bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrating Production Analysis as a Plan of Pattern Selection for Chemical Flood Pilot Project in Limau Block, Pertamina EP
Authors: Nugroho Susanto Budi , Ardianto Reza Nur
Published: January 2010

Limau Block, operated by Pertamina EP lies in South Sumatera basin, located 90 Km Western part of Prabumulih. Consisted of eight fields, the first well was drilled in April 1951. The production reached a peak of 49,000 BOPD. The reservoir was divided into 22 layers mainly due to faulting. The pilot water flood operation was initiated in April 1991 by injecting water. Currently, Limau block is a mature oil field. By April 2009 production had declined to 10,000 BOPD. It is estimated that more than 80% primary reserves have already been produced and recovery factor has reached 36 %. Most of the reservoirs have been intensively produced over the life of the field and only a few of them are still producing today at low rate due to depletion.

EOR department tried to identify reservoir with remaining production potential that are candidates for Pilot Chemical Flooding Project, which will be the first Chemical Flood Project for Pertamina EP. The chemical selection is ongoing progress. It has become much more of a challenge for the team consisting of integrated Geophysics, Geology, Reservoir, Production, Process Facility, Project Management and Economic Evaluation.

This paper presents the result of Production Part as integrated analysis for Chemical Flooding. The analysis, which was performed by integrated analysis of production and injection, tracer test, well history and surface data, has identified inter well communication between injection well and production well. It shows that the most prospective candidate for Chemical Flood pilot project was S layer in Q-51 field, the pilot project was planned for inverted five (5) spot patterns and predicted breakthrough time was 90 days, it was also predicted a tertiary peak of 3,100 BOPD. Currently, Q-51 field, which had reached a primary peak of 20,600 BOPD and secondary peak of 2,000 BOPD, is injecting 36,820 BWPD through seven (7) peripheral injection wells and producing 31,031 BFPD through 13 production wells. This analysis is useful result as a part of countercheck for Geology and Reservoir Modeling regarding to the plan of Chemical Flooding Pilot Project.
Residual Hydrocarbons – A Trap for the Unwary
Authors: O'Sullivan T. , Praveer K. , Shanley K. , Dolson J. C. , Woodhouse R.
Published: January 2010

Residual hydrocarbons occur in a range of habitats and can take various forms: they may be oil or gas, they may be present within high-quality or poor reservoirs; and may appear as a single palaeo-column or as thin columns interspersed with beds of producible hydrocarbons. Residual hydrocarbons are sometimes easy to identify but when not recognised they may lead to optimistic reserves estimates.

This paper illustrates the range of habitats of residual hydrocarbons and provides techniques to enable their identification, such as novel log cross-plots and log overlays. In most cases the non-productive nature of the residual hydrocarbon can be confirmed using flow tests, with the possible exception of very low permeability reservoirs containing residual gas.

The results of not recognising residual hydrocarbons include (a) overbooking of reserves which may have serious commercial consequences, (b) the application of incorrect saturation-height functions, (c) pessimism in calculated formation-water resistivities estimated from water legs containing residual hydrocarbons, (d) lower effective permeabilities in water legs which may affect waterflood design, and (e) excessive expenditure on wireline formation testing and drill stem testing.

From an exploration perspective, residual hydrocarbons provide direct evidence of migrated hydrocarbons and/or breached oil fields and hydrocarbon loss due to regional post-migration tilt. Thus they provide important clues to the location of additional traps along the migration pathways.

We present examples of residual hydrocarbons from the Indian subcontinent and elsewhere. The subcontinent is particularly prone to the presence of residual hydrocarbons as many basins have undergone polyphase deformation and multiple periods of secondary migration and fill.

By raising the awareness of residual hydrocarbons, we hope that this paper leads to greater accuracy in reserves estimates, and perhaps even the discovery of additional hydrocarbons.
Monobore Design Optimises Slimhole Raageshwari Deep Gas Development
Authors: Jha Mihir , Singh Ratan , Vermani Sanjeev
Published: January 2010

The Raageshwari Deep Gas field, situated within Barmer Basin in the State of Rajasthan, India, was discovered in 2003. The field is a tight gas condensate reservoir, with excellent gas quality of approximately 80% methane, low CO2 and no H2S. The wells in Raageshwari Deep Gas field have tested at gas production rates in the range of 2- 4MMscfd and producing condensate gas ratios in 40-50 bbl/MMscf range. The condensate gravity varies across the field but approaches 60 API.

