bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Solids Concentration and Formation Characteristics on Formation Damage and Permeability Recovery
Authors: Ismail Abdul R. , Peden James M. , Arshad Azmi M. 
Published: December 2007

ABSTRACT
An experimental study has been made to investigate the effect of solids concentration and filter media on fluid loss and permeability recovery of cores. KC1- polymer muds of different barite concentrations and different types of core were used to perform the tests.
Filtration tests showed that fluid loss increased as solids concentration in the mud increased. Increasing the solids concentration in the mud appears to improve permeability recovery when the cores were backflushed. However, high spurt loss and poor permeability recovery were observed if muds containing polymer materials were used without the addition of solid particles.
Filtration and permeability restoration are not only affected by the size, shape and solids concentration in the mud but also to the pore size distribution and core characteristics. Detailed observation using scanning electron microscope was used to identify the solids impairment at the core face. Therefore, to reduce formation damage and improve recovery, suitable size, shape and concentration of solids in the mud must be properly selected.
Reservoir Saturation Determination in the Eromanga Basin Using Carbon/Oxygen Logging
Authors: Goode P. A. , Sibbit A. M. , Looi S. Y. 
Published: December 2007

Abstract
The Jurassic oil reservoirs of the Eromanga Basin in Central Australia can be characterised as having high permeability and strong aquifer influx. The problem of determining which zones in a well have been swept is difficult due to the very low salinity (&lt;2,000 ppm) of the formation water. Traditional methods of pulsed neutron capture are not suitable at such low salinity. Carbon/Oxygen (C/O) pulsed neutron logging tools which were introduced to address this particular problem were hampered by several short comings including large tool size, slow logging speeds and sensitivity to the borehole fluid. Recently a new generation of C/O tools have been in-troduced which permit faster logging speeds, less de-pendence on borehole fluids and can operate through tubing.
This papef presents several examples of the use of C/O logging in the Eromanga Basin and describes how the results have been used to identify potentially unswept oil pools for exploitation. A comparison with the older-generation tools is discussed and the advantages of the new tools highlighted. The results obtained from the C/O logging are verified with subsequent production data and standard logging suites run in offset wells.
The Effect of Temperature in Sweet Corrosion of Horizontal Multiphase Carbon Steel Pipelines
Authors: Vuppu A. K. , Jepson W. P. 
Published: December 2007

ABSTRACT
The effect of temperature on sweet corrosion in carbon steel pipelines at different liquid velocities under various oil-water concentrations was studied. Carbon steel coupons were used to study the corrosion products formed. With an increase of temperature up to 60 C, corrosion rate increases. Above 60 C, protective carbonate layers were observed. At lower temperature and pressures, the corrosion rates are similar to those predicted by de Waard and Milliams. With an increase in temperature, the corrosion rate increase is more pronounced at higher pressures and is greater than the de Waard and Milliams. No maximum in the corrosion rate is seen for oil water mixtures for temperatures up to 80 C.
Trials of a Gamma-Ray Multiphase Flow Meter on Oil Production Pipelines at Thevenard Island
Authors: Roach G. J. , Watt J. S. , Zastawny H. W. , Hartley P. E. , Ellis W. K. 
Published: December 2007

ABSTRACT
CSIRO has developed a gamma-ray multiphase flow meter (MFM) for the on-line determination of the flow rates of oil, water and gas in oil production pipelines. It is based on two gamma-ray transmission gauges mounted on a pipe carrying the foil flow of the multiphase fluid.
In trials, two of these MFMs were mounted on a test pipeline linking the test manifold to the test separator at the oil processing facilities on Thevenard Island. One MFM was always mounted on the vertical upflow section of the pipe. The other was in turn mounted on the vertical downflow section, and on two horizontal sections with different upstream conditions.
The MFM mounted on the vertical (upflow) pipeline determined the flow rates to 4.0% relative for liquids, 7.5% for oil, 4.5% for water and 7.9% for gas. Water cut was determined to 3.6% relative. The MFM mounted on the vertical downflow pipeline determined flow rates to 3.3% relative for liquids, 6.1% for oil, 4.5% for water, and 7.7% for gas. Water cut was determined to 3.7%.
Predicting the Quality and Performance of Oilfield Cements Using Artificial Neural Networks and FTIR Spectroscopy
Authors: Fletcher Philip , Coveney P. V. , Hughes T. L. , Methven C. M. 
Published: December 2007

