Main Oil Source Research Articles

GEOLOGICAL CHARACTERISTICS AND SOME PROBLEMS IN DEVELOPMENT FOR OIL SHALE IN NORTHWEST CHINA

With the amount of oil resources becoming increasingly scarce, non-conventional resources such as oil shale, oil sands, and heavy oil, have caught our attention. There are abundant oil shale resources in Northwest China. Our analysis of field geological section surveys, standard mining investigations, and the laboratory analysis of important samples indicate that the oil shale in Northwest China is characterized by the following features: oil shale strata is 1–36 m thick, the color of slightly greasy, shiny and flaky oil shale is mostly brown-black, black with light brown streaks, but some oil shale outcrops appear maroon. Oil shale is of layered structure, irregular shape, conchoidal fracture, and low hardness, composed mainly of clay and silt-sized detrital minerals (feldspar and quartz). SiO2 and Al2O3 comprise a total of 52.54% of the rock, this indicates that oil shale is of the medium ash type. Organic carbon content of oil shale is 14% and that of total carbon 16.28%. Oil yield is generally 1.5–13.7%, overall caloric value 1.66–20.98 MJ/kg. Density of oil shale is 1.55–2.46 g/cc. Younger oil shale strata are characterized by progressively higher REE abundances. There are mainly three types of oil shale deposits: the littoral-neritic facies sedimentary deposits of the Middle and Upper Carboniferous – the Lower Permian, remnant lake bay-lacustrine facies sedimentary deposits of the Upper Permian, and shale which formed in inland deep water – half deep water lacustrine facies of the Mesozoic, the latter being of the major industrial type, and its origin is similar to “the Black Sea model.” Oil shale layers are also the main oil source rock in the Ordos Basin. Oil shale layers which formed in deltaic environments in the Middle and Late Carboniferous and the Jurassic are mostly paragenetically related to coal beds. In the area, the total amount of predicted resources of oil shale is at least 31,000×10 8 t which is equivalent to about 2000×10 8 t of shale oil. Oil shale resources in the Ordos Basin account for 99% of the total and can be compared to oil shale resources in the Green River area of western North America. In Northwest China, the identified oil shale deposits are located in

Leaves in turbidite sands: The main source of oil and gas in the deep-water Kutei Basin, Indonesia: Discussion

Saller et al. (2006) have concluded that leaves in the upper Miocene turbidite sands were the main source of oil and gas in the deep-water Kutei Basin, East Kalimantan (Borneo), Indonesia. They have reported that oils from the Kutei Basin have high (4–7) pristane/phytane ratios, suggesting a coaly organic source. This is consistent with other observations made on oils from the Gippsland Basin in Australia, showing high pristane/phytane ratios (5–6) that were attributed to coniferous rain forests and related land-plant organic matter (Shanmugam, 1985). Saller et al. (2006) have also concluded that leaf fragments were carried into deep water along with sand by turbidity currents during lowstands of sea level. This conclusion deserves close scientific scrutiny. Although Saller et al. (2006) have discussed both geochemical and sedimentological aspects, I confine this discussion to sedimentological details. I also take this opportunity to introduce more clarity into our understanding of deep-water deposition through discussing conceptual, observational, and interpretational problems. First, Saller et al. (2006, p. 1588) stated that “Specific well names and depths are not included in this manuscript for confidentiality reasons.” The strength of any scientific article is its transparency of data, which provides other researchers an opportunity to verify the conclusions of an article without constraints. Saller et al. used cuttings samples from 50 wells and conventional core samples from 16 wells, but because they did not provide a map showing well locations, it is impossible to evaluate the relative position of a sample with respect to the paleoshelf edge. This is critical to the central theme of this article, which is the source of land-plant organic matter (i.e., highstand delta versus lowstand shelf-edge delta). Saller et al. could have included a location map of wells, but could have changed the original well names. Second, the basic tenet of …

Leaves in turbidite sands: The main source of oil and gas in the deep-water Kutei Basin, Indonesia: Reply

Leaves in turbidite sands: The main source of oil and gas in the deep-water Kutei Basin, Indonesia: Reply

Oil and Gas Potential of South-Caspian Basin

Existing views on hydrocarbon generation, migration and accumulation in the South-Caspian Basin are analyzed. A secondary nature of hydrocarbon accumulations in the major commercial interval (Middle Pliocene) is substantiated. It is shown that the main source of oil is the underlying Paleogene-Miocene clay sequences, and that of gas and condensate is the deep Mesozoic section. The geochemical age of hydrocarbons is determined. Dominant role in the hydrocarbon accumulation and placement of the intraformational vertical migration through fractures and faults is established. A thermodynamic model of the formation and distribution of different hydrocarbon phases is developed.

