Practical Criteria for Determining Grouting Methods Considering Rock-Type-Specific Groutability

Rock Grouting ◽  
1985 ◽  
pp. 300-340 ◽  
Author(s):  
Friedrich-Karl Ewert
Keyword(s):  
Rock Type

scholarly journals Gravity Analysis for Subsurface Characterization and Depth Estimation of Muda River Basin, Kedah, Peninsular Malaysia

2021 ◽  
Vol 11 (14) ◽  
pp. 6363
Author(s):  
Muhammad Noor Amin Zakariah ◽  
Norsyafina Roslan ◽  
Norasiah Sulaiman ◽  
Sean Cheong Heng Lee ◽  
Umar Hamzah ◽  
...  
Keyword(s):  
River Basin ◽  
Rock Type ◽  
Gravity Data ◽  
Power Spectral Analysis ◽  
Depth Estimation ◽  
Structural Features ◽  
Peninsular Malaysia ◽  
Gravity Survey ◽  
Basement Rock ◽  
Geophysical Techniques

Gravity survey is one of the passive geophysical techniques commonly used to delineate geological formations, especially in determining basement rock and the overlying deposit. Geologically, the study area is made up of thick quaternary alluvium deposited on top of the older basement rock. The Muda River basin constitutes, approximately, of more than 300 m of thick quaternary alluvium overlying the unknown basement rock type. Previous studies, including drilling and geo-electrical resistivity surveys, were conducted in the area but none of them managed to conclusively determine the basement rock type and depth precisely. Hence, a regional gravity survey was conducted to determine the thickness of the quaternary sediments prior to assessing the sustainability of the Muda River basin. Gravity readings were made at 347 gravity stations spaced at 3–5 km intervals using Scintrex CG-3 covering an area and a perimeter of 9000 km2 and 730 km, respectively. The gravity data were then conventionally reduced for drift, free air, latitude, Bouguer, and terrain corrections. These data were then consequently analyzed to generate Bouguer, regional and total horizontal derivative (THD) anomaly maps for qualitative and quantitative interpretations. The Bouguer gravity anomaly map shows low gravity values in the north-eastern part of the study area interpreted as representing the Main Range granitic body, while relatively higher gravity values observed in the south-western part are interpreted as representing sedimentary rocks of Semanggol and Mahang formations. Patterns observed in the THD anomaly and Euler deconvolution maps closely resembled the presence of structural features such as fault lineaments dominantly trending along NW-SE and NE-SW like the trends of topographic lineaments in the study area. Based on power spectral analysis of the gravity data, the average depth of shallow body, representing alluvium, and deep body, representing underlying rock formations, are 0.5 km and 1.2 km, respectively. The thickness of Quaternary sediment and the depth of sedimentary formation can be more precisely estimated by other geophysical techniques such as the seismic reflection survey.

scholarly journals A Model for Complex Subsidence Causality Interpretation Based on PS-InSAR Cross-Heading Orbits Analysis

2019 ◽  
Vol 11 (17) ◽  
pp. 2014 ◽  
Author(s):  
Bahaa Mohamadi ◽  
Timo Balz ◽  
Ali Younes
Keyword(s):  
Regression Analysis ◽  
Urban Areas ◽  
Rock Type ◽  
Linear Regression Analysis ◽  
City Center ◽  
Causal Factors ◽  
Final Model ◽  
Alexandria City ◽  
The City ◽  
Central South

Urban areas are subject to subsidence due to varying natural and anthropogenic causes. Often, subsidence is interpreted and correlated to a single causal factor; however, subsidence is usually more complex. In this study, we adopt a new model to distinguish different causes of subsidence in urban areas based on complexity. Ascending and descending Sentinel-1 data were analyzed using permanent scatterer interferometry (PS-InSAR) and decomposed to estimate vertical velocity. The estimated velocity is correlated to potential causes of subsidence, and modeled using different weights, to extract the model with the highest correlations among subsidence. The model was tested in Alexandria City, Egypt, based on three potential causes of subsidence: rock type, former lakes and lagoons dewatering (FLLD), and built-up load (BL). Results of experiments on the tested area reveal singular patterns of causal factors of subsidence distributed across the northeast, northwest, central south, and parts of the city center, reflecting the rock type of those areas. Dual causes of subsidence are found in the southwest and some parts of the southeast as a contribution of rock type and FLLD, whereas the most complex causes of subsidence are found in the southeast of the city, as the newly built-up areas interact with the rock type and FLLD to form a complex subsidence regime. Those areas also show the highest subsidence values among all other parts of the city. The accuracy of the final model was confirmed using linear regression analysis, with an R2 value of 0.88.

