The SPE has split the former "Management & Information" technical discipline into two new technical discplines:
- Data Science & Engineering Analytics
The SPE has split the former "Management & Information" technical discipline into two new technical discplines:
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Lanzarone, Peter (University of Georgia, and BP America) | Seidel, Marc (University of Cologne) | Brandt, Steven (University of Florida) | Garrison, Ervan (University of Georgia) | Fisher, Erich C. (Arizona State University)
Rockshelters can serve as important prehistoric settlements that commonly preserve stratified archaeological materials; however, few geophysical surveys have proven successful in these environments. We carried out a 2D GPR survey at Mochena Borago Rockshelter, an archaeological site located in southwest Ethiopia. Here, we present the processing and interpretation methodology of the GPR dataset and describe its impact on the understanding of the site. Data processing included DC-drift removal and time-0 correction, as well as post-processing steps including background, band-pass, and f-k filtering. Across some 2D profiles, the GPR signal was contaminated with high amplitude above surface diffractions, spurious signals generated from the rockshelter walls and ceiling. Separating these from subsurface reflections posed a challenge that we’ve attempted to overcome during processing. Interpretation was carried out by mapping major reflection packages and grouping these into radar facies. We then compare these with geologic facies defined by stratigraphic descriptions examined in the excavation units. Finally, we mapped the deepest coherent, laterally extensive reflection as the basement, which appears significantly deeper than any excavations at the time of writing (upward of ~4-m) in some areas of the shelter. We conclude that GPR provides a valuable dataset to understand the nature of stratigraphic deposits at Mochena Borago. The success demonstrated here supports further geophysical work at Mochena Borago and other rockshelter sites in Ethiopia and elsewhere around the world. Presentation Date: Wednesday, October 14, 2020 Session Start Time: 9:20 AM Presentation Time: 10:10 AM Location: Poster Station 5 Presentation Type: Poster
Abstract In a space of less than a year, in fact between February to October 2018, 4 fatal accidents happened with six persons died as consequence. We have heard and read a lot about human factors and how unsafe acts account for >85% of incidents, what has remain a big challenge for employees and management across decades is an almost foolproof approach to learn from the experiences of others incidents to prevent the incidents from happening again. To understand the precarious challenge, let us look at the summary of the four sad events that led to the six fatalities. On 5th May 2018, a contracted truck loaded with 23m of gasoil and 25m of kerosene overturned 120km from Addis-Ababa. It then collided with a 4tonne truck that came in front and caught fire. Both drivers died. On 22nd July 2018, death of a contracted Driver occurred following handling operation accident on the Total E & P Congo Industrial Base. During a storage operation of steel slings, the mast of a forklift has dislodged at the bottom of the mast and has tilted to the driving position of the machine (around the axis of the inclination cylinders). While falling, the mast crushed the cabin and the operator.
Due to its inherent mountainous topography some of the main access roads of Ethiopia are known to be susceptible to landslide problems. The most well know of these areas are the GohaTsion-Dejen road of the Abay (Blue Nile) Gorge; Debresina-Armania road sector in central Ethiopia; and the Kombelcha-Dessie, Wuchale-Wurgessa-Mersa; Alamata-Korem-Maichew-Alaje; and the Adigrat-Mugulat-Bizet main road sections of northern Ethiopia. Some other areas have also been threatened by slope failures when roads cross the landslide susceptible landscapes especially in areas on both the eastern and western sides of the rift margins. The Debresina-Armania area, which is the subject of this study is one of the most landslide prone areas of Ethiopia and is located in the Afar Rift Margin/western scarp of the Ethiopian Rift valley. A major asphalt road connecting the capital with the northern parts of the country (Addis Ababa-Dessie-Mekelle) and as such the life line of a large population,hasrepeatedly been affected by slope failure and the development of many major cracks and landslide caused problemsin areas close toDebresina-Armania towns. To protect the loss of lives and cost suffered from landslide incidences, it is useful to understand the causes and characteristics of the landslide processes; determine the extent of the slope instabilities and carry out appropriate mitigation measures. Therefore, this study was designed to understand the subsurface conditions of the problematic section of the main asphalt road between Debresina and Armania with a view to identifying the triggering mechanisms of the landslide problem, and recommend possible mitigation measures. Geophysical investigations using 2D electrical imaging and magnetic methods have been conducted to study the landslide problem on the road located at DokakitKebele near SarAmbaKidaneMhiret locality between Debresina and Armania towns in central Ethiopia (Figure 1).
