bluuebunny/crossref_metadata_2025 huggingface dataset:
Blended Source/Nodal Ocean Bottom Seismic Acquisition
Authors: Walker Chris , Hays David
Published: May 2016

Ocean bottom seismic (OBS) data have been used for appraisal and development applications for a number of years in the North Sea, West Africa, Gulf of Mexico, and more recently offshore Brazil and SE Asia but the scale of the surveys, by dint of their focus on field specific imaging, has been limited compared to towed streamer surveys in both size and duration. One of the challenges set by the oil companies has been to reduce the unit costs of OBS data - "If only the square kilometer rates were lower we would shoot more data" is a common mantra.

The difficulty in doing this has been the inherent technical downtime experienced by all the contractors operating ocean bottom systems - the terminations, connectors, power distribution and data telemetry components within a traditional ocean bottom cable (OBC) system are inherently prone to failure due to the intrinsic nature of the cable deployment/recovery cycle where the cables are stressed and de-stressed every time they are laid onto/recovered from the seabed. It is akin to recovering the full streamer spread every line change for towed streamer operations.

The desire to improve operational performance was the driving force behind the development of the Z700 autonomous nodal system and its extreme reliability has allowed ever larger seafloor spreads to be operated which has multiple benefits.

Operations

Since its commercial introduction in 2009 more than 250,000 Z700 (Figure 1) node deployments have been made in water depths ranging from 20 to 1200m in the Red Sea, North Sea and Gulf of Mexico.
Ensuring Safety Of Residents In An Emergency Planning Zone While Maintaining Sensitive Public Relations With The Affected Residents - Best Practices Shared.
Authors: Daher Elie , Dowd Darrell , Pye Don , Wicker Bob
Published: May 2016

Establishing an Emergency Planning Zone (EPZ) map lays the foundation for a successful Emergency Response Plan. A safety company was tasked with the responsibility of ensuring the safety of residents living in a neighboring community where potentially hazardous drilling activity in a critical sour well with high H2S concentrations and potential high release rates was about to commence. The safety company was responsible for managing and monitoring the EPZ while constantly updating residents about progress on the drilling activity.

An EPZ of 5.8 kilometers and an awareness zone of 11.6 kilometers were identified; the area of management contained one town and two hamlets of roughly 2000 inhabitants. To effectively monitor and ensure the safety of residents within the EPZ, the safety company dispatched and managed close to 100 onsite personnel. This large team was responsible for manning roadblocks, monitoring the various zones within the EZP, and maintaining buses on standby to evacuate low mobility groups.

Another key element of this project was the successful handling of crucial public relations to defuse and manage potentially very tense situations. The sensitive nature of the issue required careful, consistent and regular communications as residents needed to be constantly updated on the impending drilling operations. To handle the daunting community relations issues effectively, the safety company deployed a number of ‘rovers’ to monitor and communicate with the public through house visits. A call centre was also set up for residents to reach out for more information.

The project was so effectively managed that it even superseded the expectations of the regulatory body responsible for overseeing the drilling project. This paper will discuss in-depth details, learnings, insights and the various factors that were responsible for making this Emergency Response Planning project such a complete success.
Geologically Guided Prestack Depth Imaging - a Case History From Greater Burgan, Kuwait
Authors: Hafez Karam Mohamed , Mukherjee Pradip Kumar , Anandan Mudavakkat , Al-Ghareeb Aisha , Zahran Wael Abdel Alim , Saleh Tamer , Cunnell Chris
Published: May 2016

Prestack depth migration (PSDM) can provide superior seismic volumes even in areas of low relief structures. A pilot PSDM study over the Greater Burgan oilfield in Kuwait demonstrated not only the uplift versus prestack time migration (PSTM), but also pointed to areas of further improvement in the velocity model building workflow. A full field (FF) study was subsequently performed, and incorporated the lessons learned from the pilot. The main area for enhancement was the integration of geological information into the velocity model. This included near-surface velocity characterization and incorporation of existing 3D log-based velocity models into the initial PSDM model, plus implicit geological constraints during the model updating workflow.

The results were a more geologically plausible velocity model with enhanced imaging versus both the legacy PSTM and pilot PSDM volumes, establishing the FF PSDM volume as the main seismic volume for interpretation, well planning and reservoir characterization for the Greater Burgan field.

Introduction

The Greater Burgan oilfield is located in southeast Kuwait and is the main production field for Kuwait Oil Company (KOC), covering an area of approximately 850 km2. The geology is well documented (Carman, 1996), and is expressed as a broad, low relief anticlinal dome draped over a basement horst structure. The primary producing reservoirs are the Cretaceous-era Wara and Burgan sands (Figure 1), which are observed as a seismically quiet section with low acoustic impedance on the well logs. Deeper targets also exist in the Jurassic limestone reservoirs (e.g., Marrat).

A 3D seismic survey was acquired in 1997–98 covering an area of 1372 km2 using parameters commonly used at that time. This covered the complete Greater Burgan oilfield. Offset and azimuth distribution was mostly restricted to the inline direction (low aspect ratio survey geometry), which, in turn, imposes limitations on the utilization of full-azimuth information in the data processing and imaging sequence.

