bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling Gas Deliverability from a Group of Fields that Communicate Via an Aquifer
Authors: Tucker C. C. 
Published: March 2016

ABSTRACT
Several hydrocarbon reservoirs in the Triassic Showground Formation of Queensland's Bowen Basin share an aquifer of moderate strength. Field discovery pressures have indicated depletion levels of up to 330 psi [2.28 MPa] due to communication via the aquifer with neighbouring fields. Reliable estimates of original gas in place (OGIP) are not attainable by conventional material balance techniques. Modelling the fields as interconnected tanks, linked to a two stage aquifer system, enabled ten years of historical performance to be matched. The derived OGIP's and aquifer size/strength are consistent with the current geologic model.
A production forecasting model was developed which integrates the reservoir/aquifer system with well inflow, tubing pressure drop and surface facility constraints. The timing of wells watering out is critical to deliverability predictions and development planning. The model tracks the gas-water contact by performing reservoir sweep efficiency calculations according to depth versus volume curves. Wells are scheduled according to liquids yield priority to meet sales gas demand.
Various sales gas market alternatives have been successfully evaluated by the model. The modelling of the interconnected reservoir/aquifer system allowed the sensitivity to field withdrawal rates to be addressed. This capability was essential in establishing the optimal timing for field compression. Future plans for development wells and the timing of new field tie-ins have also resulted from model predictions.
Model for Predicting Wellbore Pressures in Cement Columns
Authors: Chenevert M. E. , Jin Liang 
Published: March 2016

Abstract
A model for calculating the time dependent wellbore pressure response of a hole filled with cement is presented. Variables include the time dependant characteristics of chemical shrinkage, filtration, and rheological properties.
Cement properties of chemical shrinkage and gelation were experimentally determined and used in model calculations.
Calculated results for neat cement agree quite well with field data. Model results also show that more rapid declines in wellbore pressures exist for cements with higher chemical shrinkage, filtration, or gelation.
Equations are derived and analytical techniques presented for the development and application of the model.
Also presented are model results for two cements which show that large differences in wellbore pressures can be obtained from cements with varying characteristics.
An Analysis of Predicted Wellbore Trajectory Using a Three-Dimensional Model of a Bottomhole Assembly With Bent Sub, Bent Housing, and Eccentric Contact Capabilities
Authors: Williams J. B. , Apostal M. C. , Haduch G. A. 
Published: March 2016

ABSTRACT
Bent subs and bent housing motors are one of the most important class of tools available to aid drilling engineers in deviation and directional control of wellbores. Even though such tools may spend very little actual time drilling a hole, the quality of their performance often determines the difference between success or failure of a well as far as execution of the trajectory plan (or design) of the well is concerned.
Despite the importance of bent subs and bent housing motors to the drilling community, the previous lack of available rigorous analytical models has assured that the design and selection of these tools remain confined to the realm of experience.
Recently, however, a sophisticated numerical algorithm has been developed by the authors which implements the Finite Element Method in modeling the nonlinear behavior of steerable bottomhole assemblies containing motors with multiple bends, bent subs, bent housing motors, steering tools, eccentric contact stabilizers, and wear pads (kick pads).
First, this paper provides a brief description of the steerable bottomhole assembly analysis software model. Second, this paper presents a variety of applications of the model in field drilling situations to demonstrate the model's ability to (i) accurately predict the actual response in these field cases, and to (ii) permit a drilling engineer to isolate the pertinent downhole structural mechanism operable during a given wellbore trajectory deflection scenario.
Gas Kick Experiments in Oil-Based Drilling Muds in a Full-Scale, Inclined Research Well
Authors: Rommetveit R. , Olsen T. L. 
Published: March 2016

