bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development Strategy and Reservoir Management of a Multilayered Giant Offshore Carbonate Field
Authors: Tewari R D , Rao Mohan , Raju A V 
Published: December 2007

Abstract
The reservoir performance and management of the Bombay High field with 25 years of production history has been reviewed. Bombay High is one of the most complex fields in terms of reservoir heterogeneity. The major reservoir (L-III) is multi- layered with 10 limestone layers of 5-10m thick which are separated by 2 to 5m shale. More than 600 development wells, both producers and injectors have been drilled. The very nature of this giant field and large and aging facilities have necessitated frequent reviews and changes in the development strategy of the field. The field is in the decline phase and has associated problems like increase in water cut and high GOR, which in-turn is effecting the oil production. Pressure maintenance by water injection is uneven in the reservoir due to heterogeneity. Problems being faced are differential depletion of sub-layers and associated poor primary cementation and mud losses during drilling of infill wells.
Infill drilling through available spare slots and side-tracking/re- drilling of the existing wells, drilling of horizontal wells, drainholes and ERD have been taken up to increase the production and also to augment the water injection. Massive well intervention programs like water shut off and gas shut off are being taken up to reduce the excess water and gas production. The paper also discusses, the utilization of tools like Downhole video and PLT for problem identification, Ball sealer for selective stimulation and Gel treatment for controlling excessive water and gas production, water flood surveillance programs and facilities optimization.
Sectorial approach, adopted for reservoir management has helped, in better well level monitoring, which becomes very essential in mature fields like Bombay High, in the identification of pressure sinks and better voidage compensation, fluid movements and design of well intervention programs and facilities optimization.
A multi-disciplinary team concept has been embraced for better reservoir management. The advantages of multidisciplinary teams, which are working for the re-development plan, with detailed/improved reservoir characterization, incorporating the 3D seismic data and reservoir simulation model, is highlighted.
Sand Management in Bongkot Field, Gulf of Thailand: An Integrated Approach
Authors: McPhee C. A. , Lemanczyk Z. R. , Helderle P. , Thatchaichawalit D. , Gongsakdi N. 
Published: December 2007

Abstract
Sand production in the Bongkot Field, Gulf of Thailand, has led to significant incremental costs and has increased the risk of potential key flowline and control equipment failures. The geological complexity of the field and the many layers that may be perforated in any given well, makes direct identification of sand producing zones problematic.
A multi-disciplinary sand production task force was established to identify the current sand production mechanisms; to evaluate various technical options for implementing sand control; and to recommend appropriate completion and intervention strategies. An integrated core, log and reservoir data acquisition programme allowed the development of a continuous, log-derived and core-calibrated rock strength prediction model, which was coupled to two independent sand prediction models. The models were used to delineate high risk sanding zones and indicated that sand production in Bongkot results from rock failure brought about by rapid and progressive reservoir depletion. The predictive models represent key tools in the development of effective sand management and control strategies for the reservoir life cycle.
Conventional downhole sand control methods are largely inapplicable to Bongkot since they are constrained by the existing well completion types, sand layer heterogeneity, and practical installation problems in both existing and new wells. Cost effective containment of sand production in Bongkot will rest on the application of "best practice" reservoir management policies and the application of emerging sand control technology where conditions allow. Modelling individual well and field network performance will form an important platform for designing and evaluating sand management strategies.
Bokor: Development and Technology Challenges of a Mature Field
Authors: Pauzi N. , Low F. N. , Husin M. T. , Maksari H. 
Published: December 2007

Abstract
Development for further opportunities in a mature field offers a unique set of challenges. The approach to this requires a focused multi-disciplinary team to arrive at a proper understanding of the reservoirs and the right technical solution. These challenges were experienced in the development of the Bokor Field, located 45 km northwest offshore Lutong, Sarawak in the Baram Delta region.
The Bokor Field is featured as a simple domal uplift with a collapsed crest superimposed onto a rollover anticline resulting from growth faulting. The field is deposited in a series of multiple stacked deltaic to shallow marine sandstone reservoirs that contain both oil and gas.
The field was discovered in November 1971 by BO-2 but was put on production only in 1982. The reservoirs were completed commingled to maximize completion strings' utilities and production from the stacked reservoirs. Limited spare well slots and unconsolidated reservoirs which often hinder further development in the past has ignited a flurry of technical creativity in the application of new technology. Due to development strategy of placing wells clustered at the crest of the domal structure in the past, the extent of the structural flank limit of the field is still relatively uncertain providing further future appraisal opportunities. The current field activity is mainly related to maximizing oil recovery and further development opportunity identification.
This paper discusses how it is possible to turn around a "brown" field by identifying the occurrences of the bypassed oil and at the same time replenishes reserves from the appraisal targets. It will also highlighted on the effectiveness of the new technology that has been implemented in the Bokor Field; from multi-lateral to "Triple wellhead" technology. This technology has allowed more reserves to be developed with fewer wells.
Identifying, Evaluating and Modelling Key Dynamic Parameters: Sunrise Troubadour Gas Condensate Fields
Authors: Stephenson P. M. , Ainsworth R. B. , Johnson D. A. , Koninx J.M. P. , Seggie R. J. 
Published: December 2007

