bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Thermal Finger Print in Accelerating Rate Calorimetry for Air-Injection Enhanced Oil Recovery Processes.
Authors: Bhattacharya S. , Mallory D. G. , Moore R. G. , Ursenbach M. G. , Mehta S. A. , Belgrave J. D. 
Published: November 2015

Abstract
The Accelerating Rate Calorimeter (ARC) is unique for its exceptional adiabacity, its sensitivity and its sample universality. Accelerating Rate Calorimetry is used as one of the screening tests employed to determine the suitability for Air-Injection enhanced oil recovery. These tests indicate oil reactivity and exothermicity over a broad range of temperatures: low temperature range, negative temperature gradient region and high temperature range. An experimental and simulation study was carried out to expand understanding and interpretation of the data derived from high pressure closed ARC tests.
Athabasca bitumen was used for the experimental study in a closed ARC at 13.8 MPag (2000 psig) to identify the temperature ranges over which the oil reacts with oxygen in the injected air. Experimental analysis for self-heat rate from accelerating rate calorimetry data and mass loss rates from differential thermo-gravimetric analysis shows the influence of mass transfer of oxygen within bitumen in the low and high temperature range. A numerical model was developed to predict the solubility, diffusivity and reactions of oxygen with bitumen. The model incorporates solubility of oxygen using partition/equilibrium coefficient (K-value) which transfers throughout oil layer by diffusion. This model considers both low and high temperature oxidation and thermal cracking reactions.
The results show by integrating mass transfer with the traditional kinetic model it is possible to predict the negative temperature gradient region which will therefore predict the onset in the exotherm of Self- Heat-Rate. The results also show that the swellability of bitumen due to solubility of air and product gases creates a concentration gradient of oxygen inside the bitumen. Viscosity and temperature dependence of the mass transfer of oxygen is linear, as time passes and chemical reaction becomes more important with increasing temperature, the relationship deviates from linearity. With an increase in temperature, the influence of chemical interaction on the oxygen distribution becomes greater, and this results in a shorter initial stage of mass transfer of oxygen within the bitumen film at low temperatures. This implicates that the ARC can be an effective tool for understanding the role of mass transfer on the oxidation characteristic for predicting low, negative temperature gradient and high temperature regions.
Innovative Concepts in Wire Line Focussed Sampling in Open Hole: Case Studies From an Oil Field Off the West Coast of India
Authors: Garg Vivek , Medhekar Sharad , Pratap Mahendra 
Published: November 2015

Abstract
The paper deals with focused sampling in two reservoirs of a carbonate field off the west coast of India. It was imperative to characterize the fluid through down hole optical spectroscopy prior to trapping the PVT samples. The fluid type in both the reservoirs was known. In one case gaseous phase was predominant for a long time even though the reservoir is oil bearing. The near well bore permeability was very low of the order of 1 md/cp due to drilling induced damage. Because of low permeability high draw down was applied resulting in low flow line pressure which was below the bubble point pressure of the reservoir and therefore the gas fraction was mainly being pulled into the flow line. The well was drilled with oil based mud and fluorescence channel was indicating high fluorescence. The possibility of the fluorescence due to oil based mud was ruled out after the flow line pressure was considerably reduced resulting in no fluorescence. This indicated that fluorescence seen earlier was due to liquid fraction along with gas, an effect similar to that seen with an atomizer. More over the fluorescence values were high which further strengthened the assumption that oil droplets were in the flowing media. With meticulous analysis of the down hole optical spectra from the fluid in the tool flow line and subsequent pressure adjustments oil started to flow after pumping for about six hours and oil PVT sample was trapped
The other case is related to trapping an uncontaminated gas sample. The sample purity was essential as the same was to be matched with leaking gas at the surface and thereafter to track down the gas reservoir that was contributing to the leakage. The reservoir from which this sample was being trapped is a depleted reservoir and no PVT sample was available for this reservoir. Sample studies for other gas reservoirs in the field were available. Due to pressure depletion there was considerable mud loss and after eleven hours of pumping and simultaneous analysis of the down hole optical spectra, the gas sample was trapped with contamination less than 9%
Petrophysical Rock Type Based Saturation Model To Reduce The Uncertainty In A Deepwater Low Resistivity Clastic Gas Reservoir.
Authors: Dhar Samir Kumar , Kumar Alok , Nandipati Viswanath , Bhattacharya Aumeya 
Published: November 2015