ABSTRACT
Inherent batch to batch variability, ageing and contamination are thought to be major factors contributing to variability in cement slurry performance. Of particular concern are problems encountered when a slurry is formulated with one cement sample and used with a batch having different properties. This situation occurs regularly in operations. Such variability imposes a heavy burden on performance testing and is often a major factor in operational failure.
Methods are described herein which allow the identification, characterisation and prediction of cement variability for Class G, Class A and Class H cements. Specifically, the technique involves predicting cement compositions, particle size distributions and thickening time curves from the Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectrum of neat cement powders. Predictions are based on either linear statistical procedures or non-linear Artificial Neural Networks (ANNs).
For some simple slurry formulations thickening times can be predicted with uncertainties of less than ±10%. Composition and particle size distributions can be predicted with uncertainties a little greater than measurement error but general trends and differences between cements can be determined adequately.
The results establish the infrared spectrum of cements as a ‘signature’ of cement performance and composition since it yields subtle information on the nature and condition of the cement which is not given by API measurements.
A summary of the main features of this technique is as follows: Predicts the performance of some cement slurriesDetects the presence of major contaminantsPredicts cement composition and particle size distributionsIdentifies the nature and extent of cement ageingPredicts the effect of ageing on slurry performanceIdentifies and quantifies differences between cement samplesDifferentiates cement/silica blends from neat cementsDetects non-API cements
The potential benefits of the technique can be summarised as follows: Improves the assessment of cement quality or expected cement performanceHelps avoid operational failures due to batch to batch variation, ageing or contaminationEstablishes a basis on which to reject or accept cementsHelps to identify suitable local cements in new locationsImproves the efficiency of formulation design by identifying performance characteristics of cement
The objectives of the paper are (a) to review the factors controlling cement hydration and variability, and show that many of these properties are captured within the FTIR spectrum of cement and (b) to show that performance and composition can be predicted from spectra using suitable statistical techniques. Several cases studies are given to emphasise the use of the techniques.
In-Situ Wettability Determination: Field Data Analysis
Authors: Causin Emilio , Bona Nicola 
Published: December 2007

ABSTRACT
Rock wettability may explain some apparent discrepancies that occur in defining water-oil contacts by RFT and logging measurements. Analysing these discrepancies makes it possible to estimate the wettability state of the reservoir. This paper presents the studies carried out on three oil reservoirs in order to check the applicability of this method. The major limitations are identified. All results are confirmed by laboratory wettability tests.
The Markham Field, A Trans-Median Development
Authors: Sharples D. M. , Myres J. C. , Morgan C. L. , Kuzemko N. C. J. 
Published: December 2007

ABSTRACT
The Markham project is unremarkable by most current project benchmarks. It is not a marginal field and it is being developed with essentially conventional technology. It does however differ from most conventional developments in several key areas. It is the first field to be developed which straddles the UK/Netherlands median line and needed a treaty. A coordinated response from both the UK and Netherlands governments was therefore required to ensure that a treaty would be in place in time for production to commence on schedule.It is the first field involving the export of UK gas to continental Europe. It is also one of a very few fields in the UK or Netherlands to produce gas under various contracts.The reservoir quality varies in a general North West-South East direction across the UK/Netherlands median line. This led to concerns that distribution of recoverable reserves would be different to that of Gas-in-Place. This resulted in a variation on standard equity determination methodology.
Its geographic location is noteworthy in that it lies along the northern margin of the Rotliegendes sandstone fairway at some distance from any other known Rotliegendes field of a significant size.
Predicting Gas Saturation Buildup During Depressurisation of a North Sea Oil Reservoir
Authors: Scherpenisse Wim , Wit Krijn , Zweers A. E. , Shoei Gert , van Wolfswinkel Avend 
Published: December 2007