Abstract
The Sunrise and Troubadour Fields form a massive offshore gas-condensate resource located in the Timor Sea, 450 kilometres northwest of Darwin. The commercialisation, marketing and contract negotiations for such a world scale gas development requires confidence in reservoir performance and product composition, plus a clear appreciation of their uncertainties. This paper discusses how the key dynamic uncertainties have been identified, evaluated and modelled to determine their impact on development decisions.
Early cross section models identified connected gas- initially-in-place and reservoir quality as key uncertainties, impacting field performance. Simultaneously, preliminary marketing efforts and facility design recognised fluid properties as a key parameter. This directed data acquisition through appraisal wells, which were fully cored and production tested.
Iso-kinetic sampling and careful well test design has resulted in representative compositional data and identified compositional variations across the field. High rate dependent skins measured in appraisal wells have been evaluated and re- quantified for development wells. Detailed single well models have evaluated the effects of condensate banking.
As marketing efforts progressed, full field simulation became warranted to capture remaining uncertainty on reservoir quality and distribution, and fault transmissibility. A suite of full field dynamic models built around the key dynamic uncertainties has provided confidence that uncertainties are manageable and that the development and customer commitments are robust. The case for further data acquisition, aimed at optimising the final development, can readily be made using the suite of dynamic models which integrate the input from all sub-surface disciplines.
Focused appraisal has reduced and quantified the key uncertainties. The leading edge evaluation methods have removed the need for several additional appraisal wells that might otherwise have been required.
Effective communication and teamwork between sub- surface, facility engineering, commercial and marketing has proved crucial to ensure that the appropriate uncertainties were addressed in a timely manner as each discipline matured their part of the project.
Application of HDR Stimulation Technology to Develop Tight Gas Reservoirs
Authors: Hossain M. M. , Rahman M. K. , Rahman S. S. 
Published: December 2007

Abstract
Conventional, cross-linked gel, hydraulic fracture treatments face several challenges in naturally fractured, tight gas, hard rock environments. These challenges include the potential for fracture complexity, pre-mature screen-out caused by pressure dependent leak-off and the likelihood of severe gel induced formation damage. To alleviate these potential problems and to economically develop these challenging environments, a new stimulation technology, which has been proven to be successful for Hot Dry Rock (HDR) reservoirs, has been investigated in this paper in the context of tight gas reservoir stimulation. The paper first presents a 3D model in which naturally fractured, tight gas reservoirs can be simulated by integrating available log and core data. Simulated natural fractures are then treated considering a novel fracture propagation and shear dilation concept. The model presented also predicts the resultant hydraulic conductivity and the reservoir growth pattern.
Finally, the paper reviews the productivity performance of the ‘shear dilation’ fracture treatment and compares this with a conventional style fracture treatment. Results are useful to indicate reservoir conditions under which the economic viability of ‘shear dilation’ fracture treatments may exceed conventional fracture treatments.
Quick Look Methodology for Gas Detection Using NMR and Density Porosity
Authors: Breda Eduardo , Silveira Anibal , Homovc Juan , Minetto Carlos 
Published: December 2007

Abstract
The constant compromise between oil production and reserves requires differentiating gas from oil. For the detection of gas we have used the density porosity vs. neutron porosity plots, including all the environmental correction processes and the influence of the clay content in the evaluated layers. Nevertheless, it is not always an accurate method because of the nature of the stratigraphic column of the San Jorge basin which is composed of fine sand and shale layers of lenticular geometry, with different types of clay, mostly generated in a continental environment with marked volcanic participation that make forecasts unreliable.
With the introduction of NMR technology we have obtained, among other parameters, a total porosity curve. From this data, a successful quicklook technique has been developed using the cross over density porosity vs. total porosity, which allows the identification of gas levels and to figure out the clay content for its use in the log analysis.
This paper presents the method for gas detection at well site and its economic impact in logging costs. In some oilfields of the San Jorge Basin, Argentina, logging costs were reduced by 12 %.
A Non-Destructive Method of Cake Thickness Measurement
Authors: Amanullah Md. , Tan C. P. 
Published: December 2007