ABSTRACT
Gas kicks in oil-based muds have been studied with experiments in an inclined research well.
A total of 24 different gas kick experiments were performed, and various parameters were varied. The instrumentation and data acquisition systems were complex, and nine surface and 10 downhole parameters were logged simultaneously.
The data presented reveal the dynamic development of kicks in OBM, helps understanding the kick process and give important implications for kick detection and well control. The data are analysed with relation to physical processes and drilling operations.
New Gas Logging System Improves Gas Shows Analysis and Interpretation
Authors: de Pazzis L. L. , Delahaye T. R. , Besson L. J. , Lombez J. P. 
Published: March 2016

ABSTRACT
A new gas logging system has been developed, field-tested and is now fully integrated in mud-logging units. In this system, the volume of mud put through degassing per time unit is a constant, whatever the actual drilling mud flowrate may be. Also, the greater amount of energy spent at the degasser increases extraction efficiency. Moreover, mud samples can be taken close to the bell nipple, without modifying the rig equipment, thus reducing surface gas losses. The gas show analysis is done through a double Flame Ionization Detector (FID) system, faster than most conventional systems. The sensitivity, even at low detection level, is remarkable.
Field tests have been performed in the Paris Basin, where the GOR of the oil produced is very low. When conventional gas analysis devices do not detect anything, the new gas logging system enables a clear reservoir identification with good correlations with wireline logs. Another main feature of the system, also demonstrated by field tests performed in the North sea, is its ability to determine the compositional ratios of the light end components of reservoir fluids. This was verified by correlations with analyses of the associated gas produced with oil.
The quality of the measurements performed by the new gas logging system will probably reinforce the reliability of mud-logging formation evaluation techniques.
Formation Evaluation While Drilling With a Dual Propagation Resistivity Tool
Authors: Fredericks P. D. , Hearn F. P. , Wisler M. M. 
Published: March 2016

Abstract
The Dual Propagation Resistivity (DPR*) tool provides two electromagnetic propagation resistivity measurements to improve formation evaluation in all types of muds. It transmits a 2 MHz signal into the formation and measures the phase difference and amplitude ratio between two closely spaced antennas. These measurements are converted into phase difference resistivity, Rpd, and amplitude ratio resistivity, Rar, and together with gamma ray they are transmitted to the surface for real-time decision making. They are also stored in downhole memory and can be sampled as fast as every 5 seconds producing a high density data log for petrophysical analysis. The sample rate can be adjusted on the rig for changes in the drilling rate of penetration.
The depth of investigation of Rar is deeper than Rpd but both are deep enough to eliminate most borehole effects. Beds as thin as the antenna spacing can be detected and the vertical resolutions are such that no corrections are needed in beds too thin for conventional induction tools. Two curves allow the effects of invasion and hydrocarbon to be distinguished, and log quality to be better controlled.
Log behavior is similar to a dual induction log in most lithologies but there are important differences. Normally, the DPR logs are made just after drilling when invasion is not deep enough to affect either Rar or Rpd. In this case they both will read true formation resistivity, Rt. In a hydrocarbon sand Rpd and Rar will both read high, though Rar will be less accurate than Rpd if Rt is over 20 ohm-meters. Ideally, Rpd and Rar should read the same in impermeable lithologies, regardless of resistivity. In high resistivity formations Rpd is more accurate than Rar and it is less affected by the dielectric constant of the formation.
Log quality is monitored in real-time by evaluating the separation of the two resistivities as a function of the lithology. In an impermeable, low resistivity formation the curves will read the same. If they do not, and the lithology does not change, then damage to one, or both, of the antennas is indicated. The DPR tool is calibrated for temperature and the antennas are hardened against the effects of hydrostatic pressure.
Calculation of MWD Electromagnetic Resistivity Tool Response by a Finite-Element Method
Authors: Brooks A. G. , Hall H. E. 
Published: March 2016

Abstract
A Finite Element Method (FEM) model of an electromagnetic resistivity tool has been developed. Verification of the model indicates agreement with both analytical and experimental methods, while noting the differences between the two approaches. FEM results for a new electromagnetic resistivity tool include correction charts as well as data on field distributions, pseudo-geometric factors, and bed response in the presence of a borehole (which can be difficult to obtain by other methods). Appendices present the theory of the analytical and FEM approaches.
Cyclic Steam Pilot in Gravity Drainage Reservoir
Authors: Chiou R. C. S. , Murer T. S. 
Published: March 2016

