academic institute in Thailand who are collectively called "the research team".

The research team conducted a walk-through survey and performed preliminary physical examination at an onshore and all offshore platforms. The survey included characteristics of each work, intensity and frequency of workload, work environment and potential risk factors. Physical fitness assessment including muscle power and weakness was also determined.

The findings from the walk-through surveys, work procedure were analyzed to identify risk factors of work-related musculoskeletal injuries. The findings from preliminary physical examination in approximately 300 operating workers, upper cross and lower cross syndromes were found, indicating muscle imbalance in MMH workers. Task activities were analyzed on each procedure which has risk factors including awkward posture, repetitive movement, manual handling, forceful exertion, work environment, equipment, and cognitive and psychosocial issues. The research team reported risk factors with consequences and provided recommendation for each factor regarding engineering, administrative, and individual controls. For example, offshore platform has many floors which are designed for particular function (office, bedroom, dining room, etc.). Offshore workers regularly perform high repetitive stepping up and down stairs making them prone to hip and leg muscles imbalance. There is high compression at knee joint which may lead to early degenerative joint or knee pain. The recommendation is to provide properly work break and training with principle of ergonomics in workplaces including ergonomic risk factors; risk prevention; and strengthening exercise.

Findings on this study lead to the specific designed exercise program and training to counteract the effect of heavy musculoskeletal activities related to MMH in daily work. The study will also serve as a guide for developing of MMH guideline for the company.
Design of Inter-Well CO2EOR Pilot Test in Offshore Field
Authors: Murai D. , Kuroki K. , Takayanagi M. , Kawaura K. , Takahashi S. , Son L. N. , Trung P. N.
Published: November 2016

CO2EOR has much advantage not only in enhancing oil recovery but also in CO2 storage. It is, however, necessary to confirm or estimate the technical, operational and economic uncertainties by pilot test for applying CO2EOR to actual oil fields. This paper describes the methods and the procedures to design an inter-well CO2EOR pilot test.

As a result of subsurface study, the number of pilot wells is determined to be 1 injection well and 2 production wells in order to estimate CO2 areal sweep efficiency in the minimum cost. To confirm the effect of CO2EOR, well interval, cumulative CO2 injection volume and duration were determined to be 300 m, 2,000 tonnes and 2 weeks, respectively. The oil production rate begins to increase 1 month after the beginning of the pilot test, and the gas production rate and the vapor phase CO2 mole fraction also begins to increase at the same time. Then, the oil production rate reaches the peak after 1.5 months from the beginning, and the effect of CO2EOR is confirmed clearly. If oil saturation is high in the target reservoir, it will be difficult for confirming the oil bank clearly. In such case, pre-water injection before CO2 injection is found to be an effective countermeasure.

As a result of surface study, a CO2 procurement method and a new platform were designed through the process optimization study. Manufactured CO2 was selected as CO2 source for the pilot test. The packed manufactured CO2 into tank containers are transported to the injection site by trucks and supply vessels. Moreover, CO2 impact study was conducted, and it is found that we can manage the potential risks related to corrosion and scale formation by using suitable countermeasure such as CRA's and inhibitors. Finally, based on the result of corrosion and scale formation studies, the operation guidelines were prepared. When the CO2EOR pilot test will be planned in any oil field, it will be possible to make the test design with the similar procedure to this study.
Challenging Operation in Block A South - How to Enhance Development Success in Abnormal Pressure
Authors: Wasawat Y. , Sittichod S.
Published: November 2016

Due to highly abnormal pore pressure observed in Block A South phase I development, several unexpected problems were encountered. Well targeting, operation and integrity issues were studied to minimize in the next phase of Block A South development. Phase II well designs were renewed to gain reservoir optimization. This paper presents the field mitigation and operational improvement of Block A South development from phase I to II, and the proposed guideline to later Block A South phases. For instance, Block A South phase III is another achievement to perform on these development strategies.

Block A South comprises many reservoir sections from shallow target – 2E unit, down to deep target – FM1. Pore pressure starts to ramp up at lower 2D unit and back to normal pressure at lower 2A unit. All targets were combined in a single well for reservoir maximization in phase I. However, it caused problems in terms of well operation and integrity during production. Therefore, new well design was planned to segregate reservoir targets as shallow, intermediate and deep sections to minimize operational issues. These three types of new well designs were also incorporated with pressure pregnant profiles. After two batches of fifteen wells drilled in Platform A, many operation issues, well control, borehole collapse and well integrity, were experienced. Average well cost was approximately 30 percent in excess of plan. Only half of drilled wells cannot be put on stream as planned due to cementing and integrity problems.