Abstract
A novel non-destructive laboratory technique and apparatus have been developed to eliminate inaccuracies associated with the conventional direct contact methods of mudcake thickness measurement. The system consists of a laser head containing a transmitter and a position sensitive receiver, a signal conditioner, a digital read-out system and a DC power source. The position of the laser beam spot incident on the measuring surface is recorded by the receiver, transferred to the control box where it is amplified and then displayed as a standard current signal on a digital read-out system. As the method is non-destructive, the mechanical characteristic of the cake such as softness has no influence on the accuracy of the measurement.
The conventional methods of cake thickness measurement provide an estimate only due to damage to the cake during measurement. The accuracy varies depending on the cake consistency. The variation is low for hard mudcakes but high for soft cakes. The newly developed apparatus and measurement technique eliminate the direct contact-related errors and thus can provide reliable input values for modelling mudcake thickness dependent parameters such as formation and cake permeabilities, sticking force, friction coefficient etc. Statistical analyses of the measured values show a standard deviation of less than 0.025 mm and a coefficient of variation of less than 1%.
The apparatus is portable, easy to operate and suitable for quick measurement of mudcake thickness at the rig site. The performance of the system was reviewed by analysing the results of a range of muds and also by comparing with the measured values obtained using other methods.
5-axis CNC Whirlwind Milling Method of PDM's Rotors
Authors: Yi Xianzhong 
Published: December 2007

Abstract
The positive displacement motor (PDM) is a very important downhole motor in petroleum exploration and production. The key element in positive displacement motors is the rotor/stator coupling which convert hydraulic potential of fluid medium into mechanical energy. Normally both the rotor and the stator are cylindrical helix surfaces. The special properties of PDM directly rely on the machining quality of a rotor and a stator.
3-axis and 4-axis NC milling machines are usually used to machine the rotor helix surface or helix surface of stator mandrel, which is an injecting moulding part utilized to shape the inside cavity of rubber stator. The current CNC milling technology for manufacturing large and complex spiral curved surfaces still retains the drawbacks such as consuming time of long duration, over-tolerance and gouging scores. In this paper, a new 5-axis CNC machining scheme with the whirlwind milling method is proposed based on 5-axis CNC rotary-table horizontal milling machine specialized. The important strategy of the whirlwind milling technique is to optimize the directions of principal curvatures of the surface being machined with those of the rotational surface of milling cutter to generate a perfect fit. So, it can avoid the above-mentioned shortcomings and enhance the productivity. This paper focuses on the analytical characteristics of helix surfaces, the fundamental mathematical equations of whirlwind milling technique and its implementation.
The Application of Thin Bed Information Resolution of Well-Logs to Enhance the Vertical Resolution of NMR Logs
Authors: Wang Ning , Qian Yongxian 
Published: December 2007

Abstract
The concept of thin bed information resolution (TBIR) of well logs was first published by Yongxian Qian (1995; Acta Geophysica Sinica, v. 38, Supp. 1). The resolution of thin bed information is carried out by the Walsh Transforms (WT) inversion. NMR logging, among other logging tools, faces the issue of vertical resolution because the aperture of the tool is relatively large (about 24 in.); and the raw echoes acquired have to be stacked to some degree. Until now, WT inversion was not applied to NMR data, but its application to NMR data follows naturally as part of an effort to enhance its vertical resolution.
As long as an application's response functions are of an averaging nature and its final products are results of a linear signal processing, WT inversion can be applied. The T2 distribution from NMR logging falls into this category of final products. Therefore, it is not necessary to start with the raw echoes and the complexity of the algorithms to achieve a higher vertical resolution can be reduced.
After the brief review of Walsh functions, Walsh expansion and TBIR, this paper focuses on their application to NMR data. In order to demonstrate that WT inversion does improve NMR vertical resolution, controlled data were used. The best way to provide these data was through simulation; and the paper provides information about a simulation procedure for a layered formation and the NMR data derived from it. The results of WT inversion on the simulated NMR data clearly shows that vertical resolution is enhanced to a third of the simulated tool's aperture for the assumed logging conditions.
WT inversion was also applied to the NMR data from a well in the southeastern part of the United States. These results show an improvement of NMR vertical resolution as illustrated by comparison of density porosity with NMR effective porosity before and after WT inversion.
Lithology, Gas Detection, and Rock Properties From Acoustic Logging Systems
Authors: Kithas Bill A. 
Published: December 2007

