bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressure Transient Analyses for Unfavorable Mobility Ratio Flooding Operations
Authors: Beliveau Dennis , Chapman Thomas , Merrill Robert 
Published: April 2017

Abstract
Proper reservoir surveillance and management are critical for all oilfield operations, but especially so for secondary and tertiary recovery processes. In older waterfloods developed several decades ago, one might be fortunate to have a single pressure falloff (PFO) test recorded per injection well, with multiple PFOs for any single injector being a rare occurrence. However, an increased focus on reservoir management has driven a growing appreciation of the value of time-lapse pressure transient analyses (PTA) to monitor various aspects of reservoir performance. Time-lapse interpretations often show changes as operations mature, and the new data helps to guide and reduce uncertainties inherent in earlier interpretations, maximizing the value of the data gathering and surveillance program.
The reservoir management programs for viscous oil waterfloods in India’s Barmer Basin include timelapse injection profiles and PFOs as key elements to help monitor flood front progression. However, the multiphase flow of fluids of different viscosities poses an interesting challenge for conventional PTA. For waterfloods with favorable mobility ratio (M), PFOs may look like a classic radial composite model, with a lower-mobility near-injector region exhibiting water properties and a higher-mobility outer region with oil properties. However, things change quite dramatically for unfavorable (end-point) mobility ratios as in the Barmer Basin waterfloods, where 10&lt;M&lt;300 or more. With unfavorable mobility ratios, a surprisingly large volume of injected water (and time) is required for even the near-injector wellbore region to approach "residual" oil saturation, and there is significant multiphase flow throughout the reservoir for the entire waterflood life.
A PFO from an unfavorable mobility ratio flood is more complex, no longer resembling a radial composite model, but one with a smooth "transition zone" of varying fluid saturations and mobilities extending all the way from injector to producer. Accurate PTA must account for this saturation profile via the use of actual fluid viscosities and relative permeability (relative mobility) curves. Simple PTA assuming a single effective permeability and a single fluid viscosity (either water, oil or some "average" viscosity) will produce misleading results.
With unfavorable mobility ratios, numerical PTA is required to provide reasonable estimates of reservoir properties and information on flood front progression from an injection well. Similar issues apply to PTA for mature high-watercut production wells. At a minimum, numerical analyses should be used to provide an appropriate anchor for simple PTA which uses oil and/or water viscosities.
Integrating Pressure Transient and Rate Transient Analysis for EUR Estimation in Tight Gas Volcanic Reservoirs
Authors: Beohar A. , Verma S. K. , Sabharwal V. , Kumar R. , Shankar P. , Gupta A. K. 
Published: April 2017

Abstract
Raageshwari Deep Gas (RDG) is a clastic-volcanic reservoir located in the southern Barmer basin, India. RDG is a tight retrograde gas-condensate reservoir of permeability in the range of 0.01-1 md with a condensate gas ratio (CGR) of ~65 stb/mmscf. RDG is composed of a poorly sorted sandstone interval (Fatehgarh formation) overlying low net-to-gross (NTG) stacked succession of thick cycles of volcanic units (Basalt and Felsic) of ~700m gross thickness at a depth of 2800 m. RDG field is being developed using pad-drilled deviated wells, with multi-stage hydraulic fractures.
In tight gas fields, one of the major challenges is obtaining the right set of parameters to accurately forecast the estimated ultimate recovery (EUR) per well. EUR per well depends on fracture parameters such as fracture half-length (Xf), fracture height (Hf), fracture conductivity (Fc) and reservoir characteristics like matrix porosity (Φ), matrix permeability (k), net pay thickness (h), drainage area, reservoir pressure, reservoir fluid and operating conditions.
EUR may be estimated using decline curve analysis (DCA), rate transient analysis (RTA), and reservoir simulation. DCA is the simplest method but has high uncertainty early in a well’s production history, reservoir simulation is complex and requires detailed reservoir characterisation. RTA is easier compared to reservoir simulation and gives reasonable estimations of fracture and reservoir parameters. Since RTA is performance based it provides continuous evolution of high confidence EUR, even with limited production history.
To characterize tight fields, estimating kh of various layers through pressure transient analysis (PTA) requires long shut-in data. Thus PTA is generally only available for analysing early time effects (like fracture parameters). Thus, in low permeability reservoirs, RTA becomes preferred tool since it does not require shut-in data. RTA models and type curves generate non-unique solutions. Hence, integrating the petrophysical database with production logs, PTA results and RTA results is utilized to reduce uncertainty in k, h, Fc, and Xf. By utilizing all these data, the uncertainty in EUR estimation per well is reduced. These parameters are used as input for history matching to validate the interpretation and to optimize the RTA solutions. It was observed that history matches in RTA were improved when Fc and Xf from PTA were available. Flowing material balance (FMB) was then used to estimate drainage area, GIIP and EUR per well.
This paper demonstrates the workflow to use PTA, RTA, production logs, and petrophysical data to obtain the right set of parameters to get high confidence in EUR per well.
The finalized EUR per well for different well types can then be used for field development and deciding well spacing. Full field production forecasting based on RTA provides additional validation or an alternative to the estimates done through reservoir simulation.
Intervention and Abandonment Operations Utilising a Rigless Well Servicing Unit: Case Studies
Authors: Canny Steven A 
Published: April 2017

