bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvements to Reservoir Material Balance Methods
Authors: Pletcher J. L. 
Published: December 2007

Abstract
Experience with a number of material balance data sets from the field and from simulation has revealed some procedures that can be used to improve analysis of both oil and gas reservoirs: Failure to account for a weak water drive can result in material balance errors that are not insignificant.The assertion of previous authors that a weak water drive exhibits a negative slope on the Cole Plot (gas) and Campbell Plot (oil) has been confirmed. A weak water drive is detected on these plots much more unambiguously than on other common plots such as the p/z plot for gas.A Modified version of the Cole Plot is proposed to account for formation compressibility.The reservoir drive indices are a useful tool for determining the correctness of the material balance solution because they must sum to 1.0. The drive indices should never be normalized to sum to 1.0 because this obscures their usefulness and leads to a false sense of security.A modified version of the Roach Plot (for gas) is proposed that improves interpretation in some water drive situations.Material balance has not been replaced by reservoir simulation, rather it is complementary to simulation and can provide valuable insights to reservoir performance that cannot be obtained by simulation.
Worldwide Crude Oil Production Capacity, Supply, and Demand: What is Your Baseline?
Authors: Jentsch W. A. , Merryman A. A. , Littell G. S. , Groppe H. 
Published: December 2007

Abstract
Reasonably accurate information of worldwide crude oil production capacity, supply and demand (CSD) is crucial to management and investment decisions in the energy industry in particular and the economy in the aggregate. As the industry relies on consistently flawed reporting processes, the industry encounters dynamics outside those normally experienced in a commodity industry.
The International Energy Agency (IEA) is the primary source of the public data. The IEA was created in 1974 as the response to the 1973 Arab oil embargo of 16 member countries of the Organization for Economic Cooperation and Development (OECD). This paper will help the reader to understand the IEA's organization and some of the inaccuracies inherent in the reporting processes. This understanding should assist those using the data to develop better forecasts and should be of interest to those seeking to improve the reporting process.
Coupled with this investigation will be a brief glance at the historical worldwide crude oil supply, capacity and demand and the corresponding price trends. The reader will gain a tool for enhancing their strategic planning in addition to increasing the accuracy of price forecasts by seeing the relationships between recent price trends and the IEA reports of capacity, supply and demand,
Relative Permeability Measurements for Post-Waterflood Depressurisation of the Miller Field, North Sea
Authors: Naylor Peter , Fishlock Terrence , Mogford David , Smith Robert 
Published: December 2007

Abstract
This paper describes a determination of critical gas saturations and relative permeabilities relevant to the depressurisation of the Miller field. A series of reservoir condition coreflood experiments and associated numerical simulations is described. Three experiments were conducted with aged Miller core and fluids at 120°C and each comprised of a waterflood at about 414 barg, followed by depressurisation at different rates. The laboratory data included extensive three-phase in-situ saturation measurements which were used to derive gas relative permeabilities through the simulations.
The rate dependent critical gas saturations varied between 0.06 and 0.21 and gas relative permeabilities of the order of 0.0001 were deduced. These laboratory results are consistent with published data and demonstrate that conventional Corey-type gas relative permeabilities are an order of magnitude too large and do not represent the depressurisation process.
This paper is believed to be the first publication of: A reservoir condition study of the depressurisation of aged, waterflooded cores.Extensive, reservoir condition, three-phase in-situ saturation measurements which enable critical gas saturations and gas relative permeabilities to be determined.A slow depressurisation experiment with a duration of 141 days.
Mobilisation of gas in Miller has been found to have a significant impact on oil production profiles and project economics, and the data from this study can be used to reduce the risk associated with depressurisation.
Directional Surveying: Rotating and Sliding Operations Give Different Wellbore Position Accuracy
Authors: Torkildsen Torgeir , Bang Jon 
Published: December 2007