This paper discusses the fit for purpose monobore well design for Raageshwari Deep gas development wells. The design is suitable for handling fracture stimulation treatment, which is typical for a tight gas reservoir, by taking into consideration the suitability of the completion vis-à-vis surface and bottomhole treatment pressure during a fracture screen-out. The well completion supports the long term production from the gas condensate wells taking care of liquid loading issues. The paper also delves into the various well designs that were implemented during the appraisal phase and advantages offered by the current monobore well design especially in de-coupling well completion from well stimulation activity thus reducing the overall field development cost.
Determination of Wettability and its Effect on Oil Recovery in a Carbonate Rock of an Offshore Field Under Ambient and Elevated Temperature
Authors: Kumar Rajesh , Verma S.K.
Published: January 2010

Wettability indices were derived using centrifuge capillary pressure tests on two sets of core samples of carbonate reservoir of Mumbai High, an Indian offshore field. One set of samples were aged in crude and then displaced with Isopar mineral oil so that the test sequence could be conducted at ambient temperature. Another set of samples were aged in crude and the subsequent testing conducted using crude oil at elevated temperature. The wettability indices indicated intermediate wettability character with slightly water wet to slightly oil wet and the field is expected to yield higher oil recovery. Moreover, similar wettability indices derived from both sets of tests indicated that displacing crude with Isopar left the samples in a reservoir representative wetting condition. Hence subsequent testing using Isopar at ambient temperature would yield valid results at much lower cost, and in a much faster time frame, than conducting tests at reservoir temperature and pressure with crude oil.
Depositional Environment and Sequence Stratigraphy of Eocene Reservoirs, Assam Shelf, India: A Multiwell Log Study
Authors: Bora D. S. , Baruah Neelimoy , Shrivastva Chandramani , Bharali Binayananda
Published: January 2010

Although the Palaeocene-Eocene reservoirs of the Assam shelf have been prolific producers of oil and gas, the production profiles of various fields have caused concerns because of their departure from the geological model originally envisaged. An attempt is made to understand the temporal and spatial reservoir heterogeneity within a broader depositional model framework using micro- resistivity image and open hole log data from four fields in the assam Shelf; Baghjan, Katahloni, Bhogpara and Nahorkatia. Using image data, whole cores, dip patterns, openhole logs, image derived neural network facies and image derived textural facies, the key reservoir facies associations are identified. Facies associations in different wells are made use of to reconstruct depositional sequences, which enable to conceive a broader depositional model for the sedimentation of major Plaeocene to Eocene formations, namely Langpar, Lakadong, Narpuh, Prang and Kopili.

This study infers marginal marine to coastal plain channelized sedimentation for the Langpar formation with reservoirs likely to be oriented in a NW-SE to E-W direction. These basal clastics are overlain by lagoon–barrier island to coastal plain channel environment of the Lakadong formation with reservoir orientation along E-W to NW-SE direction. Beach-strand plain to chenier plain depositional environment is encountered in the Narpuh formation with the reservoir appearing to have an extension along N- S to NW-SE direction. Overlying Prang and Kopili formations are inferred as restricted marginal marine deposits. The Prang shows occurrences of carbonate facies whereas the Kopili shows feeder channels facies of thick argillaceous sequence. Overall, the Eocene-Oligocene petroleum system seems to have been deposited in a marginal marine depositional setting. Analysis of depositional units in a sequence stratigraphic context suggests that the overall sequence has evolved in a transgressive system. Using a sequence stratigraphic framework allowed us to better define reservoir distribution patterns of the Assam Shelf, and these facies associations may prove useful in future reservoir modeling studies.
Permeability Transforms and Geologic Modeling of The Heera Field, India
Authors: Bhattacharya S. , Rao N. S. , Datta-Gupta Akhil
Published: January 2010

Permeability predictions are a critical aspect of reservoir description and are particularly challenging for carbonate reservoirs because of the complexities rooted in diagenesis, grain size variations, cementation etc. Conventional multiple regression techniques very often yield unsatisfactory results.

The paper proposes a simple approach to obtain permeability correlations in heterogeneous carbonate reservoirs using commonly available well logs. The approach follows a two-step procedure. First, the well log data is classified into electrofacies types. This classification is based on the unique characteristics of well log measurements reflecting minerals and lithofacies within the logged interval. A combination of principal component analysis and model-based cluster analysis is used to identify and characterize electrofacies types. Second, a non-parametric regression technique has been applied to predict permeability using well logs within each electrofacies. The main advantage of this technique is that it is primarily data driven as opposed to model driven and does not require a priori specification of functional forms, which makes conventional multiple regressions difficult.

This method has been successfully applied to a heterogeneous carbonate reservoir, the Heera and the South Heera field in offshore India. The field is producing for over twenty five years and a major redevelopment effort is ongoing to improve production from the field by targeting the bypassed oil. Geologic modelling and flow simulations are important aspects of the redevelopment planning efforts. Our proposed approach results in improved predictions of permeability using commonly available well logs. The permeability correlations were incorporated into the geologic modelling to generate field-wide 3-D distributions of permeability. A scaling of the cumulative probability distribution was carried out to modify these permeabilities to account for well test data. Preliminary simulation runs indicate that the 3-D geolgic model is able to adequately reproduce the pressure trends and the waterfront movement in the reservoir. Detailed history matching is currently in progress.
Geosteering Long Horizontal Holes in Abu Dhabi Heterogeneous Carbonate Reservoirs
Authors: Dawoud Ahmed , El Mahdi Ahmed , Ayoub Mohammed , Bin Saad Mohamed , Al Marzouqi Khalid , Hendrawan Irfan , Daif-Allah Samy , Khalil Ghazi
Published: January 2010

