The use of borehole logs to study the reservoir properties of Shiranish formation in Qayarah field in Northern Iraq

Abstract

The present study consists of evaluating the reservoir properties of Shiranish formation of two wells: (Qayarah-54 well QY-54 and Qayarah-84 well QY-84) in the Qayarah oil field, Northern Iraq. It relies on the information of borehole logs of these wells to clarify the reservoir properties of the Shiranish formation in order to assess the petro physical properties. The most important borehole logs that are used: density log, sonic log, neutron log, gamma ray log, and resistivity logs. They are converted into digital values by using Didger program while the petro physical parameters are calculated by using Microsoft excel program. The petro physical properties of this formation are drawn by using the log plot program. In the Qayarah field, Shiranish formation is divided into three reservoir units depending on the petro physical properties: the reservoir unit (RU-1), the second reservoir unit (RU-2), and the third reservoir unit (RU-3). The petro physical properties of Shiranish formation shows that the best reservoir unit according to the hydrocarbon saturation is the unit (RU-3), regardless of the thickness variation in both wells. The lithology study of Shiranish formation shows that it consists of limestone, marley limestone, dolomite limestone, dolomite, and layers of marl.