Abstract
With depressed oil markets and restrictions on project funding, and the sanctioning of developments, there is an acute focus on identifying areas where capital and operational expenditure can be reduced, maintaining capability and safety. One area of focus is on the conveyance method, namely the structure. With rig costs well construction and de-construction operations typically accounting for over 50% of the project cost base, it has been identified as an area where the introduction of new technology has the potential to significantly reduce overall project costs. The market adoption of alternative technologies, such as the "Rigless" approach is in its infancy in the Indian market, however regions such as the Gulf of Mexico and South East Asia have successful track record in the implementation of the technologies in completions, intervention and abandonment projects.
The paper describes alternative facilitating technology, focused on providing the required level of specification for the operations, with a reduction in the base cost of the technology, namely Rigless operations. The core technology is presented, with key facilitators. The application of the technology is presented in two case studies, each demonstrating the specific challenges of the operations and the novel solutions engineered to address these, and as such the significant potential benefits from a Rigless approach. The detailed and operational engineering presented in the case studies, and the identification of functionality requirements that can be improved to operate in technically challenging high cost projects, demonstrate the potential savings that can be achieved through the core technologies, and bespoke interfacing of them to client requirements.
Case study 1 presents a uniquely challenging abandonment campaign undertaken with a Supermajor in the Gulf of Mexico with a bespoke Rigless Unit. With the platform suffering hurricane damage and listing, bespoke technology was required to mobilize to the structure and safely isolate the hydrocarbon bearing reservoirs.
Case study 2 presents a large integrated well re-entry and abandonment campaign, with multiple partially abandoned and suspended wells. The integration of drilling equivalent circulating density techniques to the technology, present solutions that were devised to re-enter wells with annular communication and potentially underbalanced conditions. The flexibility of the Rigless Unit, and its ability to combine new technologies typically only available to integrate to drilling technologies, presents the value proposition of the Rigless Unit and approach.
Field Trial of Surfactant Stimulation in Low PI and Intermittently Flowing PCP Wells: A Successful Case Study of Bhagyam Field
Authors: Poptani R. V. , Mishra L. , Gupta A. K. , Saurav S. , Singh C. K. , Agrawal N. , Patel N. , Hammond P. 
Published: April 2017

Abstract
Bhagyam field is located in the prolific Northern Barmer Basin in Rajasthan, India. It has nearly 110 producers and some of these wells have limited pressure support and are geologically distinct from the rest of the field. These wells are flowed intermittently according to a pre-defined cycle based on flowing bottom-hole pressures to optimise their production. Various stimulations have been attempted to increase near wellbore productivity. However, these have largely been unsuccessful. A further restriction is posed by the completion of these wells on Progressive Cavity Pumps (PCPs) as the artificial lift method which inhibits the use of acids and aromatic compounds.
This paper illustrates the successful trial of surfactant stimulation in increasing the productivity of these wells. Surfactants were considered as an alternative technique for stimulation as they pose no harm to the PCP elastomers. In addition to this, they help alter the wettability in the mixed wet to oil wet reservoir of Bhagyam field. The stimulations were designed to get the maximum penetration and were bull-headed from surface. This paper also discusses the unsuccessful stimulations carried out prior to field trial of surfactant stimulations and the studies done in the field to understand the damage mechanism behind low productivity/productivity decline. More than 10 wells (both low PI wells and intermittently flowing wells) have been successfully stimulated with surfactants till date in the field and have helped substantially in sustaining the overall field production.
Seismically Constraining the Static and Dynamic Models of a Complex Fluvial System, Mangala Field, Rajasthan
Authors: Pahwa N. , Malkani A. , Sarkar S. , Singh R. 
Published: April 2017

