bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simplified Method for Calculation of Minimum Miscibility Pressure or Enrichment
Authors: Yuan Hua , Johns Russell T. 
Published: December 2007

AbstractLocal displacement efficiency from gas injection is highly dependent on the minimum miscibility pressure (MMP) or minimum miscibility enrichment (MME). Analytical methods, which are inexpensive and quick to use, have been developed to estimate MMP's for complex fluid characterizations. Published methods,1,2,3 however, often require estimation of numerous parameters and little has been written with regard to method robustness. This paper presents a simplified and robust method for MMP or MME calculation.The approach relies on finding key crossover tie lines for a dispersion-free displacement using method of characteristic theory (MOC). The new method, however, differs from published methods by significantly reducing the number of equations and unknown parameters, and by providing a fast and robust method that can avoid trivial and false solutions. We demonstrate the improvements by calculation of the MMP and MME for a variety of gas/oil systems and also give new analytical solutions for constant Kvalue systems that give insight into the nature of the false solutions.
Determination of Environmental Liabilities and Development of a Facility Closure Plan for a State Oil and Gas Company
Authors: Sookdeo Nigel 
Published: December 2007

Abstract
Good business practices by oil and gas operators require a responsibility to decommission uneconomic assets (wells, pipelines, structures) to prevent any ongoing environmental damage resulting from the improper abandonment and closure of all or any of its operations. With the introduction of the International Accounting Standards (IAS)-37 regulations for Contingent Assets and Liabilities, many oil and gas operators are now required to state current and past liabilities as a result of oil and gas exploitation, their current assets, and a phased closure plan for these assets when deemed uneconomic.
Prior to the introduction of the IAS-37 accounting standards, many operators ignored the concept of life cycle costing when developing and exploiting assets. The result was that provisions for the cost of decommissioning of assets when uneconomic were not originally factored into the economic analysis and accounting for major projects or field development. When an asset was spent, improper abandonment resulted in many operators being faced with environment, health and safety (EHS) liabilities and a strain on financial resources for abandonment that were not originally catered for.
Proper life cycle analysis and decommissioning of assets is crucial for regulatory compliance, due diligence, and reduction of internal and external liabilities. The requirement for the development of a facility closure plan includes (1) the identification of all areas of activity requiring closure, (2) the closure procedures and costs, and (3) the implementation of phasing of items identified for closure. Some of the benefits of a facility closure plan to an operator include the reduction of HSE risks, conformance with the IAS-37 standard, financial management, and internal asset management. Some of the challenges faced by an operator in developing a facility closure plan include the lack or unavailability of data, limited financial and human resources, limited technical data on oil and gas reserves, and the lack of environmental baseline data.
The intent of this paper is to highlight the requirements by operators to develop a "facility closure plan" and to determine the closure liabilities associated with the implementation of that plan that would conform to International Accounting Standard-37 and accepted business practice. Reference will be made to the efforts of Petrotrin-Trinmar S.B.U., an oil and gas operator in Trinidad and Tobago in the development of a facility closure plan for all areas of operation.
Quantification of Multi-Phase Fluid Saturations in Complex Pore Geometries from Simulations of Nuclear Magnetic Resonance Measurements
Authors: Toumelin E. , Torres-Verdin C. , Chen S. 
Published: December 2007

Abstract
We develop a numerical algorithm to simulate nuclear magnetic resonance (NMR) measurements in the presence of constant magnetic field gradients. The algorithm is based on Monte Carlo conditional random walks in restricted and unrestricted space. Simulations can be performed of threedimensional (3D) porous media that include both arbitrary bimodal pore distributions and multi-phase fluid saturations. The ability to account for the presence of a constant external magnetic field gradient allows us to replicate actual well logging conditions that include the effect of CMPG pulse sequences at a microscopic level. This is accomplished by simulating pulse acquisition techniques that include multiple inter-echo times (TE) similar to those currently used by the well-logging industry. Benchmark examples are presented to validate the accuracy and internal consistency of our algorithm against previously published results for the case of a null magnetic field gradient. Validation examples are also presented against actual NMR measurements performed on core samples of carbonate rock formations.
Interpretation work is focused to the petrophysical assessment of both partial oil/water saturations and pore structures exhibiting hydraulic coupling. Simulation examples are designed to quantify whether the inclusion of diffusion under a magnetic field gradient can improve the interpretation of multi-phase fluid saturations when hydraulic coupling is significant. The simulation algorithm sheds light to new NMR data acquisition strategies that could be used to improve the detection and quantification of (a) fluid types, (b) complex fluid saturations, and (c) complex pore geometries.
PVT Sampling With Multiphase Flowmeters—Theoretical Justifications and Field Limitations
Authors: Jayawardane S. , Theuveny B. C. 
Published: December 2007

