scholarly journals Diagenetic Processes Overprint and Pore Types of Mauddud Formation, Badra Oil Field, Central Iraq

2020 ◽  
pp. 1353-1361
Author(s):  
Mena Jamal Faisal ◽  
Thamer A. Mahdi
Keyword(s):  
Effective Porosity ◽  
Oil Field ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Diagenetic Processes ◽  
Different Types ◽  
Interparticle Porosity ◽  
Calcite Cement ◽  
Primary Porosity ◽  
Pore Types

Diagenetic processes and types of pores that control the reservoir properties are studied for Mauddud Formation in selected wells of Badra oil field, central Iraq. The microscopic study of the thin sections shows the effects of micritization, cementation, neomorphism, dissolution, dolomitization, compaction, and fracturing on Mauddud Formation carbonate microfacies. The decrease of porosity is resulted from cementation, compaction, and neomorphism. Different types of calcite cement occlude pore spaces such as drusy cement, syntaxial rim cement, and granular (blocky) cement. The neomorphism of micritic matrix and skeletal grains reduces porosity as indicated by development of microspar or pseudospar. Evidence of decreasing porosity by compaction includes closer packing of grains, which reduces interparticle porosity. Dissolution process has prominent effect in creating and increasing the effective porosity in different depositional textures of Mauddud Formation. Reservoir properties are increased in grain-supported microfacies, which have vuggy porosity or primary porosity, whose pore size differs depending on the size of the grains. The reservoir properties in the mud-supported microfacies are reduced due to the low occurrence of pores and their lack of connectivity if they exist.

scholarly journals Hartha Formation divisions Based on Well Logs Analysis in Majnoon Oil Field, Southern Iraq

2020 ◽  
pp. 1362-1369
Author(s):  
Gheed Chaseb ◽  
Thamer A. Mahdi
Keyword(s):  
Water Saturation ◽  
Effective Porosity ◽  
Oil Field ◽  
Well Logs ◽  
Petrophysical Properties ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Facies Associations ◽  
Log Interpretation ◽  
Well Logs Interpretation

This study aims to evaluate reservoir characteristics of Hartha Formation in Majnoon oil field based on well logs data for three wells (Mj-1, Mj-3 and Mj-11). Log interpretation was carried out by using a full set of logs to calculate main petrophysical properties such as effective porosity and water saturation, as well as to find the volume of shale. The evaluation of the formation included computer processes interpretation (CPI) using Interactive Petrophysics (IP) software.  Based on the results of CPI, Hartha Formation is divided into five reservoir units (A1, A2, A3, B1, B2), deposited in a ramp setting. Facies associations is added to well logs interpretation of Hartha Formation, and was inferred by a microfacies analysis of thin sections from core and cutting samples. The CPI shows that the A2 is the main oil- bearing unit, which is characterized by good reservoir properties, as indicated by high effective porosity, low water saturation, and low shale volume. Less important units include A1 and A3, because they have low petrophysical properties compared to the unit A2.

scholarly journals Petrophysical Properties and Digenetic Evolution of Shuaiba Formation in Nasiriyah Oil Field, Southern Iraq

2021 ◽  
pp. 4810-4818
Author(s):  
Marwah H. Khudhair
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Middle Part ◽  
Effective Porosity ◽  
Oil Field ◽  
Neutron Density ◽  
Petrophysical Properties ◽  
Secondary Porosity ◽  
Primary Porosity ◽  
Gamma Ray Log

     Shuaiba Formation is a carbonate succession deposited within Aptian Sequences. This research deals with the petrophysical and reservoir characterizations characteristics of the interval of interest in five wells of the Nasiriyah oil field. The petrophysical properties were determined by using different types of well logs, such as electric logs (LLS, LLD, MFSL), porosity logs (neutron, density, sonic), as well as gamma ray log. The studied sequence was mostly affected by dolomitization, which changed the lithology of the formation to dolostone and enhanced the secondary porosity that replaced the primary porosity. Depending on gamma ray log response and the shale volume, the formation is classified into three zones. These zones are A, B, and C, each can be split into three rock intervals in respect to the bulk porosity measurements. The resulted porosity intervals are: (I) High to medium effective porosity, (II) High to medium inactive porosity, and (III) Low or non-porosity intervals. In relevance to porosity, resistivity, and water saturation points of view, there are two main reservoir horizon intervals within Shuaiba Formation. Both horizons appear in the middle part of the formation, being located within the wells Ns-1, 2, and 3. These intervals are attributed to high to medium effective porosity, low shale content, and high values of the deep resistivity logs. The second horizon appears clearly in Ns-2 well only.

scholarly journals An Integrated Microfacies and Well Logs-Based Reservoir Characterization of Yamama Formation, Southern Iraq

2021 ◽  
pp. 3570-3586
Author(s):  
Mohanad M. Al-Ghuribawi ◽  
Rasha F. Faisal
Keyword(s):  
Reservoir Characterization ◽  
Water Saturation ◽  
Effective Porosity ◽  
Well Logs ◽  
Petrophysical Properties ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Porosity And Permeability ◽  
South Of Iraq ◽  
Southern Iraq

