bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Dipole Array Sonic Tool for Vertical and Deviated Wells
Authors: Tello Lucio N. , Blankinship Thomas J. , Roberts Edwin K. , Kuzmiski Rick D. 
Published: December 2007

Abstract
Dipole array sonic tools are particularly suited for estimating acoustic shear wave velocities in soft, unconsolidated, slow formations. Dipole sources induce flexural waves which are sustained in such formations. By contrast, monopole sources create pseudo-Rayleigh waves, related to shear wave velocity, which, in slow formations, refract away from the borehole and vanish before reaching the receivers.
One of the main challenges of dipole sonic logging has been to descend into deviated wells. Operating in deviated wells requires a tool body competent enough to withstand compressive forces. But for a dipole tool, a rigid tool body is impractical because it conveys a strong direct arrival that interferes with the flexural mode. Therefore, in most traditional dipole tools, the sonde body is replaced by an acoustic isolator made of steel cables, which suspends the receiver array from the transmitter array. While such designs eliminate nearly all body arrivals, they restrict the range of application to wells with little or no deviation.
A new tool design overcomes these problems, allowing comfortable logging of both dipole and monopole in deviated wells. The main feature of the design is a semi-rigid tool body, which consists of a series of interlocking steel rings configured in a special pattern and individually isolated by an elastomer. The dipole acoustic source has a broad frequency bandwidth extending down to the 600 Hz range, low enough to excite large boreholes and very slow formations. A comparison log in a vertical well between a cable-type isolator and the new semi-rigid isolator yields nearly identical data. Furthermore, a series of example logs run in deviated wells with the semi-rigid acoustic isolator validates this new approach for both the dipole and the monopole arrays. Random road noise, which is observed in deviated wells, is filtered using frequency and depth domain processing. Logging in free and bonded cased wells is also possible with this device. Comparison of travel time and porosity calculations in previously run open-hole logs with cased-hole dipole and monopole logs provided accurate results in both bonded and free casings.
Novel Approach to Optimization of Infill Drilling Using Conformance Mapping Technique
Authors: Beecroft W. J. , Shtern V. N. 
Published: December 2007

Abstract
Predicting, monitoring, and optimizing oil production from fields, having complex shape, require powerful and user-friendly software. This paper develops such software using conformal mapping and analytical functions. The approach includes (a) geometrical and (b) fluid mechanics parts. Part (a) approximates the horizontal projection of an oil field by a polygon and then transforms the polygon onto the upper half-plane. Part (b) models production and injection wells by point sinks and sources. The advantages of the approach are (i) separation of the geometrical and flow problems and (ii) analytical solution for the velocity field. These two features significantly accelerate modeling and allow optimization of well positions in a few minutes on a laptop computer as shown here for a real oil field. The software currently addresses two-dimensional (2D) domains and will be generalized for 3D domains.
Empirical Risk Assessment of Infill Drilling Locations, Barrow Island, Australia
Authors: Allard D. N. , Hillyer M. G. , Gerbacia W. E. , Rychener L. M. 
Published: December 2007

Abstract
The Barrow Island Field has been producing oil since 1967. Full development of the field with 40 acre inverted 9-spot injection patterns was completed by 1970. In order to increase production, infill drilling started in 1979. Infill drilling was carried out in a campaign manner, with a total of 182 infill wells drilled to date. The most recent infill drilling campaigns were Phases 1, 2 and 3 in 1995, 1996 and 1997 respectively. There are now approximately 450 active producing wells and 250 water injectors in the field.
Infill well location selection-methods were primarily empirical. These methods were modified as more information was learned from subsequent campaigns. The last three campaigns utilised an empirical algorithm based on the offset producer liquid-rate and water-cut. The algorithm was adjusted based on the results of Phases 1 and 2 such that by Phase 3 its statistical accuracy was within a few percent. Indicative economics based on forecast decline curves showed positive results.
There are still many viable infill locations in the field. A Phase 4 campaign has been evaluated with the same algorithm that was used in the successful Phase 1, 2, and 3 campaigns. In order to continually improve the accuracy of economic performance prediction, a probabilistic approach was used for this campaign. The results of the previous campaigns were used to define the uncertainties in each of the parameters. These uncertainties were then used in a decision analysis model to estimate an expected value and the financial uncertainty of the project. After incorporating risk, the planned Phase 4 program showed good economics.
The simple empirical methodology proved very effective in selecting infill locations, and the probabilistic approach effectively reduced the risk uncertainty. The evolution of this methodology is discussed and analyzed in this paper.
Conditioning of Lévy-Stable Fractal Reservoir Models to Seismic Data
Authors: Gunning J. , Paterson L. 
Published: December 2007