Field development of a heterogeneous carbonate reservoir in Abu Dhabi-United Arab Emirates focused mainly on the geo- steering technique to penetrate the target level of the reservoir and drill and place long radius open horizontal hole for final completion as single producers or injectors. Tough drilling environment of natural islands, manmade islands, shallow and deep waters based on poor seismic data and depth uncertainties added to difficulties of predicting the setting depth of the 7" liner before geosteering operations of the open horizontal hole. Wells clustering to minimize drilling and surface facilities foot prints, top drive drilling using rotary steering system (RSS) techniques together with real time LWD helped to better control trajectory and placement of the horizontal holes as planned. Fluid identification in pilot holes as well as across the horizontal holes was successfully acquired to capture necessary reservoir fluid samples.

Geosteering operations and the experienced difficulties of placing the horizontal holes as planned were affected by rock heterogeneity, rate of penetration, mud system, and real time monitoring and follow up. The implemetation of geosteering and real time data acquisition was supervised by the team abd resulted in timly decisions for proper action and achievement of the target development plan. However, depth uncertainties resulted in improper placement of three wells but these well were worked over to correct the location. In addition, coiled tubing accessibility problems have been experienced following production and injection commissioning. This problem was attributed to the undulating horizontal hole and the well completion technique.

This paper presents a field case of drilling and geosteering of long radius open horizontal holes and wells completion. It points to possible reasons for experienced poor coiled tubing accessibility and the lessons learned for future development.
Novel Microbial Process for Mitigating Wax Deposition in Down hole Tubular and Surface Flow Lines
Authors: Rana Dolly Pal , Bateja Surendra , Biswas Susanta Kumar , Kumar Ashok , Misra Tilak Ram , Lal Banwari
Published: January 2010

Many oil fields producing waxy crude, face severe wax deposition problem in down hole tubulars and surface flow lines. Sometimes this problem is also encountered at the face of producing zone in the well bore region due to changes in temperature & pressure conditions. This problem frequently results in complete blockage of the crude passage and poses severe production problem. Conventional methods such as thermal, magnetic, mechanical scraping, solvent cleaning and chemical treatment etc. are not only cumbersome, costly and hazardous but provide only temporary respite. Two separate microbial systems, capable of mitigating the vexed problem of paraffin deposition in oil well tubulars and surface flow lines have been developed.

The microbial system for down hole tubular comprises of paraffin degrading bacterial (PDB) consortium named as PDS-10, nutrient supplements and growth enhancer. Laboratory studies showed significant reduction in pour point and flow behaviour of the crude. The process is effective up to 900C but maximum efficiency was observed at 550C. Field trial in 100 wells of different fields of Western & Eastern sector has shown that the treatment not only checked the paraffin deposition in all the treated wells but also improved oil production by 20-80 % in many wells. Most of the treated wells flowed without any wax deposition for 6-8 months after the treatment.

For flow assurance in surface flow lines bacterial consortium named as FIB-19, which shows high degree of wax degradation capability has been developed. The bacterial consortium is aerophilic, mesophilic and remains active upto 430C. Field trial in surface flow lines of twelve wells of Ahmedabad Asset was quite successful resulting in elimination of requirement of line flushing for considerable time along with reduction in pressure in the flow line. The average period of effectiveness of the jobs has been found to be around 4-5 months.
Laboratory Investigation of Low Salinity Waterflooding as Secondary Recovery Process: Effect of Wettability
Authors: Ashraf A. , Hadia N. J. , Torsæter O. , Tweheyo M. T.
Published: January 2010

Laboratory studies along with field tests conducted over the decade reveal that reducing the salinity of water injected into reservoirs improves the oil recovery. Different phenomena e.g. increase in pH (alkalinity), fines migration, multi-component ionic exchange, etc., have been proposed by researchers for improved oil recovery during low salinity waterflooding (LSW). Though LSW has attracted attention among reservoir engineers as tertiary recovery process, limited studies have reported the potential of LSW as secondary recovery process. Also, the relationship between reservoir rock parameters such as wettability, rock minerals, etc. and oil recovery is not well established for LSW.

The objective of this paper was to investigate the relationship between rock wettability and oil recovery with low salinity water injection as secondary recovery process. Coreflooding experiments have been performed at room conditions on Berea cores with four different wettabilities ranging from water- to oil- wet. Brines and n-decane were used as displacing and displaced phases, respectively. The results showed that, for all the salinities, oil recovery increases as wettability changes from water- to neutral- wet conditions. Further change in rock wettability from neutral- to oil-wet condition resulted in decreased oil recovery. It was also interesting to observe that oil recovery is higher for LSW as compared to high salinity waterflooding when used as secondary recovery process. Increase in pressure drop and hence decrease in effective permeability was also observed during LSW process in most of the cases considered.
Coal Bed Gas Productivity Prediction By Stoneley Wave Analysis
Authors: Dey Swapan Kumar
Published: January 2010

