bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Scale Inhibitor Assay for Sulphonated Polymers in Oilfield Brines
Authors: Graham Gordon M. , Munro Ian , Harvison Nicola , Marshall Kirsty , Kyle Mark 
Published: July 2010

Abstract
Residual scale inhibitor analysis in produced waters, particularly for the sulphonated co-polymers is recognised as an ongoing challenge for many offshore production environments. Although methods have been well documented (e.g. dialysis / hyamine based techniques), there are a number of known difficulties when assaying residual ppm and sub ppm levels of sulphonated polymers where separation of the inhibitor from the brine phase can be a time consuming, labour intensive and often difficult operation. This paper describes a number of recent developments made to enable rapid, accurate, reliable and robust analysis of sulphonated polymers in oilfield brines. The work focuses primarily on those inhibitors which are not readily separated by conventional C18 techniques. This includes more appropriate solid phase extraction, SPE, techniques which demonstrate near 100% retention of sulphonated polymers from brines of different salinities and therefore negate the requirement for dialysis. The work couples these newly developed separation techniques to different assay methods including conventional post separation Hyamine derivitisation as well as direct analysis using appropriate HPLC detection systems. The paper will describe the challenges faced with residual scale inhibitor analysis in oilfield produced waters. Present advances made in the separation and assay of these and other polymeric species include the ability to obtain reliable separation and when required concentration using SPE methods as well as the utility of a variety of different detection systems. Extensive validation tests in a range of high salinity brines demonstrating the limits of detection and repeatability at ppm and sub ppm level for a variety of different polymers including PVS, VS-Co and more conventional polyacrylate as well as phosphorus containing polymers. In short, the results will demonstrate the ability to accurately assay a range of different polymers in different brine systems and mark a significant advancement over previously employed dialysis / Hyamine approaches. The paper will also illustrate the potential application of the techniques for separation and individual assay of different polymers from mixtures, which still represents a significant challenge for produced water analysis in many situations.
The Evolution and Effect of Information Application Technology about Oilfield development of ShengLi
Authors: Yang YaoZhong , Zhou Yongyi , Zhang Mingan , Sun Yeheng 
Published: July 2010

Abstract
The information technology has been the key supporting technology for the oilfield development. The routine information application technology of the oilfield development has obtained tremendous advancements such as structure interpretation, reservoir forecast, and reservoir simulation, etc. It has played a pioneering role in the engineering of EOR, detailed reservoir modeling, thermal injection of heavy oil reservoir, and chemical flooding. At present, the target of information application in the oilfield has been in the stage of data sharing in the whole field, and integral application and the modeling of the tracking application. In this paper, we propose some ideas to enhance the development performance for the mature and very mature oilfield, and indicate the necessity of technical development and the future direction for the development of information technology, especially in the field of conglomerate, shoal and bar sandstone reservoir, and the geological modeling and tertiary recovery advancement. Moreover, we also reviewed the applications on the detailed geological modeling, foaming flooding and in-situ combustion, and integrated reservoir description that is facies constrained, and the significance for the EOR of mature oilfield.
The Effect of Sulfide Scavengers on Scaling Tendency and Scale Inhibitor Performance
Authors: Williams Helen , Dyer Sarah , Bezerra Maria Carmen , Graham Gordon , Wright Rob 
Published: July 2010

Abstract
Use of continually injected sulfide scavengers has become more widespread in recent years with increased requirement for sulfide scavengers to be injected directly into water producing streams. The chemicals used, especially those based on common triazine chemistries, impact the pH of the produced water, leading to much more severe scaling tendency and impaired scale inhibitor performance. We have found this to be the case with both water-soluble and oil-soluble scavengers, although the effect is less severe with oil-soluble chemicals. The paper describes the results from a range of tests to examine the performance of a number of different scale inhibitor chemical types in the presence of different scavenger chemicals and different brine systems. We also describe the results of scale prediction modelling, as compared to the lab results and show methodologies which improve the reliability of the scale prediction programmes.
Advantages of Permanent Integrity Monitoring using Guided Wave Tomography
Authors: Bloom J. G. , Heerens G. J. , Volker A. W. 
Published: July 2010

