Petroleum system modeling and risk assessments of

Authors: Thamer K AlAmeri Heba S AlMimar John Zumberge

Publish Date: 2014/08/31

Volume: 8, Issue: 8, Pages: 5739-5766

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Abstract

Oil biomarkers and isotope values of the analyzed samples from the Sa’adi and Yamama Formation reservoirs of Santonian and Valanginian ages respectively from well Da1 as well as Yamama Formation extracts are plotted on sterane triangle hopane diagram tricyclic terpane diagram pristane to phytane ratio with canonian variables δ 13C saturate aromatics and pristinephytane diagrams and have indicated a source environment and lithology of marine algal type II that are nonbiodegraded and deposited in anoxic environments of carbonate and shale Source maturation at the time of the oil generation is assessed by plots of oil and the analyzed values of the Yamama source rocks on the pristinephytane diagram indicate these to be mature with T max equivalent of 435 °C based on plots of methyldibenzothiophene ratio MDR and vitrinite reflectance of R o = 070–085 based on methylphenothrene ratio MPI Source age assessment is taken from δ 13C and the calculated C28/C29 sterane ratio indicates early Lower Cretaceous age The Yamama Formation in this study showed excellent hydrocarbon potential with extracted organic matter of up to 16674 ppm with a total organic carbon TOC equivalent of 1664 wt Correlation of the analyzed data from Ad’daimah field with other oil fields in the Mesan Governorate indicates the same characteristics and revealed this to be clustered in one place in all the diagrams but the source age shows two oil families where the first is sourced from Upper JurassicLower Cretaceous as in the case in the Ad’daimah field while the second is sourced from Middle and Upper Jurassic as in the case in the Halfaya field Sourceoil correlation is confirmed in this study by plots of values from the analysis of Sa’adi and Yamama oil of well Da1 with the extracts from the YamamaSulaiy formations in isotopic δ 13C saturate and aromatics calculated C28/C29 sterane ratio diagram sterane triangle and MPI versus R o These showed grouping of the oil and extracts of the analyzed data into one place of depositional environment maturation and age characteristics that indicate a very good correlation with excellent hydrocarbon generation from the Yamama Formation that measures up to 16674 ppm of extracted organic matter PetroMod software basin modeling has confirmed hydrocarbon generation from the Yamama Formation under burial thermal temperature of 114–120 °C with 285–300 mg HC/g TOC for 95  hydrocarbon transformation from the disseminated organic matters with critical point of hydrocarbon migration and accumulation at 10 million years ago Palynomorphs have indicated ages of ValanginanBerriassian for the Yamama Formation and TithonianBerriassian for the Sulaiy Formation Marking places of source rocks and oil reservoir on seismic section across well Da1 for the Jurassic and Cretaceous strata have shown model assessments of the hydrocarbon generation places of the Yamama Formation migration pathways and accumulation site as well as places of enriched oil to assess reservoir sites and suggest for risk assessments of drilling sites for hydrocarbon production from the Yamama and Sa’adi formations On the other hand seismic sections in Halfaya and Buzargan fields showed hydrocarbon migration from the Sargelu FormationWe acknowledge with many thanks the Exploration Oil Company and Mesan Oil Company—Ministry of Oil for the supplies of crude oil and core rock samples as well as raw material of logs and seismic section for well Da1 of Ad’daimah oil field Great thanks are also due to GeoMark Research Limited of HoustonTexas for performing organic geochemical analysis for the crude oil and core rock samples especially GCMS isotopes aromatics and the organic matter extracts and the Department of Geology College of Science of the University of Baghdad for their facilities to prepare palynological slides in the geochemistry lab and thin section in the petrology workshop Thanks are also due to Dr Rami I AlAzzawi of the University of AlMustansiriya and Qahtan A AlObaydi of the Oil Exploration Company for their help in the PetroMod software run as well as for their help extended in the well site

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