Abstract
This paper describes the performance of a cyclic steam pilot project in a steeply dipping (40 degrees) heavy oil reservoir in the Sho-Vel-Tum Field in southern Oklahoma. Steam injection was initiated in 1986 and there have been nine cyclic steam stimulations on four new wells to date.
The cyclic steam response shows a significant increase in oil production, as expected, relative to pre-stimulation production. The cyclic steam operation is quite unique because of its extremely high injection pressure (up to 1900 psi at the surface). In addition, incremental production from existing offset wells shows evidence of interwell communication of injected steam. Optimization of difficult field operating controls has a major impact on the cyclic steam performance in this reservoir. Techniques developed from the pilot experience may be extended to other areas where production is limited by problems inherent with high injection pressure, high downhole temperature, and excessive sand entry. Use of analytical and numerical models has provided insight in the salient aspect of cyclic steaming and aids in the evaluation of pilot performance.
Molecular Diffusion in Naturally Fractured Reservoirs: A Decisive Recovery Mechanism
Authors: da Silva F. V. , Belery P. 
Published: March 2016

ABSTRACT
The purpose of this paper is to demonstrate the importance of the Fick's molecular diffusion in fractured reservoirs and to present a numerical solution to predict the related mass transfer.
As opposed to porous media where molecular diffusion is generally small, in naturally fractured reservoirs, molecular diffusion may be very important, as the dispersive flux through fractures rapidly increases the contact area for diffusion. Fick's molecular diffusion potential may even override viscous forces when hydrocarbon or inert gases are injected and the fracture spacing is small.
The importance of Fick's diffusion is largely illustrated in the present paper showing results from analytical models applied to field cases.
A method to predict molecular diffusion is presented and has been implemented in a very recent dual porosity, fully implicit, fully compositional, EOS based reservoir simulator. One advantage of the proposed algorithm, which is an extension of the Sigmund correlation, when compared to others, is that it requires only the component critical properties and other parameters used in any equation of state.
Results from the above referred reservoir simulator are also presented to illustrate the effect of molecular diffusion while injecting separator gas or inert gas in a North Sea volatile oil reservoir.
Solutions for molecular diffusion of gas in fractured undersaturated oil reservoirs, using single porosity simulators, are also described in the paper.
Displacements, Saturations, and Porosity Profiles from Steady-State Permeability Measurements
Authors: Potter G. F. , Groves D. R. 
Published: March 2016

Abstract
Steady-state permeameters were extensively automated to decide when steady-state conditions are reached and when to change the fluid injection ratios for reduced operator demand and improve data quality. A communication system was installed to allow monitoring and control of the permeameter using computers at remote locations. The permeameters use a X-ray scanning system to determine the fluid saturations. Since data are collected at incremental points along the length of the test rock, the saturation measurement system was used to determine the shapes of displacement fronts. Examples are given of immiscible gas-brine and oil-brine displacement fronts. A method for determining porosity profiles from steady-state data is given. Several examples of porosity profiles for sandstone and carbonates are presented.
Foam Performance Under Reservoir Conditions
Authors: Suffridge F. E. , Raterman K. T. , Russell G. C. 
Published: March 2016

ABSTRACT
Foams that effectively reduce gas permeability were formed over a wide range of experimental conditions. The ability of selected foaming agents to form foam was evaluated in bulk foam measurements, screening core tests, and in reservoir condition core tests. Results reported show that oil usually adversely affected foam performance with higher molecular weight alkanes showing less of an adverse effect for the foaming agents tested. Foam can be effectively generated in an oil-wet porous medium but was shown to be much less effective than in a water-wet medium for the foaming agents studied. High pressure gradients of up to 4524 kPa/m (200 psi/ft) resulted in effective foam generation with an effective foam continuing to 8500 pore volumes of injected nitrogen. The enriched gas mixture used in this study was shown to adversely affect foam even though the foaming agent was selected through screening testing. This showed the importance of including reservoir condition testing prior to the final selection of a foaming agent for a given reservoir application. Effective foaming agents were identified for use in pilot tests in a typical West Texas CO2 flood and in a typical Canadian hydrocarbon miscible flood.
Tension Leg Platform Grout Logging
Authors: Carroll J. F. , Dupin R. M. , Leslie H. D. , Seligman K. , Briaud J. L. 
Published: March 2016