Abstract
Corrosion and erosion are two major degradation mechanisms of piping systems and pipelines that both lead to wall thickness loss. To ensure sufficient integrity levels of these assets NDE is currently conducted at time based intervals often associated with shut downs. However, both economical and social requirements are pushing the industry to higher levels of availability, reliability and safety of installations at minimum costs. Using permanent sensors that continuously monitor the wall thickness of assets over large areas allows improvement of the availability of installations at lower inspection costs. Because when inline data is continuously available the maintenance can be planned (just) in time at the most optimal moment. Therefore, the permanent sensors will save inspection costs and minimize unplanned maintenance. This can not be achieved with the current method of periodic inspections and local measurements even when this is done risk based, because some corrosion processes behave unpredictable. This paper demonstrates a system that monitors the wall thickness of pipe lines over large areas in an economical attractive way using a limited number of low-power ultrasonic transducers. By applying tomographic inversion to the travel time of guided wave modes along different paths, a wall thickness map with 100% coverage can be obtained. Experimental results on a 10" steel pipe with a wall thickness of 8 mm show that this system is able to detect and size defects with a depth of 10% and diameter of 15 cm. The area covered in this case was the complete wall of a pipe with a length of 4 m. This paper further explains the performance and it will give an outlook of the possible applications and possibilities to integrate other functionality like crack monitoring with the same system.
In this paper there will be a focus on applying this concept in new build installations because of the low additional costs involved when applying the sensors while manufacturing the assets. This makes it very attractive for remote oil and gas production installations. However, it has been shown that it can save costs also for existing installations by replacing inspections at sections of installation, which are not piggable and difficult to approach. This is in general the case in oil and gas (offshore) production installations. Cost of inspection projects are extremely high in off shore environments and saving one inspection job can probably guarantee already your return on investment. Next, when using this technique it will also allow to make a wall thickness map of areas that are not accessible by current inspection techniques like corrosion under supports and feed through.
Evaluation of Alternative Horizontal Well Designs for Gas Production from Hydrate Deposits in the Shenhu Area, South China Sea
Authors: Zhang Keni , Moridis George J. , Wu Nengyou , Li Xiaosen , Reagan Matthew T. 
Published: July 2010

Abstract
Gas hydrate deposits were confirmed in the Shenhu Area, the north slope of South China Sea during a drilling expedition in 2007. Hydrate deposits in the area are distributed in disseminated forms in forams-rich clay sediments with permeable overburden and underburden layers. Production of gas from such a type of hydrate deposits is very challenging. In this study, we develop a numerical approach for investigation of gas production strategies by horizontal wells and preliminary estimation of the production potential based on the limited data that are currently available. Numerical models are built to represent the typical hydrate deposits in the area, including the thickness of the Hydrate-Bearing Layer (HBL), hydrate saturation, water depth, temperature at the sea floor, initial thermal gradient and pressure distribution. The models are used to simulate the different production schemes and well designs. In this paper, production strategies of horizontal well system with combination of depressurization and thermal stimulation are investigated through numerical models. Gas production potential from the deposits and effectiveness of the different production methods are evaluated. The simulation results indicate that with current technology, gas production from Shenhu hydrate deposits may not be economically efficient for all the production strategies we have investigated.
Use of Elemental Capture Spectroscopy to Accurately Determine Reservoir Lithology and Porosity in High Pressure and High H2S Environment
Authors: Zhao ZuoAn , Tang XuePing , Yu DaiGuo , Murray Doug , Zhao HaiPeng 
Published: July 2010

Abstract
The lithology of a producing gas reservoir in an area of the Sichuan basin in southwest China is a complex carbonate. Core analysis has revealed a strong correlation between dolomitization and reservoir quality, the process of dolomitization increases reservoir porosity and permeability, and hence overall reservoir rock quality. As such dolomite content is a key parameter in the classification of reservoir rock quality.
Historically, in carbonate reservoirs the estimation of dolomite content from wellbore geophysical data has been via neutron-density cross-plots. The technique was successful when reservoir lithology was relatively simple, such as a combination of limestone and dolomite, and the reservoir fluid was either oil or water. The presence of gas can shift both the neutron porosity and formation density measurements such that a dolomite lithology could be misinterpreted as limestone. However, the photo-electric absorption measurement acquired with modern formation density logs is strongly dependent on lithology and only minimally affected by reservoir fluid. Hence from the combination of neutron porosity, formation density and photo-electric absorption one can resolve simple carbonate lithology even in the presence of gas.
The aforementioned gas reservoir in the Sichuan basin has both high reservoir pressures and high concentrations of H2S, hence to maintain a safe drilling environment the drilling fluid is weighted with barite. The addition of barite makes photo-electric absorption measurements meaningless for petrophysical evaluation.
This paper describes a new technique to accurately describe complex reservoir lithology from elemental capture spectroscopy. The technique is independent of photo-electric absorption and includes elemental measurements of magnesium, calcite, quartz and sulfur. Additionally formation matrix density is derived from the measured elements, which dramatically improves the evaluation of formation porosity. A field example is shown where excellent agreement with core is achieved.
Reserves Estimations under New SEC 2009 Rules when using Probabilistic Methods
Authors: Wheaton R. , Coll C. 
Published: July 2010