Coal is an organic sedimentary rock which acts like a dual porosity reservoir where the vast majority of gas is stored in the low porosity coal matrix (primary porosity) by adsorption. But the production of coal bed methane occurs through the natural fracture systems (cleats) of the coal (secondary porosity) because coal matrix has virtually nil permeability. Hence the determination of petrophysical characteristics of fracture system in coal beds and the properties of the fluid present in the cleat systems are the key parameters that ultimately determines the deliverability of a CBM reservoir. Laboratory and field test have shown that under some conditions the dynamic stresses imposed on an interconnected fracture by a propagating wave can produce fluid motions, the magnitude of which is a function of fracture permeability. The energy used in producing the fluid motion in turn affects the wave propagation. Different studies were carried out by A. Norris (1989) and Tang et al. (1991) on the interaction of Stoneley waves with fractures intersecting a borehole has related the attenuation characteristics of Stoneley waves to the permeability of interconnected fracture and the properties of the fluid present in it. The physics of the interaction of Stoneley wave with fracture and fracture fluid is well understood in principle but the complexity of cleat geometry and lithological composition of different types of coal imposes the need of simplifying the theory so as to make it applicable for analysis of field data. The detailed study of the Stoneley wave attenuation characteristics observed in complete acoustic waveform in CBM wells acquired by sonic imaging tools and subsequent processing of the data along with other logs has helped in prediction of the gas producilbility of the coal beds, thus making it a key productivity indicator of CBM reservoir.
Well Integrity Issues in Malacca Strait Contract Area
Authors: Calosa Weka Janitra , Sadarta Bambang , Ronaldi Ronaldi
Published: January 2010

The Malacca Straits contract area is located on the east of Sumatera Island between Sumatera and the Malaya Cape. This area started oil production in the early 1980’s, and consist of 175 onshore and offshore oil wells spread over five fields, namely the Kurau, Melibur, Selatan, Lalang, and Mengkapan oil fields.

A 7.9 Richter scale earthquake occurred on 12 September 2007. The epicenter of the earthquake was 159 KM south west of Bengkulu, a province in the southern part of Sumatera. Two days later, during a snubbing unit service on the K-02 well, the 9-5/8" casing suddenly dropped down six feet. It was believed that the area had been impacted by the earthquake since another snubbing unit found lateral movement on wellhead while doing workover on nearby well. Following the incident, the well services team inspected the K-02 well and found it had an integrity problem.

This finding lead to a wider investigation, which revealed that other wells also suffered integrity problems, including unsecured wellheads, leaking wellheads and christmas trees, severe corrosion of well components, failure of cement bonding, and casing elongation / casing drop due to top soil compaction / reservoir subsidence. At this point, it was decided to initiate a comprehensive well integrity study.

The integrity problems are due to several causes: wells exceeding their design life (most wells were constructed in the mid to late nineteen-eighties), exploration wells being used as producers without improvement, environmental degradation from deforestation (drop in the water table causing top soil compaction), and more than twenty years of production (causing formation subsidence).

This paper details the well integrity study, including the well assessment, the evaluation of well operation in term of safety, environment and profitability, and recommended effective temporary remedial actions.
System Approach to Horizontal Well Completion in the Vankor Field
Authors: Semenov A. A. , Malyasov V. J. , Nukhaev M. T.
Published: January 2010

The Vankor oil field is one of the largest oil fields in the world that was put into production recently. Main reserves are situated in the two thin productive layers. Each of them has active aquifer and huge gas cap. Wells with horizontal section of 1 km are used. Due to high reservoir heterogeneity and variation in permeability, inflow to the horizontal well is not uniform. As a consequence, recoverable reserves are various in different parts of the same well. Development of the approach to selection the best well completion system, its implementation and control were main purposes of this investigation.

The first stage of this investigation includes preliminary estimation of appropriate well completions before field development starts. An NPV criterion is used for comparison. Very limited field data were available on this step. An approximate model and special decision-making procedures were used. According to this estimation the use of ICD in some wells helps in managing inflow profile efficiently.

One of the main issues consists in a forecast of flow profile to a horizontal well. In this research we used LWD data as a source of online information about rock properties distribution in the horizontal section. PLT data were used to select an appropriate inflow model. On this stage, an approximate model was developed and validated using surface measurements of multiphase flow, horizontal part flow and pressure distribution. This model includes reservoir, ICD, horizontal section, inclined wellbore and surface choke.

Last, a design of a completion system (the sand screen with ICD) was made. Different cases were compared using the sector hydrodynamic model. Oil, water and gas flow profiles in the horizontal part at different times were used to select a choke level and swellable packer's positions. So the optimal completion design in terms of cumulative oil, water and gas production from well was selected and installed in the number of the Vankor wells.

