bluuebunny/crossref_metadata_2025_split huggingface dataset:
AUV-Based Seabed Characterisation Using a Lightweight Towed Array System
Authors: Pallayil Venugopalan , Chotiros Nicholas P 
Published: March 2016

Abstract
Offshore technology operations often require knowledge about the properties of seabed and sub-seabed to aid in their drilling operations, identifying geo-hazards and building of sub-sea structures. The analysis of marine sediments from the core samples is also routinely carried out to detect any presence of near-surface hydrocarbon seepage, which is a strong indicator of presence of active petroleum system in the area under investigation. The most conventional and also much practiced way of doing this is by collecting seabed samples using corers. The core sample analysis provides valuable information with regard to the above requirements. However, the process of coring is complex and heavily resource intensive. As the core analysis can only provide localised information, to survey an area of interest many such core samples would have to be collected to have a clear understanding of the seabed properties. Acoustic technologies have been extensively used for remotely monitoring the seabed properties. A coring operation is often preceded by a seismic survey, which again involves huge resources. The explosive sound sources (air guns) often used with these systems have always been a target of criticism from marine mammal conservationists as it compromises on the safety of marine mammals. The advancement of AUV technology has opened up alternatives to remote monitoring of the seabed. Commercially available AUVs are operationally reliable and are often equipped with many acoustic sensors such as high-resolution side scan sonar and multi-beam sonar. As AUVs can operate pretty close to the seabed, it places less demand on the source levels of the sound sources reducing the risk for marine mammals. In this review paper we look at the feasibility of adding a towed array sensor to the AUV platform so that some of the benefits of conventional seismic surveys can be obtained at a relatively lower cost. Initial results from a shallow water indicate that the seabed type can be classified to a first level using this approach and comply well with the model predictions. The study also made use of the acoustic modem signals from the AUV as the signal source so that there was no need for a custom made source. Though this study was targeted more towards understanding the effect of seabed on the sonar performance, the technique can be adapted and extended for offshore applications.
Unconventional Drilling in Southern Sumatra Area. Evolving Technique for the New Drilling Culture
Authors: Dharma Dion Satria , Irawan Fikri , Hidayat Andri Mustari 
Published: March 2016

Abstract
Recent drilling operations in Southern Sumatra area, especially Jambi and South Sumatera district, have experienced various problems upon drilling the top section, intermediate section, as well as production section.
Overpressures, loss circulation and narrow window between pore and fracture gradient are common problems when drilling the top hole section. In some wells, coal caving and shale sloughing are claimed to be the reason of drilling day extension in this particular section. Overpressure zone within permeable system have cornered several field operators to activate well control system. Some field operators even had to experience blow out. The upper zone of intermediate section sometimes experience tight hole and shale sloughing, which require adequate drilling fluid management. In several wells, reactive shale is identified within the lower intermediate section, which requires the operators to utilize oil based mud to avoid clay swelling. Total loss circulation inflicted with high gas content is a normal condition when penetrating the intermediate and production section. This condition increases operational days when drilled conventionally with high potential of pipe stuck, complications in formation evaluation such as cuttings recovery and well logging, or even forcing the operators to side track the well due to sloughing. Extensive well bore clean out period also have been experienced by some operators when drilled with high barite concentration within the production zone.
This paper elaborates a new drilling convention that has been practiced by the operators within these areas, evolving the commonly known Managed Pressure Drilling technique into a culture when penetrating such problems. Success stories will be highlighted when drilling through the top section, intermediate, and production section presenting risks associated from economical and operational perspective.
HP/HT Carbonate Acidizing—Recent Discoveries and Contradictions in Wormhole Phenomenon
Authors: Karale Chaitanya , Beuterbaugh Aaron , Pinto Mario , Hipparge Gulam , Prakash Anand 
Published: March 2016

