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Horizontal wells are being employed in innovative ways in steam injection operations to permit commercial exploitation of reservoirs that are considered unfavorable for steam, such as very viscous oils and bitumen and heavy oil formations with bottomwater. This page discusses some of the ways in which horizontal wells have been used to enhance steamflooding. Numerous papers have explored steam injection using horizontal- vertical-well combinations by use of scaled physical models or numerical simulators. For example, Chang, Farouq Ali, and George used scaled models to study five-spot steamfloods, finding that for their experimental conditions, a horizontal steam injector and a horizontal producer yielded the highest recovery. Figure 1 shows a comparison of oil recoveries for various combinations of horizontal and vertical wells and for four different cases: homogeneous formation, 10% bottomwater (% of oil zone thickness), 50% bottomwater, and homogeneous formation with 10% pore volume solvent injection before steam.
Although conformance-improvement gel treatments have existed for a number of decades, their widespread use has only begun to emerge. Early oilfield gels tended to be stable and function well during testing and evaluation in the laboratory, but failed to be stable and to function downhole as intended because they lacked robust chemistries. Also, because of a lack of modern technology, many reservoir and flooding conformance problems were not understood, correctly depicted, or properly diagnosed. In addition, numerous individuals and organizations tended to make excessive claims about what early oilfield gel technologies could and would do. The success rate of these gel treatments was low and conducting such treatments was considered high risk. As a result, conformance-improvement gel technologies developed a somewhat bad reputation in the industry. Only recently has this reputation begun to improve. The information presented in this chapter can help petroleum engineers evaluate oilfield conformance gels and their field application on the basis of well-founded-scientific, sound-engineering, and field-performance merits.
This course begins with examining the origins of the Toyota Production System (TPS) with Ford in Detroit, TWI during WW2, and the Demin PDCA cycle in post-war Japan. These principles are now used by every automobile company and we have successfully applied them to upstream work in the oil industry. Actual examples will cover from initial reservoir characterization work to well selection and planning to drilling and completion. Time will be spent on why and how to streamline day-to-day work using a multi-year infill drilling project (over 500 wells per year for 12 years) and project to drill 190 horizontal well with the world's closest spacing. Throughout, participants will be encouraged to share their experiences an ho they might apply the principles in their own work.
Summary Since the 1980s, experimental and field studies have found an anomalously slow propagation of foam (Friedmann et al. 1991, 1994; Patzek 1996), a phenomenon that cannot be fully explained by surfactant adsorption. Friedmann et al. (1994) conducted foampropagation experiments in a cone-shaped sandpack and concluded that foam, once formed in the narrow inlet, was unable to propagate at all at lower superficial velocities near the wider outlet. They concluded that long-distance foam propagation in radial flow from an injection well is in doubt. Ashoori et al. (2012) provide a theoretical explanation for a slower and/or nonpropagation of foam front at decreasing superficial velocity. Lee et al. (2016) and Izadi and Kam (2019) find a minimum velocity for foam propagation from analysis of a similar population-balance model but associate it with the minimum velocity for foam stability. In this study, we extend the experimental approach of Friedmann et al. (1991) in the context of the theory of Ashoori et al. (2012). We observe dynamic propagation of foam in a cylindrical core with stepwise increasing diameter such that the superficial velocity decreases from inlet to outlet (in a ratio of 16:1). Previously (Yu et al. 2019), we mapped the conditions for foam generation (at large superficial velocities) in a Bentheimer sandstone core, in relation to surfactant concentration and injected gas fraction (foam quality). In this study, we enrich the map with the conditions for downstream propagation of foam (at significantly smaller superficial velocities). We also interpret our results for both foam generation and propagation in terms of local pressure gradient (following the implications of Ashoori et al. 2012), which plays a dominant role in the mobilization and creation of foam. Our results suggest that the minimum superficial velocities for both foam generation and propagation increase with increasing foam quality and decreasing surfactant concentration, in agreement with theory (Rossen and Gauglitz 1990). In addition, the minimum velocity for propagation of foam is much less than that for foam generation, as has been predicted by Ashoori et al. (2012).
