scholarly journals Petrophysical core-based zonation of OW oilfield in the Bredasdorp Basin South Africa

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Mimonitu Opuwari ◽  
Blessing Afolayan ◽  
Saeed Mohammed ◽  
Paschal Ogechukwu Amaechi ◽  
Youmssi Bareja ◽  
...  
Keyword(s):  
South Africa ◽  
Reservoir Rock ◽  
Reservoir Quality ◽  
Rock Types ◽  
Flow Units ◽  
Reservoir Zonation ◽  
Class 1 ◽  
Core Permeability ◽  
First Time ◽  
Clastic Reservoir

AbstractThis study aims to generate rock units based on core permeability and porosity of OW oilfield in the Bredasdorp Basin offshore South Africa. In this study, we identified and classified lithofacies based on sedimentology reports in conjunction with well logs. Lucia's petrophysical classification method is used to classify rocks into three classes. Results revealed three lithofacies as A (sandstone, coarse to medium-grained), B (fine to medium-grained sandstone), and C (carbonaceous claystone, finely laminated with siltstone). Lithofacies A is the best reservoir quality and corresponds to class 1, while lithofacies B and C correspond to class 2 and 3, which are good and poor reservoir quality rock, respectively. An integrated reservoir zonation for the rocks is based on four different zonation methods (Flow Zone indicator (FZI), Winland r35, Hydraulic conductivity (HC), and Stratigraphy modified Lorenz plot (SMLP)). Four flow zones Reservoir rock types (RRTs) were identified as RRT1, RRT3, RRT4, and RRT5, respectively. The RRT5 is the best reservoir quality composed of a megaporous rock unit, with an average FZI value between 5 and 10 µm, and HC from 40 to 120 mD/v3, ranked as very good. The most prolific flow units (RRT5 and RRT4 zones) form more than 75% of each well's flow capacities are supplied by two flow units (FU1 and FU3). The RRT1 is the most reduced rock quality composed of impervious and nanoporous rock. Quartz is the dominant framework grain, and siderite is the dominant cement that affects flow zones. This study has demonstrated a robust approach to delineate flow units in the OW oilfield. We have developed a useful regional petrophysical reservoir rock flow zonation model for clastic reservoir sediments. This study has produced, for the first time, insights into the petrophysical properties of the OW oilfield from the Bredasdorp Basin South Africa, based on integration of core and mineralogy data. A novel sandstone reservoir zonation classification criteria developed from this study can be applied to other datasets of sandstone reservoirs with confidence.

scholarly journals Petrophysical Core-Based Zonation of An Oil Field In The Bredasdorp Basin South Africa

2021 ◽  
Author(s):  
Mimonitu Opuwari ◽  
Blessing Afolanyan ◽  
Saeed Mohammed ◽  
Paschal Ogechukwu Amaechi ◽  
Y Bareja ◽  
...  
Keyword(s):  
South Africa ◽  
Oil Field ◽  
Reservoir Quality ◽  
Dominant Effect ◽  
Rock Unit ◽  
Flow Units ◽  
Rock Quality ◽  
Reservoir Zonation ◽  
Class 1 ◽  
Core Permeability

Abstract This study aims to generate rock units based on core permeability and porosity of an oil field in the Bredasdorp Basin offshore South Africa. In this study, we identified and classified lithofacies based on sedimentology reports in conjunction with well logs. Lucia's petrophysical classification method is used to classify rocks into three classes. Results revealed three lithofacies as A(sandstone, coarse to medium-grained), B (fine to medium-grained sandstone), and C (carbonaceous claystone, finely laminated with siltstone). Lithofacies A is the best reservoir quality and corresponds to class 1, while lithofacies B and C correspond to class 2 and 3, which are good and poor reservoir quality rock, respectively. An integrated reservoir zonation for the rocks is based on four different zonation methods (Flow Zone indicator (FZI), Winland r35, Hydraulic conductivity (HC), and Stratigraphy modified Lorenz plot (SMLP)). Four flow zones were identified as high(HFZ), moderate (MFZ), Low (LFZ), and tight (TFZ), respectively. The HFZ is the best reservoir quality composed of a megaporous rock unit, with an average FZI value between 5 to 10µm, and HC from 40 to 120 mD/v3, ranked as very good. The most prolific flow units (HFZ and MFZ zones) form more than 75 % of each well's flow capacities. The TFZ is the most reduced rock quality composed of impervious and nanoporous rock. There appears to be a slight increase of illite in the tight and low zones that block pore throats, thereby decreasing permeability. Therefore, illite has a dominant effect on flow zones. Quartz is the dominant framework grain, and siderite is the dominant cement that affects flow zones. This study has demonstrated a robust approach to delineate flow units in an oilfield. A novel sandstone reservoir zonation classification criteria developed from this study can be applied to other datasets of sandstone reservoirs with confidence.