Abstract
Matrix acidizing is a technique used for stimulating carbonate formations. Fluids used for this purpose are routinely characterized in the laboratory by means of core flood testing. Though several key insights can be obtained using the laboratory core flood technique, simulating exact downhole environments and extrapolation of the results obtained to field-scale has proven challenging. This paper addresses two specific topics related to acid wormholing—upscaling laboratory results to field scenarios and the interaction of reaction products in high pressure reservoirs.
To study the upscaling of acid wormholing experiments in field scenarios, a radial core flood testing apparatus was set up to better mimic actual wellbore acidizing flow conditions. The effects of radial flow path and completion type (i.e. openhole versus cased hole) as well as the applicability of the upscaling wormhole propagation model were studied. Furthermore, CT scans of related core samples were performed to characterize wormhole patterns generated by acid dissolution. In addition, tests were performed at high pressures and flow rates to study the effects of the interaction of reaction products on the wormholing process at typical high bottomhole pressure values.
Results from radial core flood techniques showed significant differences in terms of pore volume to breakthrough (PVBT) based on well completion type. Further, a current upscaling algorithm for wormhole propagation modeling was verified by comparison to corresponding experimental data, thus demonstrating the suitability of described linear core flow testing methods for fluid characterization and data modeling. The wormhole propagation model (based on the use of fitting coefficient) is well-justified by the probability of increased fluid loss from the wormhole in the case of deeper radial penetration, which overall reduces the efficiency of wormholing. CT scan results revealed nonuniform radial distribution of wormhole propagation, thus shedding light on challenges associated with achieving 360° stimulation around the wellbore. Experiments at higher pressures showed that, at higher flow rates investigated (or beyond optimum) wormhole propagation has a higher than one third dependence on interstitial velocity, signifying that high pressure reservoirs require greater volumes of acid for proper stimulation. Experimental observations are presented to correlate the results obtained thus far and help resolve controversies between various publications.
Presented studies highlight the effects of higher pressure in acid wormholing and signify the need for proper volume accounting in terms of job design. A simple radial core flood technique has been developed in this work, and has an advantage in terms of diversion studies by providing a means of arranging high and low permeability core samples in the same order as formation layers and accounting for fluid entrance position.
An Efficient Geosteering Tool for CBM Drilling
Authors: Gao Wenkai , Sheng Limin , Chen Wenyi , Wang Lei , Zhang Liancheng , Peng Liexin 
Published: March 2016

Abstract
In CBM drilling, high-efficient, low-cost MWD and geosteering tools are needed to ensure the cost-efficiency of large-scale gas development. Especially in a cluster and horizontal coalbed methane well drilling environment, one of the most effective methods to enhance the individual well producing rate is to keep the bit always in the best position to extend along the target layer.
The DREMWD CBM drilling geosteering system adopts electromagnetic information transmission technology. Compared to traditional mud pulse technology, it has such advantages as a wide range of media applications, deep non-relay transmission, a fast signal transmission rate, and a low failure rate of field applications. Moreover, it can measure wellbore trajectory and geological parameters, so as to ensure actual wellbores to penetrate into coal seams and get the best position. Therefore, it has quickly become a leading geosteering tool for CBM drilling.
The DREMWD system consists of downhole tools and surface units. Downhole tools are mainly composed of the high-power generator, orientation sensor, natural gamma sensor, electromagnetic transmitter circuit, insulation transmitting antenna, and non-magnetic drill collar. Surface units are mainly composed of the signal receiver, ground antenna, driller display, and signal processing and analysis software. With its unique high-power downhole generation technology, greatly enhancing emission intensity and formation penetration. The rotary dynamic azimuth natural gamma measurement module is composed of a natural gamma sensor, a rolling angle sensor and a signal processing circuit. It can perform real-time measurement of the formation natural gamma within a certain fan-shaped range at upper and lower levels. The system has been widely used in the CBM drilling in Qinshui basin in China with good effect.
With this geosteering tool, the drilling performance and recovery efficiency have been remarkably improved. This paper will highlight the technical development and present helpful case histories and recommendations.
Seamless and Welded Tubes Alloy 825 for Sub Surface Safety Valve Control Line Application Evaluation
Authors: Soerowidjojo Kukuh Wanengkirtyo , He Wenle 
Published: March 2016

Abstract
Seam welded tube production technology has developed to a point where seam-welded tube quality reaches very closely to seamless tube combining advanced welding technology and drawing technique. Improvements have been gained over the years to minimize welding effects and smoothened both outer and inner diameter of the tube from welding material excess. Unfortunately, micro defects and metallurgical changes caused by welding are still present in the product that might influence its performance when it is used for sub surface safety valve control lines and also chemical injection lines.
High alloyed nickel based material UNS N08825 is selected in this study where similar dimensions and chemical composition were chosen in the observation by using electrochemical potentio-dynamic polarization in chloride solution, and scanning electron microscope (SEM), glow discharge optical emission spectrometry (GD-OES) for the surface analysis. The result of this investigation shows that the seam welded tubes have the same level of hardness with seamless tubes. Nevertheless, the weld defects along the fusion line could be the cause of diminishing corrosion resistance of the tube. Chromium nitride precipitates and lack of fusion have been observed in the outer tube surface of the Alloy 825 seam welded tubes which could not be detected by non-destructive testing (NDT) methods.
This study signifies that seamless tubing is a better option as SSSV control line to maintain well integrity than seam welded tube.
Behind Fault Well Planning: The Strong Influence of Geological Structure in Planning Complex Well Trajectories in the Gulf of Thailand
Authors: Kaeng Geovani Christopher , Natepracha Jatuphat , Sausan Sarah , Chongrueanglap Pongsit , Anansatitporn Natthanicha , Srisuriyon Kittipong 
Published: March 2016