In 2010–11, a small test area was selected for a 3D PSDM pilot study. The aim of the pilot was to provide improved imaging compared to recent PSTM and a better input to ongoing horizontal and multilateral well programs. Particular attention was placed on enhancing the section between the primary reservoirs, the intra-reservoir clastic sequences, and imaging the minor faults that control compartmentalization. Key challenges included the near-surface complexity, characterized by rapid vertical and lateral velocity heterogeneity down to the Rus horizon (the shallowest mapped horizon in the field, between 200 and 500 m in depth, and consisting of high-velocity anhydrites), noise and multiple contamination of the legacy seismic data set, and reliable depth control of low relief structures across the pilot area.
New Approach To Hydrocarbon Migration In The Polish Carpathians Based On Outcrops Analyses
Authors: Lesniak Grzegorz , Irena Matyasik , Jankowski Leszek
Published: May 2016

The research was carried out in different tectonic units of the Polish Carpathians. Three stages of migration were indentified with the use of fluidal inclusions in cements analyses and bitumen traces in the pore space. The main migration paths of hydrocarbons are usually mélange tectonic zones revealing signs of diversified mineralization. These out-of-sequence thrusts may demonstrate the connection with the Carpathian basement. Location of hydrocarbons reservoirs along mélange and tectonic active zones, which form the flower structures, suggests the possibility of migration of hydrocarbons from the very deep zones subsidented within the Central Carpathian Depression (CCD) graben. Hydrocarbons generated at great depths migrates along mélange and active tectonic zones. These flower structure, consisting of network of fractures, in which crucial role in hydrocarbons migration plays the most active tectonic zone (so called master fault) plays a main role in hydrocarbons accumulation e.g. CCD margin zone is an essential element for the process of charging these flower structures with hydrocarbons. Mineralogical, petrographical and geochemical (bitumen extracts, biomarkers) analyses were performed on sediments trapped in mélange zones. Completed studies have shown diversified mineralization processes and bitumen type along the main zone of the tectonic mélange. This is related to the depth of mélange zone rooting and fluid migration from the Carpathian basement rocks. Determination of hydrocarbons generation, its nature and the origin of crude oil trapped in mélange zones have a great impact on new directions in oil exploration in the CCD area.
Theory and Experimental Setup of the New Rise In Core Reservoir Wettability Measurement Technique
Authors: Ghedan Shawket G. , Canbaz Celal Hakan
Published: May 2016

Reservoir wettability has direct impact on the relative movement of reservoir fluids and oil displacement efficiency by EOR techniques. The industry standard wettability laboratory techniques of Amott, USBM and modified Amott/USBM are very time demanding due to its complex experimental setup and procedure.

This paper describes the theory and experimental setup and procedure of a new wettability laboratory technique. Rise In Core, RIC, technique is based on a modified version of the Washburn Equation. The modified equation could be solved for the wettability contact angle by only substituting the slope of a fitted straight line of the square line of the square of core sample mass change with time, resulting from either water imbibition into oil saturated core sample, and/or vice versa. A constant of the equation, that is characteristic of the rock type, needs to be determined prior, however, by conducting an imbibition experiment of a reference liquid into air saturated twin core sample. The reference liquid completely wets the core sample with zero contact-angle.

The new technique was applied to measure the wettability of Berea sandstone core samples. The wettability of natural outcrop cores was found to be weakly water wet. Experiments conducted on neighboring samples, produced similar wettability result, indicating good repeatability. The applicability of the RIC in other wettability regions was also tested, resulting in repeated strong wetness for standards that were artificially treated to be either strongly water wet, and oil wet. The technique was also compared to the existing industry technique and proved to provide equivalent and more consistent wettability measurements for more than ten twins of carbonate core samples.

RIC technique is theoretically sound, and requires simple experimental setup and procedure. Moreover, it determines wettability in terms of contact angles rather than wettability index. It is more consistent and applicable to all wettability regions.
Integrity and Efficiency in LNG Transfer Operations with Flexibles.
Authors: van Bokhorst Evert , Twerda Aris
Published: May 2016

The work presented contributes to the LNG supply chain by the development of a validated calculation model for corrugated flexible hoses or pipes developed for LNG Transfer. The model builds upon experience gained by TNO Technical Sciences (Fluid Dynamics) in a large number of flow tests carried out on hoses in a large range of diameters from 4 to 18-inch.

LNG transfer rates are in general relatively high as the time involved should be limited from economical point of view. In large scale offshore LNG transfer, flow rates up to 5000 m3/h are applied and in future flow rates up to 10.000 m3/h are foreseen. Typical values mentioned for offshore operations in tandem transfer range from 50 to 150 meters hose length and hose diameter up to 20-inch.

The pressure losses in LNG offshore transfer, but also in smaller scale applications, can be considerable. The pressure loss depends on flow rate, length of the hose, internal diameter and internal hose corrugation geometry. High pressure losses will impose additional requirements on LNG pumps and might result in cavitation at the downstream end of the hose as the average pressure drops below vapor pressure.

Furthermore the impact of local boiling phenomena due to heat-ingress and cavitation, possibly effected by vortex shedding along the internal corrugations, is not known.