     The Yamama Formation includes important carbonates reservoir that belongs to the Lower Cretaceous sequence in Southern Iraq. This study covers two oil fields (Sindbad and Siba) that are distributed Southeastern Basrah Governorate, South of Iraq. Yamama reservoir units were determined based on the study of cores, well logs, and petrographic examination of thin sections that required a detailed integration of geological data and petrophysical properties. These parameters were integrated in order to divide the Yamama Formation into six reservoir units (YA0, YA1, YA2, YB1, YB2 and YC), located between five cap rock units. The best facies association and petrophysical properties were found in the shoal environment, where the most common porosity types were the primary (interparticle) and secondary (moldic and vugs) . The main diagenetic process that occurred in YA0, YA2, and YB1 is cementation, which led to the filling of pore spaces by cement and subsequently decreased the reservoir quality (porosity and permeability). Based on the results of the final digital  computer interpretation and processing (CPI) performed by using the Techlog software, the units YA1 and YB2 have the best reservoir properties. The unit YB2 is characterized by a good effective porosity average, low water saturation, good permeability, and large thickness that distinguish it from other reservoir units.

Depositional Environment and Diagenesis processes impact on the carbonate rock quality: a case study, southeastern of Iraq

2019 ◽  
Vol 60 (5) ◽  
pp. 1104-1114
Author(s):  
Afrah Hassan Saleh
Keyword(s):  
High Energy ◽  
Negative Influence ◽  
Depositional Environments ◽  
Carbonate Reservoir ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Diagenetic Processes ◽  
Marine Lagoon ◽  
Lagoon Environment ◽  
Low Porosity

Deposition environment and diagenesis processes are very important factors which affect and control the reservoir properties.  The carbonate Mishrif Formation has been selected as a carbonate reservoir in selected wells from southeastern Iraq to understand the influence of the Deposition environment and diagenesis processes on the carbonate reservoir. A core examination of thin sections, shows that Mishrif Formation comprises of six depositional environments, these are: deep marine, lagoon, rudist biostrome, back shoal, and shallow open marine.  These environments have effect by many diagenetic processes, including dolomitization, dissolution, micritization, cementation, recrystallization and Stylolite, some of these processes have improved the reservoir properties of the Mishrif reservoir, these are: dissolution, dolomitization and the stylolization.  The others diagenetic processes have negative influence on the Petrophysical properties, such as cementation, compaction, and recrystallization processes, which damage the porosity and decrease the pore size. The reservoir properties are controlled by deposition environment, where lagoon environment is mostly compact with low porosity, shoal environment reflects a high energy and grain-supported environment and has good reservoir potential, deep-marine environments consist of mudstone to wackestone, which represents low energy level with low porosity and represents the non-reservoir environment.

scholarly journals Reservoir units of Mishrif Formation in Majnoon Oil field, Southern Iraq

2019 ◽  
pp. 2656-2663
Author(s):  
Layla khudhur Abbas ◽  
Thamar Abdullah Mahdi
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
High Volume ◽  
Effective Porosity ◽  
Oil Field ◽  
Reservoir Properties ◽  
Marine Facies ◽  
Wireline Logs ◽  
Low Volume ◽  
Southern Iraq

The reservoir units of Mishrif Formation in Majnoon oil field were studied by using available wireline logs (gamma ray, porosity and resistivity) and facies that derived from core and cutting samples for three wells including Mj-1, Mj-15, and Mj-20. The reservoir properties were determined and interpreted by using IP software. The results showed that unit D have the best reservoir properties due to high effective porosity, low water saturation and very low volume of shale. Furthermore, a large part of this unit was deposited in shoal environment. The other reservoir units are then graded in reservoir properties including units B, A, F & E respectively, except unit C, which is considered as a cap unit, because it consists of restricted marine facies so that; it has high volume of shale and water saturation and very low effective porosity.

scholarly journals Diagenetic evolution of fault zones in Urgonian microporous carbonates, impact on reservoir properties (Provence – SE France)

2019 ◽  
Author(s):  
Irène Aubert ◽  
Philippe Leonide ◽  
Juliette Lamarche ◽  
Roland Salardon
Keyword(s):  
Fault Zone ◽  
Polarized Light ◽  
Fluid Flows ◽  
Fault Zones ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Calcite Cement ◽  
Diagenetic Evolution ◽  
Isotopic Measurements ◽  
Se France

Abstract. Microporous carbonate rocks form important reservoirs with high a permeability variability depending of sedimentary, structural and diagenetic factors. Carbonates are very sensitive to fluids-rock interactions that trigger to secondary processes like cementation and dissolution leading to reservoir properties modifications. As they can act as drains or barriers, fault zones influence the fluid flows in the upper part of Earth crust and increase the fluid-rock interactions. The aim of this study is to identify fault zone impact on fluid flows and reservoir properties during basin geodynamic history. The study focuses on 2 fault zones of the Eastern part of La Fare Anticlinal (SE France) where Urgonian microporous carbonates underwent polyphase tectonics and diagenesis. We took 122 samples along 4 transects cross-cutting two fault zones. Porosity values have been measured on 92 dry plugs. Diagenetic properties of samples have been determined on 92 thin sections using Polarized Light Microscopy, cathodoluminescence, red alizarin, SEM and isotopic measurements (δ13C and δ18O). Height calcite cement stages and 2 micrite micro-fabrics have been identified. This study highlight that fault zones acted as drain canalizing low temperature fluids at their onset, and induced fault zone cementation with two cementation phases, what has strongly altered and modified local reservoir properties.