Abstract
Initial water saturation (Swi) in a gas reservoir is an important parameter for inplace resource (GIIP) and ultimate reserve estimation, which in turn impacts the economic decision. Swi estimation in a low resistivity deep-water clastic reservoir is more challenging because limited well data in less number of (costly) appraisal wells in a large area. Conventionally, Swi is computed from open hole logs and validated with core plug data to reduce the range of uncertainty in estimation. But this standard methodology fails when resistivity log derived Swi shows a variance with the saturation measured from the core plugs and increases the range of uncertainty. Sometimes, log derived Swi shows high water saturation in the gas bearing interval due to low anomalous resistivity which is beyond correction.
Saturation height modelling is an age old solution for this sort of problem and the same was attempted first to estimate Swi. But single saturation height function does not represent all the rock types of the reservoir and replicate log derived Swe curve. Petrophysical rock typing was carried out using porosity and permeability from the core plug in the first step and then by using the concept of flow zone index (FZI) and rock quality index (RQI). FZI-RQI based rock types were able to characterize the reservoir in a better way in 3D-Geologic model and also able to separate the different behaviours of Capillary pressure curves.
Two saturation height functions were made after characterizing good rock and poor rock type, which were tested in the dynamic model for flow simulation and recovery factor estimation successfully. This innovative concept of FZI-RQI based petrophysical rock typing (PRT) and saturation height modelling finally added value to recreate the Swi curve against the low resistivity pay interval and to reduce the range of uncertainty in Sw estimation.
Technology Challenges in Deep Water Subsea Well Intervention - A focus on Equipment Design Advancements
Authors: Suresh D. , Manikandan S. , Rajashree S. 
Published: November 2015

Abstract
Due to the current challenging environment in Oil and Gas industry, cost effective hydrocarbon recovery from Subsea Wells is mandating innovative methods in equipment design construction and qualification. Different types of intervention systems are required based on the issue being addressed, the intervention technique being used, depth of water, geographical locations, vessel types and pressure/temperature conditions. The industry is increasingly utilizing well access solutions such as Open water riser system and Light Well Intervention System not only for equipment installation, but also to improve efficiency of operations, to facilitate life-of-field hydrocarbon production enhancement and restorative intervention techniques. Suppliers and Operators of subsea intervention system need to rise to the challenge of meeting increasingly stringent industry standards and customer requirements. This necessitates but is not limited to the importance of utilizing effective seal design, robust barrier design, advanced materials and safety rated control systems with rigorous design and qualification test validation.
The more demanding requirements of the move to deeper and deeper water and higher pressures and temperatures have led to enormous challenges both at the component and system level. This is driving the incorporation of the latest technology on both metallic and non-metallic seals for high temperature application. This is particularly relevant in valve qualification for field producing hydrocarbons with high levels of sand. Size and weight reduction design strategies for equipment destined to be used in deep water allows for effective selection of existing rigs and vessels of opportunity. Advanced design validation including 3D printing of components has resulted in more accurate and predictable results for Component interactions, Strength Integrity and Fatigue Capacity. Thermal analysis used for prediction has allowed for prevention of hydrate formation which has proved essential to validation of the intervention system performance.
To qualify subsea components in deep water, technology enhancements, the latest manufacturing techniques and supply chain approaches, welding techniques etc. are critical to success. Deepwater System challenges include communicating and controlling the well and Xmas tree remotely through an Installation and Workover Control System. This can be resolved with design of optimized safety-rated electro-hydraulic system along with a robust sensor system which provides a safe and reliable method for hydrocarbon containment during critical well intervention operations.
This paper will depict some of the latest design techniques required to deliver advanced equipment to the Intervention market. The areas addressed will be: Identification of the technology challenges, providing right solution, usage of design tools for equipment design advancement and managing risk.
An Innovative Approach for Curing Severe Loss Control Problems in Mumbai Offshore while Drilling - A case study
Authors: Rastogi R. , Lal Kishori , Singhal R. , Sinha M. P. , Pratap K. Krishna 
Published: November 2015