Once the gaps in the data base are filled a validated prediction model is available, which can be used in guidelines and standards. So far the EN1474 (part 2: Design and testing of transfer hoses) does not specify a maximum allowable pressure loss and the prescription of the requirement for the test is limited: "Flow rate testing (ambient or cryogenic): demonstrate that the hose is capable of operating at its maximum flow rate and confirm the predicted head loss"

The final goal of the project is to obtain a validated prediction model for the calculation of pressure losses in LNG transfer with flexible multi-composite and metal hoses based on input of parameters as operating conditions and hose geometry. Also input for guidelines and standards in LNG transfer with flexibles such as EN1474 will be generated, which can be used in for qualification of LNG equipment.
The Present-day stress pattern in the Middle East and Northern Africa and their importance: The World Stress Map database contains the lowest wellbore information in these petroliferous areas
Authors: Rajabi Mojtaba , Tingay Mark , Heidbach Oliver
Published: May 2016

Knowledge of the present-day stress field is vital for a range of earth science disciplines, including hydrocarbon and geothermal energy production, mine safety and seismic hazard assessment. The scientific importance of understanding the present-day maximum horizontal stress orientation has been demonstrated by the findings of the World Stress Map (WSM) Project, which has spent over 25 years building an extensive freely-available repository of present-day stress information as a collaborative project between academia, industry and government. The WSM project has revealed that the plate scale present-day stress is controlled by the tectonic forces exerted at tectonic plate boundaries. However, numerous studies in sedimentary basins have shown that stresses in the oil-patch can be complex, and controlled by both major far-field forces (plate boundaries, body forces from mountain belts) and intra-basinal forces, such as detachment zones, salt, faults and basin geometry.

The World Stress Map project contains free and public information for over 80 basins around the world. However, the project contains almost no wellbore data for the Middle East and Northern Africa, despite this region hosting much of the world's global oil production and extensive industry activity. To date, the World Stress Map Project only contains limited datasets from petroleum wells in Egypt, Oman and Iran - but no data at all for Saudi Arabia, Iraq, Libya, Algeria, UAE, Kuwait or Qatar.

In this paper we first review different methods for determining and calculating the present-day stress pattern in the region, then we highlight the lessons learned from the World Stress Map project on the controls of present-day stress in the oil-patch. Finally, we focus in detail on the stress data that currently exists for the Middle East and Northern Africa.

Introduction

Knowledge of the crustal present-day stress pattern is important for a range of earth science disciplines including:Geodynamic applications (e.g. Richardson 1992; Zoback 1992);Neotectonic and intraplate deformation (e.g. Tingay et al. 2005; King et al. 2010);Geomechanical characterization of petroleum basins (Tingay et al. 2005);Earthquake hazards (Sandiford et al. 2004), and;Rock mechanics and engineering (e.g. Reinecker et al. 2006; Zang et al. 2012).

The Present-day stress has numerous applications in petroleum basins, particularly in borehole stability, reservoir drainage and flooding patterns, pore pressure prediction, fluid flow in naturally-fractured reservoirs, hydraulic fracture stimulation, seal breach by fault reactivation and any geomechanical modeling. Hence, present-day stress analysis, as a part of 'petroleum geomechanics', has received extensive attention in petroleum industry in recent years (Barton et al., 1995; Sibson, 1996; Jones and Hillis, 2003; Rajabi et al., 2010; Tingay et al., 2010a and b).
Design, Implementation And Results Of An Inter-Well Chemical Water Tracers Pilot Test To Improve Water Flood In Complex Reservoirs
Authors: Cuauro Antonio , Frans Frederic , Knowles Dale , Wigley Paula , de Mas Carolina , Jevanord Kjersti , Al-sadah Abdulla
Published: May 2016

The use of water tracers to better understand and improve water flood performance has long been part of the reservoir management toolbox. Its use is even more relevant when applied to complex and heterogeneous reservoirs. This paper describes the planning and implementation phases of a chemical tracer injection pilot in the Al Shaheen oil field, offshore Qatar.

In Al Shaheen injection water has historically been used as natural tracer to identify inter-well communication in the field by analysis of the salt and ionic content of produced water. However, this approach has become less effective over time. Identification of short-circuits is getting more complex with the increasing number of wells completed.

A tracer pilot including chemical water tracers was designed to identify inter-well communication and flow paths of injected water in a complex area of the field. The geology of this area is highly heterogeneous, with a stacked sequence of carbonate and clastic reservoirs. Numerous features were identified as the possible cause of these inter-well communication paths, including faults and fractures, thief zones, permeable shale and/or absence of shale.

The pilot includes two water injection wells completed in two different reservoirs and twenty six oil production wells. This paper reviews the selection of the candidate wells, the operational constraints as well as the detailed analysis and interpretation of the results. Based on this pilot, interwell connection has been proven in most of the area of interest. Tracers have been detected in six of the twenty six wells, with breakthrough times ranging from three to seventy days. Communication between the carbonate and clastic reservoirs was confirmed in two wells. For some of the early samples, anomalous results were obtained. This has been attributed to contamination during sampling at the platform, and was remediated by improving the quality control during sampling.