Abstract
The new SEC rules (Jan 2009) allow the use of probabilistic methods for reserves estimations. The main advantage of probabilistic modelling methods is that they provide an understanding of the confidence levels associated with each reserves/resources category. Reserves evaluators need to ensure regulatory compliance of the output of these probabilistic methods with the reserves definitions adopted by the SEC or other regulatory bodies. A Cumulative Distribution Function of hydrocarbon recovery is obtained as part of a probabilistic modelling workflow, from which estimates of P90, P50 and P10 result. However, these estimates are not necessarily SEC compliant. We may therefore require an additional analysis of the parameters that have been used for each model. The aim of the paper is to provide technical guidance on methodologies for obtaining P90, P50, P10 reserves and on obtaining compliant reserves estimates when these are available. This approach should help to standardize industry external reserves reporting.
To understand and quantify the impact of major uncertainties in a reservoir there are different methodologies used in industry with the objective of achieving a fully integrated probabilistic reserves analysis. An examination of different methodologies depending on the stage of appraisal and development of a field is presented. The output of this analysis will be a cumulative distribution of hydrocarbons from which P90, P50, mean and P10 reserves are selected.
In summary the aim of this paper is to provide technical guidance on how to estimate reserves for external complaint reporting if probabilistic methods are used.
Application of Ferrofluid for Enhanced Surfactant Flooding in EOR
Authors: Kothari Nikita , Raina Bhavna , Chandak Krishna , Iyer Venkat , Mahajan Hrishikesh 
Published: July 2010

Abstract
Improved Oil Recovery (IOR), techniques offer prospects that enhance the displacement of oil from the reservoir, ultimately producing 30 to 60 percent, or more, of the reservoir's original oil in place. The most important criteria in IOR- Surfactant Flooding is to determine if the interfacial tension (IFT) can be reduced enough to produce incremental oil.
One of the key recovery problems in oil-wet reservoir is overcoming the surface tension forces that tend to bind the oil to the rock. In water wet reservoirs, surface tension forces act to create bubbles of oil, which can block pore passages as the bubble resists movement in the increased surface area associated with squeezing through the passages. These surface tension forces are the primary reason why reservoirs become increasingly impermeable to oil, relative to water, as the water saturation increases.
Ferrofluids are a special category of smart nano-materials, in particular magnetically controllable nanofluids. The ferromagnetic nano-particles are coated with a surfactant to prevent their agglomeration. As a result of their composition, Ferrofluids possess a unique combination of fluidity and the capability to interact with a magnetic field. The addition of a surfactant will greatly reduce the Interfacial Tension and in water-wet reservoirs, where oil globules are formed, ferrofluid shatters it. Also, as ferrofluid comes in contact with the reservoir fluid, it interacts with the crude in the reservoir & due to the presence of dipole moment, the reservoir fluid molecules align, thus reducing the resistance to the flow.
To sum up, reduction in Interfacial tension, thus reducing resistance to the flow, can be easily achieved by making use of Ferrofluid-enhanced surfactant. Oil can be made even more polar using Ferrofluid which will act as a better solvent for the surfactant.
Pre-selection of Reservoir Models From a Geostatistics-Based Petrophysical Seismic Inversion
Authors: Ravalec-Dupin M. Le , Enchery G. , Baroni A. , Veiga S. Da 
Published: July 2010

Abstract
A new geostatistics-based seismic inversion method is introduced in this paper for determining reservoir models consistent with base seismic information. The proposed methodology entails two steps, the second one only being examined in this paper. First, cubes of acoustic velocities or impedances are derived from seismic inversion. Second, these data are incorporated into a matching process to identify reservoir models leading to acoustic responses close to the reference acoustic data. The parameterization of the facies and petrophysical properties populating the reservoir models is based upon the gradual deformation method (GDM), which relies on geostatistical concepts. This particular feature makes it possible to change the spatial distribution of the property of interest from a few parameters while preserving its spatial variability. The matching process is driven from a global optimization algorithm known as the particle swarm optimization (PSO). Such a global approach is reasonable for the problem considered as the forward modeling is very fast. A variant of the PSO algorithm is implemented to take advantage of the gradual deformation method properties. This approach yields reservoir models which honor the seismic data better than those derived from stochastic simulation only with seismic used as a secondary variable. A numerical experiment is then presented to stress the applicability of the proposed matching methodology: the GDM-based PSO approach is used to identify facies reservoir models and water-oil contact consistent with some reference acoustic P-wave impedances.
Research on Development Rules and Strategies in the Low R/P Ratio of Tarim Major Sandstone Reservoirs
Authors: Yu Lijun , Feng Jilei , Zhang Shuguang , Lian Zhanggui , Chang Yuwen , Feng Jinde , Yan Jianwen 
Published: July 2010