Abstract
This paper relates severe lost circulation problems often encountered when the well is drilled overbalanced through high-permeability, fractured, or easily fractured formations. As numbers of LCM pills, neat cement plugs were placed in damaging and non-damaging reservoirs, resultant failed to provide an adequate solution.
Recently, severe mud loss problems were encountered during drilling in Mumbai Region from depleted reservoirs, unconsolidated, highly permeable, fractured and fragile limestone formations, both from nonproducing and producing reservoirs (L-III, L-II, L-I, H1A, H3B, etc.). The losses range from 100 BPH to total loss. Attempts are made to stop the losses with the placement of advanced lost circulation treatments. To mitigate these types of losses, an innovative technique developed with a temperature-activated Rapid Setting Fluid (RSF) Pill from indigenously available chemicals and used as an alternative to LCM / cement plugs for severe loss control problems in Mumbai Offshore. The RSF system has proven successful for curing severe dynamic and static losses by pumping treatments through the drill string bottom hole assembly (BHA) (no trip out required) and taking advantage of its highly controllable fast setting properties.
The RSF pill is a stoichiometric mixture of magnesium compound, forming hard and a series of high mol. wt. magnesium inorganic poly-hydrates, displaying characteristics of conventional cement slurry in pumpability, but very different chemically. As the RSF Pill enters the lost zone, it sets rapidly (a rapid transition from liquid to solid) and builds sufficient compressive strength within 5-6 hrs. The reaction causing solidification is wholly a function of time and temperature and unaffected by hydrostatic pressure. The pill is non-damaging as it is non-invasive, sets at the lost zone mouth and 90-100 % soluble in 15 % Hydrochloric acid. The pill can be successfully used up to 140 °C BHST.
The field trial has been carried out successfully in two wells of Mumbai Offshore: N_12#3Z (Mumbai High L-III reservoir) in partial loss conditions and HG#6H (Miocene Bandra Limestone formation) with total losses. It has also established that the new Loss Control Solution, RSF Pill can be placed successfully in all types of lost zones (like L-III, L-II, L-I, H1A, H3B) to mitigate the mud losses.
The paper also details the specific chemical and mechanical characteristics and field performance of the RSF pill. It concludes that the combination of unique fluid properties and best practices in fluid placement procedures plays a vital role in the successful implementation and development in the treatment of loss circulation in limestone formations. This technique is unique, easy, very effective and provides cost benefits.
Novel Approach for Evaluation of Simultaneous Water and Gas Injection Pilot Project in a Western Offshore Field, India
Authors: Agrawal G. , Verma V. , Gupta S. , Singh R. , Pandey A. , Kumar A. , Chadha H. K. , Agarwal A. K. , Chaudhary S. , Saxena R. 
Published: November 2015

Abstract
A field in western offshore India proved to be a major hydrocarbon-bearing structure, but wells in the field gradually declined in reservoir pressure and production when they were self-flowing. To improve recovery, water injection was performed, which almost doubled the field production. However, water cut eventually increased drastically, thereby reducing oil production. To curtail increasing water cut and improve oil recovery, a tertiary recovery method was sought.
After closely studying various recovery methods, simultaneous water and gas (SWAG) injection was proposed in which a predefined mixture of produced gas and water was injected to improve oil sweep and reduce residual oil saturation by oil swelling, ultimately increasing oil recovery. However, to practically observe field suitability and feasibility of the SWAG method, a pilot project that included four injectors and one producer was launched.
Efficiency of SWAG injection increases as a result of the consistent gas and water fine bubble flow regime developed in the wellbore, depending on casing size, tubing-shoe distance from perforation, and deviation. To evaluate this efficiency, production logging with optical probes to detect gas holdup was proposed in three injectors with different casing sizes and deviations. The existing wellbore flow regime from results of production logging were observed and compared with respect to favorable flow behavior to understand the effect of these factors on SWAG injection effectiveness. We found and suggested the deviation and casing-size configuration that was deemed optimal.
This was the first time production logging was used in India to evaluate the SWAG injection wellbore flow regime, and the method proved effective. The results are to be used for full-field SWAG injection implementation to improve overall field recovery.
Microseismic Monitoring Reveals Hydraulic Fracture Development in Clustered Horizontal Well Completed in High-Temperature Tight Gas Reservoir, Sultanate of Oman
Authors: Nadezhdin Sergey , El Gihani Mahmoud , Al Alqam Amin , Briner Andreas , Harrasi Othman , El-Taha Yasin , Batmaz Taner 
Published: November 2015

Abstract
Since 2012, Petroleum Development Oman (PDO) has attempted several hydraulic fracture monitoring (HFM) evaluations in deep, high-temperature, tight gas wells in the Amin Formation of the Fahud salt basin. The first successful job was executed in late 2014 for treatments placed in a horizontal wellbore. Following this job, in-depth HFM analyses were conducted that led to recommendations on well completion and fracturing treatment improvements. The purpose of the HFM trial in this challenging tight gas Amin reservoir of the Fahud salt basin was evaluating hydraulic fracture geometries, fracture propagation, and orientation. The horizontal well had been purposely drilled in the vicinity of an earlier completed vertical well to enable execution of the HFM job. Microseismic monitoring provided a direct measurement of the rock-failure coordinates and helped in gauging the effectiveness of the hydraulic fracture treatment placed in two clusters of the same fracturing stage. A large set of raw data representing 52,000 triggers was recorded and processed through different filtering methods including processing noise generated from gas flow in the monitoring well behind the casing. The evaluation suggested that the fractures have grown upward. It also revealed fracture length dimensions and stimulated reservoir volume along with the previously unmeasured fracture azimuthal orientation. The HFM job provided insight on how the hydraulic fractures propagate when two perforation clusters are placed in different stress zones, and if it is possible to place comparable hydraulic fractures in both. HFM results were coupled with geomechanics work and post-fracturing production logging to develop recommendations for future well completion improvements.
Arresting Decline in the Ravva Field: Success Story of Phase-5 Drilling Campaign
Authors: Sarkar S. , Kumar S. , Reddy K. , Shankar V. , Mishra U. S. , Sabharwal V. 
Published: November 2015