scholarly journals Rock typing based on hydraulic and electric flow units for reservoir characterization of Nubia Sandstone, southwest Sinai, Egypt

2021 ◽  
Author(s):  
Abdel Moktader A. El-Sayed ◽  
Nahla A. El Sayed ◽  
Hadeer A. Ali ◽  
Mohamed A. Kassab ◽  
Salah M. Abdel-Wahab ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Reservoir Characterization ◽  
Flow Unit ◽  
Reservoir Quality ◽  
Thin Sections ◽  
Hydraulic Flow ◽  
Rock Types ◽  
Flow Units ◽  
Reservoir Quality Index ◽  
Hydraulic Flow Units

AbstractThe present work describes and evaluates the reservoir quality of the sandstone of the Nubia Formation at the Gebel Abu Hasswa outcrop in southwest Sinai, Egypt. Hydraulic flow unit (HFU) and electrical flow unit (EFU) concepts are implied to achieve this purpose. The Paleozoic section made up of four formations has been studied. The oldest is Araba Formation followed by Naqus formations (Nubia C and D) overlay by Abu Durba, Ahemir and Qiseib formations (Nubia B), where the Lower Cretaceous (Nubia A) is represented by the Malha Formation. The studied samples have been collected from Araba, Abu Durba, Ahemir and the Malha formations. The hydraulic flow unit (HFU) discrimination was carried out based on permeability and porosity relationship, whereas the electrical flow unit (EFU) differentiation was carried out based on the relationship between formation resistivity factor and porosity. Petrographic investigation of the studied thin sections illustrates that the studied samples are mainly quartz arenite. Important roles to enhance or reduce the pore size and/or pore throats controlling the reservoir petrophysical behavior are due to the diagenetic processes. The present study used the reservoir quality index (RQI) and Winland R35 as additional parameters applied to discriminate the HFUs. The study samples have five hydraulic flow units of different rock types, where the detected electrical flow units are only three. The differences between them are may be due to the cementation process with iron oxides that might act as pore filling, lining and pore bridging, sometimes bridges helping to decrease permeability without serious reduction in porosity. The reduction between the number of EFUs and HFUs comes from the effect of diagenesis processes which is responsible for a precipitation of different cement types such as different clay minerals and iron oxides.

scholarly journals Comparative Permeability Estimation Method and Identification of Rock Types using Cluster Analysis from Well Logs and Core Analysis Data in Tertiary Carbonate Reservoir-Khabaz Oil Field

2019 ◽  
Vol 25 (12) ◽  
pp. 49-61
Author(s):  
Adnan Ajam Abed ◽  
Sammer Mohammed Hamd-Allah
Keyword(s):  
Cluster Analysis ◽  
Carbonate Reservoir ◽  
Flow Unit ◽  
Well Logs ◽  
Analysis Approach ◽  
Flow Zone ◽  
Hydraulic Flow ◽  
Rock Types ◽  
Flow Units ◽  
Reservoir Zonation

Characterization of the heterogonous reservoir is complex representation and evaluation of petrophysical properties and application of the relationships between porosity-permeability within the framework of hydraulic flow units is used to estimate permeability in un-cored wells. Techniques of flow unit or hydraulic flow unit (HFU) divided the reservoir into zones laterally and vertically which can be managed and control fluid flow within flow unit and considerably is entirely different with other flow units through reservoir. Each flow unit can be distinguished by applying the relationships of flow zone indicator (FZI) method. Supporting the relationship between porosity and permeability by using flow zone indictor is carried out for evaluating the reservoir quality and identification of flow unit used in reservoir zonation.  In this study, flow zone indicator has been used to identify five layers belonging to Tertiary reservoirs. Consequently, the porosity-permeability cross plot has been done depending on FZI values as groups and for each group denoted to reservoir rock types. On the other hand, extending rock type identification in un-cored wells should apply a cluster analysis approach by using well logs data. Reservoir zonation has been achieved by cluster analysis approach and for each group known as cluster which variation and different with others. Five clusters generated in this study and permeability estimated depend on these groups in un-cored wells by using well log data that gives good results compared with different empirical methods.