This water tracer pilot paves the way for further application across the field. Ultimately the tracer results will be used in combination with other surveillance techniques to identify by-passed oil and design fit-for-purpose solutions to target higher recovery.
Smart Horizontal Well Drilling and Completion for Effective Development of Thin Oil-Rim Reservoirs in Malaysia
Authors: Chan Keng Seng , Masoudi Rahim , Karkooti Hooman , Shaedin Ridzuan , Othman Mohamad
Published: May 2016

For thin oil-rim reservoirs, well placement, well type, well path and the completion methods shall be evaluated with close integration of key reservoir and production engineering considerations. This involves maximizing reservoir fluid contact and drainage, optimizing the well productivity, and optimizing well life-cycle production profile along the wellbore. Field implementation cases in Malaysia have been shown that this integrated approach to design and drill horizontal wells can significantly minimize the well count, enhance the well performance, and improve the ultimate recovery per well in thin oil-rim reservoirs with varying reservoir complexity and uncertainties.

45 horizontal wells were progressively drilled and all completed with ICD in a relatively flat thin oil-rim reservoir offshore in peninsular Malaysia. In this successful oil development, well path between the GOC and OWC was optimized to delay the water breakthrough and reduce the decline trend in different reservoir sectors with varying horizontal well length up to > 2,000 m. Good performance of the ICD was confirmed by PLT surveys and by tracer effluents evaluation with different type of tracers implemented in various sections of the horizontal well completion.

For a low pressure thinner oil-rim reservoir in offshore Sabah, horizontal wells were drilled with ICV completed in the gas cap. This smart well design enables having in-situ gas lift operation during the initial oil production, and progressively changing to the planned gas-cap blow-down operation for maximizing the overall hydrocarbon recovery. In another oil-rim reservoir, a long horizontal wellbore with ICD design was completed with dual-strings to further optimize drawdown pressure distribution along the long wellbore and improve oil drainage and oil recovery.

This paper is to share not only the lessons learnt in drilling and completion of these smart horizontal wells but also illustrate the impact of these smart well designs in adding values to the field development projects.

Introduction

Development of oil-rim reservoirs in Malaysia has been progressively improved over the recent years through a series of reservoir engineering studies and successful field implementations. Although, typical oil-rim reservoirs are characteristically wedged between a gas-cap and underlying aquifer, they can be structurally very complicated with faults and flow boundaries, having varying dips and saddles. Oil-rim reservoirs of various sand thickness can also be stacked and compartmentalized. Aquifer support varied from reservoir sector to sector, resulting in uneven pressure depletion and fluid contact change. Figure 1 showed such a vast oil-rim reservoir in Peninsular Malaysia.
Well Testing in Challenging Environments: A Case Study from Onshore China
Authors: Peng Xin Ling , Liang Mei Sheng , Hu Jie , Wu Xiao Lei , Qin Dong Lin , Tellapaneni Prasanna Kumar , Ren Bo Nan , Zhang Tao , Guo Zhi Hong
Published: May 2016

The Pugang gas field situated in the Sichuan province near the city of Dazhou is one of the biggest inland gas discoveries of the last decade in China. With significant reserves, it is an important and strategic field for the operator and the region. However, with H2S concentrations as high as 10%, surface and downhole facilities design and execution still remains a challenge. Testing these wells has also proved difficult due to the surface risks inherent in a conventional testing operation. Also, with approximately 500 m of perforations, it is critical to identify the individual contributing zones before any meaningful analysis of the test can be done.

Well testing using production logging tools has recently been introduced in this field and it has proven to be of tremendous benefit to the operator in terms of both identifying the inflow zones and also in performing well test analysis. Production logging was done in two phases, namely shut in and flowing passes to identify cross flows (if any) and to identify potential inflow zones. Once this is established, a buildup analysis is done to measure the productivity potential and the average reservoir pressure. A good pre-job design and real-time analysis of the data was made to avoid unnecessary exposure of the logging tools to this highly corrosive environment.

This paper illustrates the challenges in planning and executing a production logging operation in challenging conditions and also shows the utility of performing these operations.

Field Introduction

The Puguang gas field, discovered in 2002, is the second largest gas field in China and the largest sour field discovered in the last decade (Ma, 2005). This field is located north of Chongqing in the Sichuan basin (Fig. 1). The giant field is a combination structural-stratigraphic trap closed by lateral depositional change and fault closure. The exploration area is a challenging environment, as it is located in a mountainous region with high surface elevations (up to 1,200m). The thickness of producing formations is between 176.4m~838.8m, and 395 on average. The reservoir fluid in this field is dry gas with high H2S (14.4%) and CO2 content (Ma 2007) (9.91%). The field is flanked on the west with a GWC at 5140 m TVDSS. With no voidage replacement mechanism in place yet, the production of water due to the contact movement is also a concern for the operator. Therefore production logging as a reservoir monitoring and surveillance tool has been introduced since 2010 and more than 18 wells have been tested to date.
Development of Piezoelectric Tool for Preventing Wax Deposition in Oil Flow Lines.
Authors: Sulaiman Ibrahim Alh-Dodo , Ajienka Joseph Atubokiki , Ikiensikimama Sunday Sunday
Published: May 2016

Recently oil and gas production activities are moving to offshore which in many cases have low temperature below wax appearance temperature of the oil & gas produced from these reservoirs. Therefore oil and gas industry spend huge amount of money to prevent/treat wax deposits. The primary aim of this research work is to develop a tool for preventing /eliminating wax deposition in oil and gas production and transport system, using locally sourced piezoelectric energy generating materials.