Abstract
We present a novel method for analysing the position uncertainty of directional surveys. By this method, the uncertainty can be accurately calculated by conceptually simple analytical formulae. The theory covers any correlation in measurement error and any correlation in toolface, for both stationary and continuous surveys.
The results demonstrate the importance of handling the toolface dependence properly. A direct benefit is that too optimistic or overly pessimistic accuracy estimates are avoided. Furthermore, the difference between rotating and sliding operation is significant for many error terms. For example, a misalignment error typically causes 10 times higher position uncertainty in sliding mode than in rotating mode, for a 3000 m long survey.
These findings should have implications for the future specification of survey instrument operation procedures, and thus the design of directional survey programs.
Asia Pacific Colloquium on Petroleum Engineering Education 1999
Authors: Pinczewski W. V. , Akbar Tajudin Abdul Wahab Tuan Hj. 
Published: December 2007

Abstract
This paper provides a summary of the discussions and major outcomes of the 1999 SPE Asia Pacific Colloquium on Petroleum Engineering Education (17–20 October 1999 in Langkawi, Malaysia). The colloquium attracted a total of 49 delegates from 13 countries and was held in the context of continuing rationalization and downsizing in industry and a general economic downturn in Asia.
The colloquium proved to be a valuable forum for constructive Industry – University dialogue. A wide range of issues was discussed, some generic and some specific to the Asia Pacific region. There was clear recognition that PE courses will need change to become more responsive to changing industry needs and conditions.
Predicting Connected Hydrocarbon Volume Uncertainty Ranges: From Static Fault Model to Dynamic Simulator
Authors: Ainsworth R. B. , Stephenson P. M. , Johnson D. A. , Seggie R. J. 
Published: December 2007

Abstract
In this paper we present two methods for calculating uncertainty ranges for connected hydrocarbon volumes as applied to the Sunrise gas-condensate field, Timor Sea. A "quick look" approach which uses a simplified, exploration scale fault data set.A more detailed fault interpretation which is integrated with 3-D geological and dynamic reservoir modelling techniques.
Despite the differences in sophistication, the two methodologies generate similar results in terms of absolute connected hydrocarbon volume ranges.
In both studies the fractal relationships between the fault throws, lengths and frequency of occurrence were used to determine the minimum throw of faults fully interpreted on the seismic. This structural interpretation was then augmented by the probabilistic infill of sub-seismic faults with throws greater than the critical juxtaposition-sealing throw of 20 m. The resulting maps were then used to estimate a range of potentially connected gas volumes.
The large number of across fault sand-sand juxtapositions within the areally extensive field suggests that as a most likely case the reservoir is 100% connected due to effective communication across faults or around fault tips. Sensitivities were analysed around this most likely case. As a worst case scenario all faults were assumed to be totally sealing due to the potential effects of shale gouge or cataclasis. The quick look study, which took no account of any sedimentological connectivity issues, predicted a worst case connectivity of 77% whilst the detailed 3-D dynamic simulator study predicted a connectivity of 72%.
Although the areal distribution of connected hydrocarbons was different for the two approaches, the similarity of the final connected volume figures suggests that the quick look methodology provides a useful technique for the rapid estimation of connected hydrocarbon volume ranges in fields with limited data content and perceived simple sandbody architectures.
Well Planning Under Uncertainty: Application of a Systematic Procedure for Risk Assessment and Uncertainty Analysis for New Well Targets on the Brage Field
Authors: Hersvik Karl J. , Aanonsen Sigurd I. , Petersen Lasse S. , Fjellbirkeland Hege , Robson Adrian , Sperre Thomas 
Published: December 2007