For Block A South phase II, pressure prediction is precisely conscious to avoid operational problems. Platform H was first developed with abnormal pressure of 1.65 sg. The new designs show success in the platform development. The Platform H new well drilling gives rise to about 20% increase in success rate from Platform A drilling. Also, average well cost is as planned. Platform G, which investigates maximum observed pressure up to 1.85 sg, exhibited all methods to avoid operational problems. 85% of wells drilled in Platform G have no problems and average well cost is within 5 percent exceeding plan. Actual operation cost and time yield better results than expected. Additionally, larger amount of volume in Platform G has been produced comparing to Platform A. The overall result of Platform G is favorable to the next phase of Block A South development.

The strategies are acceptable results to control operation with abnormal pressure. It is beneficial to Block A South development and investment. Lesson learned from these practices will provide operational improvement in later Block A South phase. These designs can be applied to other fields in the Gulf of Thailand.
Computational Method for Hydraulic Fractures Spacing of Multi-Fractured Horizontal Well in Ultra Low Permeability Reservoirs
Authors: Mingqiang Hao , Yongle Hu , Xingfan Zheng
Published: November 2016

Hydraulic fractures spacing of multi-fractured horizontal well (MFHW) is an extremely important item for the optimization of MFHW in ultra-low permeability reservoirs. By adopting the maximum condition that fluid at the midpoint of the two adjacent hydraulic fractures is just able to flow, the mathematical model and computational method to determine the hydraulic fractures spacing of MFHW were established based on the non-Darcy flow theory, the elliptical seepage theory, and average mass conservation law. Then the influences of the reservoir permeability, thickness, hydraulic fracture half length and conductivity, producing pressure drop on hydraulic fractures spacing of MFHW were studied quantitatively. The results show that hydraulic fractures spacing increases as the permeability increases and they have a preferable double logarithmic linear relationship; the fractures spacing decreases as the reservoir thickness and fracture half length increases, and the influences of the reservoir thickness and fracture half length on the fractures spacing are related to the hydraulic fracture conductivity. When the fracture conductivity is high, the fractures spacing is relatively broad, but with the fracture conductivity increasing, the fractures spacing growth gradually slows. The relationship between the producing pressure drop and the fractures spacing is approximately linear. The larger the producing pressure drop, the broader the fractures spacing of MFHW.
Hydraulic Fracture Optimization Based on Discrete Fracture Network Model in Shale Reservoirs
Authors: Mi Lidong , Jiang Hanqiao , Wang Yuhe , Pei Yanli , Li Junjian , Gao Sunhua , Killough John
Published: November 2016

Horizontal well drilling and multistage hydraulic fracturing are two main technologies in the development of shale gas reservoirs. In this study, a multi-scale percolation mathematical model for the shale gas reservoirs was established based on the discrete fracture network (DFN) model and the derived nonlinear equations were solved based on the Newton-Raphson method through programming in C Sharp. Finally, the comprehensive evaluation was conducted to evaluate the influence of hydraulic fracture stages/spacing, half-length, aperture, orientation and natural & hydraulic fracture connectivity on the shale gas exploitation in a basic geological model with complex natural fractures network. Numerical simulation results indicate that the hydraulic fracture stages/spacing, half-length and orientation only influence the early period (the first 100 day in this model) production rate which becomes consistent after that, but the fracture aperture has a little effect because the matrix permeability is the main factor to limit the gas flow. There are a demarcation point that the cumulative production acceleration slows down when the number of hydraulic fracture stage increase (20 stages for this case) and the cumulative production acceleration speed up when the hydraulic fracture half-length increase (45m for this case). The hydraulic fracture aperture has a little effect on the cumulative production when the matrix permeability is 800nD for the presented fractures network in this work. When the angle of natural fractures and horizontal well are 45°, the angle of hydraulic fracture and natural fracture varies between 45° and 75° or the angle of hydraulic fracture and well varies between 90° and 120° is most beneficial to enhance the cumulative production. The cumulative production of shale gas well is positively correlated to the all fracture intersecting node number which is changed by only adjusting the fracture stage (or fracture length, fracture orientation), we also find that the effect of the fracture length change on cumulative production is the most obvious, and the descending order of the fracture parameters is fracture length> fracture stage> fracture orientation.
Building More Realistic 3-D Facies Indicator Models
Authors: Blévec Thomas Le , Dubrule Olivier , John Cédric M. , Hampson Gary J.
Published: November 2016

