bluuebunny/crossref_metadata_2025 huggingface dataset:
Trends in the Evolution of Organic Food Market in Romania
Authors: Sima Violeta , Gheorghe Ileana Georgiana
Published: March 2018

This article describes how organic farming is a dynamic sector in Romania, which has showed an upward trend in recent years. Although the Romanian market of organic food is still far from the developed markets, an increasing trend in the demand for organic products has appeared among consumers. This pattern can be explained, on the one hand, by increasing the Romanian consumers' access to information and on the other hand, by the increasing living standard. Accordingly, this evolution has required adjustments to the offer. In this regard, there is an increase in the number of operators in the organic farming system. Development opportunities remain very high if we consider the potential of the bio-agricultural area of Romania and annual rhythm of the number of certifications of organic operators in developed EU countries. In this context, we can state that organic farming plays an important role, contributing significantly to sustainable development.
Navajo Weavings in John Ford Westerns
Authors: Patin Thomas , McLerran Jennifer
Published: March 2018

This article describes how although placed in the periphery or backgrounds of many scenes, Navajo weavings are central to the presentation of the spectacle of wilderness, savagery, warfare, heroism, and salvation in many of John Ford's westerns. In this article, the authors examine specific examples of visual rhetoric in two of Ford's westerns: Stagecoach and The Searchers. They articulate how Navajo weavings constitute a strategic component of set designs and have consequences for viewers' expectations and understandings of these films. These weavings are key elements of a powerful visual rhetoric in Ford's films.
Adult Dyslexia and Word Puzzles
Authors: Burley Priscilla Beatriz , Cuneo Natasha , Ellis Emanuel , Smith Lillian
Published: March 2018

This article describes how dyslexia is a real disease that is linked to specific semiotic systems, such as the alphabet and word orthographical rules. As such, it is likely to be a result of an asymmetry between developmental cognition and particular semiotic structure. If this is so, then an appropriate intervention approach that is based on this hypothesis might involve the use of word puzzles that play on the alphabetic and semantic structure of words. This article presents the findings of a pilot project in which selected adult dyslexics were asked to participate in a word puzzle study, consisting of word searches, anagrams, and word squares, whereby they would be asked to solve a set of puzzles under the supervision of a researcher. The latter documented and annotated the actual behaviors of the participants as they solved the puzzles. The overall result of the project is a promising one in that it suggests that the use of such “enigmatological” strategies may have a definite role to play in dyslexia intervention, although much more research is needed in this area.
Tectonic Evolution and Hydrocarbon Prospectivity of East Coast Basin, Offshore Hawke Bay, New Zealand
Authors: Erdi Aurio , Huuse Mads , Bachtiar Andang
Published: March 2018

East Coast Basin (ECB) is situated on an active convergent margin that has been influenced by a long subduction history between the Pacific and Australian plates. Exploration activity in the onshore region of this area is shown by 40 wells with over 300 hydrocarbon seeps indicating the presence of an active hydrocarbon system. On the other hand, the offshore area has only three wells, all of which encountered significant gas shows. Regarding the offshore area, one of the problems is less understanding of migration pathway leading to uncertainty in prospect identification.

This study tries to approach this issue by identifying the relationship between regional tectonic framework, pathways for fluid to flow and hydrocarbon potential in the offshore ECB particularly in the thrust triangle zone within this area. While 2D and 3D seismic analysis has identified the tectonic features, palinspastic reconstruction, complemented with recent knowledge of regional tectonics, was performed to represent reasonable solutions for the tectonic evolution of offshore ECB. On the other hand, seismic observations complimented by seismic attribute analysis identify fluid related features related to faults in the offshore area.

Analysis of the datasets indicate four main tectonic events in the offshore area consisting of (1) Pre-Miocene deposition in passive margin settings, (2) Early-Middle Miocene deposition while thrust faults formed in the compressional phase, (3) Late Miocene deposition while listric faults formed in the extensional phase and (4) Pliocene-Holocene deposition with structural inversion in the compressional phase until recent. On the other hand, observations of chimneys associated with listric faulting indicates the Late Miocene extensional phase created migration pathway for fluid to flow from Cretaceous-Paleogene source rock. An assessment of trapping configuration, as well as a presence of high amplitude anomaly bounded by reactivated fault in the study area, offers a promising late Miocene prospect in the offshore ECB. Understanding the tectonic evolution, fluid related features and hydrocarbon potential within the offshore ECB provides insight into the petroleum system as well as potential prospectivity identification in this area.
Velocity Estimation by Joint Migration Inversion: An Example from a Field in the Malay Basin
Authors: Arshad Abdul Rahim Md , Ghosh Deva Prasad , Latiff Abdul Halim Abdul
Published: March 2018

