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Africa (Sub-Sahara) Oranto Petroleum has signed two production-sharing agreements (PSAs) with Uganda for oil and gas exploration around Lake Albert, the Nigerian company said. The deal covers the Ngassa Shallow and Ngassa Deep plays in blocks near the southern part of Lake Albert, according to the Uganda Ministry of Energy and Mineral Development. The pacts closely followed the signing of a PSA by Australia's Armour Energy that covers the Kanywataba block, a 133-square-mile area that was relinquished by three international companies in 2012 after failed exploration attempts. The agreements with Oranto and Armour involve acreage that was offered in Uganda's first competitive exploration licensing round last year. Uganda discovered oil in 2006 in the Albertine rift basin along the Democratic Republic of Congo border.
The PDF file of this paper is in Russian.
The variations of hydrogen index pH in the bottom sediments of North-Eastern outskirts of the Black Sea in the region of the Gudauta uplift are studied. Here the potentially oil- and gas-bearing structures and carbonaceous reef-forming buildings are singled out by seismic data. The sampling of bottom sediments was carried out in the course of the maritime science-research expedition in the August of 2010. The sampling stations were placed at 7 profiles oriented perpendicular to the coast line, 1500 m further on. The profiles were placed at the distance 3000 m from each other. In all, 260 samples were picked out. The pH measurement was carried out by potentiometric method using the analyzer Expert-001, measuring electrode and chlorine-silver comparison electrode. The established pH values are in the interval of 7.68–9.3. The median value makes 8.16, modal – 8.1, mean arithmetical – 8.26, at inaccuracy of average estimation – 0.037. The planar interpolation of pH values of bottom sediments was carried out in the environment ArcGis 9.1 with use of function kriging. It was established that marine sediments in the limits of Gudauta uplift are characterized by increased values of pH (7.86–9.27), in comparison with sediments of other sections of continental outskirts of Black Sea (7.55 – 8.4 at the Crimean shelf, 7.14 – 8.7 at the South-Eastern continental slope), i.e. are more alkaline. For all that, anomalous values of pH do not depend on the composition of sediments and coincide with the shelf zone and leveled parts of continental slope. It is established that the anomalous pH values of bottom sediments, according to published data, can be tied with the flows of carbohydrate fluids, ascending from industrial deposits. These fluids are oxidized at the interaction with oxygen of the seawater bicarbonate and also with methane-oxidizing bacteria. Therefore, the established by us spatial coincidence of areas of anomalously increased pH indices of bottom sediments of Gudauta uplift with areas of development of potentially oil- and gas-bearing geological structures, revealed earlier by seismic data, is connected with possible existence of carbohydrate deposits in them.
Изучены вариации водородного показателя pH в донных осадках северо-восточной континентальной окраины Черного моря в районе Гудаутского поднятия. Здесь по сейсмическим данным выделяются потенциально нефтегазоносные структуры и карбонатные рифогенные постройки. Отбор проб донных осадков осуществлялся в ходе проведения морской научно-исследовательской экспедиции в августе 2010 г. Станции отбора располагались на семи профилях, ориентированных перпендикулярно береговой линии, через 1500 м. Профили располагались на расстоянии 3000 м один от другого. Всего отобрано 260 проб. Измерение pH проводилось потенциометрическим способом с помощью анализатора Эксперт-001, измерительного электрода и хлорсеребряного электрода сравнения. Установленные значения pH находятся в интервале 7,68–9,3. Медианное значение составляет 8,16, модальное – 8,1, среднеарифметическое – 8,26 при погрешности оценки среднего 0,037. В среде ArcGis 9.1 с помощью функции kriging проведена площадная интерполяция значений pH донных осадков. Установлено, что морские осадки в пределах Гудаутского поднятия характеризуются повышенными значения pH (7,86–9,27) по сравнению с осадками других участков континентальной окраины Черного моря (7,55–8,4 на Крымском шельфе, 7,14–8,7 на юго-восточном материковом склоне), т.е. является более щелочными. При этом аномальные значения рН не зависят от состава осадков и приурочены в основном к шельфовой зоне и выровненным участкам материкового склона. Установлено, что аномально повышенные значения рН донных осадков, согласно опубликованным данным, могут быть связаны с потоками углеводородных флюидов, восходящих от промышленных залежей. Эти флюиды окисляются при взаимодействии с кислородом бикарбоната морской воды, а также метанокисляющими бактериями. Следовательно, установленное совпадение в пространстве участков аномально повышенных показателей pH донных осадков Гудаутского поднятия с участками развития потенциально нефтегазоносных геологических структур, выявленных ранее по сейсмическим данным, связано с возможным наличием в них углеводородных залежей.
