The Hartha Formation has been investigated from a biostratigraphic view in three subsurface sections in the Nasiriyah Oil field, wells Ns1, Ns3, and Ns4, South of Iraq. Hartha Formation is composed of limestone and has various areas of intense dolomitization alternating with marly limestone. The formation ranges in thickness from 126 to 182 meters. Thirteen large and small benthic foraminifer species and genera are identified from Hartha Formation. Based on the large benthic foraminifer's assemblage, one distinct biozone was recognized after an examination of the paleontological datum in the investigated area showed that the studied wells contained a diversity of foraminiferal species, the larger foraminifers biozone was proposed: Orbitoides medius- Orbitoides tissoti - Orbitoides gensacicus -Orbitoides apiculatus - Omphalocyclus macroporus assemblage zone (Late Campanian- Early Maastrichtian), this biozone divided in two range subzone: Orbitoides medius Partial Range Zone (Late Campanian) and Omphalocyclus macroporus Range Zone (Early Maastrichtian). This biozone indicated that the Hartha Formation deposited through (Late Campanian- Early Maastrichtian).
This study deals with establishing the depositional environment of the Fatha Formation through facies analysis. It also deals with dividing the formation into units based on the rhythmic nature. Data from selected shallow wells near Hit area and deep wells at East Baghdad Oil field are used. Five major lithofacies are recognized in this study, namely, greenish grey marl, limestone, gypsum (and/or anhydrite), halite and reddish brown mudstone (with occasional sandstone).The limestone lithofacies is divided into three microfacies: Gastropods bioclastic wackestone microfacies, Gastropods peloidal bioclastic packstone, and Foraminiferal packstone microfacies.The lithofacies of the Fatha are nested in a rhythmic pattern or what is known as sh
... Show MoreThis study is achieved in the local area in Eridu oil field, where the Mishrif Formation is considered the main productive reservoir. The Mishrif Formation was deposited during the Cretaceous period in the secondary sedimentary cycle (Cenomanian-Early Turonian as a part of the Wasia Group a carbonate succession and widespread throughout the Arabian Plate. There are four association facies are identified in Mishrif Formation according the microfacies analysis: FA1-Deep shelf facies association (Outer Ramp); FA2-Slope (Middle Ramp); FA3-Reef facies (Shoal) association (Inner ramp); FA4-Back Reef facies association. Sequence stratigraphic analysis show there are three stratigraphic surfaces based on the abrupt changing in depositional
... Show MoreYamama Formation is an important sequence in southern Iraq. Petrographic analysis was used to determine and analyze the microfacies and pore types. The diagenetic processes and the impacts on the petrophysical properties of the rocks were also identified. The petrographic identification was based on data of 250 thin sections of cutting and core samples from four wells that were supplied by the Iraqi Oil Exploration Company (O.E.C). The present study focuses on the depositional environment and the microfacies analysis of Yamama Formation. The results revealed several types of microfacies, including peloidal wackestone-packstone, algal wackestone-packstone, bioclastic wackestone-packstone, fo
... Show MoreThe Yamama Formation represents a part of the Late Berriasian-Aptian sequence, deposited during the Early Cretaceous period within the main shallow marine depositional environment. The studied area covers three oil fields; Sindbad oil field, Halfaya and Ad'daimah oil field, located in southeastern Iraq. Six major microfacies were recognized in the succession of the studied area represented by the Yamama Formation to determine and recognize depositional paleoenvironments. These microfacies are; Peloidal Packstone, Algal Wackestone to Packstone, Bioclastic Wackestone – Packstone, Foraminiferal Bioclastic Wackstone, Packstone, Peloidal – Oolitic Grainstone and Mudstone Microfacies. These microfacies are classified int
... Show MoreSeventy three species of calcareous nannofossils are recorded from the studied section of Tanjero Formation at Azmer anticline, Sulimaniya, Northern Iraq. The studied section reveals four biozones arranged in an ascending order from oldest to youngest as follows; Tranolithus phacelosus Interval Biozone (CC23) Part, Rienhardtites lives Interval Biozone (CC24), Arkhangelskilla cymbiformis Interval Biozone (CC25), and Nephrolithus frequens Rang Biozone (CC26) Part. These biozones are correlated with other calcareous nannofossil biozones of both local and regional sections, leading to conclude a possible age of Late Campanian- Maastrichtian.
The current research deals with studying the petrophysical properties represented by the porosity and its distribution on the level of all units of the top and bottom of the Kirkuk Formation Group. The study area is located in Maysan province in the south-eastern part of Iraq in the Amara field. The Kirkuk Group was deposited in the Tertiary Age. The post-stack method using seismic inversion and creating a relationship between seismic data was accomplished using Hampson-Russel software at well Am-1 and Seismic lines Ama 20 and 30. The research results indicate high porosity values on top of the formation with a decrease in acoustic impedance (Z) and, therefore, a reduction in the density. At the same time, low porosity values were indica
... Show MoreThere are varieties of reasons lead for drilling horizontal wells rather than verticals. Increasing the recovery of oil, especially from thin or tight reservoir permeability is the most important parameter.
East Baghdad oil field considered as a giant field with approximately more than 1billion barrel of a proved reserves accompanying recently to low production rate problems in many of the existing wells.
It is important to say that presence of of horizontal wells in East Baghdad field especially by converting some of already drilled wells by re-entry drilling horizontal sections may provide one of best solutions for the primary development stage in East Baghdad field which may be followed by drilling n
... Show MoreThere are varieties of reasons lead for drilling horizontal wells rather than verticals. Increasing the recovery of oil, especially from thin or tight reservoir permeability is the most important parameter. East Baghdad oil field considered as a giant field with approximately more than 1billion barrel of a proved reserves accompanying recently to low production rate problems in many of the existing wells. It is important to say that presence of of horizontal wells in East Baghdad field especially by converting some of already drilled wells by re-entry drilling horizontal sections may provide one of best solutions for the primary development stage in East Baghdad field which may be followed by drilling new horizont
... Show MoreReservoir unit classifications can be used in reservoir characterization of carbonate reservoirs where there is variability in the distribution of petrophysical properties. This requires the integration of geological and petrophysical data at different scales. In this study, cores and thin sections from Yamama Formation (Lower Cretaceous) at Gharaf oilfield, southern Iraq, were studiedto identify reservoir units.
Ninereservoir units (units Y1 to Y9) were identified based on petrophysical evaluation by using interactive Petrophysics program (IP) software and depositional environments and related microfacies.The unit Y2 have the highest reservoir quality, which consists of grain-supported facies(packstone a
... Show MorePetrophysical properties of Mishrif Formation at Amara oil field is determined
from interpretation of open log data of (Am-1, 2 ,3 ,4 ,5 ,6 ,7 ,8 ,9 ,10 ,11 ,12
and13) wells. These properties include the total, the effected and the secondary
porosity, as well as the moveable and the residual oil saturation in the invaded and
uninvaded zones. According to petrophysical properties it is possible to divided
Mishrif Formation which has thickness of a proximately 400 m, into seven main
reservoir units (MA, MB11, MB12, MB13, MB21, MC1, MC2) . MA is divided into
four secondary reservoir units , MB11 is divided into five secondary reservoir units ,
MB12 is divided into two secondary reservoir units , MB13 is divided into