We present a generalization of Pluri-Gaussian Simulation (PGS) of facies that is constrained by facies transiograms instead of variograms. The main benefit is that the transiogram can be different in opposite directions whereas the variogram is symmetric. This is important as geology shows vertical (e.g. shoaling upward successions) and lateral (e.g. proximal-to-distal trends, preferential facies pinch-outs) asymmetries in facies transitions that cannot be quantified by variograms. Mathematically, the modelling approach is based on the incorporation of a spatial shift between the underlying gaussian random functions ("shifted PGS"). The matching with the transiograms is achieved by numerical computation of a multi-gaussian integral. Consequently, the modelled heterogeneities can account for a spatial polarity that may be vertical (upwards/downwards), lateral (proximal/distal), or oriented in any other direction. The method is illustrated using outcrop data from a reservoir analog deposited in a carbonate shoal environment over a lateral distance of about 2 km, i.e. equivalent to inter-well spacing in a typical hydrocarbon reservoir. A comparative study is performed between classical PGS and shifted PGS methods. The shifted PGS method successfully models the spatial ordering/asymmetry between high-permeability shoal and low-permeability backshoal facies. This new method widens the possibilities of facies modelling in complex geological environments, and produces more realistic predictive geological models.
Mechanical and Microstructural Studies of Nanoclay Based Oil Well Cement Mix under High Pressure and Temperature Application
Authors: Murtaza M. , Rahman M. K. , Al-Majed A. A.
Published: November 2016

To prevent cement sheath damage, a robust cement sheath is required to ensure long-term integrity and stability of the well from the imposed stresses. Successful completion of cementing job has become more complex, as drilling is being carried out in high pressure high temperature (HPHT) wells. Recently, application of nanomaterials in enhanced oil recovery, drilling fluid, oil well cementing and other applications are being explored. This paper presents the outcomes of an experimental study conducted to investigate the effect of nanoclay as an additive on the properties of Type G cement slurry under HPHT conditions. An organically modified nanoclay in which natural montmorillonite is modified with a quaternary ammonium salt is used in a cement mix, typically used in the Saudi Arabian oil field under HPHT conditions. Nanoclay based cement mixes were prepared with 1%, 2% and 3% BWOC nanoclay, along with silica flour, and other chemical admixtures. Development of compressive strength properties, microstructural studies using SEM and XRD techniques and permeability and porosity studies were conducted. It was observed that nanoclay at 1%BWOC reduced the permeability and porosity and enhanced the compressive strength with the accelerated strength development at early ages. A crystal product that is interweaved and joined together to build strong and well-proportioned structure is developed in the harden cement paste. The smaller size particles fill the capillaries of the cement paste that resulted in a dense structure of the matrix. In addition, this novel slurry formulation with low permeability and porosity and high compressive strength, is suitable in zones where the possibility of gas migration is very high.
Well Planning Optimization Process: The Collaboration Way of Saving Well Planning Time in Gulf of Thailand
Authors: Luckanakul M. , Chuemthaisong N.
Published: November 2016

With the world oil price crisis, reducing both well costs and drilling time are primary goal of leading E&P companies. Helping PTTEP to achieve these goals is its Well Planning Optimization Process, which shortens well planning time and increases time to optimize well design through collaborated communication among subsurface and drilling teams and advanced pre-identification of risks. PTTEP's new process gives 2 years advance time to optimize wells, supporting the company concept of "Drilling Factory Model". The well planning optimization process consists of geosciences and drilling well planning database integration, optimizing the well planning process, and a 3D visualization well planning optimization meeting. Further, it creates a collaborative environment among subsurface and drilling teams to work more efficiently and provides quick decision making for well design, optimizing targets, identifying risks, and analyzing offset wells. The significant reduction of well planning days give more time to plan ahead for future platforms. This paper presents a case study from the Gulf of Thailand using this new well planning optimization process. Also addressed is the methodology of an integrated process and data flow for better well planning.
Development and Utilization Dynamic Temperature Modeling: A Case Study in High Temperature Well Planning
Authors: Suryadi Hendrik , Van Chinh Phan
Published: November 2016

