Accumulation and Quantitative Assessment of Terrigenous Organic Matter in Upper Oligocene to Lower Miocene Marine Source Rocks of the Qiongdongnan Basin.

The intense collision between marine and terrestrial agents results in the dual-source (marine and terrigenous) characteristics of marine source rocks. Our research quantitatively assessed terrestrial organic matter and revealed the crucial role of terrestrial organic materials in the organic matter enrichment of lower Miocene to upper Oligocene marine source rocks in the Qiongdognnan Basin. The quantitative assessment was achieved using partial least-squares analysis with eight biomarker parameters associated with -alkanes, isoprenoids, bicadinanes, taraxerane, tricyclic terpanes, and gammacerane.

Influence of HEM Drilling Fluid on Organic Geochemical Characteristics of Deep-Water Source Rocks in the Qiongdongnan Basin.

The influence of oil-based drilling fluid on the geochemical characteristics of source rocks has been widely reported in the northern South China Sea. However, contamination from water-based HEM drilling fluid has long been neglected in previous deep-water petroleum exploration. To further understand the impacts of HEM drilling fluid on deep-water source rocks, the organic matter abundance and type, kerogen maceral composition, and saturated biomarkers of the deep-water source rocks in the Qiongdongnan Basin were investigated.

Characterization of Crude Oil, Formation Water, and Fluid Inclusions of Hydrocarbon-Bearing Strata and Their Hydrocarbon Geological Significance in the Wuliyasitai Southern Sub-sag of the Erlian Basin, China.

The hydrocarbon-bearing inclusions, formation water, and crude oil contain a wealth of information regarding the process of accumulation of oil and gas. Their research has been one of the hotspots in the field of oil and gas geology. Chemical analysis data was systematically employed for the first time to identify the properties of liquid fluids in the oil-bearing system of the Wuliyasitai southern sag in the Erlian Basin.

Shift in the Mode of Carbon Cycling Recorded by Biomarkers and Carbon Isotopic Compositions in the Yanchang Formation, Ordos Basin: Autotrophy vs Heterotrophy.

Organic-rich shales and mudstones have long been investigated regarding the control of source, environment, climate, etc. on the enrichment of organic carbon. However, little is documented about how autotrophy and heterotrophy influence organic carbon cycling/export.

Paleoenvironment and Organic Characterization of the Lower Cretaceous Lacustrine Source Rocks in the Erlian Basin: The Influence of Hydrothermal and Volcanic Activity on the Source Rock Quality.

Lower Cretaceous lacustrine source rocks in the Erlian Basin are highly heterogeneous. It is important to assess and explain these heterogeneities for the reconstruction of paleoenvironments and the prediction of high-quality source rock distributions. In this study, well-logging, organic, and elemental geochemical data were comprehensively analyzed for the source rocks of Member 4 of the Aershan Formation (Fm) and Member 1 of the Tengger Fm in the southern Bayindulan (BNAN), southern Wulanhua (WLHs), Anan, Aer, and southern Wuliyasitai sags of the Erlian Basin.

Geochemical Characteristics of Three Oil Families and Their Possible Source Rocks in the Sub-Sag A of Weixinan Depression, Beibuwan Basin, Offshore South China Sea.

Three oil families from the sub-sag A of the Weixinan Depression are identified by integrated analysis of physical properties, stable carbon isotopes, and gas chromatography-mass spectrometry (GC-MS). Their similarities and differences in relative thermal maturities, depositional environments, and biological sources of organic matter (OM) are investigated. A possible oil-source correlation of this area is established.

Origin and Geochemical Implications of Hopanoids in Saline Lacustrine Crude Oils from Huanghekou East Sag and Laizhouwan Northeastern Sag, Bohai Bay Basin.

A suite of low-mature crude oils (five high-sulfur oils and six low-sulfur oils) from the Huanghekou and the Laizhouwan Sags, Bohai Bay Basin, are analyzed to investigate the fate of the hopanoids. Abundant hopanes, such as secohopanes, 25-norhopanes, benzohopanes, aromatized secohopanes, and sulfide hopanes, are identified, and their carbon isotope compositions are determined. Varying C isotope values of C hopane (-38.

Tracking alterations of alkyl side chains of N species in heavy crude oil after anaerobic biodegradation with negative-ion electrospray ionization coupled with high-field Fourier transform ion cyclotron resonance mass spectrometry.

Rationale: Heteroatomic compounds are relatively abundant and believed to be bio-resistant in heavy crude oils. However, few studies have focused on the biodegradation of these heteroatomic compounds.

Methods: Heteroatoms, especially N species, in a blank crude oil and in three treated oils co-incubated with anaerobic sulfate-reducing bacteria, nitrate-reducing bacteria and fermentative consortia cultures were detected using negative-ion electrospray ionization coupled with high-field Fourier transform ion cyclotron resonance mass spectrometry.

Dynamics of a microbial community during an effective boost MEOR trial using high-throughput sequencing.