Section Excellence Award 2019 President's Award for Section Excellence 2018 Show More Awards Show Fewer Awards Date Established: 19 December 2011 http://connect.spe.org/uganda/home Director Mr. Rossini Paul Silveira, Silveira Energy Consultants Africa Communications Chairperson Susan Asiimwe Student Chapter Liaison Maria Assumpta Nakibuule Student Chapter Liaison Mr. Arnold Mugisha YP Chairperson Ms. Proscovia Nabbanja, Uganda National Oil Company Staff Liaison Erin O'Sullivan, Society of Petroleum Engineers Staff Liaison Ola Davies, Society of Petroleum Engineers If you are a section officer, you may sign in to see more details.
Bailey, Adam H.E. (Geoscience Australia) | Jarrett, Amber J.M. (Geoscience Australia) | Bradshaw, Barry (Geoscience Australia) | Hall, Lisa S. (Geoscience Australia) | Wang, Liuqi (Geoscience Australia) | Palu, Tehani J. (Geoscience Australia) | Orr, Meredith (Geoscience Australia) | Carr, Lidena K. (Geoscience Australia) | Henson, Paul (Geoscience Australia)
The Isa Superbasin is a Paleoproterozoic to Mesoproterozoic succession (approximately 1670-1575 Ma), primarily described in north-west Queensland. Despite the basin's frontier status, recent exploration in the northern Lawn Hill Platform has demonstrated shale gas potential in the Lawn and River supersequences. Here, we characterise the unconventional reservoir properties of these supersequences, providing new insights into regional shale gas prospectivity.
The depths, thicknesses and mappable extents of the Lawn and River supersequences are based on the 3D geological model of Bradshaw et al. (2018). Source rock net thickness, total organic carbon (TOC), kerogen type and maturity are characterised based on new and existing Rock-Eval and organic petrology data, integrated with petroleum systems modelling. Petrophysical properties, including porosity, permeability and gas saturation, are evaluated based on well logs. Mineralogy is used to calculate brittleness (see also
Abundant source rocks are present in the Isa Superbasin succession. Overall, shale rock characteristics were found to be favourable for both sequences assessed; both the Lawn and River supersequences host thick, extensive, and organically rich source rocks with up to 7.1 wt% total organic carbon (TOC) in the Lawn Supersequence and up to 11.3 wt% TOC in the River Supersequence. Net shale thicknesses demonstrate an abundance of potential shale gas reservoir units across the Lawn Hill Platform.
With average brittleness indices of greater than 0.5, both the Lawn and River supersequences are interpreted as likely to be favourable for fracture stimulation. As-received total gas content from air-dried samples is favourable, with average values of 0.909 scc/g for the Lawn Supersequence and 1.143 scc/g for the River Supersequence
The stress regime in the Isa Superbasin and the surrounding region is poorly defined; however, it is likely dominated by strike-slip faulting. Modelling demonstrates limited stress variations based on both lithology and the thickness of the overlying Phanerozoic basins, resulting in likely inter- and intra-formational controls over fracture propagation. No evidence of overpressure has been observed to date, however, it is possible that overpressures may exist deeper in the basin where less permeable sediments exist.