Standard seismic processing method of estimating velocity is to remove multiples. In this paper, we utilized multiples that contain valuable subsurface information. A line from a field in the Malay Basin were used to estimate an interval velocity using the Joint Migration Inversion (JMI) method. The motivation for this approach are 1) multiples increase illumination especially in the shallow shadow zones, 2) multiples provide an additional sensitity to velocity errors and 3) the velocity estimation process is automated. In the JMI method, seismic imaging is done in a closed-loop manner as opposed to the standard seismic processing open-loop method. The initial migrated seismic image is feedback to a forward modelling algorithm. This allows an iterative minimization of the difference between the simulated and the real measurements. This also enable velocity estimation to be carried-out simultaneously. The method was first applied on a synthetic data before an application to a real data set from the Malay Basin. The results obtained showed that multiples can be utilized to get an accurate velocity model while at the same time getting a better seismic image of the subsurface.
Wheatstone Subsea Installation - Challenges Associated with Large Numbers of Subsea Heavy Lifts and Spools Offshore Australia
Authors: Cosson Damian , Rowe Michael , Koolhof William
Published: March 2018

This paper describes the installation scope for the Chevron-operated Wheatstone Project, including the following items: A number of heavy subsea structures comprised of Pipeline Termination Structures, Subsea Isolation Valves (SSIV) and drill centre manifolds.Fabrication, metrology and installation of a large number of clad tie-in spools of widely varying weight, length, shape and stiffness.Tie-in spools at the Wheatstone Platform (WP) to connect the WP risers to the SSIVs and flowlines (and associated diver-assisted flanged connections).

A Dynamically Positioned Heavy Lift Vessel (DPHLV) was used for the subsea structures installation campaign. The DPHLV performed 13 heavy structure lifts in a range of water depths. The maximum structure weight was 527 tonnes (Te).

A Heavy Construction Vessel (HCV) was mobilised to perform the deployment of 68 spoolpieces, ranging in size from 4" to 44" internal diameter. A range of spool spreader-beam arrangements was incorporated depending on the spool geometry and weight. The maximum combined spool plus spreader weight was 188Te.

The subsea structures were installed within very tight seabed landout tolerances. Such tolerances were achieved using the vessel's Class 2 Dynamic Positioning capability, as well as the calibration of an acoustic seabed survey array which provided the necessary global subsea positioning reference.

The spools offshore lifting operation, including multi vessel-interactions, was a technically challenging and weather sensitive activity. Safe and efficient methods were developed for the transfer of personnel from HCV to barge, mooring the barges to the HCV, and tagging the spools during lift off barge. The HCV was also used to tie-in the spools at the drill centres using diverless connection systems.

The spools deployed in the vicinity of the Wheatstone Platform were tied-in using a Dive Support Vessel. Pipe handling frames and air bags were operated by the divers to assist flange tie-ins of the stiff and large diameter spools.

The structures were installed in seastates up to 1.8m Significant Wave Height, with the governing case for the installations being seabed landout. A high capacity Passive Heave Compensator (PHC) was incorporated into the rigging arrangement to dampen the load during seabed landout, hence allowing landout within the maximum allowable speed. The PHC also ensured that vessel roll was kept to a minimum by allowing for a controlled unloading of the crane, and that there was no structure re-impact with seabed during de-ballasting operations upon seabed landout.
Least-Squares Reverse Time Migration Using Generalised Diffraction-Stack Imaging Condition
Authors: Moussavi Alashloo S. Y. , Ghosh Deva , Bashir Yasir
Published: March 2018

Reverse time migration (RTM) is a wavefield-continuation method which is accepted as the best migration method currently available for imaging complicated geology. RTM is defined as a reversal procedure of seismic wave propagation, but, conventional RTM does not formulate this reversal procedure as an inverse problem. This problem can be solved using least-squares migration (LSM). This paper presents developing RTM by utilizing least squares inversion process. A matrix-based least squares RTM (LSRTM) algorithm is studied by employing the generalized diffraction-stack migration method. A simple layered model with an anticline structure, and Marmousi model are used to monitor how LSRTM can improve the imaging of dip reflectors, steep dips and the pinch-out. The LSRTM method succeeded to image the flanks, remove noises and improve the resolution. Inversion process of least squares RTM was more efficient than conventional RTM to enhance the resolution of image, remove the artifacts, and correct the amplitude.
Experimental Research on Lateral Vibration of Drill String in the Highly Deviated Well
Authors: Wen Xin , Guan Zhichuan , Zhou Yingcao , Zhang Bo
Published: March 2018

Drilling is one of the most costly and risky activities in oil and gas reservoir exploration and field development. A portion of this high cost is related to unwanted vibrations of the drill string. Assumed as the primary cause of many problems, drill string vibration is an ongoing challenge for drillers. In this paper, the lateral vibration characteristics of drill string in the highly deviated well are quantitatively analyzed and the influence of different drilling parameters on lateral vibration are fully evaluated.