Abstract
We have developed methods of conditioning non-stationary Levy-stable geostatistical models1,2 to 3D seismic data. The technique involves adapting the sequential Levy simulation method such that the convolutional response of the realisations acceptably ‘matches’ the seismic amplitude map. A rejection scheme is used, which requires fast repetitive simulation of gridblock columns and generation of convolutional responses. The non-stationarity of the model means that this cannot be achieved using the conventional large kriging system. We use a different, but comparably rapid method, based on storing the relevant parts of a sequential simulation calculation for the column. Working directly with the amplitude traces also has the advantage of avoiding the ambiguities and non-uniqueness involved in inverting the traces to acoustic impedance.
The most difficult part of the problem is estimation of the seismic wavelet, and this is often done non-optimally. We describe a sophisticated method of estimating the wavelet, and show that this can yield better than expected results. Suitable rejection criteria are proposed, based on reasonable probabilistic models. The application of the technique is demonstrated with a field example.
Creation of the Fractional Flow Curve from Purely Production Data
Authors: Macary Sameh , Al Hamid Walid A. 
Published: December 2007

Abstract
The paper uses the X-plot technique for recovery prediction and for obtaining permeability ratio and the fractional-flow curves, which have great importance in the displacement efficiency calculations. This technique being applied only to reservoirs producing with water cuts higher than 50%, requires the linearization of the relationship between recovery and water cut. The straight line allows extrapolating to any desired water cuts to obtain the corresponding recovery. Before running linear regression production data have been treated by some filteration and considerations that comply the logic evolution of oil field exploitation. The slope and the intercept of this straight line are used to generate a plot of field relative permeability ratio, which forms the basis for creating the fractional flow curve. This approach was applied to two actual field cases: El-Morgan South Kareem and South Belayeem reservoirs. Both reservoirs are producing with water cuts higher than 50% since 1987. In addition to recovery prediction, the created permeability ratio and fractional-flow curves, unlike the laboratory derived ones, are composite curves that include not only the displacement characteristics of the fluids but also the reservoir geometry, heterogeneity and operational conditions of the field. Therefore, the created Frac-Flow curve could serve as a quality-check tool for lab measurements. Another important privilege is that the method is cost-free and completely relies on production data.
Application of Diamond-Enhanced Insert Bits in Underbalanced Drilling
Authors: Tetley N. P. , Hazzard V. , Neciri T. 
Published: December 2007

Abstract
Drilling underbalanced with foam fluids affects bit selection. Compound the use of foam drilling with a known abrasive, hard sandstone and proper bit selection becomes critical. This paper details the application of fully diamond-enhanced insert bits using foam fluid systems to the drilling of a depleted reservoir. It discusses the field trials, which have been carried out at the Rhourde el Baguel field of Algeria and the conclusions that have been reached. The paper also presents the outcome of investigations to further improve rate of penetration by offering a more aggressive point-loading to the rock through the application of shaped inserts instead of the semi-round, top inserts currently used.
Integrated Modelling of the Southern North Sea Carboniferous Barren Red Measures Using Production Data, Geochemistry, and Pedofacies Cyclicity
Authors: Stone Greg , Moscariello Andrea 
Published: December 2007

Abstract
Effective development of the Carboniferous Barren Red Measures in the Silverpit Basin of the U.K. Southern North Sea, is reliant on a robust correlation framework. This complex, low net:gross, fluvial reservoir is interpreted as being deposited as discrete, low sinuosity, braidplain channel bodies within a floodplain shale. Production history over the last 2 years indicates significant vertical and lateral variability of reservoir architecture, and drives the requirement for improved reservoir performance prediction. Biostratigraphic markers are sparse in the Barren Red Measures and previous attempts at defining reliable stratigraphic subdivisions were based on the identification of potential ‘flooding surfaces’ derived from the correlation of Gamma Ray (GR) peaks between wells.
Geochemical analysis has enabled the generation of a robust, 5-zone chemostratigraphic correlation framework. Each zone defined broadly equivalent packages of strata, recording changes in the basin wide hydrology of the depositional system, and as a result provided a reliable, stratigraphic subdivision. Through analysis of reservoir parameters, and production data, the regional palaeogeographic model was refined, and an improved understanding of the reservoir architecture controls on hydrocarbon flow were achieved.
Incorporation of detailed core analysis resulted in the interpretation of pedofacies in each stratigraphic unit. Sediment maturity was described in terms of the degree of bio/pedoturbation of the original sediment fabric and a link to aggradation rates and reservoir architecture proposed. The cyclic nature of the reservoir was analysed and direct links to the geochemical subdivisions identified. This supported the theory of basin wide hydrological changes fuelling the architectural variations in the reservoir. The integration of production data into the geological model provided support for the formulated theories on reservoir architecture.
Through this integration of geochemical correlation techniques, analysis of pedofacies, cyclicity and production data, it was possible to redefine the geological model and derive a robust framework on which to base both static and dynamic reservoir modeling. This in turn enables improved reservoir performance prediction.
Erskine Field: Early Operating Experience
Authors: Allen R. F. , Walters M. 
Published: December 2007