ABSTRACT
When a waterflooded oil reservoir is to be depressurised, it is important to predict the production of solution gas from the by-passed and trapped oil. To quantify the gas saturation build-up and the relation between gas mobility and gas saturation, We have carried out a large number of experiments on core samples. These pressure-depletion experiments, which were conducted at various depletion rates and with both model fluids and actual reservoir fluids, began from one of two starting conditions: reservoir rock at initial conditions (i.e. containing oil and connate water) or watered-out reservoir rock (i.e. containing brine and residual oil). Relating the experimental results to field conditions was a major concern for two reasons: The experimental results were sensitive to the depletion rate (and the field depletion rate is two orders of magnitude lower than what was possible in the laboratory).The experimental results were sensitive to the fluid/rock system used.
In this paper we discuss the interpretation of the experimental results and the approach we have adopted for extrapolating them to field conditions, so that the reservoir engineer can assess their practical consequences for field development. We found that when the experiments were run starting under initial reservoir conditions, the nucleation properties of the fluid/rock/pressure combination, together with the depletion rate, determine the gas saturation build-up. To extrapolate such laboratory results to the pressure-decline rate of the field, it is essential that the experiments be conducted with reservoir fluids at reservoir pressure and temperature. When the experiments were run under watered-out conditions, no such dependency on nucleation properties was found. Instead, the mobility of the gas could be correlated with the total hydrocarbon saturation, the same correlation applying to different fluid/rock/pressure combinations.
A Study of the Physical Mechanisms of Sanding and Application to Sand Production Prediction
Authors: Cook J. M. , Bradford I. D. R. , Plumb R. A. 
Published: December 2007

ABSTRACT
The complications involved in understanding and predicting sand production are discussed. The need to predict sanding potential on a foot-by-foot basis means that a simplifying approach is required, and this paper sets out experimental and initial modelling progress in this direction.
We have induced sand production in simple, reproducible and easily monitored systems, in order to be able to vary one parameter at a time and examine its effect. This has meant the use of synthetic rocks, moulded rather than perforated holes, and two simple geometries.
The effects of stress, flow rates, fluid viscosity and rock strength have been examined so far. For the high permeability rocks used in the experiments, the stresses in the rock produced by radial flow into the perforation tunnel have little influence on sanding; flow along the axis of the tunnel is found to be the controlling flow. This allows the sanding problem to be split into the prediction of damage around the tunnel induced by far-field stresses, and the transport of damaged material by axial flow.
Porosity as a Geomechanical Indicator: An Application of Core and Log Data and Rock Mechanics
Authors: Farquhar R. A. , Somerville J. M. , Smart B. G. D. 
Published: December 2007

Abstract
There is a growing awareness among petroleum engineers of the value of rock mechanics based analytical approaches to wellbore stability and sand production problems. It is readily accepted that the key to successful engineering lies in the acquisition of reliable data. Geomechanical properties testing is often perceived, however, as being expensive. All to often only limited numbers of samples are tested. This paper demonstrates how porosity can be employed as a geomechanical index to enable rock mechanics materials properties to be estimated using general and field specific correlations. Such an approach can be used to extend the application of a limited number of calibration samples.
General correlations exist between porosity and the uniaxial compressive strength and Young's modulus of sandstones and carbonates. Most of the work reported in the literature has concentrated on correlating porosity with absolute values of mechanical properties. Strength is, however, a stress sensitive property, increasing as confining stress increases. It is shown that porosity correlates with the constants required to construct theoretical and empirical failure criteria which describe such behaviour. Porosity also reflects other geomechanical characteristics of sedimentary rocks including failure mode, fracture intensity, drilling rate and perforation penetration.
The utility of porosity as a geomechanical index enables existing core and log data to be utilised to extend the use of limited core material.
Single-Well Wideband Borehole Seismics in the UNIWELL Configurations: An Approach to Monitoring Hydrocarbon Production
Authors: Peveraro R. C. A. , Leavy P. C. , Crampin Stuart 
Published: December 2007

