Biomarkers in oils (seeps) as indicators of the conditions for the derivation of oil-bearing deposits (Halabja block, eastern region of Iraqi Kurdistan)

UDK: 553.98
DOI: 10.24887/0028-2448-2021-5-54-58
Key words: geochemistry, geology, organic matter, biomarkers, oil-oil correlation, seep, Halabja, Iraqi Kurdistan, depositional environment, maturity of the oil
Authors: N.N. Kosenkova (Gubkin University, RF, Moscow), A. Hama Amin Rebaz (Gubkin University, RF, Moscow), S.F. Khafizov (Gubkin University, RF, Moscow)

Gas chromatography and gas chromatography / mass spectrometry methods are used to analyze crude oils obtained from southern and northern blocks of Halabja field in eastern part of Iraqi Kurdistan, using different biomarkers coefficients. Biomarkers characterization is used to provide information on the source of the organic matter, depositional environment, degree of maturity, age determination of the crude oils. The data which was used is including normal alkanes and acyclic isoprenoids distributions, terpans, hopanes, steranes and diasternes aliphatic biomarkers, the distribution of aromatic biomarkers naphthalenes, dibenzothiophene, phenanthrene. The oil samples from the southern and northern blocks of Halabja are characterized by a low Pr/Ph ratio (< 1.0), a relatively low and absent oleanane and lupan ratios, an abundance of moderate C29 regular steranes and diasteranes, a relatively low C27 sterane, the presence of tricyclic terpenes, relatively low dibenzothiophene / phenanthrene ratios etc. All biomarker parameters indicates that the source rocks of the oils from southern and northern blocks of Halabja are represented by clay-carbonate and clay sediments with II-III types of organic matter were deposited under anoxic ─ reducing marine environments and were generated at high stage of maturity. All of the age diagnosed biomarker parameters indicate a Cretaceous source of oils from the south part of Halabja and a Jurassic source in oil from the northern part.


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