In short this paper presents new system approach to the selection of a completion system. Appropriate numerical models (approximate, sector hydrodynamic) are used on each step depending on the available information and its confidence level. This method is used in some typical wells of the Vankor field.
Managing Oil Spill Risks of Transnational Onshore Pipelines
Authors: Guevarra Joselito
Published: January 2010

The management of oil spill risks of large transnational onshore pipelines is a huge and demanding task but one that is not impossible as shown by the examples of the BTC and Trans-Alaskan pipelines. Their trans-boundary nature poses significant challenges in terms of positioning of the infrastructure, the supporting logistics and the deployment of resources to combat accidental oil spills. This paper looks at industry best practices and presents a methodology and framework for managing oil spill risks by distilling lessons from industry and using the experience of Oil Spill Responsein responding to inland oil spills from pipelines.
Hiding the Evidence of Valid Theories: How Coupled Search Processes Obscure Performance Differences among Organizations
Authors: Siggelkow Nicolaj , Rivkin Jan W.
Published: January 2010

Theorists argue that an organization's high-level choices, such as its organizational design or the attributes of its top management team, should influence its performance, yet empirical researchers have struggled to detect such influence. The impact of high-level choices may appear weak, we theorize, because the choices are embedded in coupled search processes. A coupled search process exists in an organization when managers search for high-level choices that shape the search for low-level, operational choices, which in turn determine performance. Using a simulation model, we show that coupled search processes obscure the performance impact of high-level choices through two mechanisms: (1) a survivor effect, arising because firms that persist with poor high-level choices are those that luckily happened on good low-level choices despite their poor high-level choices, and (2) a wanderer effect, arising when firms use good high-level choices to find good low-level choices and achieve strong performance but then wander toward poor high-level choices. We show that these effects are particularly strong in stable environments, and we identify empirical strategies that can tease out the true performance impact of high-level choices.
Bioenergy II: Tin Catalysed Esterification of Free Fatty Acids
Authors: da Silva Marcio Jose , Cardoso Abiney Lemos , Natalino Ricardo
Published: January 2010

Tin(II) chloride dihydrate (SnCl2.2H2O) has been an efficient Lewis acid catalyst in the ethanolysis of saturated and saturated free fatty acids (FFA). This compound is stable under aerobic conditions and it has shown to be as active as the mineral acid H2SO4, a common acid catalyst in the conventional production of biodiesel. The carbon chain length of FFA and the fatty acid/alcohol molar ratio were parameters of investigation herein in association with the yield and reaction rate of free fatty ethyl esters (FAEE) formation. The efficiency of the process of recovery of SnCl2 also has been evaluated. It was verfified that the catalytic activity of the recovered SnCl2 has remained unaltered in successive reactions with oleic acid. The residual content of catalyst in the biodiesel was determinated by spectrophotometry of atomic absorption. The use of SnCl2 has advantages in comparison with mineral acid catalysts. For instance, the absence of corrosion in the reaction vessel as well as the unnecessary neutralization of the catalyst after the reaction finishes. The results in this work put forward the SnCl2 as a promising catalyst for the production of biodiesel.
Study of the Behaviour of a Catalytic Ceramic Candle Filter in a Lab-Scale Unit at High Temperatures
Authors: Simeone Eleonora , Hölsken Emilie , Nacken Manfred , Heidenreich Steffen , De Jong Wiebren
Published: January 2010

Solid particles and tars are among the non-desirable products of synthesis gas produced during biomass gasification. Removal of fly ashes is necessary in order to comply with emission limits as well as avoid their deposition in downstream units. Condensation of tars, on the other side, can cause clogging. A catalytic hot gas filter can remove both solids and tars, when operating at temperatures as high as 850°C. Catalytic hot gas filter elements are under development in order to solve this issue.A lab-scale filtration unit has been designed and constructed at Delft University of Technology. The unit contains one ceramic hot gas filter candle which is made of a SiC porous structure coated with a mullite membrane. The integration of a Nickel-based catalyst layer allows the dual function of particle filtration and tar cracking. The filter vessel is part of a set-up that is equipped with a tar evaporator and a pre-heater, both located upstream of the filter unit.This paper presents the results of the first set of experimental tests that have been performed with this unit. A dust-free model gas was used and consisted of a mixture of CO (14%), CO2 (14%), H2 (7%), CH4 (5%), and varying concentrations of N2 (30, 40, 50%) and H2O (30, 20, 10%). Naphthalene (varying concentrations up to 9 g/Nm3) was adopted as model compound in order to study the catalytic conversion of heavier hydrocarbon species to H2. A gas face velocity of 2.5 cm/s and 3 cm/s was selected for tests performed at atmospheric conditions and at operating temperatures varying between 700 °C and 850 °C. The pressure drop through the filter candle was continuously monitored during the process. The gas composition was measured upstream and downstream of the filter unit by means of an on-line micro-GC, while naphthalene concentration was attained with the SPA method.The following findings were obtained: higher naphthalene conversion with increasing temperatures and better conversion at any temperature with lower concentrations. Tests at 850°C and 30 vol% H2O produced a conversion of 99.4% with 2.5 g/Nm3 while 98.5% with 7.8 g/Nm3. Experiments with higher steam content showed higher conversion values. Methane concentration was also affected thus indicating that reforming reactions took place as well. Low toluene concentration was detected as a product of the reactions while no benzene was identified.
A condensed succession at the Jurassic/Cretaceous transition in a shallowing basin on the eastern Russian Platform
Authors: Zorina Svetlana , Ruban Dmitry , Van Loon
Published: January 2010