Abstract
The Gulf of Thailand is characterized by pull-apart rift basins containing extensive en-echelon grabens and half-graben intra-basin fault systems. Both act as the pathway for hydrocarbon upward movement and as the trapping mechanism. The main reservoirs are compartmentalized sands and show rapid lateral stratigraphic changes because of their fluvial nature further segmented by faults. In this geological setting, the highest hydrocarbon pays often lie behind (upthrown side) the fault. To maximize the possibility of encountering trapped hydrocarbons, wells are drilled along and as close as possible to the fault plane. This paper reviews the impact of this complex geological setting on well trajectory characteristics and their planning aspects.
The Gulf of Thailand is also known for its fast drilling rate, which motivated operators to implement a factory drilling approach in their field development programs. The fast track nature of the drilling program requires an unconventional methodology to complete complex well plans in very limited time. The study revealed that strong collaboration between geoscientists and engineers are instrumental to significantly improve the well planning workflow. It further seeks to establish a preferred methodology through the implementation of integrated technology combined with a multidisciplinary collaborative culture. Using this methodology resulted in a significant improvement in terms of planning time and a better choice of trajectories.
Time-Lapse Seismic Feasibility Modelling and AVO Sensitivity Analysis for Quantification of Pressure-Saturation Effects in Fields Located in Malaysian Basins
Authors: Danaei Shahram , Hermana Maman , Rafek Abdul Ghani , Ghosh Deva 
Published: March 2016

AbstractTime-lapse seismic has established itself as a valuable tool to monitor dynamic changes in oil and gas reservoirs. These changes occur continuously in a reservoir due to production and/or injection operations and are manifested broadly in pore pressure and also water saturation changes. These changes might occur either independently or concurrently and affect seismic wave velocities. Therefore, this can be studied by 3D seismic surveys from different times or 4D seismic. The change in seismic response can be large or subtle depending on the magnitude of dynamic reservoir changes. Time-lapse feasibility modeling is the practice that realizes whether a detectable 4D signal can be captured or not. In this research, a 4D seismic feasibility model has been developed to assess the possibility of obtaining a 4D signal in an oil zone located in the Malaysian basins. This model is based on different production and water injection scenarios and a new rock physics workflow. Gassmann fluid substitution has been used to model the effect of different water saturation changes on seismic velocities. For pore pressure changes, Hertz-Mindlin geo-mechanical model in conjunction with pore space stiffness theory and the constant ratio approach for sandstone is used to simulate the effect of various pressure changes on seismic responses. This 4D feasibility model is followed by amplitude versus offset (AVO) modeling to exam the sensitivity of AVO intercept and gradient attributes resulting from different injection and production scenarios. In 1999, the AVO analysis method was presented to estimate fluid saturation and pressure changes from time lapse seismic data. This research has tested the AVO method in an oil zone located in the Malaysian basins. Finally, it is shown that AVO intercept and gradient cross plot is capable of distinguishing between water saturation and pore pressure changes in this zone. Therefore, this can be generalized in the Malaysian basins, where the AVO method can be used to differentiate between pore pressure and water saturation changes from 4D seismic data.
Novel Technology to Achieve the Fastest and Cleanest Formation Sample Data: An Introduction to Focused Sampling Probe Methodology
Authors: Tomar Ashish , Parashar Sarvagya , Wu Ivan Zhia Ming 
Published: March 2016

Abstract
This paper presents a technology designed to obtain the most representative formation samples in minimum time with less contamination. An innovative formation testing technology using the new focused sampling probe and real-time downhole fluid identification service, which enables users to save time and expense by eliminating the need for long pump outs and a second run, particularly in deepwater wells with unconsolidated sand reservoir formations. Representative formation sampling requires minimal differential pressure to move fluid and is uniquely able to provide low-contamination samples in extremely difficult unconsolidated formations. The in-situ fluid ID sensor data, which included fluid density, capacitance, resistivity, pressure, and temperature information, was used in conjunction with contamination forecasting software to provide accurate fluid-contamination predictions.
The formation testing tool "focused sampling probe" delivers a purer fluid sample than the traditional sampling techniques with less pumping time. This decreases uncertainty in terms of establishing connectivity and flow assurance while increasing operational efficiency. The formation sampling service incorporates oval pad geometry with large surface area, resulting in lower forces acting on the formation sandface and reduced sanding. Fluid flow is segmented into an inner and outer flow section; fluids in the outer section will be more contaminated and will be discarded back to the borehole. Fluids in the inner section will be purer and very low contamination is achieved much faster compared to traditional pumpout. In some cases, contamination is too low to be measured. The large flow area of the oval focused pad results in higher flow rate than a circular probe. The fast and versatile pump in the formation sampling service enables reduced cleanup times.
Sand Control from a Supply Vessel: Mobile Fracturing Fleet Saves Rig Time in Subsea Completions
Authors: Agee Daniel M. , Sutherland Andy , Syifaai Arfi , Malik Badar Z. , Tsangueu Barbara , Emmanuel Ignatius , Peacock Kevin B. 
Published: March 2016