Using 454 pyrosequencing of 16S rRNA gene amplicons, microbial communities in samples of injection water and production water during a serial microbial enhanced oil recovery (MEOR) field trial in a water flooded high pour point oil reservoir were determined. There was a close microbial community compositional relationship between the injection water and the successful first round MEOR processed oil reservoir which was indicated by the result of 43 shared dominant operational taxonomic units detected in both the injection water and the production water. Alterations of microbial community after the injection of boost nutrients showed that microbes giving positive responses were mainly those belonging to the genera of , , , , , and , which were detected both in the injection water and in the production water and usually detected in oil reservoir environments or associated with hydrocarbon degradation.

Draft genome sequence of Paenibacillus sp. strain A2.

Paenibacillus sp. strain A2 is a Gram-negative rod-shaped bacterium isolated from a mixture of formation water and petroleum in Daqing oilfield, China. This facultative aerobic bacterium was found to have a broad capacity for metabolizing hydrocarbon and organosulfur compounds, which are the main reasons for the interest in sequencing its genome.

Isolation and characterization of a crude oil degrading bacteria from formation water: comparative genomic analysis of environmental Ochrobactrum intermedium isolate versus clinical strains.

In this study, we isolated an environmental clone of Ochrobactrum intermedium, strain 2745-2, from the formation water of Changqing oilfield in Shanxi, China, which can degrade crude oil. Strain 2745-2 is aerobic and rod-shaped with optimum growth at 42 °C and pH 5.5.

High quality genome sequence and description of Enterobacter mori strain 5-4, isolated from a mixture of formation water and crude-oil.

Enterobacter mori strain 5-4 is a Gram-negative, motile, rod shaped, and facultatively anaerobic bacterium, which was isolated from a mixture of formation water (also known as oil-reservior water) and crude-oil in Karamay oilfield, China. To date, there is only one E. mori genome has been sequenced and very little knowledge about the mechanism of E.

Permanent draft genome sequence of Bacillus flexus strain T6186-2, a multidrug-resistant bacterium isolated from a deep-subsurface oil reservoir.

Previous studies suggest that antibiotic resistance genes have an ancient origin, which is not always linked to the use of antibiotics but can be enhanced by human activities. Bacillus flexus strain T6186-2 was isolated from the formation water sample of a deep-subsurface oil reservoir. Interestingly, antimicrobial susceptibility testing showed that this strain is susceptible to kanamycin, however, resistant to ampicillin, erythromycin, gentamicin, vancomycin, fosfomycin, fosmidomycin, tetracycline and teicoplanin.

Permanent draft genome sequence of Geobacillus thermocatenulatus strain GS-1.

Geobacillus thermocatenulatus strain GS-1 is a thermophilic bacillus having a growth optimum at 60°C, capable of degrading alkanes. It was isolated from the formation water of a high-temperature deep oil reservoir in Qinghai oilfield, China. Here, we report the draft genome sequence with an estimated assembly size of 3.

Genome sequence of Brevibacillus agri strain 5-2, isolated from the formation water of petroleum reservoir.

Brevibacillus agri strain 5-2 was isolated from the formation water of a deep oil reservoir in Changqing Oilfield, China. This bacterium was found to have a capacity for degrading tetradecane, hexadecane and alkanesulfonate. To gain insights into its efficient metabolic pathway for degrading hydrocarbon and organosulfur compounds, here, we report the high quality draft genome of this strain.

Genomovar assignment of Pseudomonas stutzeri populations inhabiting produced oil reservoirs.

Oil reservoirs are specific habitats for the survival and growth of microorganisms in general. Pseudomonas stutzeri which is believed to be an exogenous organism inoculated into oil reservoirs during the process of oil production was detected frequently in samples from oil reservoirs. Very little is known, however, about the distribution and genetic structure of P.

Microbial diversity in long-term water-flooded oil reservoirs with different in situ temperatures in China.

Water-flooded oil reservoirs have specific ecological environments due to continual water injection and oil production and water recycling. Using 16S rRNA gene clone library analysis, the microbial communities present in injected waters and produced waters from four typical water-flooded oil reservoirs with different in situ temperatures of 25 °C, 40 °C, 55 °C and 70 °C were examined. The results obtained showed that the higher the in situ temperatures of the oil reservoirs is, the less the effects of microorganisms in the injected waters on microbial community compositions in the produced waters is.

Impact of an indigenous microbial enhanced oil recovery field trial on microbial community structure in a high pour-point oil reservoir.

Based on preliminary investigation of microbial populations in a high pour-point oil reservoir, an indigenous microbial enhanced oil recovery (MEOR) field trial was carried out. The purpose of the study is to reveal the impact of the indigenous MEOR process on microbial community structure in the oil reservoir using 16Sr DNA clone library technique. The detailed monitoring results showed significant response of microbial communities during the field trial and large discrepancies of stimulated microorganisms in the laboratory and in the natural oil reservoir.

Molecular biologic techniques applied to the microbial prospecting of oil and gas in the Ban 876 gas and oil field in China.

Currently, molecular biologic techniques achieve a great development in studies of soil samples. The objective of this research is to improve methods for microbial prospecting of oil and gas by applying culture-independent techniques to soil sampled from above a known oil and gas field. Firstly, the community structure of soil bacteria above the Ban 876 Gas and Oil Field was analyzed based on 16S rRNA gene clone libraries.