XXII.—The Petrology of Picritic Rocks in Minor Intrusions—a Hebridean Group

1959 ◽  
Vol 63 (3) ◽  
pp. 459-499 ◽  
Author(s):  
H. I. Drever ◽  
R. Johnston
Keyword(s):  
Source Rock ◽  
Rock Type ◽  
Basaltic Magma ◽  
Ultrabasic Rock ◽  
Working Hypothesis ◽  
Selective Fusion ◽  
Rich Liquid ◽  
Factual Data

SynopsisThe results are presented of a detailed petrological reconnaissance of a group of picritic minor intrusions in the Hebrides. A substantial amount of new factual data is subjected to a unified treatment as a basis for reference and discussion. Olivine phenocrysts are not appreciably zoned and there is no evidence that they have a reaction relation with the liquid represented by the groundmass. Variations in the size and amount of olivine in individual intrusions are examined in detail and attributed to composite intrusion of differentiated material. A distinctive non-porphyritic facies found in several sills and in one dyke is chemically analyzed. Four analyses from widely separated localities establish this facies as a remarkably invariant, eucritic rock-type. The composition of the groundmass of the picritic rocks is variable and there is no evidence whatever of the participation of basaltic magma in their formation. Although no attempt is made to explain the new data in detail, a comprehensive working hypothesis is formulated. The origin of such picritic intrusions is believed to be due to selective fusion of pre-existing ultrabasic rock. Liquid more basic than normal basalt magmas can be formed by this process. Some re-precipitation of olivine may have preceded final emplacement of a magnesia-rich liquid which contained xenocrysts, mainly of olivine, from the source rock.

Mineral nutrient mobilization by plants from rock: influence of rock type and arbuscular mycorrhiza

2015 ◽  
Vol 124 (1-3) ◽  
pp. 187-203 ◽  
Author(s):  
C. Burghelea ◽  
D. G. Zaharescu ◽  
K. Dontsova ◽  
R. Maier ◽  
T. Huxman ◽  
...  
Keyword(s):  
Arbuscular Mycorrhiza ◽  
Rock Type ◽  
Mineral Nutrient ◽  
Nutrient Mobilization

Rock Type Constrained 3D Reservoir Characterization and Modeling

2002 ◽  
Author(s):  
Fernando P.T. Silva ◽  
Ahmed A. Ghani ◽  
Abdulla Al Mansoori ◽  
Asnul Bahar
Keyword(s):  
Reservoir Characterization ◽  
Rock Type

Unsupervised machine learning using 3D seismic data applied to reservoir evaluation and rock type identification

2021 ◽  
pp. 1-69
Author(s):  
Marwa Hussein ◽  
Robert R. Stewart ◽  
Deborah Sacrey ◽  
Jonny Wu ◽  
Rajas Athale
Keyword(s):  
Machine Learning ◽  
Seismic Data ◽  
Rock Type ◽  
Seismic Attributes ◽  
Reservoir Quality ◽  
3D Seismic ◽  
Reservoir Properties ◽  
Unsupervised Machine Learning ◽  
Amplitude Data ◽  
3D Seismic Data

