Reservoir management optimization: case study of an oil rim located in the Gulf of Guinea comparing dynamic simulation of low cost smart wells with conventional wells

Imperial Users onl

Sedimentary lithofacies, petrography and diagenesis of the Kapuni group in the Kapuni Field, Taranaki Basin, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science with Honours in Earth Science at Massey University, Palmerston North, New Zealand

The reservoir architecture and quality of the Kapuni Group sandstones in seven wells (Kapuni−1, −3, −8, −12, Deep−1, 14 and −15) in the Kapuni Field are characterised using available core and digital geophysical log data. The study focused primarily on the Eocene Mangahewa Formation, but where limited core permits the older Kaimiro and Farewell formations are also examined. Eleven lithofacies in the Kapuni Group, identified and defined in core on the basis of colour, lithology, bedding, texture and sedimentary structures, are interpreted to represent tidal sand bar, tidal-inlet channel, fluvial-tidal channel, spit platform, sand flat, shallow marine, tidal channel, meandering tidal channel, mud flat, swamp and marsh environments. Correlation of core lithofacies with geophysical log motifs enabled lithofacies identification where core data are not available. Log motifs representing each of the lithofacies were then extrapolated to uncored sections of the Mangahewa Formation in the Kapuni Field wells. Interpretation of lithofacies in core and geophysical log motifs indicate that the Mangahewa Formation was deposited in an estuarine setting. During initial deposition of the Mangahewa Formation tide-dominated estuarine lithofacies were deposited. A major coal horizon, the K20 coal, in the field represents a period of maximum infilling. Above this coal core and log data indicate a wave-dominated estuary exhibiting a clearly- defined, "tripartite" (coarse-fine-coarse) distribution of lithofacies. Provenance studies suggest that low-grade metamorphic and granitic rocks are the dominant source for the Kapuni Group sandstones. Minor input from sedimentary and acid volcanic source rocks are also identified. A volcanic source, however, is more important in sandstones from the Farewell Formation, than in the younger Kapuni Group formations. Probable sources include the low-grade metamorphic rocks of Lower Cambrian to Permian age, Permian to Carboniferous Karamea Granite, Triassic and Jurassic greywacke-argillite sediments. Upper Cretaceous Pakawau Group sediments and Pre Cambrian to Upper Cretaceous acid volcanics. Reservoir quality variations in the Kapuni Group sandstones are directly related to environmental and diagenetic processes that have controlled porosity reduction and enhancement. Porosity has been reduced mainly by mechanical and chemical compaction, clay formation (predominantly kaolinite and illite in the Mangahewa and Kaimiro formations and smectite in the Farewell Formation), carbonate precipitation (primarily siderite and calcite), quartz and feldspar overgrowths and pyrite precipitation. While, porosity has been enhanced primarily by carbonate dissolution and subordinately by grain and clay dissolution and minor grain fracturing. The Mangahewa Formation sandstone lithofacies of tidal sand bar and tidal channel environments exhibit the best reservoir characteristics. Future reservoir development in the Kapuni Field and exploration in the Kapuni Field should focus on identifying and exploiting these lithofacies

Towards design of prognostics and health management solutions for maritime assets

With increase in competition between OEMs of maritime assets and operators alike, the need to maximize the productivity of an equipment and increase operational efficiency and reliability is increasingly stringent and challenging. Also, with the adoption of availability contracts, maritime OEMs are becoming directly interested in understanding the health of their assets in order to maximize profits and to minimize the risk of a system's failure. The key to address these challenges and needs is performance optimization. For this to be possible it is important to understand that system failure can induce downtime which will increase the total cost of ownership, therefore it is important by all means to minimize unscheduled maintenance. If the state of health or condition of a system, subsystem or component is known, condition-based maintenance can be carried out and system design optimization can be achieved thereby reducing total cost of ownership. With the increasing competition with regards to the maritime industry, it is important that the state of health of a component/sub-system/system/asset is known before a vessel embarks on a mission. Any breakdown or malfunction in any part of any system or subsystem on board vessel during the operation offshore will lead to large economic losses and sometimes cause accidents. For example, damages to the fuel oil system of vessel's main engine can result in huge downtime as a result of the vessel not being in operation. This paper presents a prognostic and health management (PHM) development process applied on a fuel oil system powering diesel engines typically used in various cruise and fishing vessels, dredgers, pipe laying vessels and large oil tankers. This process will hopefully enable future PHM solutions for maritime assets to be designed in a more formal and systematic way

Advanced reliability modeling of fault-tolerant computer-based systems

Two methodologies for the reliability assessment of fault tolerant digital computer based systems are discussed. The computer-aided reliability estimation 3 (CARE 3) and gate logic software simulation (GLOSS) are assessment technologies that were developed to mitigate a serious weakness in the design and evaluation process of ultrareliable digital systems. The weak link is based on the unavailability of a sufficiently powerful modeling technique for comparing the stochastic attributes of one system against others. Some of the more interesting attributes are reliability, system survival, safety, and mission success

Dependability analysis of web services

Web Services form the basis of the web based eCommerce eScience applications so it is vital that robust services are developed. Traditional validation and verification techniques are centred around the concept of removing all faults to guarantee correct operation whereas Dependability gives an assessment of how dependably a system can deliver the required functionality by assessing attributes, and by eliminating threats via means attempts to improve dependability. Fault injection is a well-proven dependability assessment method. Although much work has been done in the area of fault injection and distributed systems in general, there appears to have been little research carried out on applying this to middleware systems and Web Services in particular. There are additional problems associated with applying existing fault injection technologies to Web Services running in a virtual machine environment since most are either invasive or work at a machine level. The Fault Injection Technology (FIT) method has been devised to address these problems for middleware systems. The Web Service-Fault Injection Technology (WS-FIT) implementation applies the FIT method, based on network level fault injection, to Web Services to create a non-invasive dependability assessment method. It allows targeted perturbation of Web Service RFC parameters as well as more traditional network level fault injection operations. The WS-FIT tool includes taxonomies that define a system under test, fault models to apply and failure modes to be detected, and uses these taxonomies to generate fault injection campaigns. WS-FIT has been applied to a number of case studies and has successfully demonstrated its effectiveness. It has also been successfully applied to a third-party system to evaluate dependability means. It performed this dependability assessment as well as allowing debugging of the means to be undertaken uncovering unknown faults