Abstract
Multiphase flowmeter technology probably is the most significant innovation in surface well testing in more than 30 years. Multiphase flow measurement is becoming a globally accepted technique for well and reservoir performance evaluations. The qualification of the validity of samples collected during these operations is required to validate the full potential of multiphase well testing techniques.
This paper discusses the new methodology developed for collection of samples using dual-energy spectral gamma ray Venturi multiphase flowmeter technology in field operations. The paper presents some of the theory and assumptions underlying multiphase flow computations and valid sample collection with the flowmeter. Field operations are detailed in the paper and provide operational guidelines to improve safety and optimize sampling operations. A description of the laboratory pressure/volume/temperature (PVT) analysis procedures required to physically recombine these nonconventional gas and oil samples is provided, and a series of field examples illustrate the efficiency of using multiphase flowmeters for well testing.
A sensitivity analysis is conducted for various gas and oil sample recombinations and resulting PVT properties computed by equation of state-(EOS-) based compositional simulations. The parameters considered are possible variations in sampling temperature or pressure and their impact on the resulting recombined fluid PVT properties.
Connecting Laboratory and Field Results for Gelant Treatments in Naturally Fractured Production Wells
Authors: Marin Amaury , Seright Randy , Hernandez Maria , Espinoza Maria , Mejias Fanny 
Published: December 2007

AbstractThis paper demonstrates the connection between laboratory measurements and field results from gelant treatments in production wells at the naturally fractured Motatan field in Venezuela. Using a HPAM polymer with an organic crosslinker, laboratory corefloods revealed that under reservoir conditions, the gel provided oil and water residual resistance factors of 20 and 200, respectively. This gel was placed in several production wells in the Motatan field. In Well P-47, 1,000 bbl of this gel reduced the water cut from 97% to 64% and increased the oil production rate by 36%. The success of these treatments depends on the distance of gelant leakoff from the fracture face and the in situ residual resistance factors in the oil and water zones. Analyses were performed to determine these parameters, based on formation permeabilities, porosities, fluid saturations, fluid properties, fluid production rates, and pressure drops before, during, and after gelant placement. Accurate pressure drops before, during, and after gelant placement were particularly important. Sensitivity studies were performed to demonstrate their significance and the impact of measurement errors. A methodology is presented for optimizing the volume of gelant injected for these applications.
Comparing Production Responses from Devonian Shale and Berea Wells Stimulated with Nitrogen Foam and Proppant vs. Nitrogen-Only, Pike Co., Kentucky
Authors: MacDonald R. J. , Frantz J. H. , Merriam G. W. , Schlotterbeck S. T. 
Published: December 2007

Abstract
This paper presents results of a production data comparison and an economic analysis of two stimulation methods (nitrogen foam with proppant versus nitrogen only) pumped in more than 200 wells owned and operated by Equitable Production Company. The wells, located in Pike County, Kentucky, were completed in the Berea and Devonian shale formations, and each formation was stimulated separately. About half the wells were stimulated with nitrogen foam containing proppant; the other treatments consisted of nitrogen only.
These wells were drilled in the 1990s and sufficient production data were available to make definitive comparisons. The results indicated that the wells treated with foam containing proppant significantly outperformed the wells treated with nitrogen only. Economic results also illustrated that it is more profitable to pump nitrogen foam with proppant even though the cost of the treatment is more than double.
In furtherance of this study, the operator is currently pumping foam with proppant in wells within the study area and is identifying additional acreage for use of this stimulation treatment. Existing wells are also being evaluated for restimulation potential. The results of this paper are noteworthy for the Appalachian Basin because many operators pump multiple stages of nitrogen-only treatments.
Estimation of Underground Blowout Magnitude Using Temperature Logs
Authors: Ipek G. , Smith J. R. , Bassiouni Z. 
Published: December 2007

