Keywords : Porosity


Determination of the Petrophysical Properties of the Khasib Reservoir, East Baghdad Oil Field, Middle Iraq

Muneef Mohammed; Ashraf Naif Hameed; Hussain Najem Abd

Iraqi National Journal of Earth Science, 2022, Volume 22, Issue 1, Pages 65-75
DOI: 10.33899/earth.2022.133567.1013

This study aims to determine and evaluate the petrophysical characteristics of the Khasib Formation, which represents the main oil-producing reservoir in the East Baghdad oilfield. To accomplish the aim of the study, the log data for five wells have been interpreted using the Schlumberger Techlog 2015.3 software. The main lithology of the Khasib Formation has been determined as limestone based on the interpretation of neutron, density, and sonic logs and using the M-N cross plot method. The shale volume was determined based on the gamma ray log, and the results showed that the shale volume in the Khasib Formation ranges from about 15% to about 27%, and this value increases toward the top of the formation. The total porosity of the Khasib Formation has been determined based on the density and neutron logs, and it is value ranges from about 12% to 23%. The effective porosity was calculated depending on the relationship between the total porosity and shale volume, and the value of this type of porosity ranges from 8% to 18%. The study showed that the B and C units of the Khasib Formation represent the best hydrocarbon-bearing zones, where these units are characterized by high values of effective porosity and oil saturation.

New Petrophysical Equations for Hartha-Tannuma Interval in the East Baghdad Oil Field

Maan Al-majid

Iraqi National Journal of Earth Science, 2019, Volume 19, Issue 2, Pages 136-152
DOI: 10.33899/earth.2019.170285

This study deals with empirical equations linking density and porosity with depth. The density and porosity information were taken from five well logs distributed in the East Baghdad oil field. New empirical equations (porosity - depth, density - depth) for two geological formations (Harta and Sa'di) within Hartha- Tannuma period were produced. The correlation coefficient (R) of these equations ranged from -0.37 to 0.68, which was attributed to variability in lithology and compaction. The depth data of (133) points suited at seismic lines grid scattered in the field were used for applying the new equations. After the new empirical equations that are applied on the whole field, porosity and density contour maps for the period (Hartha- Tannuma) and the two formations (Hartha and Sa'di) were plotted. The high porosity zones were identified, are related to the compaction and petroleum distribution in the field.

Porosity of Avanah Formation and its Stratigraphical Distribution in Selected Wells of Kirkuk Oil Field

Mohammed A. M. Sulaiman; Abdalaziz M. AL-Hamdany

Iraqi National Journal of Earth Science, 2014, Volume 14, Issue 1, Pages 49-66
DOI: 10.33899/earth.2014.87488

The dolomitic and recrystallized carbonates of Avanah Formation (Middle - Late Eocene) successions are characterized by relative high porosity and permeability. These successions, in the selected wells (K-432,K-117,K-149,K-319,K-339), start with brown-white, fractured, rigid and porous at lower dolomitic unit, overlain by dense-fractured, high porous, relatively rigid and brown dolomitic limestone; and finally ending by low-fractured, moderately rigid and porous white limestone. The rocks of the formation are rich in sieve mosaic dolomitic texture with lesser suture, spotted, fogged and poikilotopic textures, in addition to another diagenetic features, which are formed due to recrystallization, cementation, dissolution, physical compaction, dedolomitization and micritization. It is obvious that the dolomitization and dissolution have played a positive role in improving the porosity of specified rock units. On the contrary of the upper unit, both lower and middle units are characterized by their high porosity (vuggy, intercrystalline, fractured and moldic), whereas the porosity of the upper unit is restricted to fracture and intergranular types. By merging density and neutron logs for calculating the total and effective porosity of the successions, it is revealed that they are of high porosity (2-30%) which is coincident with the results of the plotted density - neutron log values on (b-ØN) chart. It is believed that the relative domination of diagenetic porosity diagnosed in the rocks of lower and middle successions of the formation, and its observed association with fractured porosity (Hybrid-2) on the other hand have improved the porosity and permeability of these rocks making them efficient to store and produce hydrocarbons.