امين عدنان محسن الشمخي

This geochemical study concerns the Al-Teeb River sediments that accumulate in the river course or river basin. The river is one of the seasonal rivers in Iraq, located in the Missan Governorate in southeastern Iraq, northeast of Amara City. It originates from the Himrin mountains near the Iranian border and flows into Hor Al-Snnaf. It has a maximum length of about 63 km and runs through the Al-Teeb District. Eight samples were collected and subjected to geochemical analyses by XRF. Numerous geochemical parameters and major and trace element relationship diagrams have been used to infer the origin and type of sediments, paleoclimate, and source rocks. The average chemical alteration index (44.12) indicates that the sediments have undergone low to moderate weathering. Results obtained from the chemical index of weathering (55.043), plagioclase index of alteration (50.5), and index of chemical variability (2.37) support this conclusion and confirm the low weathering of the source rocks and low maturity. The climate of source rocks is semi-arid to sub-humid and mean annual temperature is 15.22°C. The chemical classification of Al-Teeb river sediments is greywacke and originated from continental arc or oceanic arc environments.

Rock physics recently became widely utilized in classifying lithological units for various purposes in geophysics, depending on well-logging and seismic inversion datasets. Nahr Umr Formation is the targeted reflector, which was studied in well NS-1 as one of the most productive oil fields in Iraq, the Nasiriya field, to prove the performance and accuracy of Rock-physics productivities. Six cross plots were extracted and interpreted depending on the units of Density (RHOP) and Neutron (NHPI ) logs, which were used for lithology-predicting of the Nahr Umr Formation, which consists mainly of porous sandstone, dolomite, clay, and shale. The challenge of locating the most profitable layer in hydrocarbon production was achieved using rock physics procedures to classify lithologic units of the Nahr Umr Formation. The matching between the results of well logging analysis and hydrocarbon probability for targeted units was extremely good due to the use of more reliable tools. The probability density function (PDF) technique was applied to visualize the space of rock physics in two dimensions, and the density distribution within rock units was prominently clear. Polynomial equation of Nasiriya oil field was extracted for Nahr Umr Formation, and it was equivalent to the standard equation of Nafe Drake according to density/ velocity curve readings.