Abstract
Lithology and physical rock properties of formations can be derived by utilizing acoustic logging systems. Compressive travel time from acoustic logs and shear travel time from full wave train logs are the two systems that are considered here. The ratio of shear travel time to compressive travel time is the relationship from which lithology is identified. Established techniques and existing commercial services we used to derive physical rock properties.
In order to establish the practicability lithology derivation, it was decided to incorporate this calculation into a computer program from which the physical rock properties program from which the physical rock properties are calculated from Acoustic, MICRO-SEISMOGRAM, and Density logs. The results of actual field tests in West Texas and Southeastern New Mexico were interesting and also uncovered a technique of gas identification from well logs.

Introduction
With the advent of large-volume frac treatments, interest has increased in obtaining in-situ rock properties for use in well treatment design. Also, studies have been made relating acoustic properties of formations to lithology. In the process of applying techniques for these purposes using well logs, it was observed that the presence of gas distorted the usual relation between compressive and shear velocity for the particular lithology. particular lithology. In the application of these techniques, compressive travel time is measured with conventional Compensated Acoustic Velocity Logs. Shear travel time can be calculated from full wave train logs. The relationship between compressive and shear travel time as a function of lithology is shown below.
delta ts = 1.9 = LIMESTONE delta tc 1.8 = DOLOMITE
1.6 - 1.7 = SANDSTONE
where delta ts = shear travel timedelta tc = compressive travel time
Physical rock properties such as Poisson's ratio are determined from the ratio of compressive to shear travel time.
Employing both Damage Control and Stimulation: A Way to Successful Development for Tight Gas Sandstone Reservoirs
Authors: Kang Yili , Luo Pingya , Jin Xu , Xinghua Xu 
Published: December 2007

Abstract
Tight gas sands exhibit extremely low porosity and permeability, so most people think that it is impossible to produce gas economically without stimulation. During past several decades, great efforts have been paid to improve hydraulic fracturing, but the results are mixed. Formation damages induced by drilling and completion fluids to natural fractures and tight matrix retard artificial fractures to give full conductivity.
Tight gas sands in Western Sichuan Basin are characterized with natural fractures developed in heterogeneity, complexity in micro-macro multi-scale structures, and very sensitive to environmental changes. Drilling fluids invasion into tight formation mostly occurred through natural fractures, which leads to solid plugging, water trapping, clay mineral impairments, chemical adsorption and retention. The paper presents application cases of temporary plugging fluids for naturally fractured sands in two tight gas fields. As the invasion depth localized to within 3cm of the well-bore, perforation can bypass the cake easily and efficiently. Wells with damage control give relatively higher initial production and the production rates after hydraulic fracturing treatments are highest owing to the fact that artificial fractures can connect natural fracture systems and matrix without damages. These wells also show stable and high productivity with longer periods and output satisfactorily economical results.
A Study of the Phase Behavior in Gas-Cap Reservoirs
Authors: Guo Ping , Li Shilun , Liu Shunsheng , Budurexiti A. 
Published: December 2007

Abstract
A conventional viewpoint is that almost all of the gas-cap reservoirs are saturated oil reservoirs. However, based on the studies and research, there exist some other special gas-cap reservoirs. What types are the gas cap reservoirs? Because of the effect of sample collection and the representation of producing data, to judge the type of a gas cap reservoir is a difficult problem. This paper analyzes and summaries different kinds of gas cap reservoirs that can be classified as saturated and equilibrilium reservoirs and special unsaturated reservoirs. The special unsaturated reservoirs can be classified as following three categories: 1) either the gas cap or the oil rim is saturated, the other phase is under-saturated (SGCR1), 2) both the gas cap and the oil rim are not saturated (SGCR2), and 3) the saturated pressures and properties of fluids vary with formation depth (SGCR3). This paper takes gas-cap reservoir RES1 (saturated and equilibrilium) and RES2 (special unsaturated) as examples to show how to determine the types of gas-cap reservoirs. And this paper analyzes the phase behaviors of all kinds of gas-cap reservoirs. In the examples, we use phase state regaining theory and phase equilibrium principles, and use a software Desktop-PVT, Landmark, USA to analyze and calculate.