Abstract
The Norwegian North Sea Brage field came on production in Sept. 1993. The field is currently producing approx. 8000Sm3/d and is on steep decline from its plateau rate of 19400Sm3/d.
In March 1999 it was decided to stop the drilling for approximately one year. During this year new reservoir models were built and history matched. Although this work proved to be both complicated and tedious it was fairly successful. However there was still a high degree of uncertainty in the understanding of the flow pattern and the pressure behaviour of the field. It was therefore decided to perform a comprehensive uncertainty analysis to get better estimates of the expected production and risk related to a resumed drilling. The analysis was performed both on a well to well basis and combined into a drilling campaign.
The paper will describe analysis in detail illustrated with field examples.
A reservoir simulator is utilized to estimate the unconstrained well potential for each well. Then total field water handling constraints is imposed using a tool that optimizes the production given the individual well profiles and the platform constraints. This gives a basis for determining the base case Present Value, PV, for each well's contribution to the field production. For each well target, the most important uncertainties with corresponding probability distributions are identified, and their effect on the PV determined by simulations. In cases where the simulation model is judged not to represent the reservoir behaviour correctly, analytical methods are used. Finally, these results are used together with the drilling cost into a Monte Carlo simulation loop to determine probability distributions for the NPV of each well and for the total drilling program.
It is shown that even though most of the individual well targets has a high risk of a negative NPV, the economy of the total drilling program is robust and has a significant upside economical potential.
The procedure, which is based on commercially available software only, has proven to be very flexible. It is easy to incorporate new uncertainties related to a well target, or to include or exclude a well target from the drilling schedule. Finally, the resulting NPV probability distributions provide an easy way of ranking well targets based on expected NPV and risk.
Hydrocarbon Field Planning Tool for Medium to Long Term Production Forecasting from Oil and Gas Fields Using Integrated Subsurface - Surface Models
Authors: Beliakova N. , van Berkel J. T. , Kulawski G. J. , Schulte A. M. , Weisenborn A. J. 
Published: December 2007

Abstract
The Hydrocarbon Field Planning Tool (HFPT), recently developed by Shell, provides capabilities for rigorous integrated subsurface-surface production forecasting in the medium to long term (1-30 years). HFPT can be used for gas, gas-condensate, oil and mixed gas-oil fields. HFPT models allow business optimisation by making more efficient use of the existing assets and by reducing investment costs in the new fields.
In the simulation, HFPT uses a pressure-balanced solution of the integrated system: from the reservoir(s), through wells and surface facilities, to the delivery point. A wide range of fluid models is available, from simple gas-condensate and black oil PVT models to multi-component models with EOS flash calculations. HFPT provides optimisation functionality for maximising the returns in oil and gas fields, while accommodating operational preferences for production allocation and network constraints. It can also model injection networks and optimal lift gas distribution.
Geo-Oriented Horizontal Drilling in the Rotliegend – A Learning Experience
Authors: Werngren Oonagh 
Published: December 2007

Abstract
This paper describes the successful application of geo-oriented LWD technology to the precision drilling of 4 horizontal reservoir sections in complex Rotliegend wells in the UK Southern North Sea (SNS). Detailed planning, teamwork and acquisition of real-time data enabled the sub-surface team to drill the wells efficiently, applying continuous improvements to the geo-orienting technique through an inherent feedback and learning process. As a result, a significant reduction in cost/foot was achieved throughout the campaign. One of the field developments was subsequently benchmarked as a Best In Class project by the 1999 IPA benchmarking report.
Early Production Systems (EPS) in Ultra Deep Water, a Way to Improve Reservoir Management and Field Economics
Authors: Valenchon C. P. , Anrès S. J. , Baudouin B. F. , Biolley F. M. 
Published: December 2007