Abstract
Temperature logs can be used to identify entry and exit points of underground blowouts. The magnitude of the flow can be estimated using relationships that are applicable after a flow time of several days. However, the ability to estimate the flowrate as soon as the blowout is detected is critical for the selection and design of a kill method.
A model relating underground blowout rate and the flowing fluid temperature that is valid for short flow-time was derived. The model uses transient radial heat transfer conditions from the wellbore to the surrounding rock and constant heat transfer coefficient inside the well. Application of the method is illustrated for several hypothetical and two real field examples.
Case Study: Combining Pulsed Neutron Spectroscopy and LWD Resistivity for Analysis Behind Casing in Small Holes.
Authors: Beaumont-Smith N. , Webber G. D. , Shepherd P. J. , Kalyanaraman R. S. 
Published: December 2007

Abstract
Formation analysis from behind casing is gaining more relevance in assessing reservoirs not only in ageing fields but also in new wells completed without the full complement of openhole petrophysical measurements or with openhole measurements of inadequate quality. Before this technology was available, formation evaluation in freshly drilled holes was dependent on the availability of openhole log measurements. This paper discusses field examples where reservoirs were evaluated without a full suite of openhole log measurements. Examples from two sidetracks in a mature North Sea field supported by water injection are presented. The small hole size limited openhole data acquisition to resistivity and gamma ray, which were acquired using logging-while-drilling (LWD) technology.
In both cases pulsed neutron (PN) measurements were recorded through casing to augment the existing data. Porosity and formation sigma (macroscopic thermal neutron capture cross-section) measurements were obtained. Fluid saturations were computed using this porosity and the LWD resistivity. Saturations were also computed from the carbon-oxygen measurement and these agreed with the resistivity-based answers. Lithology analysis was performed using elemental spectral capture yields and was reliable and consistent field wide.
The results show that in a mature oil field, PN measurements can provide a complete lithology and saturation analysis in circumstances where insufficient openhole petrophysical measurements are available.
Hierarchical Organization of Flow Network in Fractured Carbonate Reservoirs: Identification and Characterization of Key Parameters
Authors: Massonnat G. , Viszkok J. , Vrignon M. 
Published: December 2007

Abstract
From field data, outcrop observations, and ground-water flow studies, this paper illustrates that if the assessment of the fracture network organization is effectively an important stage of the reservoir characterization, it cannot be dissociated from the evaluation of the scale relationships, the relation with stratigraphy, and the distribution of fracture hydraulic properties.
In Lacq Field, a giant gas field in a fractured carbonate reservoir, the flow network is assessed through the use of dynamic data. Vertical distribution of producing zones shows a very clear control of effective open fractures by stratigraphy, and therefore carbonate lithology.
In the same time, producing zones are not located in the areas in which fracture density is the highest. Same results are obtained from the observations of in-situ fracture networks and water incomes in a tunnel and a subsurface quarry. It clearly demonstrates that fracture density is the not the driving parameter for flows, and could be anti-correlated with fracture effective aperture.
The computation of equivalent permeability on fracture models shows that fracture aperture distribution (and therefore hydraulic properties distribution) is a more prevalent parameter for uncertainty assessment than fracture distribution.
Lastly, the spacing between open producing fractures along vertical or horizontal profiles show either exponential or power-law experimental distributions, regarding the spatial correlation between geological features. This proves the hierarchical organization of the flows, together with the needs for an evolution of the simplistic representation of a constant matrix block size within each cell of the dual porosity reservoir model.
These studies enable to up-date the typology of fractured reservoirs we previously published
Mechanistic and Simplified Models for Oil-Water Countercurrent Flow in Deviated and Multilateral Wells
Authors: Ouyang Liang-Biao 
Published: December 2007

Abstract
Water circulation and oil-water countercurrent flow in a deviated or multilateral well has been investigated in the present paper. Flow patterns for the countercurrent flow have been identified. Two practical criteria for determining the occurrence of countercurrent flow in deviated wells are introduced. Five categories of flow patterns for the countercurrent flow in pipes or wells are identified. Transitions among different flow patterns are proposed. Both a mechanistic model and a simplified model are developed for describing the oil-water countercurrent flow in deviated and multilateral wells. Solution procedure for using the newly-developed models is discussed.
Evaluation of Fiscal Terms, Reporting Reserves, and Financials
Authors: Young E. D. , McMichael C. L. 
Published: December 2007