Petrophysical characterization, microfacies analysis, and diagenetic attributes of the Lower Jurassic surface analog sequence in Gebel El-Maghara area, north Sinai, Egypt

2021 ◽  
Author(s):  
Bassem Nabawy ◽  
Abdelbaset M. Abudeif ◽  
Marwa M. Masoud
Keyword(s):  
Clay Content ◽  
Xrd Analysis ◽  
Lower Jurassic ◽  
Reservoir Rock ◽  
Reservoir Quality ◽  
Reservoir Properties ◽  
Rock Types ◽  
Mineral Components ◽  
Reservoir Quality Index ◽  
North Sinai

Abstract This study concerns with the petrophysical characteristics of the Lower Jurassic surface analog in Gebel El-Maghara area (from base to top Mashaba, Rajabia, and Shusha formations), north Sinai, Egypt and implementation of the mineral components and diagenetic controls on reservoir characteristics. A full set of petrophysical measurements including porosity (∅He), permeability (k), grain and bulk densities (σg and σb, respectively), and true formation resistivity factor was applied. The Lower Jurassic sequence is subdivided into five hydraulic flow units (HFUs) that consist of three reservoir rock types (RRTs). These RRTs are composed of three microfacies association (MFAs). The RRT1 plug samples consist of the mostly clastic MFA1; they are porous, permeable, and have good reservoir quality that is using the flow zone indicator (FZI), and the reservoir quality index (RQI). The lowest reservoir quality is assigned to the RRT samples which are mostly composed tight carbonates. Based on the petrographical studies, SEM imaging, and the XRD analysis, dissolution and fracturing slightly enhanced the reservoir potentiality of the RRT1 samples, whereas physical compaction, tight cementation, and authigenic clay content (kaolinite, hematite, and goethite) are responsible for deterioration of the reservoir properties of RRT3 samples and reduction of the RRT2 samples.

The Legal Status of Local Government in South Africa under the New Constitutional Dispensation

2018 ◽  
Vol 33 (2) ◽  
Author(s):  
Mbuzeni Mathenjwa
Keyword(s):  
South Africa ◽  
Local Government ◽  
Legal Status ◽  
Case Law ◽  
The Status ◽  
History Of ◽  
The Republic ◽  
First Time

The history of local government in South Africa dates back to a time during the formation of the Union of South Africa in 1910. With regard to the status of local government, the Union of South Africa Act placed local government under the jurisdiction of the provinces. The status of local government was not changed by the formation of the Republic of South Africa in 1961 because local government was placed under the further jurisdiction of the provinces. Local government was enshrined in the Constitution of the Republic of South Africa arguably for the first time in 1993. Under the interim Constitution local government was rendered autonomous and empowered to regulate its affairs. Local government was further enshrined in the final Constitution of 1996, which commenced on 4 February 1997. The Constitution refers to local government together with the national and provincial governments as spheres of government which are distinctive, interdependent and interrelated. This article discusses the autonomy of local government under the 1996 Constitution. This it does by analysing case law on the evolution of the status of local government. The discussion on the powers and functions of local government explains the scheme by which government powers are allocated, where the 1996 Constitution distributes powers to the different spheres of government. Finally, a conclusion is drawn on the legal status of local government within the new constitutional dispensation.

Implications for the age of South African Devonian rocks in which Tropidoleptus (Brachiopoda) has been found

1983 ◽  
Vol 120 (1) ◽  
pp. 51-58 ◽  
Author(s):  
A. J. Boucot ◽  
C. H. C. Brunton ◽  
J. N. Theron
Keyword(s):  
South Africa ◽  
North America ◽  
South African ◽  
Early Carboniferous ◽  
Fossil Plants ◽  
Geological Time ◽  
Marine Sedimentation ◽  
History Of ◽  
Near Shore ◽  
First Time

SummaryThe Devonian brachiopod Tropidoleptus is recognized for the first time in South Africa. It is present in the lower part of the Witteberg Group at four widely separated localities. Data regarding the stratigraphical range of the genus elsewhere, combined with information on recently described fossil plants and vertebrates from underlying strata of the upper Bokkeveld Group, suggest that a Frasnian or even Givetian age is reasonable for the lower part of the Witteberg Group. The recognition of Tropidoleptus in a shallow water, near-shore, molluscan association, at the top of the South African marine Devonian sequence, is similar to its occurrence in Bolivia, and suggests a common Malvinokaffric Realm history of shallowing, prior to later Devonian or early Carboniferous non-marine sedimentation. It is noteworthy that Tropidoleptus is now known to occur in ecologically suitable environments around the Atlantic, but is absent from these same environments in Asia and Australia. Tropidoleptus is an excellent example of dispersal in geological time — first appearing in northern Europe and Nova Scotia, then elsewhere in eastern North America and North Africa, followed by South America and South Africa, while continuing in North America.

Reservoir Rock Types Application - Kashagan

2009 ◽  
Author(s):  
Arrigo Francesconi ◽  
Francesco Bigoni ◽  
Piero Balossino ◽  
nicola bona ◽  
Francesco Marchini ◽  
...  
Keyword(s):  
Reservoir Rock ◽  
Rock Types
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