scholarly journals Diagenesis Processes Impact on Reservoir Quality in Carbonate Yamama Formation /Faihaa Oil Field

2020 ◽  
pp. 92-102
Author(s):  
Mohammed A. Ahmed ◽  
Madhat E. Nasser ◽  
Sameer N. AL Jawad
Keyword(s):  
Oil Field ◽  
Reservoir Quality ◽  
Genetic Classification ◽  
Thin Sections ◽  
Positive Effects ◽  
Diagenetic Processes ◽  
Porosity And Permeability ◽  
Cretaceous Period ◽  
The Impact

The Yamama Formation is a significant reservoir in the southern part of Iraq. This formation consists of limestone deposited throughout the Lower Cretaceous period within main retrogressive depositional series. This study aims to identify the impact of the diagenesis processes on the reservoir’s characteristics (porosity and permeability). Diagenesis processes’ analysis and the identification of Yamama Formation depended on the examination of more than 250 thin sections of the core samples from two wells that were used to determine different diagenetic environments and processes. The three identified diagenetic environments that affected Yamama reservoir were the marine, meteoric and burial environments. Eight diagenetic processes were recognized in Yamama Formation and showed positive and destructive effects on the reservoir quality; Dissolution and fracture had highly positive effects through creating and improving porosity and permeability that led to improving reservoir quality. Cementation and compaction had destructive effects, through reducing porosity and permeability, that led to reducing reservoir quality. Other processes such micritization, dolomitization, bioturbation and neomorphism did not have strong effects on reservoir quality. Based on genetic classification of porosity, most of porosity within Yamama Formation in this field was formed by diagenesis processes, implying that Yamama reservoir is a type of diagenetic reservoir.

scholarly journals 3D Facies Modeling of Mishrif Reservoir in Halfaya Oil Field

2021 ◽  
pp. 180-191
Author(s):  
Medhat E. Nasser
Keyword(s):  
Water Saturation ◽  
Sedimentary Facies ◽  
High Water ◽  
Oil Field ◽  
Microfacies Analysis ◽  
Facies Modeling ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Sedimentary Environments ◽  
Log Interpretation

     This research deals with the study of the types and distribution of petrographic microfacies and Paleoenvironments of Mishrif Formation in Halfaya oil field, to define specific sedimentary environments. These environments were identified by microscopic examination of 35 thin sections of cutting samples for well HF-9H as well as 150 thin sections of core and cutting samples for well HF-I. Depending on log interpretation of wells HF-1, HF-316, HF-109, IIF-115, and IIF-272, the sedimentary facies were traced vertically through the use of various logs by Petrel 2013 software in addition to previous studies. Microfacies analysis showed the occurrence of six main Paleoenvironments within Mishrif succession, represented by basin, slope, shoal, Rudist biostrome, back shoal, and lagoon. Mishrif Formation was divided into six reservoir units depending on well logs and CPI. These units are separated by low porosity and high-water saturation of barrier beds. The reservoir beds from top to bottom are MA, MB1, MB2, MCI, and MC2. The reservoir units MB1, MB2, and MCI are the most important in the field of interest due to good reservoir properties and being the principle oil-bearing units in Mishrif Formation.

scholarly journals Petrofacies and diagenetic processes of la Victoria formation (Early Miocene), Dina oil field, upper Magdalena valley basin, Colombia.

2020 ◽  
Vol 10 (1) ◽  
pp. 33-44
Author(s):  
Juan Jose Gomez Caro ◽  
Angelica María Carreño Parra ◽  
María del Rosario P´érez Trejos ◽  
Edgar Ricardo Pérez ◽  
Luis Fernando Peña Peña ◽  
...  
Keyword(s):  
Oil Field ◽  
Early Miocene ◽  
Hydrocarbon Migration ◽  
Clastic Rocks ◽  
Diagenetic Processes ◽  
Calcite Cement

The sandstones at the base of the Honda Group (La Victoria Formation - Early Miocene), in the Dina Field, Upper Magdalena Valley Basin (UMVB) – Colombia, which are present in the analyzed interval of the Dina Norte 27 and Dina Norte 37 wells, are composed of immature clastic rocks classified as Litharenites / Feldspathic Litharenites, due to the presence of volcanic fragments, feldspar / plagioclase and unstable minerals.They are texturally immature due to poor selection and low roundness of the detritus. The following sequence of diagenetic processes is proposed: minor compaction; grain coating by illite/smectite detritical clay, dissolution of unstable minerals, zeolite (heulandite) precipitation, partial precipitation of nonferroan calcite cement and finally chloritization of clays prior to hydrocarbon migration.

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