Abstract
The Mangala field is located in the northern part of the onshore Barmer Basin in India. The Fatehgarh Formation is the primary reservoir, which was deposited during the rifting phase that created the Barmer Basin during the late Cretaceous to early Palaeocene period. The majority of reservoired oil is contained within the Upper FM1 member of the Fatehgarh Formation, composed of single storey and multi-storey stacked, meandering channel sands. These sands vary in thickness from 3 to 7 meters, with net-to-gross ranging from 18% to 78%. Well-based correlation of flood plain shales and fluvial sands in such a heterogeneous fluvial system poses a major challenge for reservoir characterization.
These thin fluvial channel sands are not resolved in the conventional seismic data, which makes it difficult to map the lateral continuity of these sand units. Sparse-layer Inversion was performed on the 3D stack PSTM data, which resulted in a dataset with improved detectability and resolution. Results were validated using well log and production data. Amplitudes of the high resolution seismic data provided information on sand continuity and connectivity. Consequently, Colored Inversion was performed on this data which provided improved understanding of the lateral distribution of the thin FM1 channel sands.
Effective Waterflood Management in Complex Carbonate Reservoir of Mumbai High Field
Authors: Ravi N. T. , Muraleedharan R. , Maurya C. R. , Ram B. , Muralidharan K. , Medhekar S. D. 
Published: April 2017

Abstract
The objective is to present an evaluation of waterflood management in a mature multi-layered carbonate reservoir using classical reservoir engineering techniques. The contrast in effectiveness of the waterflood performance is illustrated by incorporating case studies of two blocks in the field, characterized by high degree of heterogeneity with large scale vertical permeability variance. Simulation studies along with classical analysis to envisage the best way forward to improve the performance of waterflood are presented.
Successful implementation of waterflood necessitated enhancement of areal sweep and distribution of injection pattern using horizontal injectors. Studies indicate that an effective waterflood leads to additional oil recovery and improved reservoir pressure. Oil recovery envisaged before and after initiation of waterflood was established for Block-I& II. Pressure ratio (P currentto Pinitial) was plotted against recovery efficiency and compared with the standard drive mechanisms plot. Additionally, various diagnostic plots were incorporated to establish the effectiveness of waterflood. New opportunities were identified in pressure sink areas and their impact on performance of waterflood has been demonstrated using simulation.
The response to waterflood is favorable in Block-I with oil recovery more than 35%. Continuous Injection at controlled rates was possible and the created voidage was compensated appropriately. Enhancement of areal sweep employing horizontal water injectors resulted in better displacement which could be observed from sustained liquid production rates. The reservoir pressure in the area has noticeably improved resulting in reduction in Gas-Oil ratio. In addition, steep decline in oil production per string could be arrested with waterflood. Persistence of a pressure sink area in Block-I indicates the presence of a structural barrier. Block-II presents a contrasting scenario as early water breakthrough in producers resulted in poor sweep thereby adversely affecting the performance of waterflood. An analysis of Halls plot indicated that water injection at higher rates caused formation parting. Shutting of injection from highly permeable layers and controlling injection rate below threshold limit to avoid formation parting had a positive impact on producers in the area; hence profile modification of injectors could be a viable option. Moreover, for addressing the issue with isolated pressure sinks the effect of conversion of few wells into injectors has been studied. Commercially available software package has been used to simulate the field behavior after proposed injector conversion.
A Case Study on Production Enhancement Opportunity in an Existing Gas Processing Complex
Authors: Sukanandan J N , Sharmila G. , Das Barnali , Pawar A S , Singhal C P 
Published: April 2017

Abstract
One of the largest onshore process complex receives and processes sour gas, condensate and crude from the offshore fields. Due to ageing of existing fields and production from new fields with different reservoir fluid characteristic, the composition of gas varies considerably with respect to the composition at inception, especially with reference to C3+ components. Opportunities were explored for enhancement of recovery of heavier components for value addition from the available gas in the existing scenario.
Presently, irrespective of their richness, with reference to C3+ components, all the gas streams such as slug catchers gas (molecular weight around 20.65 to 21.02), off gases from stabilization units and condensate fractionation units (molecular weight around 25.11 to 27.12) are combined and are routed for gas processing with the resultant combined gas molecular weight of around 21.01.
To evaluate the effect of processing of only rich gas streams in an exclusive gas sweetening unit and then further processing at a LPG unit was conceptualized by means of an integrated simulation model developed in Aspen Hysys process simulator.
Simulation model was calibrated and matched with the existing field operating parameters. All the rich gas streams such as one of the rich trunk line gas (molecular weight around 21.02), off gases from stabilization (molecular weight around 25.11) and fractionation units (molecular weight around 27.12) were segregated and processed in an exclusive gas processing train. Study established that the envisaged resultant combined rich gas molecular weight will be around 22.01. An analysis of preferentially processing of rich gas in one of the LPG unit with reference to production of LPG & Naphtha was carried out. Study examined the adequacy check of existing equipments such as pressure vessel, pumps, columns, exchangers, pipelines and their control valves. Study reviewed the modification requirements and also indicated the optimum parameters such as temperature, pressure to be followed in various processing units for effective recovery of heavier components from the gas.
The study established that preferential processing of rich gas in one exclusive train of gas sweetening unit and then in turbo expander-propane based LPG extraction unit resulted in enhancement of around 17% increase in LPG production and around 2.6% increase in Naphtha production from the existing production level of the complex.
Presently no provision exists to preferentially process the rich gas stream. Study elaborates the ways and means to be adopted for preferential processing of rich gas in the complicated gas processing complex considering flow, pressure, and temperature parameters including safety & flexibility of the plant operations by simple modifications.
This case study highlights the hidden opportunities in an existing processing complex to enhance the product yield and to gain additional revenue generation.
Conjunctive effect of water productivity and cultivation pattern on agricultural water management
Authors: Mahsafar Hamid , Najarchi Mohsen , Najafizadeh Mohammad Mahdi , Hezaveh Mohammad Mirhoseini 
Published: April 2017