The eastern periphery of the Russian Platform houses an exceptional record of the Jurassic/Cretaceous transition, which is represented by very thin sandstone beds. The presence of glaucony grains, phosphorite concretions and shark teeth indicates that the transitional sediments constitute a condensed succession, although the allochtonous origin of the glaucony grains in itself is not a reliable indicator. The combination with thin ammonite zones and a strongly diminished sedimentation rate, as low as ~0.05 cm/ka are, however, convincing evidence. The Jurassic/Cretaceous transitional deposits accumulated in a basin the depth of which decreased simultaneously with a global eustatic sea-level fall. This coincidence suggests that condensed successions may form in shallowing environments, which contradicts the sequence-stratigraphic concept. Considering the character of the sediments under study, it appears that both stratigraphic and taphonomic condensation patterns occur in this part of the eastern Russian Platform.
the shape and size of macromolecules of carboxymethyl starch in diluted solutions
Authors: Stojanovic Zeljko , Jeremic Katarina , Jovanovic Slobodan , Nierling Wolfgang , Lechner Dieter
Published: January 2010

Carboxymethyl starch samples were prepared by etherification in heterogeneous media. Three samples were prepared from corn starch and three samples from potato starch. Degree of substitution of prepared samples ranged from 0.40 to 1.10. The samples were investigated by static and dynamic light scattering and viscosity of diluted solution in 0.10 M NaCl as solvent at 25 ?C. The values of molar mass, MW, radius of gyration, Rg, hydrodynamic radius, Rh, and limited viscosity number, [?] were determined. It was found that the samples are similar to each other regardless of the type of starch and the degree of substitution. Fractal dimension, df, was equal to 2.380 (Rg - MW) and 2.406 (R? - MW), while parameter ??was 1.195. The values of fractal dimension and parameter ??are characteristic values for the behavior of branched clusters in thermodynamically good solvents.
The effect of benfothiamine in the therapy of diabetic polyneuropathy
Authors: Nikolic Ana , Kacar Aleksandra , Lavrnic Dragana , Basta Ivana , Apostolski Slobodan
Published: January 2010

Introduction. Diabetic polyneuropathy (DPN) is one of the most common diabetic complications, which can result in a significant functional impairment and reduction of the quality of life in affected individuals. It occurs due to alterations in different biochemical mechanisms which require the presence of thiamine, which is why this vitamin is used in the therapy of DPN. Due to the low bioavailability of the hydrosolubile forms of thiamine, its liposolubile preparations (benfotiamine) are preferentially used. Objective. The aim of this study was to determine the efficacy of benfotiamine in combination with vitamin B6 in the therapy of DPN. Methods. The study group comprised of 22 patients with DPN who were treated with the combination of benfotiamine and vitamin B6 during 45 days. The effect of the therapy was evaluated by the analysis of different clinical, laboratory and electrophysiological parameters before and after conducted treatment. Results. After the treatment period, a statistically highly significant reduction of pain (p<0.01) was noted with the reduction of pain score on visual analogue scale in 86.4% of patients. A significant reduction of subjective complaints was also noted, with decreased modified total symptom score in 95.5% of patients (p<0.01). The presence of alodynia was reported at the beginning of the study in 77.3%, and after the benfotiamine therapy only in 22.7% of patients, while hyperpathy was initially present in 90.9%, and after treatment in 31.8% of patients (p<0,01). Neurophysiological parameters of polyneuropathy also significantly improved, with the improvement of the compound muscle action potential amplitude in 68.2% (p<0.01) and motor conduction velocity of the peroneal nerve in 45.5% of patients (p<0.01). The improvement of the sensory nerve action potential amplitude (p<0.01) and sensory conduction velocity (p=0.05) of the sural nerve was found in 45.5% of patients. After the treatment period, there was a highly statistically significant lowering of the glycosylated haemoglobin (p<0.01), with improved findings in 63.6% of patients. After completed study treatment protocol 86.4% of patients rated their overall condition as improved. Conclusion. Our results showed that the conducted treatment resulted in significant subjective and objective improvement of the disease signs symptoms, which confirmed that benfotiamine was good starting choice for the treatment of diabetic polyneuropathy.
The use of beta-tricalcium phosphate and bovine bone matrix in the guided tissue regeneration treatment of deep infra-bony defects
Authors: Lukovic Natalija , Zelic Obrad , Cakic Sasa , Petrovic Vanja
Published: January 2010