Abstract
Offshore developments in ultra deep waters will lead to huge investments, therefore their profitability will have to be assessed as thoroughly as possible prior to sanction.
One way to reduce reservoir risks is to use early production systems (EPS). They are cheaper to build, reduce time to first oil, and provide a better knowledge of the reservoir after one or two years of production.
Some conventional EPS solutions can be extrapolated to deep and ultra deep waters, but the cost of risers and mooring lines for such systems might become prohibitive and alternate solutions could become more economical with increasing water depth.
West Africa presents a unique situation with a large number of discoveries in deep waters as well as many prospects in ultra deep waters, combined with exceptionally mild metocean conditions.
After the review of some existing shallow and deep water EPS schemes, followed by a description of the main EPS technical and economic drivers, the paper will present the potential for such systems and the technical challenges associated with their use in West African ultra deep water.
Finally an innovative EPS solution is proposed, involving the use of a modified tanker outfitted with a central moonpool housing vertical, top-tensioned risers with surface trees.
This solution is an autonomous EPS system offering new possibilities to enhance well production tests and reservoir monitoring.
Reservoir Modeling for Giant Romashkino Field (Problems and Solutions)
Authors: Abdulmazitov R. G. , Blinov A. F. , Dikov V. I. , Ibatullin R. R. , Latifullin F. M. , Khisamov R. S. 
Published: December 2007

Abstract
History of giant Romashkino field exploration and development includes more than 50 years. Huge information bases on its geologic structure and exploitation is accumulated by now.
The field presents asymmetric uplift of areal extent about 100 × 100 km. Commercial oil inflows have been obtained from 18 horizons. Some differences in formation fluid characteristics are observed throughout the field. By present the field is divided into 21 independently developed areas. Initial division of structures was made under conditions of insufficient information and was adjusted later. In connection with uncertainty in geologic structure there might be crossflows between structures of contour division. These conditions make difficult modeling and monitoring of the whole field development.
For conductance of geologic and hydrodynamic modeling we have determined the following main principles:
structure-by-structure modeling of the field, uniform procedure principles for all being modeled structures, parallel modeling of main field elements – areas.
At present 3D geologic and hydrodynamic models for 5 areas of Romashkino field are developed and used. This is more than 6000 wells. 3D models are being brought now into commercial operation, i.e. realization of idea for continuously operating models of areas, blocks and experimental sections. This is practically possible based on fiber-optics system of communication applied in the field, which ensures interaction of all company structures. This will enable to provide application of efficient technologies and software for solution of applied tasks to most number of users.
Uniform monitoring of the whole field development as a complex of all areas will be provided upon completion of hydrodynamic modeling of all areas.
Rejuvenating Production in Brown Fields with Horizontal Sidetracks
Authors: Ogoke Victor C. , Akhideno Matthias , Akinkunmi Akin , Nwosu Chike , Ugboaja Remmy , Simon Roya , Matemilola Saka 
Published: December 2007

Abstract
Horizontal sidetracks offer a very viable technique for rejuvenating production in the redevelopment of brown fields. In brown fields where significant reserves exist, but occur as scattered pockets of by-passed oil, or in stacked reservoirs, their development with new wells will hardly satisfy economic screening criteria. The abundance of old wells that have drained the recoverable reserves in their drainage area and are either producing at very low rates or are closed-in, make horizontal sidetracks a viable tool for rejuvenating production and maximising existing assets.
With a vision to improve production in SPDC by 60% in 2004 and by over 200% (to 2.5 MMbopd) in the year 2010, producing the limit or sweating the existing brown fields is now a key factor. Most new wells are now horizontal completions, due to their higher productivity over vertical or inclined wells. This paper presents the benefits of horizontal sidetracks as a productivity improvement tool that was used to boost production from Obigbo North (one of SPDC-E brown fields) by more than 10,000 BOPD in 1999 alone. It discusses production gains, geology, well construction, completion types, environmental benefits and petrophysical data acquisition and interpretation problems that could be encountered with horizontal sidetracks in brown fields, based on our experience.
Horizontal Well Performances in Hassi-Messaoud Oil Field, Algeria.
Authors: Azzouguen A. , Mazouzi A. , Delhomme A. , Deghmoum A. 
Published: December 2007