Extended Abstract

Today, oil and gas industries have been continuously drilling into deeper reservoirs and into high temperature formations. Drilling high temperature wells poses new challenges with current available drilling tools because the operating temperatures can closely reach and at times, surpass downhole tools' temperature specifications. The temperature will affect electronics, elastomer or rubber components in tools, sensors, or even could reduce the mechanical strength of the steel collar and cause twist-off. The development of downhole tool technology continues to strengthen and increase the tool temperature rating to withstand those challenges. Utilizing high temperature rated downhole tools can be significantly expensive compared to standard temperature rating tools (150oC). Other technological developments for high temperature wells rely on mud properties and mud surface cooling system. Despite that, one of the key factors to successful drilling operations in high temperature wells still lies on the capability to simulate downhole conditions taking account various technologies and parameters involved, understand the potential challenge and risks, and predict down-hole circulating temperatures that tools will be exposed to.
Development of a DSS and Online Tools to Support Sleep Disorder Consultations using Design Science.
Authors: Blake Jacqueline , Kerr Don , Gammack John
Published: November 2016

Medical decision making takes place in a complex and dynamic environment, involving various individual and organisational stakeholders. In such contexts supportive information systems are required to be designed for practical efficacy, emphasising transparency, usability, and usefulness to their primary users. At the same time, they need to demonstrate improved efficiency and diagnostic accuracy.  In addition, they also need to provide effective communication of relevant information. This paper describes the use of design science to develop and evaluate a DSS incorporated into online tools to support sleep physician’s diagnosis of sleep disorders.  The design science approach offers guidance for developing this solution, that ensure the artefacts fit into their usage context, and that development and evaluation principles that generalise to similar problem domains are identified. How this project fits in the design science guidelines is specified, thus demonstrating how this philosophy and methodology advances theory particularly relevant to other similar medical diagnostic domains.  The usability and technical evaluation of the set of tools indicated provide clear practical benefits at patient, physician and organisational levels.
A Design Science Research Methodology for Expert Systems Development
Authors: Miah Shah Jahan , Genemo Hussein
Published: November 2016

The knowledge of design science research (DSR) can have applications for improving expert systems (ES) development research. Although significant progress of utilising DSR has been observed in particular information systems design – such as decision support systems (DSS) studies – only rare attempts can be found in the ES design literature. Therefore, the aim of this study is to investigate the use of DSR for ES design. First, we explore the ES development literature to reveal the presence of DSR as a research methodology. For this, we select relevant literature criteria and apply a qualitative content analysis in order to generate themes inductively to match the DSR components. Second, utilising the findings of the comparison, we determine a new DSR approach for designing a specific ES that is guided by another result – the findings of a content analysis of examination scripts in Mathematics. The specific ES artefact for a case demonstration is designed for addressing the requirement of a ‘wicked’ problem in that the key purpose is to assist human assessors when evaluating multi-step question (MSQ) solutions. It is anticipated that the proposed design knowledge, in terms of both problem class and functions of ES artefacts, will help ES designers and researchers to address similar issues for designing information system solutions.
Design science research for decision support systems development: recent publication trends in the premier IS journals
Authors: Miah Shah J , McGrath Michael , Kerr Don
Published: November 2016

This paper presents a contemporary literature review of design science research (DSR) studies in the domain of decision support systems (DSS) development. The latest studies in the DSS design domain claim that DSR methodologies are the most popular design approach, but many details are still yet to be revealed for supporting this claim. In particular, it is important to thoroughly investigate the trends in either the form or deeper insights in use of DSR in this field. The aim of this study is to analyse the existing DSS design science studies to reveal insights into the use of DSR, so that we can outline research agenda for a special issue, based on findings of analysis. We selected articles (from 2005 to 2014) that were published in seven selected premier IS journals (ranked as A* in the ABDC journal ranking). The selected 57 sample articles are representative of DSS design studies that used DSR in theorising, designing, implementing, and evaluating DSS solutions. We discuss the theoretical positions of DSR for DSS development through six categories: DSS artefacts, DSR methods, DSR views, user involvement, DSS design innovations and problem domains. The findings indicate that new studies are needed to fill the knowledge gap in DSS design science, for more solid theoretical basis in near future.