In order to study the lateral vibration characteristics of drill string in the highly deviated wells under different drilling parameters, a drill string dynamics simulation apparatus was built according to the similarity theory, and the vibration response in different directions was measured. The lateral vibration frequency of drill string was calculated by Fast Fourier Transform (FFT) and the non-dimensional frequency was defined to quantitatively evaluate the relationship between the vibration frequency and the excitation frequency. Moreover, the average acceleration was defined to evaluate the movement of the drill string in a period of time.

The results indicate that rotary speed is the determining factor of drill string's lateral vibration. The lateral vibration frequency is equal to the excitation frequency and the average acceleration generally increases at a relatively low rotary speed. As the rotary speed continues to increase, when it exceeds a certain critical point, the lateral vibration frequency doubles and the average acceleration encounters a shape increase. In addition, with the increase of the weight on bit (WOB), the vibration frequency and the average acceleration keep stable, but the phenomenon of doubling the vibration frequency is suppressed.
New Energy Revolution for Oil & Gas
Authors: Guérin Pierre
Published: March 2018

Since 2014, the CO2 emissions due to fossil energy combustions have been more or less stable, but compared to 2016 the emissions shall increase from 2% in 2017. [3]. The peak shall rise to 36.8 Billion of tons in 2017. Energy, with 66% of emissions, remains one the most important contributor to the gas emission sector.
Standardisation & Replication of Lean Well-Head Platform to Accelerate Hydrocarbon Maturation from Exploration to Production for Marginal Field Development
Authors: Yong H. , Kho R. , Osman B. , Rahman R. Abdul , Hamzah M. , Kona S.
Published: March 2018

Shell Malaysia embarked on a Low-Cost Exploration and Development (LCD) journey to unlock previously stranded accumulations in the Central Luconia province. By leveraging on the long history of exploration and sub-surface data, a successful exploration campaign with Joint Venture (JV) partners yielded five field discoveries. The current Low-Cost Development strategy focuses on developing these fields with the JV partners through standardized lean well-head platform (WHP) tie-back to existing infrastructure. This paper describes the journey and the paradigm shifts within the company and its JV partners to achieve a WHP design that is low cost, light weight and replicable for future exploration discoveries.

Front end loading work and competitive scoping is applied to establish minimum requirements for safety and operability resulting in barebones functionality with many functionalities removed or scope reduced. This includes evaluating novel technology application such as solar panels for power versus the conventional turbine generators. A key paradigm shift within the company is to challenge company standards and to reconcile the gap between company and industry standards. Company standards are prevalent in the oil and gas industry with standards differing for various operators. A key effort undertaken by the project team is to strip down the differences in company standards and requirements between the various JV partners and industrial standards. To capitalize on the market environment of low oil price, the project steers away from conventional segmented contracting strategy with an EpC approach with competitive bidding to leverage on contractor's capability to further bring down cost.

The outcome of the competitive scoping and the focus on minimum functional requirement is a lean standardized WHP design, half the weight of recent WHP development projects without compromising safety and operability. The standardized WHP design is replicated for three fields within the same PSC resulting in reduced FEED engineering costs and shortened project cycle for future developments. CAPEX reduction is anticipated through leveraging on economy of scale for procurement of materials and equipment as a result of the replication of standardized WHP design.

With this approach of standardized minimum requirement WHP, it allows for new strategy for future field explorations and development by focusing on clustered exploration around the vicinity of existing infrastructure allowing for stranded marginal accumulations to be developed.
Storable Liquid-Bead System as Lightweight Additives for Oilwell Cementing
Authors: Pang Xueyu , Hundt Gregory , Lewis Sam , Vargo Richard , Tan Brendon
Published: March 2018

Hollow-glass microspheres (beads) are widely used during oilwell cementing operations to produce lightweight cement slurries; this paper discusses a new method of blending hollow-glass beads into cement slurries by creating a storable liquid suspension of hollow-glass microspheres (liquid beads). This new method enables efficient delivery of lightweight cement slurries in offshore and remote locations by eliminating bulk-blending logistics.

The concept of liquid beads is not new; however, earlier attempts to develop liquid beads or similar products generally failed to address the storability problem. The buoyancy force tends to lift the beads to the surface of the suspension, forming a gel or crust and causing the mixture to lose flowability within a relatively short period of time. A special chemical-additive package developed in this study significantly extends the storability of liquid beads. This paper compares the gelation time of different liquid-bead formulas and evaluates the performance of cement slurries prepared with liquid beads.

Laboratory test data show that the chemical-additive package developed in this study can extend the storage time (shelf life) of liquid beads from a few hours to at least one month without reagitation at room temperature; the shelf life can be further extended to at least one year with regular reagitation of the mixture. Cement slurries prepared with dry-blended beads and those prepared with liquid beads exhibit similar performance in terms of laboratory test results, such as free fluid, fluid loss, thickening time, and hydration kinetics. The liquid-bead system developed can be produced with cement batch mixers for field use and remain stable in tote tanks for at least several months with regular recirculation. Liquid beads can be added to cement slurries through liquid-additive pumps during a cementing operation.