Abstract
The objective of this study is to analyze the performance of non-conventional wells drilled in Hassi-Messaoud field, Algeria. A new technique "Direct Synthesis" developed by Dr. D. Tiab1, 2 is used for the pressure transient analysis. It permits the determination of permeability tensor as well as the effective length of the horizontal well. Hence, and for the first time, the permeability tensor (Kx, Ky, Kz), and the vertical permeability anisotropy (Kv/Kh) were obtained. The results of the interpretations lead to a verity of information and correlations. Sensitivity studies allow the optimization of future horizontal drilling plannings.
The comparison between the performances of slanted, horizontal, and multilateral wells shows that slanted wells, regarding the low risk, are the most appropriate for Hassi-Messaoud field. From the spatial distribution of permeabilities, Kx, Ky, Kz, important conclusions are illustrated regarding the geological model of the field.
Horizontal wells are not only beneficial for improving productivity but also for the tremendous amount of information they provide. Form this study several recommendations are issued regarding the well spacing taking into account different geological models.
Wellbore Stability Simulations for Underbalanced Drilling Operations in Highly Depleted Reservoirs
Authors: Parra J. G. , Celis E. , De Gennaro S. 
Published: December 2007

Abstract
The need to increase productivity reducing drilling formation damage favours the use of underbalanced drilling technology. The main idea is to drill with equivalent circulating densities (ECD) below the formation pore pressure and to avoid the contact between the drilling fluid and the formation. In highly depleted reservoirs, pore pressures can be very low. Therefore, extremely low density fluids such as foams are used to achieve circulating densities below pore pressure. In such cases, the induced modification of the in situ stresses has to be supported mainly by the rock, with low contribution of the drilling fluid pressure. In that sense, the application of underbalanced drilling depends, among other factors, on the mechanical stability of the drilled formation. In general, poorly consolidated depleted formations are not suited for that technology. This paper presents the wellbore stability simulation performed in order to establish the feasibility of using underbalanced drilling in highly depleted reservoirs in western Venezuela. The in situ stress field and the mechanical properties of the formation were obtained. Pore pressure as low as 800 psi at 5500 ft (2.7 lb/gal equivalent fluid density) was measured. The finite difference method and an elastoplastic constitutive model was used to obtain the new stress, deformation and pore pressure distribution. The undrained condition (immediately after the wellbore is drilled) as well as the drained condition were analysed. The analysis showed that horizontal wells could be drilled in an underbalanced condition with low instability risk. Following the recommendations, four horizontal wells were drilled in underbalanced conditions. Values as low as 2.0 lb/gal ECD were used to drill the wells and no wellbore instability problems were reported. Production tests showed an enormous increment in well productivity index in comparison with conventional overbalanced drilling.
Borehole Acoustic Reflection Survey Experiments in Horizontal Wells for Accurate Well Positioning
Authors: Yamamoto H. , Watanabe S. , Koelman J. M. V. , Geel J. , Brie A. , Fujii K. , Coates R. 
Published: December 2007

Abstract
Reservoir management optimization requires a detailed description of the geometry and the properties of the reservoir. For horizontal wells, knowing accurately the position of the borehole in the reservoir is critical. However, seismic techniques do not have sufficient resolution to provide the position of the well with respect to the reservoir boundaries with desired accuracy. Sonic measurement on the other hand has the potential to provide such information. We conducted experiments in horizontal wells in Oman using a commercial multi-receiver sonic tool modified for imaging, with extended spacing between the transmitter and the receivers. Although the tool characteristics are not optimized for the imaging, we obtained interesting results when the reflectors have sufficient strength, thus showing the potential of this technique. The pre-processed and migrated sonic images provided useful information on the geometry of the reservoir, which could be compared with seismic interpretation and field knowledge. Furthermore, we developed a specific processing technique that uses the four different waveforms acquired around the tool at each receiver station to separate the reflections coming from above the well and the ones coming from below. In this way, we could obtain images that could be interpreted more easily. In some instances, the position of the reservoir boundaries could be determined with an accuracy of 1 m up to a maximum distance of 10 m.