Net reservoir discrimination and rock type identification play vital roles in determining reservoir quality, distribution, and identification of stratigraphic baffles for optimizing drilling plans and economic petroleum recovery. Although it is challenging to discriminate small changes in reservoir properties or identify thin stratigraphic barriers below seismic resolution from conventional seismic amplitude data, we have found that seismic attributes aid in defining the reservoir architecture, properties, and stratigraphic baffles. However, analyzing numerous individual attributes is a time-consuming process and may have limitations for revealing small petrophysical changes within a reservoir. Using the Maui 3D seismic data acquired in offshore Taranaki Basin, New Zealand, we generate typical instantaneous and spectral decomposition seismic attributes that are sensitive to lithologic variations and changes in reservoir properties. Using the most common petrophysical and rock typing classification methods, the rock quality and heterogeneity of the C1 Sand reservoir are studied for four wells located within the 3D seismic volume. We find that integrating the geologic content of a combination of eight spectral instantaneous attribute volumes using an unsupervised machine-learning algorithm (self-organizing maps [SOMs]) results in a classification volume that can highlight reservoir distribution and identify stratigraphic baffles by correlating the SOM clusters with discrete net reservoir and flow-unit logs. We find that SOM classification of natural clusters of multiattribute samples in the attribute space is sensitive to subtle changes within the reservoir’s petrophysical properties. We find that SOM clusters appear to be more sensitive to porosity variations compared with lithologic changes within the reservoir. Thus, this method helps us to understand reservoir quality and heterogeneity in addition to illuminating thin reservoirs and stratigraphic baffles.

Enhanced and Rock Typing-Based Reservoir Characterization of the Palaeocene Harash Carbonate Reservoir-Zelten Field-Sirte Basin-Libya

2021 ◽  
Author(s):  
Mohamed Masoud ◽  
W. Scott Meddaugh ◽  
Masoud Eljaroshi ◽  
Khaled Elghanduri
Keyword(s):  
Rock Type ◽  
Carbonate Reservoir ◽  
Classification Model ◽  
Reservoir Rocks ◽  
The Core ◽  
Core Samples ◽  
Rock Types ◽  
Rock Typing ◽  
Open Hole ◽  
Type Classification

Abstract The Harash Formation was previously known as the Ruaga A and is considered to be one of the most productive reservoirs in the Zelten field in terms of reservoir quality, areal extent, and hydrocarbon quantity. To date, nearly 70 wells were drilled targeting the Harash reservoir. A few wells initially naturally produced but most had to be stimulated which reflected the field drilling and development plan. The Harash reservoir rock typing identification was essential in understanding the reservoir geology implementation of reservoir development drilling program, the construction of representative reservoir models, hydrocarbons volumetric calculations, and historical pressure-production matching in the flow modelling processes. The objectives of this study are to predict the permeability at un-cored wells and unsampled locations, to classify the reservoir rocks into main rock typing, and to build robust reservoir properties models in which static petrophysical properties and fluid properties are assigned for identified rock type and assessed the existed vertical and lateral heterogeneity within the Palaeocene Harash carbonate reservoir. Initially, an objective-based workflow was developed by generating a training dataset from open hole logs and core samples which were conventionally and specially analyzed of six wells. The developed dataset was used to predict permeability at cored wells through a K-mod model that applies Neural Network Analysis (NNA) and Declustring (DC) algorithms to generate representative permeability and electro-facies. Equal statistical weights were given to log responses without analytical supervision taking into account the significant log response variations. The core data was grouped on petrophysical basis to compute pore throat size aiming at deriving and enlarging the interpretation process from the core to log domain using Indexation and Probabilities of Self-Organized Maps (IPSOM) classification model to develop a reliable representation of rock type classification at the well scale. Permeability and rock typing derived from the open-hole logs and core samples analysis are the main K-mod and IPSOM classification model outputs. The results were propagated to more than 70 un-cored wells. Rock typing techniques were also conducted to classify the Harash reservoir rocks in a consistent manner. Depositional rock typing using a stratigraphic modified Lorenz plot and electro-facies suggest three different rock types that are probably linked to three flow zones. The defined rock types are dominated by specifc reservoir parameters. Electro-facies enables subdivision of the formation into petrophysical groups in which properties were assigned to and were characterized by dynamic behavior and the rock-fluid interaction. Capillary pressure and relative permeability data proved the complexity in rock capillarity. Subsequently, Swc is really rock typing dependent. The use of a consistent representative petrophysical rock type classification led to a significant improvement of geological and flow models.

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