Abstract
Cairn India operated Ravva Field is located offshore Krishna-Godavari (KG) Basin on the east coast of India. The field was discovered in 1987 and was brought into production in 1993 from the Middle Miocene sandstones. Oil production rate reached its plateau of ~50,000 bopd by 1999. The field produced at the plateau rate for ~ 9 years before starting to decline by the end of 2007.
Two infill drilling campaigns were planned and executed in 2007 and 2011 to arrest the production decline and add incremental reserves to the field. New infill wells increased production for a short while but failed to arrest the prevailing declining trend. By the end of 2013, Ravva oil production dropped to ~21,000 bopd and was declining by 35–40% per year. Arresting the production decline by finding additional reserves in a mature waterflooded field which had already achieved ~49% oil recovery was a challenge with significant risks. Planning for additional infill drilling targeting areas of undrained oil required an integrated approach with adoption of advanced technologies to minimize risks.
A 4-D monitor seismic survey was acquired in 2010 over the Ravva field and co-processed with a vintage baseline survey to identify areas of undrained oil. Separate processing of the 2010 high density 3-D survey provided improved seismic imaging of the subsurface architecture. A high resolution 3-D model was created by using sequence stratigraphic concepts, fault seal analysis studies, detailed property modeling through integration of seismic attributes, log and core data. An integrated subsurface study was initiated in 2011 to identify infill well opportunities in the field. A full cycle of integrated reservoir modeling from seismic to simulation was carried out using advanced technologies and workflows.
The integrated study resulted in the identification of several infill opportunities as well as near field exploration and appraisal targets. The Ravva Phase-5 drilling campaign executed in 2014-15 comprising 8 infill, 1 water injector, and 2 exploration/appraisal wells was the most extensive infill campaign in the field's history. Well results from the drilling campaign have been very encouraging. The ten producers drilled in the campaign together added ~18,000 bopd to the field production and they are estimated to improve the field oil recovery by ~3%. By March 2015, when all new wells were brought online, Ravva field production had once again reached 28,000 bopd. The success in near field exploration and appraisal has extended the producing field boundary and has identified upsides that could support future drilling campaigns.
The Ravva Phase-5 drilling campaign has showcased the first successful application of a 4-D OBC seismic project in India. New technologies such as 4-D seismic combined with integrated subsurface reservoir modeling can demonstrably arrest production decline in comparable mature oil fields and drive recovery factors closer to the technical limit.
Effect of Sugar Content on Acetaldehyde Yield in Cigarette Smoke
Authors: Cahours X , Verron T , Purkis S 
Published: November 2015

Abstract
The relationship between cigarette blend sugar and acetaldehyde formed in its smoke is a matter of current regulatory interest. This paper provides a re-analysis of data from 83 European commercial cigarettes studied in the 1970s and more modern data on sugar levels and acetaldehyde yields from a series of 97 European commercial cigarettes containing both inherent sugar and in other cases inherent and added sugar. It also provides data from 65 experimental cigarette products made from single curing grades of tobacco, having a wide range of inherent sugar levels but no added sugar.
This study has shown that there is no relationship between acetaldehyde yields and blend sugar content even if a multivariate analysis is carried out taking into account Nicotine Free Dry Particulate Matter (NFDPM) as a co-factor. Such analyses should take into consideration each of the known contributory factors in order to avoid misleading conclusions.
No distinction was found between the mainstream acetaldehyde yields from dark air-cured, flue-cured or US blended style cigarettes irrespective of their sugar content after taking account of differences in NFDPM yields. Similarly, no distinction was found between mainstream acetaldehyde yields of cigarettes made from single grades of either flue-cured, sun-cured or air-cured tobaccos with no sugar added.
This work supports the conclusion that structural material in the tobacco plant is the main source of acetaldehyde in mainstream smoke after combustion during cigarette smoking.