A novel liquid-bead product that can be stored for extended periods of time without separation is presented here along with necessary laboratory testing, actual field applications, and field-application case histories using liquid beads to produce low-density cement slurries.
Reservoir Monitoring by CSEM Data: A Fictitious Domain Strategy
Authors: Amani S. , Mikada H. , Takekawa J.
Published: March 2018

Marine controlled source electromagnetic (CSEM) survey is a novel complementary geophysical method for exploring structure below the seafloor. In this research, the processing of marine CSEM data is investigated for monitoring of hydrocarbon reservoirs in the offshore. Due to highly conductive seawater and shallow conductive layers, the attenuation of any EM signals is one of the most crucial problems that has prevented the application of imaging technologies (e.g. migrations) regularly adopted in exploration seismology. Inspired by the similarity of seismic and electromagnetic data, we investigate an innovative approach by applying two popular seismic imaging methods on CSEM data for monitoring of hydrocarbon reservoirs in conductive (attenuating) media: reverse time migration (RTM) and Kirchhoff migration (KM).

The synthetic marine CSEM data is calculated for a model including a hydrocarbon reservoir in an attenuating medium. We used the realistic values for sedimentary rocks that are common for attenuating media. Then, we apply RTM and KM methods to CSEM data in the real-time diffusive domain to monitor the hydrocarbon reservoir. In marine CSEM surveys it is important to consider the direction of source implementation and here we model the effects of source implementation directions in terms of reservoir monitoring. Maxwell's equations were solved in the fictitious wave domain, a scheme allows faster calculations than conventional methods, reducing the computational cost. However, the wavefields calculated using this fictitious method are not real and should transferred to the real-time diffusive domain.

The results confirm the RTM handles both the vertical and horizontal edges and defines the hydrocarbon reservoir in attenuating media much better than KM since the RTM does not introduce any approximations of the physics of wave propagation. The main drawback of RTM, its expensive computational cost, has been significantly reduced by advent of new powerful computers., The results also show that the horizontal source implementation is a better scheme for reservoir monitoring using a marine CSEM survey.
Management of Well Integrity Across Divested Upstream Assets
Authors: Spowage A. C. , Copping S. , Lunt G. , Bhardwaj J. , Smith C. , Smith L.
Published: March 2018

The recent lower for longer environment within the Oil and Gas industry has resulted in a wide range of challenges for operators. One of the responses has been to increase the pace of divestment of mature assets from large operators to independents. The objective of this work is to distill the lessons learned through the implementation of well integrity management systems across the globe. The work focuses on those aspects of the process that are of particular relevance to mature divested assets. The methodology used is to focus on the drivers and specific challenges new operators face and then distil the key points into a simple implementation process.

A four step implementation process has been developed: Data and System Audit, Well Integrity Management Manual, Central Well Integrity Management Software Solution and Engineering Support services. Within each step the challenges are addressed within the narrative of the various steps and the lessons learned through implementation experience are outlined. The requirements of the applicable standards were extracted and found to include the management of: Operating Limits, Performance Standards, Barriers, Annulus Pressure Management, Well Monitoring and Surveillance, Well Maintenance, Management of Change, Risk Assessment Process, Well Handover and Well Integrity Reporting.

The paper aims to provide practical guidance which can be used to assist those who may face similar challenges in the future.
Drilling Fluid Impact Studies Show that Worker Health and the Environment Can Be Protected While Improving Drilling Performance
Authors: Lim Serena , Lyon Delina , Whale Graham , Lee Burnell , Boogaard Peter , Grover Pat , Slyke Don Van , Koh Jane , Abd-Rashid Azman
Published: March 2018

GTL (Gas-to-Liquid) drilling base fluids, such as Shell GTL Saraline™ 185V/NEOFLO™ 4633, are synthetic hydrocarbons produced via Fischer-Tropsch synthesis from natural gas. GTL Fluids are predominantly comprised of iso- and normal paraffins and contain virtually no aromatics or contaminants such as sulphur and amines. Saraline 185V is a Health, Safety, Security, and Environmental (HSSE)- advantaged base fluid for use in global exploration and production drilling operations onshore and offshore.

Extensive terrestrial, freshwater and marine ecotoxicity testing with Saraline 185V and related GTL Fluids confirm a lack of acute or significant chronic toxicity to a wide range of environmentally relevant organisms. Saraline 185V is also readily biodegradable in aerobic freshwater, seawater, soil and sediments and will also degrade under anaerobic conditions. The biodegradability can be exploited to bioremediate drill cuttings, as has been demonstrated in both laboratory and field trials. Furthermore, when used offshore, marine benthic surveys have demonstrated that degradation also occurs and that there is a lack of any significant environmental impact associated with the discharge of Saraline 185V contaminated drill cuttings.