Introduction. The primary goal of bone regeneration procedures with application of various regenerative biologic agents and biomaterials is to facilitate the formation of periodontal tissues lost as a result of periodontitis. Objective. The aim of the study was to compare clinical outcome of the guided tissue regeneration (GTR) treatment with the use of ?-tricalcium phosphate and with bovine bone matrix in human deep intra-osseous defects. Methods. Twenty-one systemically healthy subjects with moderate to advanced periodontitis, between 30 and 56 years of age, 11 females and 10 males, were selected. Patients having two similar inter-proximal defects with pocket probing depths following initial therapy greater than 5 mm were recruited for the study. Experimental sites were grafted with pure ?-tricalcium phosphate biomaterial (Cerasorb?) and a biomembrane, while control sites were treated with bovine-bone hydroxiapatite xenograft (Bio-oss?) and a biomembrane. Immediately before surgery and 12 months after surgery, pocket probing depth (PPD), epithelial attachment level (EAL) and gingival recession (GR) were evaluated. Results. In the experimental group PPD amounted to 6.76?0.83 mm before surgery, and decreased significantly to 2.67?0.48 mm 12 months following surgery, while in the control group PPD significantly decreased from 7.14?0.65 mm presurgically to 2.85?0.57 mm postsurgically. After one year, EAL gain was 2.76?0.99 mm in the experimental group, and 3.24?0.16 mm in the control group. After twelve months postoperatively GR amounted to 1.33?0.79 mm in the experimental group and to 1.05?0.80 mm in the control group. No statistically significant differences for PPD reduction, EAL gain and GR increase were detected between the groups. Conclusion. Results from the present study indicate that GTR treatment of deep intra-osseous defects with Bio-oss? and Cerasorb? resulted in clinically and statistically significant improvement of EAL gain and PPD reduction. A GR was slightly increased, with no statistical significance.
The role of occlusal factor in the etiology of temporomandibular dysfunction
Authors: Dodic Slobodan , Sinobad Vladimir , Obradovic-Djuricic Kosovka , Medic Vesna
Published: January 2010

Introduction. The influence of occlusal condition at the onset of temporomandibular disorders (TMD) has been strongly debated for many years and still is the source of controversy. Up to the eighties in the last century, the occlusal factors such as the presence of uncured malocclusions, discrepancies between intercuspal position and retruded contact position greater than two millimeters, retrusive and nonworking side interferences and loss of posterior teeth were considered to be the primary causes of TMD. Objective. The aim of this study was to estimate the role of occlusal factor in the etiology of craniomandibular dysfunction and therapeutic effects of irreversible occlusal therapy (occlusal equilibration) in patients with TMD. Methods. In the investigation we studied a group of 200 men and women. The average age of the selected patients was between18 and 25 years. The purpose of TMD signs and symptoms was confirmed in every patient using a special functional analysis and evaluating the craniomandibular index (CMI) according to Fricton and Schiffman. The value of craniomandibular index was determined in the group of 15 patients with signs and symptoms of temporomandibular dysfunction. In the study groups occlusal equilibration (selective grinding) was performed according to Okeson using the central position of the mandible as the referent position in the occlusal therapy. The value of CMI was determined before and 30 days after occlusal equilibration. Results. The results of this study confirmed the significant reduction in the signs and symptoms of TMD after occlusal equilibration. The statistical elaboration of the differences between the values of CMI I (before treatment) and CMI II (30 days after treatment) revealed highly significant differences. The CMI I values in the group ranged between 0.076 and 0.346 with the mean value of 0.188?0.082.The values of CMI II ranged between 0.038 and 0.19 with the mean value of 0.038?0.053. Conclusion. The study conformed the validity of irreversible occlusal therapy (selective grinding) in patients with TMD.
Frequency and relevance of concomitant diseases in elderly patients hospitalized for community acquired pneumonia
Authors: Djuric Mirna , Povazan Djordje , Secen Nevena , Perin Branislav
Published: January 2010

Introduction. Patients' age and concomitant diseases are relevant for the development and treatment outcome of pneumonia. Objective. To establish the frequency and relevance of concomitant diseases in patients over 65 years of age hospitalized for community acquired pneumonia. Methods. The research included 550 patients hospitalized at the Institute for Pulmonary Diseases of Vojvodina in Sremska Kamenica due to community acquired pneumonia. Data on concomitant diseases and mortality rate was correlated with the patients' age limit of 65 years, and then statistically analyzed and presented in tables. Results. There were 446 (81.45%) patients under and 102 (18.55%) over the age of 65 years. Dyspnea, impaired consciousness, cyanosis, tachycardia and arterial hypertension were significantly more common in patients over 65 years of age, who also had a higher prognostic score. Mortality was significantly higher (21.6% vs. 6.0%) in the patients aged over 65 years (p<0.001). Concomitant diseases were significantly more common (p<0.001) among the patients over 65 years (94.1%vs.69.2%), and the majority of the elderly patients had two or three comorbidities. The following comorbidities were significantly more common among the patients aged over 65 years: chronic obstructive disease, bronchiectasis, compensated and decompensated cardiomyopathy, cardiac arrhythmia, arterial hypertension and diabetes mellitus. The higher number of concomitant diseases was associated with a significantly elevated hospital mortality (p<0.001). A statistically significant mortality rate difference was found in both age groups regarding the comorbidity of chronic obstructive disease and decompensated cardiomyopathy. Conclusion. The patients aged over 65 years hospitalized due to community acquired pneumonia had a statistically significantly higher prognostic score, mortality rate and concomitant diseases than the patients below 65 yeas of age. Most subjects of the older group of patients had two or three comorbidities. Concomitant diseases resulted in a statistically significant hospital mortality elevation. When comborbitities involved chronic obstructive pulmonary disease and decompensated cardiomyopathy, a statistically significant mortality difference was registered in both age groups.
Uterine compression suture technique in the management of severe postpartum haemorrhage as an alternative to hysterectomy
Authors: Stanojevic Dusan , Stanojevic Marija , Zamurovic Milena , Cirovic Anka , Hajric Amira , Rakic Snezana , Srbinovic Pavle
Published: January 2010