Abstract
This paper examines the wide variety of international agreements that are currently used by host governments when granting rights to explore for, develop, produce and market hydrocarbons. The variation in fiscal terms found in these agreements covers a broad spectrum. In addition, their structures are often very complex making comparison of alternative project opportunities difficult. The key differences in the agreements and approaches that are commonly used to compare different fiscal regimes are discussed in detail. A case example with sensitivity analysis is used to illustrate the techniques used to model and perform economic evaluations of specific agreement types and terms. Commonly used definitions and accepted practice for the determination and classification of hydrocarbon volumes are presented. Host and home government regulations that govern and establish the criteria for external reporting of reserves and related financial information are also discussed in contrast with internal reporting needs for technical and business planning purposes.
Improving Production Results in Monobore, Deepwater and Extended Reach Wells
Authors: Almond Ken , Coull Craig , Knowles Peter , Smith James , Smith Michael V. , Mowbraw Kyle 
Published: December 2007

AbstractBig bore completions (i.e., those using 6-5/8-in. and larger production tubulars) are required for economical production and injection in prolific reservoirs. A variety of completion configurations exist, though only the most traditional schemes have been discussed.This paper will present the results of a study that analyzed and evaluated more than 350 large bore completions over a 20-year span to determine best practices. The study formed the basis for a new approach to well design that merges wellbore construction with the completion. The paper will discuss this approach, which includes a classification system to help operators choose the optimum design to match their completion objective.This paper will begin by reviewing the big monobore concept, discuss various enabling technologies and their opportunity to increase production while reducing costs, review configuration choices with case histories and conclude with a case history that illustrates how the big monobore concept is evolving in the world's largest gas field.
A Case History on the Use of Down-Hole Sensors in a Field Producing from Long Horizontal/Multilateral Wells
Authors: Clancy Thomas F. , Balcacer Jairo , Scalabre Sebastian , Brown George , O’Shaughnessy Paul , Tirado Ricardo , Davie Greg 
Published: December 2007

Abstract
All of the production wells in this field were drilled and completed as horizontal and multi-lateral wells. The well designs range from a single lateral in a single sand body to where the upper and lower horizontal laterals intersect several sand lenses. The oil, an extra-heavy (9 API), high viscosity oil, requires a completion using artificial lift due to the low reservoir pressure, which will not support a column of water.
The use of down-hole pressure and temperature sensors with Surface Read-Out (SRO) was an integral part of the original well completions on production wells to monitor the individual well and pump performance. Vertical monitoring wells, drilled and completed through the multiple sand lenses present, expanded the use of down-hole sensors as data was sought on the area extent and pressure drawdown in the various sands being produced.
Efforts to determine the contribution to flow and the pressure losses encountered in horizontal wells led to the use of multiple sensors installed at depths along the long horizontal lateral. A change to the drilling of complex multi-lateral wells resulted in the use of tandem sensors to determine the relative contribution to flow from the lower and the upper lateral(s). All of these approaches, combined with the inability to use conventional Production Logging Tool techniques, led to the application of new technology combining fibre optics with multiple sensors to obtain a real time alternative to a PLT. As many as 15 surface read-out sensors were successfully installed in 7000 feet long horizontal well sections with measured depths up to 10,000 feet.
Real-Time Monitoring and Control of Water Influx to a Horizontal Well Using Advanced Completion Equipped with Permanent Sensors
Authors: Bryant I. D. , Chen M. -Y. , Raghuraman B. , Schroeder R. , Supp M. , Navarro J. , Raw I. , Smith J. , Scaggs M. 
Published: December 2007

AbstractWe have tested new technologies for real-time monitoring and control of water influx to horizontal wells with sand control completions. We drilled a horizontal well in a thin oil column in Indiana, which was completed openhole with sand screens and a gravel pack. External casing packers subdivide the annulus into three zones. An electrical valve, which also records the annular and tubing pressure, controls inflow to each zone. Twenty-one centralizers act as electrodes to form a resistivity array that spans the 694-ft-long completion. The well is also equipped with a fiber-optic-distributed temperature sensing system. The well has been produced since November 2001 and provides real-time data that are shared across a geographically distributed network and used to optimize the production of oil from the well.The data from the pressure sensors and the resistivity array have been jointly interpreted to dynamically update the static reservoir model, which was initially based on observations in offset vertical wells. The pressures recorded from the three electrical valves provide high-frequency data to characterize the near-well heterogeneity of the formation. This is critical to computing an optimum production strategy. Zonal well tests, combined with interference testing between zones and wells, allow for estimation of communication between zones and the productivity index of each zone. The resistivity data enable detection of water saturation changes both in the formation and in the wellbore.The completion technology tested in this well offers the potential to intelligently operate long horizontal sand control completions by combining real-time monitoring with downhole inflow control.