Abstract
Based on the major Tarim sandstone oil reservoirs, with seven typical reservoirs as the fundamental study units, some relevant researches are conducted, which include changing patterns and their major contributing factors analysis of production decline rate, water content increase rate, ratio of reserve to production (R/P ratio) and balance index of reserve to production. The production decline rate change rules and its major contributing factors have been specifically analyzed quantitatively. It is believed that, comparing with domestic and foreign land reservoirs, the major sandstone reservoirs have made satisfactory progress. After a period of high-yield and stabilized production, the reservoir development has entered a comprehensive adjustment and low yield stage. In the decline stage, the production decline rate is high and the R/P ratio is in a low level.
Through the studying of R/P ratio and balance index of reserve to production of different kinds of reservoirs, rational boundary of R/P ratio has been defined, reasonable development system's establishment and technical development policy for 8-to-10-year stable production have been proposed.
The research indicates that, multilayer developments, multi-adjustments and pressure maintenance development are all necessary to keep the oil production stable. Through well pattern thickening, injection-structure adjusting and hydro-dynamic method, water-flood recovery can be increased by 8.7%. Thus the major sandstone reservoirs can keep stable production by 2015. However in the long run, the potential of increasing recoverable reserves by water drive is limited. For technological breakthrough in reserve replacement, the author suggests speed up the research and experiment of gas injection method to enhance recovery. These research results have already been applied in the annual plan as well as in the oil field plan for the next five years.
Drilling Optimization Based on the ROP Model in One of the Iranian Oil Fields
Authors: Mostofi M. , Shabazi K. , Rahimzadeh H. , Rastegar M. 
Published: July 2010

Abstract
In today's drilling industry, all considerations are involved to reduce drilling operation expenditure. In several cases, the drilling optimization is the key point to make a drilling operation economically satisfied. Appropriate bit selection and optimum operating condition can lower the drilling expenditure, effectively. Drilling models are drilling simulators, which can evaluate the effect of different operating conditions on the drilling rate of penetration and drilling expenditure, quantitatively.
The model constants are required to start the optimization process. The model constants are bit constants and formation rock strength. They can be determined from either laboratory tests or the drilling information of offset wells. When model constants are calculated from field data, it is beneficial to use pattern recognition and statistical tools to eliminate the noises and out of range data.
When the drilling model is developed, the optimum operating condition for each bit is calculated. Then, subsequent cost analysis is carried out to determine the cost per foot value of bits in their optimum drilling condition. Consequently, bit runs are compared based on their cost per foot values. Moreover, bit run with minimum cost per foot value along with its optimum drilling condition is selected for drilling of formation under investigation.
From Oil-Prone Source Rock to Gas-Producing Shale Reservoir – Geologic and Petrophysical Characterization of Unconventional Shale-Gas Reservoirs
Authors: Passey Q. R. , Bohacs K. M. , Esch W. L. , Klimentidis R. , Sinha S. 
Published: July 2010

Abstract
Many currently producing shale-gas reservoirs are overmature oil-prone source rocks. Through burial and heating these reservoirs evolve from organic-matter-rich mud deposited in marine, lacustrine, or swamp environments. Key characterization parameters are: total organic carbon (TOC), maturity level (vitrinite reflectance), mineralogy, thickness, and organic matter type. Hydrogen-to-carbon (HI) and oxygen-to-carbon (OI) ratios are used to classify organic matter that ranges from oil-prone algal and herbaceous to gas-prone woody/coaly material.
Although organic-matter-rich intervals can be hundreds of meters thick, vertical variability in TOC is high (&lt;1–3 meters) and is controlled by stratigraphic and biotic factors. In general, the fundamental geologic building block of shale-gas reservoirs is the parasequence, and commonly 10's to 100's of parasequences comprise the organic-rich formation whose lateral continuity can be estimated using techniques and models developed for source rocks.
Typical analysis techniques for shale-gas reservoir rocks include: TOC, X-ray diffraction, adsorbed/canister gas, vitrinite reflectance, detailed core and thin-section descriptions, porosity, permeability, fluid saturation, and optical and electron microscopy. These sample-based results are combined with full well-log suites, including high resolution density and resistivity logs and borehole images, to fully characterize these formations. Porosity, fluid saturation, and permeability derived from core can be tied to log response; however, several studies have shown that the results obtained from different core analysis laboratories can vary significantly, reflecting differences in analytical technique, differences in definitions of fundamental rock and fluid properties, or the millimeter-scale variability common in mudstones that make it problematic to select multiple samples with identical attributes.
Porosity determination in shale-gas mudstones is complicated by very small pore sizes and, thus, large surface area (and associated surface water); moreover, smectitic clays that are commonly present in mud have interlayer water, but this clay family tends to be minimized in high maturity formations due to illitization. Finally, SEM images of ion-beam-milled samples reveal a separate nano-porosity system contained within the organic matter, possibly comprising &gt;50% of the total porosity, and these pores may be hydrocarbon wet, at least during most of the thermal maturation process. A full understanding of the relation of porosity and gas content will result in development of optimized processes for hydrocarbon recovery in shale-gas reservoirs.