Leaves in turbidite sands: The main source of oil and gas in the deep-water Kutei Basin, Indonesia

More than 6 tcf of gas and 200 million bbl of oil and condensate have been discovered in upper Miocene sandstones in the deep-water Kutei Basin, offshore East Kalimantan, Indonesia. Chemical analyses of oil, gas, and condensate indicate derivation from land-plant source material. Conventional cores and cuttings of deep-water strata show that the best source rocks are sandstones, not shales. Organic material in deep-water sandstones includes laminar coaly fragments, pieces of wood, resinite, and other coaly debris. Laminar coaly fragments are dominant, and their size, shape, and cuticle structure indicate that they were leaf fragments. Fossil leaf fragments occur in all deep-water sandstone packages from the upper slope to the basin floor. Fossil leaf fragments were apparently carried into deep water by turbidity currents during lowstands of sea level. Within turbidite sandstones, fossil leaf fragments are concentrated in layers with up to 50 wt.% total organic carbon (TOC). Kerogen that was separated from these layers has hydrogen index values of 200–500 mg hydrocarbon/g TOC. Kutei Basin deep-water shales contain mainly silt-size vitrinite grains with poor generative qualities. Microscale sealed vessel pyrolysis and kinetic and generation modeling indicate that land-plant kerogens occurring in quantities similar to the upper Miocene sandstones are capable of generating the gas and oil found in deep-water fields. Hence, leaf fragments in turbidite sandstones are interpreted as the main source for deep-water oil and gas. Liquids derived from leaves have caused production problems that include high pour points because of high wax contents and emulsions formed when fatty acids combined with water.

Sida's Involvement in and Support to Research in the Western Indian Ocean

The interface between land and sea is an area where humans have found resources since pre-historical times. Today, most large cities are situated on or near the coast and the populations in these areas are growing. Around two thirds of humanity now live in the coastal areas of the world’s continents. Migration to coastal areas continues not least in developing regions of the world where coastal areas provide a tremendous potential for trade, commerce, industry, and tourism. In some developing countries, coastal tourism constitutes the major industry. Another important resource in these countries is the deposits of petroleum on the continental shelf. In the near future, offshore production may be the main source of oil and gas. At the same time, as these potentials are being developed, millions of households depend on coastal resources for their daily livelihoods. The environmental implications of this are enormous. How can countries with very limited financial and administrative/research resources manage their coastal areas in ways that hinder environmental degradation and sustain resources? Since the mid-1990s, Sida has supported a comprehensive program for coastal zone management. It is community-focused and based on an integrated management approach. The program is designed to improve resource management and foster sustainable development at the local level. One of the key ambitions has been to strengthen capacity for monitoring and research in the Western Indian Ocean region. More than 70 marine biologists have been trained to PhD and Master-levels in collaboration with Swedish and other international scientists. These African researchers constitute the core of the new research network, Western Indian Ocean Marine Science Association, WIOMSA. One important result of the Sida-supported research is the comprehensive inventory of the flora and fauna published in the Guide to the Seashores of Eastern Africa (Richmond, 1977). This guidebook illustrates the many diversified biotypes in the region, including a large number of unique species, and is a valuable asset for scientists as well as for tourists. Another example of successful cooperation is illustrated by the results of algae research. These scientific activities have guided the establishment of a large number of algae producers generating income especially for many women who live along the coasts. In 1998, African and Swedish researchers were among the first to observe the drastic coral death linked to the El Nino phenomenon. These and other findings have been reported in meetings regularly held between researchers and high-level decision-makers in the region to discuss the implications and possible action. The most important result of Sida support to the Western Indian Ocean research, however, is the enhanced capacity to follow and analyze conditions affecting coastal resources, amply illustrated by the papers in this special issue of Ambio. For those in charge of coastal management it is essential to understand the various patterns and processes that determine the structure and function of the whole coastal environment and to comprehend how humans interact with and depend on marine resources. The following articles in this issue of Ambio cover a broad range of issues including marine ecology, marine resource use, analysis of the impact of different disturbances on the marine environment, and coastal zone management. The three marine biotopes typical of tropical coastal regions are also represented including coral reefs, mangroves, and seagrass beds. Sida welcomes the initiative of the WIOMSA, the Bilateral Marine Science Programme between Sweden and Tanzania, and Ambio in making these findings available to the international as well as to the African scientific community and decision-makers.

Hydrocarbon sources and stages of reservoir formation in Kuqa depression, Tarim Basin

Kuqa depression bears not only plenty of natural gas, but also a large amount of condensate and small quantity of crude oil. Based on the geochemical correlation between the Jurassic and Triassic terrestrial hydrocarbon source rock, this paper confirms that the natural gas in Kuqa depression belongs to coal-type gas and the main gas source rock is attributed to the middle to lower Jurassic coal series formation, while the main oil source rock is the upper Triassic lacustrine mudstone. The authors indicated that Kuqa depression was slowly subsided in Mesozoic, but rapidly went down in Late Tertiary, which made the Jurassic and Triassic source rock suddenly deep-buried and rapidly evolved to high and over-mature phase since 5 Ma. The Triassic source rock is postponed to the Early Miocene during 23−12 Ma when entering the oil-generating peak, while the Jurassic is suspended to the latest 5 Ma, especially since 2.5 Ma to the dry gas-generating period, which is one of the characteristics of the source rock thermal evolution in Kuqa depression. This paper presents a two-stage trapping and late gas trapping model in Kuqa depression whose characteristics are: The main oil and gas reservoirs have different sources. The oil reservoir is formed early while the gas reservoir is formed lately. During the early stage, it, mainly as oil, takes long distance lateral migration, while in the later stage, it, mainly as gas, takes the vertical migration and also has lateral migration. The trap formed in different time on the south and north sides of the depression and evolved into a distributional pattern with oil in the south part and gas in the north, also oil on the outer ring and gas on the inner ring. This paper points out that the late trapping of the natural gas in Kuqa depression is favorable for the preservation of large gas fields.