Abstract
Although the deepest conventional platform in the Gulf of Mexico is in 1760 ft of water, platforms are being designed for 3000 ft of water, wells have been drilled in 7500 ft of water, and leases have been purchased in 8500 ft of water.
The foundation systems for shallow-water platforms are predominately driven steel pipe piles. These piles are driven with underwater hammers when the water depth becomes deep. As water depth increases, the hammers become more expensive and less efficient. Technology already exists to drill holes in very deep waters, and the idea of using drilled and grouted piles for deep-water platforms has become very attractive.
Construction for a typical pile consists of drilling a large hole to about 350 ft, lowering a large-diameter steel pipe (24 in. or larger) to the bottom, and pumping grout from the bottom of the pile through a one-way valve into the pipe-hole annulus. This procedure is repeated in stages.
The use of drilled and grouted piles appears advantageous but it also poses some new problems. During the driving of a pile, measurements can be made from which an axial capacity can be inferred. This is not possible with a drilled and grouted pile. Attention must be focused on the quality of the grout job in order to ensure good bonding between the steel pile and the soil.
Integrity of the grout curtain and capacity of drilled and grouted piles were the two major topics of a research project. The integrity aspect was studied by installing a drilled and grouted pile with intentional defects and testing various oilwell logging tools to determine if they could detect the defects and be used as control during the stages of the grout process. To determine the capacity, drilled and grouted piles were installed and tension load tests to failure were performed on those piles. The integrity testing is reported in this paper.
Aperture number influences pollen survival in Arabidopsis mutants
Authors: Prieu Charlotte , Matamoro‐Vidal Alexis , Raquin Christian , Dobritsa Anna , Mercier Raphaël , Gouyon Pierre‐Henri , Albert Béatrice 
Published: March 2016

PREMISE OF THE STUDY:Pollen grains are subject to intense dehydration before dispersal. They rehydrate after landing on a stigma or when placed in humid environment by absorbing water from the stigma or surroundings. Resulting fluctuations in water content cause pollen grains to undergo significant changes in volume. Thus, morphological or structural adaptations might exist to help pollen adjust to sudden volume changes, though little is known about the correlation between pollen morphology and its ability to accommodate volume changes. We studied the effect of one morphological feature of pollen grains, the aperture number, on pollen wall resistance to water inflow in Arabidopsis thaliana.METHODS:We used three Arabidopsis thaliana mutants that differ in the number of apertures in their pollen (zero, four, or a mix of four to eight, respectively) and the wild type with pollen with three apertures. We tested pollen survival in solutions with various mannitol concentrations.KEY RESULTS:The number of intact pollen grains increased with increasing mannitol concentration for all pollen morphs tested. At a given mannitol concentration, however, an increase in aperture number was associated with an increase in pollen breakage.CONCLUSIONS:Aperture patterns, i.e., number, shape, and position, influence the capacity to accommodate volume variations in pollen grains. When subjected to water inflow, pollen grains with few apertures survive better than pollen with many apertures. Trade‐offs between survival and germination are likely to be involved in the evolution of pollen morphology.
Hydrogel control of water uptake by pectins during in vitro pollen hydration of Eucalyptus globulus
Authors: Vieira Ana Maria , Feijó José A. 
Published: March 2016

