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Sally M. Benson is the Precourt Family Professor in the Department of Energy Resources Engineering in the School of Earth, Energy & Environmental Sciences; she studies technologies and pathways to reducing greenhouse gas emissions including geologic storage of CO2 in deep underground formations and energy systems analysis for a low-carbon future. Prior to joining Stanford, Benson was Division Director for Earth Sciences, Associate Laboratory Director for Energy Sciences and Deputy Director at LBNL. Professor Benson serves on the Board of Directors for the National Renewable Energy Laboratory and Climate Central. Currently she also serves on the Advisory Boards for Argonne National Laboratory and Pacific Northwest National Laboratory, Princeton's Carbon Mitigation Initiative, Princeton's Adlinger Center, Japan's Initiative for the Cool Earth Forum, and the Lahore University of Management Science in Pakistan. Over the past several years she participated in a number of National Academy of Sciences, Secretary of Energy, and National Petroleum Council research needs assessments related to carbon management.
Ahmed, Muhammad Farooq (Department of Geological Science and Engineering, Missouri University of Science & Technology) | Rogers, J. David (Department of Geological Science and Engineering, Missouri University of Science & Technology) | Farooq, Khalid (Department of Civil Engineering, University of Engineering and Technology Lahore)
ABSTRACT: On August 10, 2005 a landslide of approximately 133,000 m3 occurred along the Lahore-Islamabad Motorway (M- 2) near the village of Simbal, in the Salt Range area of Pakistan. A program of research was undertaken to evaluate the likely impacts of percent saturation and bulk density on mobilized shear strength along the basal rupture surface of the Simbal Landslide. A series of direct shear tests  were performed on remolded samples at different densities. The percent saturation was then varied on these samples to evaluate its impact on mobilized shear strength. The results of these tests suggest that soil cohesion and friction tended to decrease with increasing percent saturation. The tests also showed that the shear strength parameters tended to increase with increasing dry density; however, all of the samples exhibited a noticeable loss of shear strength with increasing degree of saturation, independent of soil density. Limit equilibrium slope stability analyses were performed along the most probable failure planes, based on shear strength parameters corresponding to degrees of saturation, varying between 20% to 100% over a wide range of in-situ densities. The results of these analyses suggests that the factor of safety drops significantly, (from FS = 1.6 down to 0.41) as the degree of saturation approaches unity. 1. INTRODUCTION A significant landslide occurred on 10th August, 2005 near village Simbal along the Lahore-Islamabad Motorway (M-2) in Pakistan’s Salt Range, after a period of intense precipitation. This resulted in a large volume of slide debris (approximately 91,500 m3 of colluvium and 41,000m3 of limestone and shale) moving down the slope, blocking a portion of the motorway. The relationship between the shear strength and degree of saturation for different soils has been studied by various researchers outside of Pakistan [2-6].
Technology Focus This year, most of the well-construction papers focused on long-term durability in high-pressure/high-temperature (HP/HT), tight gas/-shale, steamflood, and carbon-capture and -storage (CCS) environments, a shift toward nonconventional wells. Previously, we discussed the growing awareness of the value of measuring cement mechanical properties and modeling mechanical stresses imposed upon the cemented annulus in HP/HT, deepwater, and steamflood applications. Recognition of the technology’s value has now expanded into CCS and tight gas applications. Paper SPE 139668 discusses the many aspects and value of modeling cement-placement mechanics, cement mechanical properties, and imposed stresses. It also provides excellent tutorial insight into the complexity of modeling cement behavior in fluid and solid states. As discussed last year, lost circulation and narrow pore-/fracture-pressure windows remain key challenges in achieving casing points and targeted cement coverage. Paper SPE 130319 details field results for drilling a liner to setting depth and cementing it with a new automated managed-pressure-drilling system while providing a nearly constant bottomhole pressure, a very promising technology. Traditionally, casing- and tubing-design engineers have used a deterministic stress-limits approach that uses the API Bulletin 5C3 and the von Mises criterion. However, depending upon which of the different empirical equations and safety factors are used, the resulting tubular design may be significantly over- or underdesigned. Paper SPE 134550 details a new design methodology that uses a 3D finite-element model, variation in tubular dimensions, sensitivity modeling, and stochastic study to develop a better design specification. Manny Gonzalez, SPE, Alliance Manager for Chevron ETC, noted that when applying new metallurgies, such as titanium and high-end corrosion-resistant alloys, this statistical approach becomes critical because there is no single guide for use of the current API formulas. Well Construction additional reading available at OnePetro: www.onepetro.org SPE 142150 • “Ongoing Development of Cementing Practices and Technologies for Kuwait Oil Company’s Deep HP/HT Exploration and Gas Wells—Case History” by M.J. Al-Saeedi, SPE, Kuwait Oil Company, et al. SPE 132541 • “Determining Production-Casing and -Tubing Size by Satisfying Completion, Stimulation, and Production Requirements for Tight-Gas-Sand Reservoirs” by Y. Wei, SPE, C&C Reservoirs, et al. SPE 131489 • “Solid-Expandable Tubular Combined With Swellable Elastomers Facilitates Multizonal Isolation and Fracturing, With Nothing Left in the Wellbore To Drill, for Efficient Development of Tight Gas Reservoirs in Cost-Effective Way” by M. Ghufran Anjum, University of Engineering & Technology, Lahore, Pakistan, et al.