This course begins with examining the origins of the Toyota Production System (TPS) with Ford in Detroit, TWI during WW2, and the Demin PDCA cycle in post-war Japan. These principles are now used by every automobile company and we have successfully applied them to upstream work in the oil industry. Actual examples will cover from initial reservoir characterization work to well selection and planning to drilling and completion. Time will be spent on why and how to streamline day-to-day work using a multi-year infill drilling project (over 500 wells per year for 12 years) and project to drill 190 horizontal well with the world’s closest spacing. Throughout, participants will be encouraged to share their experiences an ho they might apply the principles in their own work.
In-situ combustion is the oldest thermal recovery technique. It has been used for more than nine decades with many economically successful projects. In-situ combustion is regarded as a high-risk process by many, primarily because of the many failures of early field tests. Most of those failures came from the application of a good process to the wrong reservoirs or the poorest prospects. The objective of this page is to describe the potential of in-situ combustion as an economically viable oil recovery technique for a variety of reservoirs.
While always an implicit goal in steamflood processes, overall process heat management became a topic in the literature in the mid-1980s. The growth of the discipline has closely followed the development of the personal computer and computer applications. Heat management consists of data gathering, data monitoring and adjustments to the process as discussed in this page. Figure 1 is a graphical representation of the major components of a heat balance that must be performed to properly manage a steamflood process. Ziegler et al. published a very good summary of a method of implementing the principle.
Designing a successful steamflooding project requires good candidate selection and an excellent understanding of the mechanisms by which recovery is enhanced. Screening criteria for identification of steamflood candidates have been published for many years. Table 1 shows the screening guides from five different sources. It is obvious from Table 1 that there is a finite envelope of properties that define successful candidates. However, within that envelope there is a relatively wide spread of values for the indicators.
This paper seeks answers, through a'philosophical' approach, to the questions of whether enhanced oil recovery projects are purely driven by economic restrictions (i.e. oil prices) or if there are still technical issues to be considered, making companies refrain from enhanced oil recovery (EOR) applications. Another way of approaching these questions is to ask why some EOR projects are successful and long-lasting regardless of substantial fluctuations in oil prices. To find solid answers to these two, by'philosophical' reasoning, further questions were raised including: (1) has sufficient attention been given to the'cheapest' EOR methods such as air and microbial injection, (2) why are we afraid of the most expensive miscible processes that yield high recoveries in the long run, or (3) why is the incubation period (research to field) of EOR projects so lengthy? After a detailed analysis using sustainable EOR example cases and identifying the myths and facts about EOR, both answers to these questions and supportive data were sought. Premises were listed as outcomes to be considered in the decision making and development of EOR projects. Examples of said considerations include: (1) Every EOR process is case-specific and analogies are difficult to make, hence we still need serious efforts for project design and research for specific processes and technologies, (2) discontinuity in fundamental and case-specific research has been one of the essential reasons preventing the continuity of the projects rather than drops in oil prices, and (3) any EOR project can be made economical, if technical success is proven, through proper optimization methods and continuous project monitoring whilst considering the minimal profit that the company can tolerate. Finally, through the'philosophical' reasoning approach and using worldwide successful EOR cases, the following three parameters were found to be the most important factors in running successful EOR applications, regardless of oil prices and risky investment costs, to extend the life span of the reservoir and warrant both short and long-term profit: (1) Proper technical design and implementation of the selected EOR method through continuous monitoring and re-engineering the project (how to apply more than what to apply), (2) good reservoir characterization and geological descriptions and their effect on the mechanics of the EOR process, and (3) paying attention to experience and expertise (human factor). It is believed that the systematic analysis and philosophical approach followed in this paper and the outcome will provide proper guidance to EOR projects for upcoming decades. 2 SPE-196362-MS