Abstract
Agricultural water resources are scarce in Iran, and agricultural water management is essential to overcome this limitation. Determination of the water productivity index (WP) using the methods of optimization of cropping patterns and optimal water allocation is the most effective tool in water management in the agricultural sector. In this study, a non-linear optimization model was used to calculate the maximum WP in the Qazvin plain irrigation network. The proposed model was applied to six different water supply scenarios including 100% and 90%, 80%, 70%, 60%, and 50% of full irrigation volume. The results showed that the scenario of 60% of full irrigation could increase the WP index by 8.5%, while with the implementation of this scenario, the net benefit from the sale of agricultural products was reduced to the amount of 247 × 109 Iranian Rials (IRR), which was 28% less than the existing conditions in the region. Therefore, the 60% water supply was selected as the economical and efficient scenario in the irrigation of Qazvin plain. It can be claimed that the most important index in agricultural water management is the WP index.
Czy Józef Zych pełnił obowiązki Prezydenta Rzeczypospolitej Polskiej w 1995 r.?
Authors: Kochanecki Adam 
Published: April 2017

Artykuł dotyczy instytucji pełnienia obowiązków prezydenta na wypadek opróżnienia się urzędu przed końcem kadencji. Rozpoczyna się od krótkiej prezentacji sytuacji, jaka miała miejsce w Polsce po tragicznej śmierci Prezydenta Lecha Kaczyńskiego, kiedy instytucja ta została wykorzystana aż trzy razy. Następnie autor dokonuje opisuhistorycznego tegoż rozwiązania ustrojowego w polskim konstytucjonalizmie, zaczynając od czasów II Rzeczypospolitej i kończąc na regulacjach obecnych w Polskiej Rzeczypospolitej Ludowej. Kolejna część traktuje o ewolucji wspomnianej instytucji w czasach III Rzeczypospolitej w jej wczesnych latach i obecnie. Autor przywołujenastępnie przypadek Józefa Zycha, który pełnił funkcję Marszałka Sejmu w 1995 r., i analizuje sytuację pod kątem przepisów ówcześnie obowiązującej Małej Konstytucji z 1992 r. W ostatniej części artykułu autor odpowiada na pytanie czy Józef Zych pełnił obowiązki Prezydenta RP w 1995 r.?
Persistence and Biodegradation of Quinalphos Using Soil Microbes
Authors: Dhanjal Noorpreet Inder Kaur , Kaur Paramjeet , Sud Dhiraj , Cameotra Swaranjit Singh 
Published: April 2017

ABSTRACT:The present study reports the degradation of the persistent and toxic organophosphate, quinalphos, by employing microorganisms that were already members of the natural soil community for degradation. Bacillus and Pseudomonas spp., both of which are capable of degrading quinalphos from aqueous streams, were isolated from different contaminated soils. Batch experiments were performed to determine the natural and induced biodegradation of quinalphos in the aqueous medium. The rate of degradation was analyzed through determination of residual concentration using UV‐Vis spectrophotometer and high‐performance liquid chromatography. A single peak of a metabolite was observed on the 160th day, and identified as dihydroxy quinalphos oxon by mass spectrometry. The presence of quinalphos and its metabolite in water over an extended period prompted the authors to investigate its induced biodegradation using indigenous microbes extracted from soil. For biodegradation studies, the isolated microbes were inoculated into minimal media with quinalphos for 17 days. The results revealed that >80% of quinalphos was degraded in 17 days in the presence of isolated microbes, and no metabolite was observed during the biodegradation process.
Study on the Application of Raman Spectroscopy on Detecting Water Hardness
Authors: Yang Chang‐Hu , Shi Xiang‐Hua , Yuan Jian‐Hui 
Published: April 2017

ABSTRACT:Laser Raman spectrum method was used to study the hardness index of four water samples. The ratio of bending vibration peak intensity to stretching vibration peak intensity of these water samples was measured. The results showed that as the total hardness of water decreases, so does the ratio. This offers a possible new approach to water quality analysis that is both simple and effective.