Introduction. One of the most dramatic conditions in obstetrics is definitely bleeding from the uterus which fails to compress. This condition is known as postpartum atony. When such a condition is diagnosed, the obstetrician has a choice of several conservative methods to stimulate the uterus to contract and several surgical methods to stop the bleeding. The most extreme measure used to save the patient's life and stop the bleeding is hysterectomy. This surgery is characterized by high morbidity, primarily by the loss of woman's fertility. In order to avoid hysterectomy, several authors have introduced the compressive uterine suture technique into gynaecological practice. Objective. The aim of the paper is to demonstrate the technique of applying compressive uterine suture after delivery to stop excessive bleeding, and to present results obtained by this technique. Methods. The paper explains the technique of applying compressive suture to the atonic uterus in cases when all other procedures to stop excessive bleeding after delivery fail. Since uterine atony is the main reason for excessive and uncontrollable bleeding after childbirth, the need to perform such surgery is rather common. Authors demonstrate the technique of applying four compressive sutures which prevent uterus dilation and thus stop the bleeding. Results. Compressive suture technique was used by the authors eight times, seven of which during caesarean section and one after spontaneous delivery. All patients had normal postpartum period and normal involution of the uterus. Conclusion. Although this surgery requires a skilful and experienced obstetrician, the authors find it rather easy to perform and it is suggested to be applied in all cases of uterine atony when excessive bleeding cannot be stopped by other any other method except hysterectomy. This surgical procedure saves the uterus and facilitates quick and easy patient's recovery.
Implementing electronic medical record in family practice in Slovenia and other former Yugoslav Republics: Barriers and requirements
Authors: Kolsek Marko
Published: January 2010

The author describes problems related to the implementation of electronic medical record in family medicine in Slovenia since 1992 when first personal computers have been delivered to family physicians' practices. The situation of health care informatization and implementation of electronic medical record in primary health care in new countries, other former Yugoslav republics, is described. There are rather big differences among countries and even among some regions of one country, but in the last year the situation improved, especially in Montenegro, Serbia and Slovenia. The main problem that is still unsolved is software offered by several companies which do not offer many functions, are non-standardized or user friendly enough and is not adapted to doctors' needs. Some important questions on medical records are discussed, e.g. what is in fact a medical record, what is its purpose, who uses it, which record is a good one, what should contain and confidentiality issue. The author describes what makes electronic medical record better than paper-based one (above all it is of better quality, efficiency and care-safe, easier in data retrieval and does it offer the possibility of data exchange with other health care professionals) and what are the barriers to its wider implementation.
Clinical effects of fixed functional Herbst appliance in the treatment of class II/1 malocclusion
Authors: Nedeljkovic Nenad , Zivojinovic Vesna , Ivanovic Mirjana
Published: January 2010

Introduction. Sagittal mandible deficiency is the most common cause of skeletal Class II malocclusion. Treatment objective is to stimulate sagittal mandible growth. Fixed functional Herbst appliance use is beneficial for shortening the time required for treatment and does not depend on patient compliance. Case outline. A 13-year-old girl was referred to the Clinic of Orthodontics, School of Dentistry in Belgrade following previous unsuccessful treatment of her skeletal Class II malocclusion using an activator. The patient's poor cooperation had led to failure of the treatment. Patient was subjected to the Herbst treatment for 6 months followed by fixed appliance for another 8 months. Lateral cephalograms before and after the treatment was performed. The remodelation of condylar and fossal articulation was assessed by superimposition of pre- and post-treatment temporomandibular joint tomograms. The promotion of oral hygiene and fluoride use was performed because orthodontic treatment carries a high caries risk and risk for periodontal disease. Skeletal and dental changes were observed after treatment (correction [Max+Mand]: molar relation 7 mm, overjet 8 mm, skeletal relation 5 mm, molars 2 mm, incisors 3 mm). Combination of Herbst and fixed appliances was effective in the treatment of dental and skeletal irregularities for a short period of time. Conclusion . In the retention period, 14 months after treatment, occlusal stability exists. Follow-up care in oral prevention is based on regular recalls at the dental office and supervision at home by the parents.