Abstract
We present the technical basis for bridging the wide structure data-gap at the heart of the oil and gas production business: the scale of geological detail in the range between a few tens of centimetres to a few meters. This scale range is at least an order of magnitude smaller than is resolvable with current means. Many reservoir properties such as permeabilities are largely determined by the microscale behaviour of pore geometries and pore throats in the range down to millimetres or less.
The underlying unifying concept is that broadband vector seismic data contain a wealth of information regarding rock fabric and fluid content. Careful seismic field experiments, observation and data analysis can bridge the gap in the spatial knowledge of the reservoir between the very detailed, but laterally very limited information provided by borehole logging data and the spatially extensive but diffuse structural information provided by 3D seismic data. Measurements obtained in boreholes and aimed specifically at capturing certain elastic formation parameters are related through the geophysical model to reservoir parameters of direct engineering and economic interest in a series of "snapshots" of in situ distributions of fluids and rock masses, taken at opportune moments in the life of the reservoir and representing a substantial amount of reservoir volume in centimetre to metre detail.
Detailed Stochastic Modelling of a Proximal Fluvial Reservoir With Realizations Used in Flow Simulation
Authors: Svanes Tarald , Karstad P. I. , Myking Beate , Hovland Frank , Madsen Martin 
Published: December 2007

ABSTRACT
Fluvial heterogeneities have been modelled for the highly heterogeneous Ness Formation of a field in the North Sea, using a marked point stochastic process. This paper describes the geological modelling and the flow simulation work done. The uncertainty in the geological parameters is large and of vital importance to the production of the formation. Therefore stochastic modelling has been applied to evaluate different sedimentological hypothesis by varying the input model parameters. Via upscaling and flow simulation the effect on reservoir behaviour has been quantified and better understanding of the geological uncertainty obtained.
Stochastic modelling is a bridge between geologists and reservoir engineers. The reservoir models are easily changed in a geologically consistent way giving better history match. This integrated modelling project led to technical developments in the modelling tool in order to improve the results.
HAZOP Implementation on a Major North Sea Project, the Ninian Third Party Entrants Project
Authors: King S. D. J. , Killick R. C. , Bonner Michael , Gilbert T. J. 
Published: December 2007

ABSTRACT
The paper will provide an insight into the role of HAZOP in a complex North Sea project involving three significant new sub-sea developments - Lyell, Staffa and Strathspey - operated by third parties and tied back to two existing Ninian platforms, Central and Southern. Major platform modifications were required involving both new process systems and the revamping of existing facilities, all whilst maintaining existing production. This presented substantial technical, project and safety related challenges of a type not hitherto encountered by North Sea operators. An integral part of the project plan was the comprehensive use of HAZOP as a core activity in ensuring that corporate safety and project operability objectives were met. HAZOP was seen as an important element in Chevron's Ninian Safety Case as the primary tool for hazard identification. The successful application of HAZOP in this complex ‘brown field' development required a range of measures, some often overlooked and some involving innovative HAZOP methodology and these are detailed.
Conceptual Design for HP/HT Surface Development Wells
Authors: Bacarreza L. J. , van Melsen R. J. , Jantschy G. 
Published: December 2007

Abstract
This paper outlines the completion design for a High Pressure High Temperature (HP/HT) platform development well. It presents the design philosophy, a brief evaluation of the existing HP/HT well completion technology and suggests further equipment and materials development.
The objective is to present a simple and reliable preliminary well design, that will reduce costs and the need for well intervention.
Use of Well Test Analytical Solutions for Production Prediction
Authors: Bourgeois M. , Couillens P. 
Published: December 2007