Extensive mammalian toxicity testing of GTL Products indicates that Saraline 185V will exert very little, if any, toxicity in mammalian species. Saraline 185V is odourless, and vapour emission tests reveal that it has >7-fold lower gas emissions when compared to conventional diesel, thereby leading to better air quality on drilling locations. A recent study which assessed emission and personal exposure levels to various hydrocarbons at key phases of drilling operations confirmed that significantly lower hydrocarbon exposures occurred for mud systems based on Saraline 185V compared to conventional diesel.

The drilling performance of GTL versus diesel based muds has also been assessed in an onshore drilling operations study. To enable a fair comparison all wells were drilled in the same formation (located in the Permian Basin of West Texas) using the same drilling rig, crews, bit, footage, fluid contractor, tools and directional driller. These field trial data indicated an overall drilling improvement for GTL over diesel mud.

This paper provides an overview of the exposure, human health, environmental and performance studies conducted on GTL drilling fluids. In combination, these create a value proposition for GTL Fluids showing that better health management combined with reduced environmental footprint and improved drilling and equipment performance leads to lower total well costs.
Impact of Data Reconciliation at Various Scales in the Construction of Reservoir Model
Authors: Murugesu Thanapala S. , Masoudi Rahim , Wibowo Suryadi , Grippo Nicolas , Johare Dzulfadly B. , Marzuki Izral Izarruddin B.
Published: March 2018

Reservoir model is widely used in oil and gas industry for hydrocarbon resources assessment, development, and management with different depletion strategies. The reservoir model is built through integration of multi-disciplinary information, data and interpretation at various scales. Integration of data from various resolutions and scales is usually a big challenge in constructing reservoir model due to its impact to the model's ability to make a reliable production forecast. The objective of this study is to analyze the impact of scale changes in clastic reservoir modelling and to evaluate its implication to hydrocarbon volume in-place and fluid flow behavior. Several examples from clastic reservoirs of different geological environments were evaluated and data from various scale were incorporated in reservoir description in constructing a representative reservoir models. Reconciliation of various reservoirs properties using database such as core data, logs, DST and production/pressure were performed.

Permeability upscaling was observed posing significant challenges compared to the other properties at each stage. Therefore, the paper puts more emphasize on permeability while briefly discuss the other properties. Other challenges including complex reservoir types such as thinly laminated reservoirs are also evaluated. The study demonstrates that different permeability modeling methods may give significant impact on the hydrocarbon in-place and fluid flow characteristic. In the absent of production data to verify the in-place, the uncertainty of in-place is inevitable. In addition to that, those different permeability models may also give different flow characteristic.

It is concluded that by recognizing the scale difference and impact of averaging/upscaling with the guidance from production/pressure performance, robust reservoir model with representative reservoir properties could be achieved. This paper shares the best practices in integrating data from various scale/discipline and highlights the impact of the data integration at right scale in constructing robust reservoir model.
First Successful Deployment of 17-Chrome OCTG CRA Corrosion Resistant Alloy Tubular as Production String in the World
Authors: Johari M Raimi , Jusoh Nur Zulaikar Md , Hong Ong Swee , Fabian Oka , Rashid Noor Hidayah A , Idris Mohd Faisal Rizal , Musa M Zarir , Balbir Orient Samuel , Rosato Miguel , Shaedin Ridzuan , Teng Chaw Kit , Riyanto Latief
Published: March 2018

PETRONAS embarked on a new challenge to drill and complete 5 wells with high bottom hole temperature (BHT) of 180°C and highly deviated fractured carbonate with high velocity gas producers. These wells utilized 7" big bore production tubing with new material 17CR instead of the expensive cold worked 22CR duplex stainless steel (DSS).

As the first application of 17CR production tubing material in the world, a lot of risks were taken into account and mitigated via various approaches from planning engineering stage until execution. These mitigation measures included the qualification of material and connection; operational details involving parties from different disciplines to ensure smooth and efficient deployment of 17CR tubing. In addition to that, optimization opportunities were explored to further increase running efficiency and reducing flat time while ensuring tubing integrity is intact.