Abstract
This paper presents an overview of switching from rig-based sand control pumping equipment to a semipermanent vessel-based pumping setup. The design, installation, and implementation of a fracturing vessel for subsea sand control and stimulation will be covered in detail. The approach taken includes an analysis of benefits and drawbacks associated with rig-based and vessel-based pumping setups as well as the design and implementation of a vessel-based fracturing package. Additional topics discussed include determining specifications for appropriate vessel selection and best practices for vessel layout design to maximize the pumping fleet functionality while minimizing the health, safety, and environmental (HSE) exposure.
We analyzed a case study in which a fracturing fleet based on a platform supply vessel (PSV) was implemented in place of rig-based equipment. Use of the methodology described here eliminated 17.7 rig days, 1540 offshore lifts, 46 helicopter flights, and 55 supply vessel trips over 11 wells in a subsea campaign. Additionally, due to the enhanced mobility of the vessel-based equipment package, it was possible to service two rigs with a single fracturing fleet. The switch from rig-based to vessel-based equipment resulted in an average savings of USD 1.3 million per well including rig day rates, fracturing equipment rental, and other associated costs.
A Development of Ocean Surface Wave and Wind Measurement From X-Band Marine Radar
Authors: Yang Y. J. , Park S. G. , Kwon S. H. , Park J. S. 
Published: March 2016

Abstract
The proposed method for ocean surface wave is carried out by a statistical analysis of the x-band marine radar image. In particular, by using the Fast Fourier Transform in 3-dimensional method and the linear dispersion relation derives a parameter of the ocean wave such as significant wave height and peak wave period.
For the ocean surface wind measurements using radar cross section, and the image superposition method is used. Signal to Noise Ratio is used to measure wave height and wind velocity.
Wave height, wave period, wind velocity, and wind direction were used for a long period of time, measuring the data from the IEODO ocean research station in Republic of Korea to the validation. In addition, compared with the measurement results of the light beacon in the radar image boundary and radar system located on the coast. The results were in good agreement with the quantitative analysis, the possibility of commercialization could be founded. Comparison data were obtained through the cooperation of the Republic of Korea Meteorological Administration and the National Oceanographic Research Institute.
It is possible to use the measurement of wind and wave radar mounted on ships and offshore plants. This system benefits the efficiency of the plant operation.
Electrohydraulic ICV Control System: A Novel Approach to Multizonal Control
Authors: Garcia Elias , Saldanha Savio 
Published: March 2016

Abstract
With the increasing number of laterals or extended horizontal-well depths, operators are seeking to maximize zonal control using intelligent completions. Electrohydraulic (EH) control systems introduce substantial reservoir-control advances by combining the benefits of both hydraulic and electric systems. This paper focuses on the features and benefits of a new EH control system, its reliability, and its overall performance when paired with interval control valves (ICVs) and other equipment.
The EH control system presented in this paper uses a novel approach to zonal control. The EH system uses two hydraulic lines and one electrical line to control up to 12 zones selectively. The system employs a unique addressing method that uses simple electronic components to selectively address different downhole tools. The system has the ability to provide the high motive power typical with existing hydraulic systems while providing fast system responses associated with electrical systems. Furthermore, system reliability is enhanced by fluid filling the electrical system with a pressurized non-conductive fluid biased to the external environment.
Careful consideration was given to both current electrical and hydraulic systems for deriving the system performance of the referenced EH system. One of the initial drivers for the EH system was the need to increase control while reducing the amount of control lines and surface infrastructure required to deploy such a system. Testing and deployment of the EH system suggests that the system response was able to meet or exceed current N+1 control systems while greatly increasing the amount of zones controlled. System response, system performance, surface infrastructure, ease of installation, number of control lines, and system modularity were assessed for this paper. Finally, the paper documents the cost savings and reliability obtained with the new EH module compared to traditional N+1 direct hydraulic control systems and current electrical systems.
This paper provides a thorough understanding of electric, hydraulic, and EH systems for downhole control in intelligent completions. It focuses on the comparison of all three systems but emphasizes the modularity of the EH system presented. Such modularity allows the EH system to be used in different intelligent completion applications while remaining compatible with other equipment deployed.