This review of the shale reservoir properties of the Lawn and River supersequences of the Isa Superbasin significantly improves our understanding of the distribution of potentially prospective shale gas plays across the Lawn Hill Platform and more broadly across this region of northern Australia.
Jarrett, Amber (Geoscience Australia, Energy Systems Branch) | Bailey, Adam (Geoscience Australia, Energy Systems Branch) | Hall, Lisa (Geoscience Australia, Energy Systems Branch) | Champion, David (Geoscience Australia, Mineral Systems Branch) | Wang, Liuqi (Geoscience Australia, Energy Systems Branch) | Long, Ian (Geoscience Australia, GA Laboratories) | Webster, Tara (Geoscience Australia, GA Laboratories) | Webber, Simon (Geoscience Australia, GA Laboratories) | Byass, Jessica (Geoscience Australia, GA Laboratories) | Gilmore, Stewart (Geoscience Australia, GA Laboratories) | Hong, Ziqing (Geoscience Australia, GA Laboratories) | Chen, Junhong (Geoscience Australia, GA Laboratories) | Henson, Paul (Geoscience Australia, GA Laboratories)
Shale gas plays require technology such as fracture stimulation to increase rock permeability and achieve commercial rates of flow. The brittleness of shales are a major control on the ease of fracture stimulation. The Brittleness Index (BI) is a proxy for rock strength, based on geomechanical parameters, and/or rock mineralogy, and provides an indication of hydraulic stimulation effectiveness. Legacy drill core does not always have the geophysical logs needed for assessment of shale brittleness, therefore mineralogical and geochemical derived proxies for shale brittlenesss are often used with varying success. Shales from the Paleoproterozoic Lawn Hill Platform of north-west Queensland and the Northern Territory are known to contain organic-rich sedimentary units with the potential to host shale-gas plays. The Egilabria 2 DW1 well demonstrated a technical success in flowing gas from the Lawn Supersequence and recent geomechanical logging in the Egilabria prospect have demonstrated the presence of brittle rocks favourable for fracture stimulation with similarities between logged geophysics and X-Ray Diffraction (XRD) derived brittleness (
Noei, Emad Ghaleh (Dept. of Geomatics Engineering University of Calgary, Canada) | Dettmer, Jan (Dept. of Geoscience, University of Calgary, Canada) | Ali, Mohammed (Dept. of Earth Sciences, Khalifa University, UAE) | Lee, Gyoo Ho (Korea Gas Corporation, Korea) | Kim, Jeong Woo (Dept. of Geomatics Engineering University of Calgary, Canada)
This work investigates nonlinear inversion of gravity data to infer Infracambrian Hormuz salt structures offshore Abu Dhabi, UAE. A Bayesian approach with a trans-dimensional parametrization of the subsurface is applied that does not require regularization, resulting in more objective inversion results. The trans-dimensional parametrizations discretize the subsurface structure including the salt dome by an irregular grid of Voronoi cells. Both the number of cells and the cell coordinates are unknown parameters estimated from gravity data. The density contrast of the salt structures is assumed as known. The solution in Bayesian inversion is given by a large ensemble of parameter sets. Here, the trans-dimensional ensemble is obtained with the reversible-jump Markov chain Monte Carlo (rjMCMC) algorithm. Residual errors are parametrized by a full covariance matrix, which is estimated and updated as part of an iterative inversion scheme. Efficient rjMCMC sampling is achieved with parallel tempering. Inversion of airborne gravity anomalies illustrates well-defined Infracambrian Hormuz salt structures offshore Abu Dhabi, where the irregular grid spatially adapts to the data information and without the need to impose explicit regularization or fixed grids. Uncertainty estimates highlight salt dome extent. This study provides new insight into the existence and shape of oil reservoirs associated with the underlying salt structures.