Samples of waxy crudes were sourced from Niger Delta field and characterized for the purpose of this experiment. Natural quartz was sourced from Bauchi State while two semi-precious metals, zinc and lead were sourced from Jos Metallurgical Development Centre, Plateau State of Nigeria. Tool was fabricated using locally sourced quartz, semiprecious metals and aluminium which was fixed in to a simulated flow line. The experiment was performed in laboratory.

The results showed that as the waxy crude samples were flown past through the tool the quantity of wax deposits reduced drastically. It was observed that zinc + quartz proved more effective (about 58%) than lead + quartz (35%) when the performance on a sample (OSS-3) was which proved to be potentially more problematic were compared. In conclusion, the fabricated tool from quartz and semi-precious metals proved various degree of effectiveness depending on the sample of oil being treated.

For the first time a tool that generates piezoelectric energy, locally fabricated in Nigeria was used to prevent wax deposition in flow lines (laboratory scale). Also mechanism surrounding the process of preventing wax deposit by piezoelectric energy has been better understood from this research work. This research has added more value to the importance of piezoelectric materials. Complete flow model has been fabricated and flow tested on laboratory scale. The basic limitation is the inability to carry out field test and lack of support/collaboration from industry.
Selection of Passive Inflow Control Devices Based on Dynamic Weight Fuzzy Evaluation
Authors: Zeng Quanshu , Wang Zhiming , Wang Xiaoqiu , Li Yiwei , Zou Weilin , Xiao Jingnan , Chen Tian , Yang Gang , Zhang Quan
Published: May 2016

In long horizontal wells, early water or gas may breakthrough into the wellbore due to the imbalanced production profile caused by the heel-toe effect, reservoir anisotropic, reservoir heterogeneity or fracture-existing. Once coning occurs, oil production may severely decrease due to the limited flow contribution from the non-coning regions. Inflow control devices (ICDs) are installed to maintain the flow across production zones uniformly by creating an additional pressure drop which cancels out the imbalanced production profile.

Since a typical well with ICDs can be in production from 5 to more than 20 years, the long-term reliability of such a device is crucial to the well's overall success. Therefore, the ICDs must exhibit certain performance features during every phase of the well's life, however, the reality is that none of current ICDs alone meet the ideal requirements of an ICD designed, and current ICD selection for a specific reservoir mainly depends on the qualitative awareness of both the reservoir condition and the ICD performance.

To make a better selection of the ICDs, dynamic weight theory is introduced into the fuzzy evaluation, and analytic hierarchy process is used for reference, which make the weight of each evaluation index change with the reservoir condition. The optimal membership degrees of these ICDs with varying flow rate, fluid density, and fluid viscosity are first calculated and then compared, which help to develop the ICD selection pattern. With the help of the pattern, we can select the optimal ICD simply and quickly once the reservoir condition is determined, which has the best corrosion resistance and the least viscosity sensitivity.

1. Introduction

In long horizontal wells, early water or gas may breakthrough into the wellbore due to the imbalanced production profile caused by the heel-toe effect, reservoir anisotropic, reservoir heterogeneity or fracture-existing (Wang et al., 2011). Once coning occurs, water/gas fast track will be generated, and then oil production may severely decrease due to the limited flow contribution from the non-coning regions. Inflow control devices (ICDs) are installed to maintain the flow across production zones uniformly by creating an additional pressure drop which cancels out the imbalanced production profile.
The Elusive Low Frequency Shadow
Authors: Barnes Arthur E. , Mad Zahir M Hafizal B
Published: May 2016

Low frequency shadows have long been accepted as direct hydrocarbon indicators, but few convincing examples have been published. A deliberate search for low frequency shadows on seismic data from multiple fields offshore Malaysia finds no clear candidates. Prospect-scale frequency shadows are difficult to detect with conventional seismic attributes because the subtle spectral changes caused by attenuation are masked by the much larger and more variable effects of reflection interference. Detectable low frequency shadows are too rare to serve as practical direct hydrocarbon indicators.

Introduction

Low frequency shadows have been widely accepted as direct hydrocarbon indicators since the 1970s (Sheriff, 1975; Taner et al., 1979). The prevailing view is that "low frequency shadows often have been observed beneath amplitude anomalies associated with gas reservoirs" (Chopra and Marfurt, 2007, p. 141). The idea is appealing. A low frequency shadow is a zone in seismic data characterized by anomalously low frequencies that occurs beneath a causative body. The body strongly attenuates the seismic energy, preferentially reducing the high frequencies Seismic reflections within a shadow lack high frequency content relative to surrounding reflections. Shadows have fairly clear beginnings but tend to fade quickly with depth. Because gas sands are the chief cause of anomalous attenuation, low frequency shadows serve as hydrocarbon indicators, and reduce risk in bright spot exploration. The large and obvious effects of gas clouds, gas chimneys, and shallow gas are not considered here as they are not primary exploration targets, but instead indicate gas escaping from deeper levels (Brouwer et al., 2008; Ghazali et al., 2013).