Abstract The objective of this paper is to demonstrate how recent technological developments in remote sensing, surveillance, and associated computing capabilities are changing the Environmental and Social Impact Assessment (ESIA) approach. Specifically, these developments include high-resolution, multi-spectral satellite imagery and LiDAR (Light Detection and Ranging) derived digital surface and terrain modelling, as well as advanced software platforms used in their analysis. Building on these technological developments, a new approach to ESIA studies is emerging – Imagery-Based Analysis and Assessment (IBAA). The IBAA approach aims to efficiently and accurately classify environmental and social sensitivities, quantify anticipated impacts from project activities and assist in the development of mitigation measures all while reducing the amount of time needed in the field to undertake baseline surveys. This is achieved through a methodology that involves semi-automated land cover and habitat classification, spectral manipulation, object-oriented analysis and valuation calculations. A large onshore oil field development project in Ethiopia will serve as a case study for this paper to illustrate the technical and commercial benefits of the IBAA approach. Specifically, the case study will show how imagery-based analysis allows for: i) the generation of a more robust, thorough and defensible environmental and social baseline, ii) an efficient and cost-effective classification of social and environmental sensitivities across large geographic areas, and iii) more targeted and comprehensive analysis of risk. This paper will culminate in the proposal of new industry best practice for utilizing IBAA methods to improve HSSE/SR performance and to identify, manage and mitigate non-technical risks throughout the project lifecycle.
Abstract The Gibe III Hydropower Project, being constructed on the Omo River, is a key project for Ethiopia, engaged in a strong development of its energy production means. It includes notably construction of a 246 m-high dam of roller-compacted concrete (RCC dam), to be the highest in Africa. The paper presents the unusual rock mechanics challenges that have been encountered during excavations of underground works and dam foundation, and the way they were dealt with. Geology of the country has been largely modelled by volcanism in relation with the African Rift System. The damsite is located within a gorge carved by the river through a thick trachyte body, having overlain former volcano-sedimentary formations. Unexpected rock mass conditions, in the form of cohesionless silty materials were found deeply seated over about 40 m length in the first reconnaissance borehole. Tunnelling of the diversion tunnels brought the additional surprises. During the excavation, a sudden, but long-lasting, flow of dry to slightly damp loose rock pieces, some of them rounded gravel, poured into the tunnel from one location in the top of the excavation front. The area was crossed using heavy support once the flow stopped. The trachyte rock itself appeared to present singularities. Although apparently massive, with joints often cemented by iron oxides, some cores from boreholes drilled in the dam foundation were found disintegrating with time into sandy-silty material. Comprehensive investigations showed that the trachyte had been injected by hydrothermal fluids, resulting in sometime extensive alteration of the rock matrix along discontinuities. Excavations for the dam foundation confirmed these conclusions, with dedicated investigations and special treatment of weak zones, whose frequency unexpectedly increased with depth. The implementation methods for the grouting curtain had to be modified, such as ensuring as much as possible removal of the weak material prior to grouting. The peculiarity of geological and hydro geological conditions can finally explain the observed phenomena, but required adaptation of design and construction methods while construction was progressing, resulting in a true "design as you go" process.
Summary An extensive high-resolution 2-D seismic survey was collected at Lake Tana in the Ethiopian highlands in support of a regional geological study of the Nile River System. The seismic data was of very high quality, exhibiting a dominant frequency of 5 kHz (20 cm wavelength) and reflectors at depths in excess of 90 m. Several reflectors were interpreted and mapped in an area of closely spaced 2D lines acquired as part of a siting survey for a deep coring. These showed complex near surface sedimentary features, channeling and a change of direction of the regional dip over time. The seismic interpretation is linked to important climatic changes that occurred during deposition. Introduction In 2004 and 2006, over 250 km of high frequency single channel seismic data was acquired at Lake Tana, Ethiopia as part of a regional palaeoenvironmental study of climate change during the Holocene and late Pleistocene. The seismic data was combined with cores from three different locations in the lake to map desiccation events, believed to be associated with Heinrich events (Heinrich, 1988) in the Late Pleistocene. Comparison of 2004 and 2006 data The 2004 data was collected with a Geoacoustic Chirp profiler (which uses controlled waveform transducers as an energy source), operated within a frequency bandwidth of 2-7 kHz. This system emits selectable frequency modulated pulses, sweeping through a series of frequencies (Mosher and Simpkin, 1999). Recorded frequencies in the Holocene section (between the water bottom and the first strong reflector 5-15 msec below the water bottom) were on the order of 2 kHz. The 2006 data was collected with a Seistec Boomer System (whose source is a boomer plate used to accelerate water mass). The source emits a 200 microsecond long pulse with a frequency bandwidth of 0.4- 10 kHz. The dominant frequency in the Holocene section was approximately 5 kHz. A composite line created from the 2004 and 2006 seismic data is shown in Figure 2. The major reflectors carry across the hinge line, from the water bottom (7 msec) to bedrock (46 msec). The frequency content, signal/noise ratio and penetration were all significantly improved from the 2004 to the 2006 data. Geophysical Interpretation The seismic interpretation and depth conversion were performed using Schlumberger’s Petrel Workflow Tools software application. The main area of investigation was at a proposed drilling site in the northern part of the lake where a closely spaced grid of 2-D seismic lines was collected (Figure 1). The reflectors in the Holocene section (previously described as z1, z2 and P1 (Bates et al, 2007)), are evident in the data, but the focus of this study is the deeper reflectors at approximately 40 msec (P4), 50 msec (D1), 65 msec (D2) and 90 msec (D3). These are all coherent, continuous and pronounced reflectors on all profiles in the seismic data. They were mapped for calibration with a planned coring to a depth of 100 meters located within the seismic coverage, and were chosen because of their reflection strength-similar to that of the desiccation surface (P1) encountered in the previous coring.