Abstract
Erskine is the first High Pressure, High Temperature (HPHT) field in production on the UK continental shelf. Modest reserves of rich gas condensate demanded innovative development concepts to achieve an economic project for field operator Texaco and co-venturer BPAmoco. A normally unattended wellhead platform is linked to a third party processing host platform by a multiphase pipeline. Since first production in December 1997 the three reservoirs have behaved broadly in line with expectations while the design concepts, technologies and operational practices have been thoroughly tested and proved to be conspicuously successful. The experience gained through design, commissioning and operation on this landmark development is recounted.
An Analysis of OSD's Well Incident Database; Results can Improve Well Design and Target Well Control Training.
Authors: Hinton Andy 
Published: December 2007

Abstract
This paper is an analysis of the well kicks recorded on the Wells IT database of the Offshore Safety Division (OSD) of the Health and Safety Executive (HSE). The purpose of the paper is to warn of failings that have led to kicks and suggest ways of avoiding these failings.
Kick frequencies have been calculated using the numbers of wells drilled and the numbers of kicks reported. The analysis indicates that kicks are taken in 11% of all wells drilled on the United Kingdom Continental Shelf (UKCS). This frequency has not decreased over the last eleven years. The frequencies are higher in wells drilling the Zechstein (13%) and for High Pressure High Temperature (HPHT) wells (22%). About 11% of the total kicks can be considered serious (That is out of 100 wells drilled in the UKCS 11 will have kicks of which 1 will be serious). Half the kicks take place during drilling operations with the others spread amongst cased hole, tripping and casing operations.
The appendix describes case histories of kicks which illustrate important lessons to be learnt. For well designers:-
♦ anticipation of raised pressures in the reservoir from water injection; ♦ assuming the worst when drilling the Zechstein; ♦ make every effort to ensure the integrity of casing shoes and liner laps before displacing to a lower mud weight.
For well control training:-
▪ emphasising the importance of monitoring pit volume during non-standard operations; ▪ ensuring the driller has authority and confidence to shut the well in if there is any doubt; ▪ the importance of a clear chain of command for kick control operations; ▪ the Offshore Installation Manager (OIM) should not be too closely involved in technical aspects of killing the kick but should concentrate on the overall safety of the installation.
Kick simulators can be useful both in training personnel and planning wells.
Kick Simulation for Well Design and Kick Management on the U.K. Continental Shelf: Current Industry Practice and Challenges for the Future
Authors: Spencer R. , Tatsis A. , Glass A. W. 
Published: December 2007

Abstract
HSE research spanning a period of nearly 10 years has resulted in approximately one hundred projects in the ‘Well engineering and operations’ topic area. About half of these projects have addressed kick development and control. A computer-based model developed for practitioners, has been thoroughly tested and applied to numerous incidents.
Having reached the position where a tool is now commercially available and is used extensively by practitioners, an evaluation of current Industry practice in the area of kick simulation for well design and kick management on the UKCS has been undertaken. The study also addresses the future direction of work in this area.
An Industry wide sample including operating companies, drilling contractors, training providers and relevant associations has been surveyed, augmented with a substantial sample of well engineering professionals.
Broadly, the results of the study suggest that the HSE's work on kick control has made a significant contribution to well design and kick management. The industry indicates that they feel more confident in their ability to predict kick pressures and manage kick incidents as a result of the use of kick simulator software.
Industry views on the needs for future work in the area of kick pressure prediction; kick detection and kick control have been received and form the basis for recommendations arising from the study.
Enhancing Activity Levels in the UK Continental Shelf in a Low Price Environment
Authors: Kemp Alexander G , Stephen Linda 
Published: December 2007

Abstract
This paper examines the longer-term prospects for activity levels in the UKCS under low oil prices with the employment of a financial model incorporating the use of the Monte Carlo technique. On current trends, from the early years of next century production could fall at a substantial pace even when discoveries from exploration are included in the analysis. Compared to recent years new investment would fall to much lower levels under the $14 price case and collapse under the $10 one. If major reductions in unit costs, such as those in the CRINE Network targets were achieved, the decline rates of production could be greatly modified. The CRINE targets are extremely ambitious and their achievement requires the widespread use of new technologies. This requires funding and contracts which encourage innovation and risk-taking.
Managing Seismic Positioning Uncertainty in HPHT Developments
Authors: Neuhaus Dietmar , Browning Greg , Estensen Odin 
Published: December 2007