PREMISE OF THE STUDY:Upon pollination, dehydrated pollen grains take water out of the stigma surface, an event that constitutes the first functional checkpoint of sexual reproduction in higher plants. Little is known about possible functional connections between rehydration speed and further steps of fertilization. Here we addressed the mechanisms of water uptake control by dehydrated pollen grains. Because dehydrated cells have no energy‐driven active mechanism such as membrane‐based osmoregulation for controlling water movement, we tested the hypothesis that another mechanism might exist, namely, the use of hydrogel‐behaving molecules.METHODS:We developed an imaging protocol to visualize and quantify the rate of water entry into pollen grains of Eucalyptus globulus and tested the influence of different treatments linked to hydrogel‐behaving molecules. We complemented these analyses by immunostaining pectins in the pollen grain with monoclonal antibodies JIM5 and JIM7.KEY RESULTS:Water entry seemed to proceed exclusively through the germination apertures of the pollen grain, and the changes observed in different hydration media are compatible with hydrogel behavior. When JIM5 and JIM7 were used to characterize pectins on the germination apertures during hydration, pectin localization and esterification changed during hydration and were affected by the hydration solutions. These results suggest that chemical modification of the pectins may change their hydrogel behavior, thus modifying the hydration speed.CONCLUSIONS:The hydrogel behavior of pectins and pectin localization on apertures strongly suggest that pectins act like “valves” for water entry, enabling a regulated process of water uptake into the dehydrated pollen grain. We propose that this regulation evolved in terms of achieving the correct self‐organization of molecules and cellular components to resume metabolism and pollen tube growth, especially in species that are subject to demanding environmental water stress.
3-cm FINE STRUCTURE MASERS: A UNIQUE SIGNATURE OF SUPERMASSIVE BLACK HOLE FORMATION VIA DIRECT COLLAPSE IN THE EARLY UNIVERSE
Authors: Dijkstra Mark , Sethi Shiv , Loeb Abraham 
Published: March 2016

ABSTRACT
The direct collapse black hole (DCBH) scenario describes the isothermal collapse of a pristine gas cloud directly into a massive,

104–106

black hole. In this paper we show that large H i column densities of primordial gas at

K with low molecular abundance—which represent key aspects of the DCBH scenario—provide optimal conditions for the pumping of the 2p-level of atomic hydrogen by trapped Lyα photons. This Lyα pumping mechanism gives rise to an inverted level population of the

transition, and therefore also gives rise to stimulated fine structure emission at

(rest-frame). We show that simplified models of the DCBH scenario amplify the CMB by up to a factor of

, above which the maser saturates. Hyperfine splitting of the 3 cm transition gives rise to a characteristic broad (FWHM ∼ tens of MHz in the observers frame) asymmetric line profile. This signal subtends an angular scale of ∼1–10 mas, which translates to a flux of ∼0.3–3 μJy, which is detectable with ultra-deep surveys being planned with SKA1-MID. While challenging, as the signal is visible for a fraction of the collapse time of the cloud, the matching required physical conditions imply that a detection of the redshifted 3-cm emission line could provide direct evidence for the DCBH scenario.
LONG DURATION FLARE EMISSION: IMPULSIVE HEATING OR GRADUAL HEATING?
Authors: Qiu Jiong , Longcope Dana W. 
Published: March 2016

ABSTRACT
Flare emissions in X-ray and EUV wavelengths have previously been modeled as the plasma response to impulsive heating from magnetic reconnection. Some flares exhibit gradually evolving X-ray and EUV light curves, which are believed to result from superposition of an extended sequence of impulsive heating events occurring in different adjacent loops or even unresolved threads within each loop. In this paper, we apply this approach to a long duration two-ribbon flare SOL2011-09-13T22 observed by the Atmosphere Imaging Assembly (AIA). We find that to reconcile with observed signatures of flare emission in multiple EUV wavelengths, each thread should be heated in two phases, an intense impulsive heating followed by a gradual, low-rate heating tail that is attenuated over 20–30 minutes. Each AIA resolved single loop may be composed of several such threads. The two-phase heating scenario is supported by modeling with both a zero-dimensional and a 1D hydrodynamic code. We discuss viable physical mechanisms for the two-phase heating in a post-reconnection thread.