The successful deployment of 17CR were attributed to the following: Connection modification from JFE BEAR to JFE BEAR DR-PK to minimize the risk of galling around the metal-to-metal seal area on the newly developed 17CR CRA materialTubing was racked back in double joints per stand offline during installation using offline activity cantilever (OAC) deck available on a tender assisted rig to improve running timeUtilization of side door elevator instead of single joint compensator to enable running tubing in double.Usage of Flush Mounted Slip (FMS) dressed with pre-qualified low penetration dies, to ensure sufficient gripping on the 17CR tubing OD surface without being affected by the surface scale which is known to have with high hardness valueUsage of low penetration dies instead of non-marking type hydraulic tong to reduce tubular running cost

With the above mitigation measures put in place, the project was delivered with high efficiency in terms of tubular running speed achieving up to 14 joints per hour on 7" high alloy CRA tubing with extremely low number of rejection rate (0.3%) for the entire project. Utilization of 17CR as an alternative to 22CR DSS has also contributed direct cost saving of up to USD 8.2 mil to the project.
Subcooling and Induction Time Measurements of Probabilistic Hydrate Formation
Authors: Lim Vincent W. S. , Metaxas Peter J. , Zhen John , Stanwix Paul L. , Johns Michael L. , Aman Zachary M. , May Eric F.
Published: March 2018

The risk of natural gas hydrate formation in oil and gas flowlines increases when production moves into deep-water regions under high pressure conditions. Unlike hydrate dissociation, which is deterministic, the formation of gas hydrates is a well-known stochastic phenomenon which has not been fully characterized to date. Currently, it is often assumed that gas hydrate will form when the subcooling exceeds 3.6 °C (6.5 °F); this value is a heuristic based on limited field-tests. To more accurately predict when and where hydrates are likely to form, large experimental datasets are required to quantify probabilistic hydrate formation. Two generations of High Pressure Stirring Automated Lag Time Apparatus (HPS-ALTAs) were developed to repeatedly measure the formation driving force in term of subcooling and induction time. These HPS-ALTAs are capable of generating statistically significant datasets – typically on the order of 100 formation events – that enable the calculation of formation probability as a function of subcooling from hydrate equilibrium. The current results demonstrate that hydrate formation is strongly dependent on shear, with mean subcooling being reduced by 45% when the mixing speed was increased by a factor of seven. Additionally, initial induction time distributions have been measured at two subcooling values, and are described well by an exponential distribution as expected from theory.
High Resolution Reservoir Parameters, a Novel Approach to Enhance Vertical Resolution of Conventional Logs
Authors: Abul Khair H. , Kantaatmadja B. , Som R. , Baharuddin S. , Goodman A. , Sedaralit F.
Published: March 2018

The ability to detect, evaluate and model thinly laminated formations, as well as to include the sand portion in the reserve calculations, has continuously been a challenging task for oil and gas service and operation companies. This challenge is directly attributed to two reasons:

The big difference between the conventional log's vertical resolution (6 inches and above) and the thickness of these beds (sometimes less than 1 inch); and The direct influence of the low resistivity shale laminations within these thin sand laminae on supressing the resistivity reading (thus masking the existing thin sand laminae, which may be oil prone)

Many efforts in the industry to characterise these thinly laminated reservoirs were put together. Yet, all the existing approaches experience some uncertainty in their results. Most of the industries current approaches contain drawbacks due to certain assumptions involving i thin beds analyses, resulting in high uncertainty. Thus, new technology is needed to improve development and production from these reservoirs.

In this research, wells from 4 fields in both Malay Basin and Sabah Basins, with over 4000 feet of core analysis, full sets of conventional logs and over 5000 feet of different types of micro-resistivity image logs were used. New methodology to calculate true resistivity at a vertical resolution of 0.1 inches was introduced in both oil and water-based mud. A modified alpha processing approach solves the mud influence by introducing a new projecting factor.

New methodology to calculate high resolution density and neuron porosity was also introduced to be used with high resolution resistivity log and to conduct full reservoir evaluation using the high-resolution logs. This includes calculating lithology, porosity, permeability and water saturation at the resolution of 0.1 inch. Calibration of the results with core data and core plug tests supported the findings and showed that the new evaluation using the high-resolution logs is better at matching the core tests than the currently available methods. Thus, this novel approach can be used to evaluate thin beds in any environment and using any type of micro-resistivity images.
A New Rheology Model for Hydrate-in-Oil Slurries
Authors: Qin Yahua , Pickering Paul F. , Johns Michael L. , May Eric F. , Aman Zachary M.
Published: March 2018

Gas hydrates are ice-like solids that can form in crude oil flowlines at high pressure and low temperature; in severe cases, hydrate particles may aggregate in the oil phase and ultimately occlude flow in the line. In order to quantify the risk of plug formation, an accurate universal predictive model for hydrate-in-oil slurries is required. Currently, only one model has been proposed to predict the viscosity of hydrate-in-oil slurries, with an average deviation of 70% from new experimental data. In this work, a temperature-controlled, high-pressure rheometer with a vane blade rotor was deployed to study the rheological properties of hydrate-in-crude oil slurries, which were reacted from water-in-oil emulsions with and without anti-agglomerants (AAs). The results indicate that the addition of AA greatly reduced the viscosity of the hydrate-in-oil slurry, while the slurry maintained shear thinning behavior. The infinite shear viscosity data showed the basis of the current hydrate slurry model is does not appropriately capture the rheological properties of hydrate suspensions. By considering the shape effect of hydrate particles, a new model for hydrate-in-oil slurry has been proposed.
Research and Test of Downhole Measurement Device for Seismic Measurement while Drilling System
Authors: Gao Wenkai , Jia Hengtian , Zhao Hong , Ai Weiping , Zhang Lei , Cao Chong , Hong Difeng , Teng Xinmiao
Published: March 2018

