Geochemical study of the early cretaceous Fahliyan oil reservoir in the northwest Persian Gulf

Three crude oil samples from the Fahliyan Formation in ‘KG’ and ‘F’ fields in the northwest Persian Gulf, namely KG-031, F9A-3H and F15-3H for the geochemical study. In this study, the physicochemical properties, gas chromatography (GC, GC Mass) and (Detailed Hydrocarbon Analysis) DHA analyses for the collected Fahliyan oils were carried out. The API, Trace Element (Ni, V) and S% parameters indicated that the Fahliyan oil was generated from a source rock which deposited in reducing environment condition with a carbonate-shale compound lithology. Moreover, low pour point, higher S% and low viscosity parameters of “KG” sample confirmed the existence of medium oil characteristics in this field. In addition, the geochemical outcomes of GC, GC–MS and DHA analyses indicated that the ‘KG’ oils are more aromatic compared with ‘F’ oil; while biomarkers revealed that Fahliyan reservoir oil is highly mature and was formed from a carbonate source rock containing types II, III kerogen. Thus, sterane/hopane biomarkers (C24/C23 and C22/C21 ratios) revealed that Fahliyan oil originated from carbonate source rocks deposited in an anoxic to dysoxic environment, which is consistent with the above analyses. It was identified that the source rock age is early Cretaceous to late Jurassic. It can be reported that the Fahliyan oils from both fields were generated in the same source rock and have almost the same physical properties, and will have the same production strategy.

Prediction of Hydrocarbon Sources in The Walio Area, Salawati Basin, West Papua, Indonesia

Substantial seismic and well data have been gathered and used for the exploration and exploitation of the Salawati Basin since the 1970s. The interpretation of these data and implementation of findings resulted into several discoveries and producing fields associated with the Tertiary petroleum system of Klasafet-Kais, particularly in the Walio Area. The presence of pre-Tertiary petroleum systems remain speculative to date although numerous pre-Tertiary structural and stratigraphic traps can be defined, and hypothetical sourcing can be inferred to origin from shales of the Permo-Triassic Aifam Group and the Late Jurassic – Late Cretaceous Kembelangan Formation. Yet the actual hydrocarbon charging of those traps has not been proven. Surface geochemical surveys were conducted in the Walio Area with the objective to characterize the origin of hydrocarbons of the area and possibly uncover the presence of a pre-Tertiary source. Pre-Tertiary sediments are encountered in three exploration wells of the Walio Area and pre-Tertiary traps were defined by the interpretation of 3D seismic. Surface geochemical surveys were conducted in the Walio Area to map the distribution of oil and gas microseeps and try to determine their source. Whole oil chromatography and isotope & biomarker analysis were also performed on Kais reservoired oil samples to determine source rock lithology, depositional environment, and age. Hydrocarbon analysis of one-meter-deep soil samples revealed the distribution of volatile and liquid hydrocarbon microseeps in the survey area. Total Organic Carbon (TOC) and Rock-Eval Pyrolysis measurement was carried out to outcrop samples of the Klasafet Fm., Kembelangan Fm., Tipuma Fm., and Aifat Fm. The outcrop samples resulted in lean TOC, and produced very low S2 values to which the Tmax cannot be estimated. Hydrocarbon microseeps were found occurring over and off existing fields and pre-Tertiary traps. Both light oil microseeps (35° API) and heavy oil microseeps (14° API) were identified over fresh and biodegraded crude oil Kais reservoirs, respectively in the Walio Area. Microseeps with lighter hydrocarbon compositions (e.g. C5/C17 ratio) may reflect leakage from deeper pre-Tertiary sources.

Hydrocarbon species in SI and HCCI engine using winter grade commercial gasoline

The study provides a qualitative and quantitative analysis of the C5-C11 hydrocarbon species generated in Spark Ignition – Homogeneous Charge Compression Ignition (SI/HCCI) gasoline direct injection (GDI) engine at range of operating conditions. The presented results and data were obtained from the combustion of winter grade commercial gasoline containing 2% w/w ethanol (C2H5OH) for the engine operated in steady-state, fully warmed-up condition. The hydrocarbon analysis in exhaust gases was executed on a Gas Chromatography-Mass Spectrometer (GC-MS) apparatus directly connected to the engine exhaust via heated line. The highest concentration of the total hydrocarbon emissions was obtained under low load HCCI engine operation at stoichiometric fuel-air ratio. The major hydrocarbon compounds detected in the collected samples were benzene, toluene, p-xylene, and naphthalene. Benzene originates from the incomplete combustion of toluene and other alkylbenzenes which are of considerable environmental interest. During the SI engine operation, increase of the engine speed and load resulted in the increase of benzene and the total olefinic species with simultaneous decrease in isopentane and isooctane. The same trends are seen with the engine operating under HCCI mode, but since the combustion temperature is always lower than SI mode under the same engine conditions, the oxidation of fuel paraffin in the former case was less. As a result, the total olefins and benzene levels in HCCI mode were lower than the corresponding amount observed in SI mode. Aromatic compounds (e.g., toluene), except for benzene, were produced at lower levels in the exhaust when the engine speed and load for both modes were increased.

The Effects of the Application of Random Sampling on the Analysis of the Biodegradation of Oil Spills in Soil

Random sampling is a part of the sampling technique in which each sample has an equal probability of being chosen. A sample chosen randomly is meant to be an unbiased representation of the total population. If for some reasons, the sample does not represent the population, the variation is called a sampling error. Thus, an unbiased random sample is important for drawing conclusions in all issues, especially when the issue relates to environmental cleanup. Biodegradation focuses largely on the cleanup of petroleum hydro carbons and the past decades have seen challenges arise in order to make biodegradation technology appropriate and productive. This is because oil spills composition varies in locations as crude oil is a mixture of thousands of organic compounds that vary from one source to another. The purpose of this work was to determine the reliability of the random sampling method on oil spills which clean up sometimes cause s more harm than the oil spill itself. Random sampling is the basis for all probability sampling techniques used in soil sampling and serves as a reference point from which modifications to increase the efficiency of sampling are evaluated. Therefore its effectiveness was measured using Oil and Grease and Total Petroleum Hydrocarbon analysis of the biodegraded soil.