Abstract
The accurate quantification and management of seismic positioning uncertainties have been paramount in securing the drilling operations and maximizing well life in two recent High Pressure/High Temperature (HPHT) developments in the UK Central North Sea.
In these HPHT fields, all development wells need to be drilled before onset of production, as drilling into depleted reservoirs is considered as high risk. Identifying the optimal development well locations that balance the needs for a safe drilling margin (downdip) vs maximizing well life (updip) is complicated by the presence of large seismic positioning uncertainties.
Very close cooperation and mutual understanding between the well engineer and the seismologist/geologist is required to develop the optimal drilling strategy. The first well was placed in an intermediate location from which recovery would have been feasible had the worst possible raybending effects materialized. While drilling, a predictive Vertical Seismic Profile (VSP) was acquired above the reservoir to check the relative position of the well and the presence/thickness of the Cromer Knoll, the seat for the production casing. Based on the first wells, a 3D Pre Stack Depth Migration finally resolved the positioning uncertainties. Risky and costly contingency operations have been avoided.
Monitoring Contact Movement during Depressurization of the Brent Field
Authors: Quint Edwin 
Published: December 2007

Abstract
The Brent field is embarking on the largest offshore oilfield depressurization project ever attempted. To allow cost-effective management of this process an extensive surveillance program is being executed; gathering formation fluid type as well as reservoir pressure data. Pressure data acquisition is well established, but for formation fluid type existing technology is pushed to its limits.
Cased-hole formation fluid interpretation has always been difficult in Brent because of the low formation water salinity combined with seawater injection. Now with oil rims moving to the crest into the original gascap and depressurization changing the properties of the gas and light oil, it has become a real challenge.
Initially Brent has used time-lapse capture sigma measurements1,2 to monitor the oil being swept by injection water. This was significantly improved upon, when the inelastic Carbon/Oxygen measurements3,4 were introduced, but the most reliable results were still obtained from simple open-hole logging data.
After the introduction of the monobore completions in Brent wells5, surveillance does not have to be restricted to slim (1 11/16") surveillance tools anymore since tool restrictions are removed in the monobore design. As a result, the larger (3 5/8") neutron and density open-hole tools can be employed in casing.
Calibrated cased-hole Neutron/Density surveys together with the original open-hole data have proven to be very successful in identifying the current formation fluids. They have also proven to be more robust against reservoir pressure decline and borehole content than Carbon/Oxygen methods.
Risk Decision Making in the Offshore Business
Authors: Tope I 
Published: December 2007

Abstract
Risk Management approaches are evolving in different industry sectors, and for different hazard groups. There is an increasing expectation for involvement and openness, with less trust in "expert" judgements. Also generally there is an ongoing change from prescriptive regulations to goal setting and the UK offshore industry is probably in the forefront of implementing a goal setting regulatory approach. This has increased in the demand for greater transparency on how the offshore industry in the UK makes decisions when managing major accident hazards. To meet this challenge, the UK Offshore Operators Association (UKOOA) commissioned the development of a framework to support such decision making.1 The framework focuses on major accidents, but its approach, and the ideas it embodies, are believed suitable for decision making involving environmental hazards.
Novel Hydrophobically Modified Natural Polymers for Non-Damaging Fluids
Authors: Audibert-Hayet Annie , Rousseau Lionel , McGregor William M. , Nicora Luigi F. 
Published: December 2007

Abstract
When drilling in the production zone the control of fluid-loss must be obtained without damaging the formation. The use of non damaging fluids is of great importance for:
the production zone of new wells, re-entry when drilling through damaged well bores, extended wells where large areas need to be protected, reaming to expose new production surfaces.
Formulations of non-damaging fluids are of growing importance especially because of the increasing number of horizontal wells being drilled. In horizontal wells, the drilling fluid is in contact with the reservoir formation for a long period of time and there are generally long, exposed zones of production which are difficult to clean up. Horizontal wells are often completed open hole without perforated casing, with therefore increased susceptibility to formation damage and reduced production.
A novel polymeric additive derived from a natural polymer which has been modified to optimise its performance is proposed. This optimisation is achieved by introducing hydrophobic attachment to the polymer backbone. This increased hydrophobicity improves dramatically the fluid loss control without increasing viscosities, in particular through the formation of a thin and impermeable filter cake which protects the production zone from fluid invasion. This thin filter cake is easily removed at low production pressures and allows excellent productivity. In simulated well conditions, such as long core formation damage test, an extremely low formation damage was shown with high return permeability values.
This new polymeric additive is especially advised for use in the preparation of drill-in fluids, in fresh water or brine, in combination with biopolymer and calcium carbonate.