In spite of a long history and popular acceptance, few examples of low frequency shadows have ever been published, and none are especially convincing hydrocarbon indicators. This contrasts markedly with the record of other hydrocarbon indicators, such as bright spots, flat spots, amplitude conformance to structure, and AVO, for which published examples are numerous and credible. This raises the question: Do low prospect-scale frequency shadows really exist?

We search for prospective frequency shadows in poststack seismic data from a number of producing fields offshore Malaysia. We employ conventional seismic trace attributes, frequency decay curves, and volume spectral decomposition. We review many gas sands, bright spots, and frequency anomalies, but none clearly constitute low frequency shadows.

Method

We apply reflection strength, average frequency, and bandwidth attributes to poststack seismic data from offshore Malaysia to characterize patterns of spectral change and identify frequency anomalies. The frequency and bandwidth attributes represent averages weighted by the instantaneous power, and are derived in 30 ms (15 sample) windows. We supplement this analysis with a simple volume spectral decomposition that separates low and high frequency components of the seismic data to reveal local frequency anomalies.
The Mahakam Delta, Indonesia: a Case Study for the Deposition and Preservation of Transgressive Deltaic Successions
Authors: Lambiase Joseph J. , Riadi Ridha , Nirsal Nadia , Salahuddin S
Published: May 2016

Introduction

Traditional models characterize the modern Mahakam Delta as a mixed river-dominated and tide-dominated delta that is presently prograding (e.g Galloway, 1975; Allen et al., 1976; Gastaldo et al., 1995; Allen and Chambers, 1998) and are commonly used as analogs to interpret subsurface successions. However, a recent quantitative study that describes the modern delta as transgressive and depositing a transgressive succession with very high preservation potential (Salahuddin and Lambiase, 2013) invalidates the use of the modern delta as a viable analog for progradational subsurface successions and suggests that transgressive successions may be relatively common in the subsurface.

The Modern Mahakam Delta

Quantitative hydrodynamic and sedimentologic data demonstrate the transgessive character of the modern delta that causes back-filling of the distributaries and relatively minor reworking of pre-transgression sediment. Very low wave energy in the receiving basin, plus rapid subsidence and burial, limits marine reworking to the uppermost pre-transgression strata and preserves the pre-transgression, progradational distributary and inter-distributary morphology. Ongoing back-filling of the distributaries is generating fining-upward successions that become increasingly marine upward. Current speed, and sediment transport capacity and competence decrease seaward so that the sediment flooring the distributaries is progressively finer downstream, which generates a fining-upward succession as transgression continues (Salahuddin and Lambiase, 2013). These successions also become more marine upward and have excellent preservation potential because of rapid subsidence rates and minor marine reworking.

Sandy back-filled distributary successions are somewhat thinner and closer together in the upper delta plain than in the lower delta plain. As these sands fill the topographically low distributaries, they are laterally adjacent to slightly older, pre-transgression progradational strata. In contrast, inter-distributary areas are developing relatively thin, sandstones directly above pre-transgression progradational strata and separated from it by a transgressive erosional surface generated by marine reworking. The three dimensional geometry of the sandstones within a transgressive succession is expected to be complex and highly dependent on the pre-transgression delta morphology. The back-filled distributary sandstones are sinuous and oriented quasi-perpendicular to the shoreline while the transgressive shoreline sandstones are shoreline-parallel with a lateral extent that is determined by the distributary spacing. Ongoing transgressive lobe-switching means that the back-filled distributary successions are not exactly contemporaneous and that they probably have highly variable thicknesses and lateral extent.
Rates of testing for BRCA mutations in young women are on the rise
Authors: Barton Mary Kay
Published: May 2016

Key Points

Genetic testing for BRCA mutations is increasing for young women, which is in keeping with current guidelines, and frequently affects treatment decisions.

Adequate genetic counseling must be widely available for young women with breast cancer.
Les joueurs de football sont-ils des esclaves ? Conditions d’emploi dans le milieu du football professionnel en Angleterre et au Pays de Galles (1945-1961)
Authors: Taylor Matthew
Published: May 2016

Les représentations populaires des conditions d’emploi des footballeurs professionnels en Angleterre avant les années 1970 sont habituellement résumées par une série de phrases interchangeables : « esclaves », « serfs », « domestiques » et « travailleurs contraints ». Les lectures nostalgiques ou misérabilistes, opposant souvent l’ancien système du salaire maximal et de la retenue-et-transfert à la relative liberté des ouvriers « normaux » de l’industrie, et du football après 1961, surtout après l’arrêt Bosman, se sont rarement fondées sur des analyses scientifiques précises. Consacré aux quatre décennies qui précèdent l’abolition du salaire maximal en 1961, cet article s’appuie sur les archives de la Ligue de football, des clubs, du syndicat des joueurs professionnels et celles du ministère du Travail, pour montrer que les conditions d’emploi des footballeurs étaient plus complexes et que le traitement des employés était plus varié qu’on ne l’admet en général. En regardant au-delà de la relation directe club-joueur et en reconnaissant que le marché de l’emploi du football et ses conditions d’emploi étaient en réalité le résultat d’un ensemble d’interactions entre l’association patronale, la fédération nationale, l’employeur, le syndicat et la main-d’œuvre du « vestiaire », il cherche à proposer de nouvelles interprétations de la façon dont les joueurs de football était réellement traités « sur le terrain ». Dans le pire des cas, on pouvait assimiler les conditions d’emploi des joueurs à de l’« esclavage » et à du « féodalisme » ; mais les réglementations, restrictives sur le papier, étaient souvent interprétées de façon telle qu’elles permettaient, en pratique, des libertés et des récompenses plus grandes.
L’engagement dans une formation immersive en langue bretonne
Authors: Pentecouteau Hugues , Servain Pierre
Published: May 2016