ABSTRACT
Using well test analytical solutions for production prediction is rarely done, as this seems to be abstract and to require assumptions that are not very physical. But it presents a good alternative to numerical simulation, which is often expensive and cumbersome, and to decline-curve analysis, which has little theoretical justification in complicated cases.
This paper presents existing methods, and generalizes them to "n" wells in the reservoir. This allows the prediction of the flowrate produced for a given pressure drop history and a given global drainage area, but without a priori knowledge of the drainage area of each well. This is especially useful in reservoir monitoring.
This work shows how changes in the imposed pressure drop can be treated, which is straightforward, as it does not affect the reservoir response. But il also shows how non-linearities, i.e. changes in the well or reservoir themselves can be treated. To some extent, this technique allows modelling phenomena which are non linear, but still classic during the life of a well: fracturing, damage, or change in skin due to the appearance of multiphase flow.
This technique thus broadens the applicability of analytical production prediction.
Analysis of Interwell Tracer Flow Behaviour in Transient Two-phase Heterogeneous Reservoirs Using Mixed Finite Element Methods and the Random Walk Approach
Authors: Yi T. , Daltaban T. S. , Archer J. S. 
Published: December 2007

ABSTRACT
This paper presents a new numerical approach which models interwell tracer flow paths in transient two-phase flow in heterogeneous porous media. The approach adopted is sequential in that the velocity and pressure fields are solved simultaneously using a mixed finite element approach, the phase saturation is solved by mass balance, and then the tracer is transported and its concentration at the production well is predicted using a random walk model. Mass conservation has been achieved throughout all the numerical procedures.
Comparative studies between conventional finite difference methods and the methods presented in this paper show a significant reduction of numerical dispersion by the new method. Effects of physical dispersion, adsorption, two-phase flow and transient state on tracer flow behaviour are presented. Tracer test cases for a quarter five-spot pattern with homogeneous permeability and with assumed heterogeneities are analysed. A multi-well, irregularly shaped reservoir case has also been presented.
Drilling Shallow Horizontal Wells in Germany Using Short-Radius Technology
Authors: Schamp Jürgen , Rohde Uwe 
Published: December 2007

Abstract
In 1993 Mobil Erdgas Erdol GmbH drilled four short radius wells in Northern Germany. The wells were drilled in two reservoirs having complex geologies and faced technological challenges in a low budget.
Three wells were gas-storage wells in a depleted oil reservoir near the city of Hamburg. Two of these were designed for water production in order to increase the storage volume and one at the top of the structure was designed for producing and injecting gas.
Because of given surface locations, fixed targets and complex geology of this highly fractured reservoir, short radius drilling and horizontal lengths of more than 400 m were necessary to achieve the different goals of the wells. External casing packers (ECP) had to be used to ensure complete gas shut off after cementing the 7" liner. The short radius curve and the complete horizontal section was reamed for running stimulation tools later on. Geology required small targets, precise directional work with complex wellplans and correct placement of casing shoes and ECPs.
The fourth well was planned as a low budget oil production well in the shallow oilfield Voigtei. Cost reductions were achieved by using a specially equipped mining rig, a simple but adequate drillsite, cementation performed with a Mobil-owned pump truck and running of used and inspected casing. The biggest challenges were to drill 430 m of horizontal section at a vertical depth of only 270 m and to stay within the thin pay zone of the Lower Cretaceous Sandstone, which required a TVD limitation of 1 1.5 meters. To fulfill this objective a nearbit inclinometer as part of the MWD was used successfully.
The short radius curve was drilled in 8 3/8" hole diameter and cased with a 7" surface string. A specially designed pull down assembly hooked to the rig's top-drive was used to run the casing through the short radius to horizontal. Drag problems while drilling the horizontal section were overcome by additional WOB from the pull down. The horizontal section was logged with the tools connected to the drill string and cased with a 4 1/2" slotted liner.
The well could prove that shallow oil-wells can be drilled inexpensively by using existing - but for the oilfield untypical - technology.