The combination of seismic exploration technology and drilling engineering forms the seismic measurement while drilling (SWD) technology, which can provide conventional borehole seismic measurements in real time while a well is being drilled. Just as conventional while-drilling services, it is effective and efficient in supporting drilling decisions.

With measurement device positioned near the drill bit, real-time processing of downhole seismic data can increase the safety and efficiency to the drilling work. We study the problem in a vertical layered media by using while-drilling measurements, the artificial signal emitted by the seismic source is recorded by surface / downhole sensors, then the direct arrival traveltimes could be obtained after basic data processing. Using the traveltimes as the input of a Bayesian inversion procedure for the estimation of the bit position and the velocity model, the engineers would get the estimated values and their associated uncertainty, which could be used to predict the formation geology ahead of the drill bit and to find the lithology, fracture and abnormal pressure in front of the drill bit in time.

Conventional system has been available to the petroleum industry for some time, with seismic sources located on the surface and receivers in a borehole. The downhole detection device for SWD is mainly composed of three sets of geophone arrays, which are distributed in different axial direction, as well as the corresponding control and processing circuit. We test the inversion strategy on realistic cases in the laboratory and oilfield. According to functions, the electronic circuit is divided into main control and communication unit, signal acquisition unit, storage unit, and power detection & data play back unit. By cross-correlation processing of the direct seismic wave and the reflected waves from formation boundary, the performance of the systems were well proved.

Based on theoretical analysis, system development and experimental study, this paper will highlight the technical development.
Approaching the Superior Management of Explosion Protection Equipment in Mature Field's Hazardous Area
Authors: Kasempong S. , Kanokwareerat N. , Phianloetworakun P. , Sawattanakit N. , Udomsri J.
Published: March 2018

With reference to international standard, IEC 60079-17, each piece of explosion protection equipment shall have their integrity ensured by an initial detailed inspection, and then is to be maintained by periodic inspections at specific times within a 3-year interval.

In the Gulf of Thailand, teams at PTTEP's offshore mature fields put high efforts into performing inspections for more than 200,000 units of Ex protected equipment in accordance with the international standards. However, they are constrained by various factors of the offshore nature e.g. man power, person on board (POB), harsh environment, inspector competency and budget (from the oil price crisis).

To optimize Ex protected equipment inspection, a risk based inspection (RBI) approach as per EI (Energy Institute) recommendation has been introduced since 2016. The end result of this approach would be significant improvement in terms of system integrity and cost effectiveness.

Nevertheless, implementation of new approach in the mature fields is not just a simple plug (in) and play. Key constraints have been proactively identified e.g. lack of a Computerized RBI Ex Protection Equipment Management System, no procedure/ guideline, database incompleteness, etc.

In response to implement successfully RBI Ex inspection, from early 2017, an implementation plan was rolled out to mitigate all issues, especially the computerized system, which is key enabler to RBI Ex inspection; the plan is in-house developed under responsibility of the corporate maintenance team and went go live by November 2017.

This paper provides a description of PTTEP's key initial approaches to this Explosion Protection Equipment Management System, which consists the planning, development, implementation and then up to the improvement phase.
Regional Suitability Mapping PRSM Project - An Update
Authors: Rohani M. J. , Marzuki W. M. , Chan N. , Tho K. K. , Lim L. W.
Published: March 2018

The PETRONAS Regional Suitability Mapping (PRSM) project was initiated in 2013 with the aim of optimising operational cost efficiency and minimising potential incidents during jack-up emplacement. This project, which is executed as a Consortium Industry Project with PETRONAS Carigali Sdn Bhd (PCSB) as the anchor, and local as well as international consultants as the consortium members, is currently in Phase 2 with Phase 1 being successfully completed in June 2016 ahead of schedule. This paper is intended to discuss the framework of this project, disseminate the key findings and provide an update on the ongoing activities of PRSM Phase 2.

The PRSM project involves integration and analysis of data from various data sources including geotechnical and geophysical site investigation data. These data, which originate from multiple sources, must first be consolidated into a common database before these data can be meaningfully analysed. This is achieved by leveraging on the capability of Geographical Information System (GIS) technology. Data integration and management are key enablers to fully maximise the value of the site investigation data, which were gathered at significant expense. With the data residing in a structured database, an objective hazard analysis framework can be systematically applied to produce a series of individual hazard maps, which are then consolidated into a composite hazard map. The hazard analysis framework, which is established through engagement and consultation with key stakeholders, is efficiently executed using the geo-processing capability of the GIS software.