À partir d’observations participantes menées dans une formation immersive en langue bretonne (Kamp Etrekeltiek ar Vrezhonegerion – KEAV), les auteurs analysent les formes d’engagement en formation comme étant à la fois individuelles et collectives. Si l’engagement collectif s’inscrit dans une démarche militante culturelle et politique en valorisant la dimension communautaire, l’engagement des individus en formation ne peut se faire que s’il existe un positionnement individuel et volontaire. C’est par conséquent à la condition d’un engagement pour soi, ayant du sens pour l’individu, que l’engagement collectif peut devenir, dans un second temps, un espace formatif, dans et par la sociabilité. L’engagement individuel est présenté ici comme une stratégie individuelle à deux entrées, se combinant le plus souvent l’une avec l’autre : un questionnement sur la filiation (linguistique) et un positionnement pragmatique sur les bénéfices de cet apprentissage.
Changement de direction dans une institution ou au sein d’une équipe : enjeux et souffrances
Authors: Meynckens-Fourez Muriel
Published: May 2016

Dans cet article, nous partageons nos réflexions sur les aléas liés au changement de personne à une fonction de direction. Nous envisageons successivement le contexte, les enjeux autour de l’engagement, l’arrivée du nouveau directeur et ses paradoxes pour aborder la question de sa légitimité et les « examens de passage » auxquels il doit faire face. Pour terminer, nous dirons quelques mots sur la supervision d’équipe dans ce contexte avant de conclure.
Repères méthodologiques pour thérapeutes de couple débutants
Authors: Delvigne Frédéric
Published: May 2016

Se basant sur dix ans d’expérience dans la formation de futurs conseillers conjugaux et familiaux, l’auteur énumère les « pièges » dans lesquels peuvent tomber les futurs thérapeutes conjugaux dans leur travail avec les couples : se centrer sur l’individu et oublier la relation, avaliser la première définition du problème, faire alliance avec un membre du couple, tenir le cadre de manière rigide, passer à côté de l’information pertinente, etc. A ces « pièges », l’auteur propose des pistes méthodologiques concrètes dans le maniement de la relation thérapeutique. Sans verser dans des recettes, l’article revisite les bases méthodologiques de la thérapie de couple sous la forme d’un questionnement : analyse de la demande, neutralité, cadre thérapeutique, profils de couple, etc. Il invite également le futur thérapeute conjugal à déconstruire certaines croyances à propos de l’acquisition de compétences thérapeutiques, du statut du « savoir » et de l’agressivité.
Ultra High Frequency Polynomial and Trigonometric Higher Order Neural Networks for Control Signal Generator
Authors: Zhang Ming
Published: May 2016

This chapter develops a new nonlinear model, Ultra high frequency Polynomial and Trigonometric Higher Order Neural Networks (UPT-HONN), for control signal generator. UPT-HONN includes UPS-HONN (Ultra high frequency Polynomial and Sine function Higher Order Neural Networks) and UPC-HONN (Ultra high frequency Polynomial and Cosine function Higher Order Neural Networks). UPS-HONN and UPC-HONN model learning algorithms are developed in this chapter. UPS-HONN and UPC-HONN models are used to build nonlinear control signal generator. Test results show that UPS-HONN and UPC-HONN models are better than other Polynomial Higher Order Neural Network (PHONN) and Trigonometric Higher Order Neural Network (THONN) models, since UPS-HONN and UPC-HONN models can generate control signals with error approaching 0.0000%.
Adaptive Hybrid Higher Order Neural Networks for Prediction of Stock Market Behavior
Authors: Nayak Sarat Chandra , Misra Bijan Bihari , Behera Himansu Sekhar
Published: May 2016

This chapter presents two higher order neural networks (HONN) for efficient prediction of stock market behavior. The models include Pi-Sigma, and Sigma-Pi higher order neural network models. Along with the traditional gradient descent learning, how the evolutionary computation technique such as genetic algorithm (GA) can be used effectively for the learning process is also discussed here. The learning process is made adaptive to handle the noise and uncertainties associated with stock market data. Further, different prediction approaches are discussed here and application of HONN for time series forecasting is illustrated with real life data taken from a number of stock markets across the globe.
Theoretical Analyses of the Universal Approximation Capability of a class of Higher Order Neural Networks based on Approximate Identity
Authors: Panahian Saeed , Zainuddin Zarita
Published: May 2016