Reginato, Leonardo Fonseca (Universidade de São Paulo) | Carneiro, Cleyton Carvalho (Universidade de São Paulo) | Gioria, Rafael Santos (Universidade de São Paulo) | Pinto, Marcio Sampaio (Universidade de São Paulo)
Artificial Neural Networks (ANN) applications have grown exponentially in all areas of science and technology. The advantages are its versatility, speed and ability to aggregate information, perform predictions of a given set of data. These attributes attract the petroleum industry, which often depends on laboratory analysis or numerical simulation to estimate various reservoir behaviors. This research, aims to predict the relative permeability curves with wettability alteration effect, given a concentration of the ionic composition in water injection. For this, machine learning methods were applied. An analytical algorithm was developed that incorporated the effect of wettability alteration, generating the database for the training process. Two different networks were applied: (i) Self-Organizing Maps - SOM and (ii) Neural Net Fitting – NNF. The forecast data of the networks are compared with calculated for analytical results. This ANN performs a good forecast of data tested (NNF with R-squared results around 90%). The analyses confirm effects on relative permeability of oil and water with salt control, indicating wettability alteration (WA). These tests were able to confirm that the applied methodology is capable to predict, using ANN, results of several laboratory tests.
Song, Xianzhi (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing) | Pang, Zhaoyu (CNOOC Research Institute) | Xu, Zhengming (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing) | Li, Gensheng (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing) | Sun, Baojiang (China University of Petroleum, East China) | Zhu, Zhaopeng (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing) | Yang, Ruiyue (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing) | Lyu, Zehao (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing)
Microhole-horizontal-well-drilling technology is a high-efficiency and low-cost technology that has developed rapidly in recent years. However, during microhole-horizontal-well drilling, cuttings deposit easily at the bottom of the wellbore because of gravity and nonrotation of the pipe. The pipe sliding on the cuttings bed will cause extremely serious friction between the pipe and cuttings bed, which is an important limiting factor on the extended length of the microhole horizontal wellbore. Therefore, it is necessary to study the influencing factors and establish a model for evaluating the friction between the pipe and cuttings bed. In this study, laboratory experiments on the sliding friction between pipe and cuttings bed were conducted. By analyzing the comprehensive sliding-friction coefficient (CSFC) between the pipe and cuttings bed, the effects of dimensionless buried depth (0.2 to 1.0) and average cuttings size (0.249 to 2.667 mm) on the CSFC between the pipe and cuttings bed were obtained. CSFC is a function of dimensionless buried depth and relative roughness in the developed model. The results suggest that the sliding-friction resistance between the pipe and cuttings bed increases as the buried depth of pipe increases or the average cuttings size decreases. We propose a model for estimating the CSFC using experimental data and the least-squares method. The predictions show good agreement with the experimental data within suitable ranges of models. This work is expected to provide the basis for predicting the friction resistance between the pipe and cuttings bed.
Based on the geophysical survey data and basin evaluation results for the area around Japan until now and the analysis of the exploratory well data drilled for resource assessment, there are porous sandy and volcano-clastic rocks in the Pleistocene and Pliocene as the formations that satisfy the conditions as a CO2 injection reservoir. For the former, it is important to evaluate the ability of the sealing layer directly above because of the shallow formation below sea bottom floor, and for the latter, it is important to evaluate the CO2 injectivity because of the deeper horizon of less permeable.
Exploratory drillings for the assessment project of oil and natural gas potential were implemented by the Ministry of International Trade and Industry (MITI) at that time, offshore Akita, and cuttings lithology description, their petrographic / mineralogy analysis for whole depth interval, sequential formation pressure measurement, well logging measurement were carried out. Referring to such geological information, we conducted well log analysis on a provided borehole data for the sake of investigating capability of CO2 injection in the drilled formations. Outline of the analysis is reported in this article, then acquisition of indispensable data of the reservoir and sealing formation in the new exploratory drillings are proposed for establishing CO2 injection reservoir model.