Reservoir Rock Properties of the Upper Cretaceous Shiranish Formation in Taq Taq Oilfield, Iraqi Kurdistan Region

Abstract

Reservoir rock properties of the tight carbonate of Upper Cretaceous Shiranish Formation was studied in three selected wells in Taq Taq Oilfield/ Iraqi Kurdistan Region. The penetrated thickness of the formation by the studied wells of TT-04, TT-20, and TT-21 were 249, 290.8, and 236m respectively. The available logs and core test data were mainly dependant in characterizing the formation. The dominant limestone lithology of the formation was identified using Neutron-Density and M-N crossplots. The shale content, as calculated from the Gamma ray log, appeared to be highest in the lower part of the formation with about 15-30%. The shale content of Shiranish Formation are mainly consists of Glauconite, Illite, and Micas with a little contribution from other kinds of clay minerals like Montmorillonite. The total porosity of Shiranish Formation is generally less than 10% whereas the lower part of the formation has the lowest porosity (less than 5%). The calculated permeability through Multiple Regression Analysis method and by using the available core test data showed that The formation is generally of less than 10mD permeability. The lower part of the formation (at the two wells of TT-20 and TT-21) has relatively higher permeability compared to the middle and upper part of the formation. Three distinctive reservoir units were identified in this study in Shiranish Formation depending on variations in the shale content, porosity, and permeability. Reservoir unit (RU-1) at the upper part of the formation in the well TT-21is considered to be of the best reservoir property among the identified reservoir units in the three studied wells. The expected contribution of minor and large fractures in enhancing the permeability of the formation approved through output of the existed Formation Micro Image log for the lower part of the formation in the well TT-21.

Hydrocarbon Potential Assessment of Carbonate-Bearing Sediments in a Meyal Oil Field, Pakistan: Insights from Logging Data Using Machine Learning and Quanti Elan Modeling

“…The presence of clay minerals is usually calibrated through the Th log, whereas the existence of feldspar and mica minerals is determined through the K log. , Also, the radioactive content can be detected through the K/Th cross-plot . On the other hand, the PEF/K plot is also widely utilized to derive useful information regarding clay minerals such as illite, mica, glauconite, and montmorillonite …”

“…80 On the other hand, the PEF/K plot is also widely utilized to derive useful information regarding clay minerals such as illite, mica, glauconite, and montmorillonite. 81 3.4. Self-Organizing Maps (SOMs).…”

Source Rocks’ Potentiality of the Sargelu Formation (Middle Jurassic) in the Taq Taq Oilfield, Kurdistan Region, Iraq

“…The field, discovered at the end of the 1950s by the Iraqi Petroleum Company (IPC), and it has an obvious reflection of its structure on the ground surface and Landsat images. Being one of the most important productive oilfields in the Iraqi Kurdistan Region in the last 15 years, a lot of research was published focusing on its reservoirs and source rocks (Baban and Sarraj, 2007;Baban and Ahmed, 2008;Abdula, 2010;Garland et al, 2010;Othman and Al-Qayim, 2010;Al-Qayim and Rashid, 2012;Al-Qayim and Othman, 2012;Baban and Ranyayi, 2013;Awdal et al, 2013;Abdula, 2015;Najaf, 2018;Hakimi et al, 2018;Baban et al, 2020). There is a broad agreement that most of the accumulated oil in the Iraqi oilfield reservoirs is generated by the middle and upper Jurassic formations of Sargelu, Naokelekan, Barsarin, and Chia Gara.…”