One of the most important problems in the theory of approximation functions by means of neural networks is universal approximation capability of neural networks. In this study, we investigate the theoretical analyses of the universal approximation capability of a special class of three layer feedforward higher order neural networks based on the concept of approximate identity in the space of continuous multivariate functions. Moreover, we present theoretical analyses of the universal approximation capability of the networks in the spaces of Lebesgue integrable multivariate functions. The methods used in proving our results are based on the concepts of convolution and epsilon-net. The obtained results can be seen as an attempt towards the development of approximation theory by means of neural networks.
Artificial Sine and Cosine Trigonometric Higher Order Neural Networks for Financial Data Prediction
Authors: Zhang Ming
Published: May 2016

This chapter develops two new nonlinear artificial higher order neural network models. They are Sine and Sine Higher Order Neural Networks (SIN-HONN) and Cosine and Cosine Higher Order Neural Networks (COS-HONN). Financial data prediction using SIN-HONN and COS-HONN models are tested. Results show that SIN-HONN and COS-HONN models are good models for financial data prediction compare with Polynomial Higher Order Neural Network (PHONN) and Trigonometric Higher Order Neural Network (THONN) models.
Cosine and Sigmoid Higher Order Neural Networks for Data Simulations
Authors: Zhang Ming
Published: May 2016

New open box and nonlinear model of Cosine and Sigmoid Higher Order Neural Network (CS-HONN) is presented in this paper. A new learning algorithm for CS-HONN is also developed from this study. A time series data simulation and analysis system, CS-HONN Simulator, is built based on the CS-HONN models too. Test results show that average error of CS-HONN models are from 2.3436% to 4.6857%, and the average error of Polynomial Higher Order Neural Network (PHONN), Trigonometric Higher Order Neural Network (THONN), and Sigmoid polynomial Higher Order Neural Network (SPHONN) models are from 2.8128% to 4.9077%. It means that CS-HONN models are 0.1174% to 0.4917% better than PHONN, THONN, and SPHONN models.
Ant Colony Optimization Applied to the Training of a High Order Neural Network with Adaptable Exponential Weights
Authors: Abdelbar Ashraf M. , Elnabarawy Islam , Wunsch II Donald C. , Salama Khalid M.
Published: May 2016

High order neural networks (HONN) are neural networks which employ neurons that combine their inputs non-linearly. The HONEST (High Order Network with Exponential SynapTic links) network is a HONN that uses neurons with product units and adaptable exponents. The output of a trained HONEST network can be expressed in terms of the network inputs by a polynomial-like equation. This makes the structure of the network more transparent and easier to interpret. This study adapts ACOR, an Ant Colony Optimization algorithm, to the training of an HONEST network. Using a collection of 10 widely-used benchmark datasets, we compare ACOR to the well-known gradient-based Resilient Propagation (R-Prop) algorithm, in the training of HONEST networks. We find that our adaptation of ACOR has better test set generalization than R-Prop, though not to a statistically significant extent.
Morphology of spermatheca in Scutelleridae (Hemiptera: Pentatomoidea) and its taxonomic significance
Authors: Czaja Joanna
Published: May 2016

Structures of spermatheca in 63 species of Scutelleridae (Hemiptera) representing 46 genera and all subfamilies currently recognised in the family were examined and compared. The morphology of three main parts of the spermatheca (receptacle, intermediate part, and spermathecal duct) was described and three main types of spermatheca in Scutelleridae were identified. The taxonomic importance of spermathecal features for the higher classification of scutellerids is discussed.
Novel Insights into the Multiple Sclerosis Risk Gene ANKRD55
Authors: Lopez de Lapuente Aitzkoa , Feliú Ana , Ugidos Nerea , Mecha Miriam , Mena Jorge , Astobiza Ianire , Riera José , Carillo-Salinas Francisco , Comabella Manuel , Montalban Xavier , Alloza Iraide , Guaza Carmen , Vandenbroeck Koen
Published: May 2016

An intronic variant in ANKRD55, rs6859219, is a genetic risk factor for multiple sclerosis, but the biological reasons underlying this association are unknown. We characterized the expression of ANKRD55 in human PBMCs and cell lines. Three ANKRD55 transcript variants (Ensembl isoforms 001, 005, and 007) could be detected in PBMCs and CD4+ T cells but were virtually absent in CD8+, CD14+, CD19+, and CD56+ cells. Rs6859219 was significantly associated with ANKRD55 transcript levels in PBMCs and CD4+ T cells and, thus, coincides with a cis-expression quantitative trait locus. The processed noncoding transcript 007 was the most highly expressed variant in CD4+ T cells, followed by 001 and 005, respectively, but it was not detected in Jurkat, U937, and SH-SY5Y cell lines. Homozygotes for the risk allele produced more than four times more transcript copies than did those for the protective allele. ANKRD55 protein isoforms 005 and 001 were predominantly located in the nucleus of CD4+ T cells and Jurkat and U937 cells. ANKRD55 was produced by primary cultures of murine hippocampal neurons and microglia, as well as by the murine microglial cell line BV2, and it was induced by inflammatory stimuli. ANKRD55 protein was increased in the murine mouse model of experimental autoimmune encephalomyelitis. Flow cytometric analysis of CNS-infiltrating mononuclear cells showed that CD4+ T cells and monocytes expressed ANKRD55 in experimental autoimmune encephalomyelitis mice, with the higher fluorescence intensity found in CD4+ cells. A low percentage of microglia also expressed ANKRD55. Together, these data support an important role for ANKRD55 in multiple sclerosis and neuroinflammation.