At the completion of PRSM Phase 1, more than a thousand regional and site-specific hazard maps have been produced. The pertinent conclusion from various stakeholders is that the PRSM project elevates the visibility of a multitude of hazards potentially affecting jack-up emplacement such that these hazards can be pre-empted and managed at an early phase.

This paper will also discuss the steps taken to overcome the challenges of incorporating legacy data, which are of a different standard and format to those commonly adopted today. In order to maximise the completeness of the database, data from as far back as the 1970s were successfully processed and integrated into the common database.
Investigation on Erosion Due to Fine Particles in Multiphase Flow
Authors: Ngo Tran Nguyet , Peng Deng-Jr , Pao William , Ya Hamdan , Rohaizad M. Norpiah
Published: March 2018

Pipeline production system often experiences complex multiphase flow and entrained fine-particles. The erosion due to solid fine particles presents one of the greatest threats to oil and gas flow assurance and consequently impacting material selection and wall thickness design. Limited literature is available on erosional effect caused by submicron particles such as fine sand, abrasive solid materials or gas bubbles. Previous studies on particle erosion are limited to particle size greater than 100 microns in single phase fluid flow. This is based on the assumption that potential for erosion by particle size smaller than 100 microns (specifically lesser than 62.5 microns) is insignificant. Additionally, very few studies have addressed the combined effect of erosion caused by micro-sized particles and multiphase flow.

Most predictive erosion models are limited to single phase flow for model simplification purposes. Hence, the effects of multiphase flow and its interaction with sand particles, specifically fine solids, are neglected. Therefore an in-depth understanding of multiphase flow regimes and its interaction with micro-sized particles is an important enabler for more accurate erosion prediction. For more accurate flow modeling and erosion characterization, computer fluid dynamics (CFD) tool is required. In this study, Multiphase CFD (MCFD) is implemented for predicting micro-fine erosion, considering two phase flow pattern features. Concurrently, trajectories of fine particles' bombardment on the pipe inner wall surface are captured using Lagrangian Particle Tracking Model. Analyses are carried out for water and gas flow at isothermal conditions, covering various particle size lesser than 62.5 microns in order to determine material removal rate. The results will be benchmarked against Tulsa multiphase erosion model prediction.

Based on the results, it is concluded that the erosional effect caused by micro-sized particles is strongly dependent on the flow patterns in the pipe, determined by superficial velocities of each phase. Additionally, erosional impact or material removal rate is predicted, which though small, is expected to significantly impact material design. The presence of these micro-sized particles acts as an enabler, which produces homogeneous "pits" on the surface of metal, significantly increasing the contact surface area for chemical and mechanical interactions to take place. The results from the proposed modeling using MCFD are expected to benefit erosion impact assessment in multiphase hydrocarbon production and piping systems.
A Review of Recent Progress in Developing Water Quality Measurement Instruments for Subsea Separation and Produced Water Re-Injection or Discharge Applications
Authors: Yang Ming , Latif Zak
Published: March 2018

Subsea separation and produced water re-injection (PWRI) or discharge has long been considered as an enabling technology for developing deepwater / ultra deepwater and marginal fields. It is an integral part of the subsea processing strategy which brings many economical, operational and environmental benefits for the offshore Oil & Gas industry. However, one of the key technology gaps remaining is in relation to water quality measurement for subsea separated produced water. This review is based on JIPs that NEL has conducted and its recent involvement in a RPSEA project. The review also includes progress made by operators and vendors.

Existing practice for subsea water quality measurement involves in sending an ROV (Remotely Operated Vehicle) to take a produced water sample and then bring it to surface for analysis. This practice is extremely expensive, time consuming and not good for operations. The technology gap has in many ways prevented the widespread of using subsea separation and produced water re-injection systems.

Good progress has been made in developing a subsea water quality measurement device in recent years. This has been achieved through a combination of efforts by operators, government bodies, vendors and independent organizations. Technologies that have the best potential for subsea applications include: Light scattering;Microscopy imaging;Laser Induced Fluorescence;Ultrasonic acoustic.

Most of the above-mentioned technologies are currently surface proven. They are of Technology Readiness Level (TRL) of 3 in relation to subsea applications, which means that they are prototype developed, function and performance assessed. Some of the key progresses to date are resulted from the use of LED as a light source, better fouling mitigation approaches, purposefully conducted lab and surface field trials. Further progresses are anticipated in which some of the mentioned technologies will be developed to TRL 4 (environmental tested) and TRL 5 (system integrated).

There are currently very few references in the literature on the subject. This paper will add valuable information to the public domain regarding the status of the development of subsea produced water quality measurement sensors.