Dietary Docosahexaenoic Acid Levels Influence the Outcome of Arabinosylcytosine Chemotherapy in L1210 Leukemic Mice

: The purpose of this study was to investigate whether dietary supplementation with the n-3 fatty acid docosahexaenoic acid (DHA) in combination with arabinosylcytosine (AraC) chemotherapy could prolong the life expectancy of mice bearing L1210 leukemia. The four control diets included rodent chow, a diet containing 5% of a blended oil mimicking the fatty acid composition of rodent chow, and diets containing 5% or 10% fat with safflower oil as the main oil source. The two DHA-supplemented diets provided 1.5% or 3.5% DHA and 5% or 10% total fat, respectively. After tumor cell inoculation, mice were treated with AraC for 10 days. Mice fed the 5% safflower oil diet (30.1 ± 4.1 days), but not those fed the 10% safflower oil diet, survived longer than the chow-fed animals (22.1 ± 3.1 days, P = 0.05). The 1.5% DHA diet (average intake 1.8 g DHA/kg/day) was associated with a longer life span (33.3 ± 3.4 days, P < 0.01 vs. chow-fed) and no incidence of death due to drug toxicity. Further increasing DHA intake (4.5 g DHA/kg/day) resulted in shortened survival time (26.5 ± 2.0 days), increased circulating tumor cell burden, and lowered red blood cell concentrations. These data suggest that a modest level of dietary DHA or linoleic acid supplementation may improve the antineoplastic efficacy of AraC. However, overconsumption of DHA reverses the beneficial effect of DHA intake on drug sensitivity.

Too Little, Too Late: An Analysis of Hitler's Failure in August 1942 to Damage Soviet Oil Production

EVEN before Operation Barbarossa petered out in December 1941, Germany's oil reserves were severely depleted. Adolf Hitler worried that his armed forces would soon grind to a halt for want of petroleum products. During the last months of 1941 and the first of 1942, economic considerations played as much of a role in the formulation of a new strategy as did the run-down state of the eastern armies and air fleets. Hitler feared heavy Soviet bombing attacks on Rumanian oilfields, his main source of oil, and knew that the Reich's reserves were almost exhausted. Consequently, he considered the protection of the Rumanian oilfields and the acquisition of new sources of oil crucial if he were to wage a prolonged war against the growing list of nations he opposed.1 He therefore formulated Fall Blau (Case Blue), a major campaign for summer 1942. This aimed first, through preliminary offensives in the Crimea, to protect Rumanian oil centres from Soviet air attacks, and second, through a powerful thrust to the Don River and then into the Caucasus, to deliver that oil-rich region into German hands. The capture of

Main oil source formations of the West Siberian Basin

Two strongly oil-prone source intervals are present in the West Siberian Basin, the Togur Formation (Early Toarcian, Early Jurassic) and the Bazhenov Formation (Volgian-Berriasian, Late Jurassic to Early Cretaceous). Clay sediments of the Togur Formation were deposited in a system of intracontinental sub-basins in the southern half of the West Siberian Basin. The marine deposits of the Bazhenov Formation accumulated throughout the entire basin. Two types of extractable bitumens and oils - marine and non-marine - may be identified from their isotopic carbon composition, sulphur content, bulk composition, and biomarker hydrocarbons (normal alkanes, pristane/phytane, C (sub 27-30) steranes, hopanes and homohopanes). Marine oils, accounting for 80% of oil resources, are sourced from the Bazhenov Formation. The genetic relationship between oils in Upper Jurassic and Cretaceous reservoirs and the organic matter from the Bazhenov Formation is indicated by great similarities in their biomarker hydrocarbon compositions and their maturation levels. Non-marine (lacustrine) oils are sourced from the Togur Formation and account for 11% of oil resources.

A Geochemical Appraisal of Oil Generation in the Taranaki Basin, New Zealand

From a basin-wide evaluation of organic geochemical data, it has been possible to characterize and differentiate various source rock units and to establish the genetic relationships of oils. Most of the oils are primarily terrestrially sourced, and it is possible to recognize varying contributions from source rocks within the Paleogene Kapuni Group and late Cretaceous Pakawau Group. This distinction is attributable to the rise to dominance of angiosperms over gymnosperms in coastal plain swamp communities by the Eocene. Apart from the Maui family (i.e., Maui field, Maui-4, and Moki-1) oils, the inferred relative contributions from the main source rock types generally correlate with the relative proportions of suitably thick and mature units near reservoirs, given that mos Cretaceous-sourced oil appears to have escaped prior to trap development. Maui family oils do appear to be primarily sourced by Rakopi Formation (late Cretaceous) coals. In the northern part of the Taranaki Peninsula, where heat flows are highest, Mangahewa/Kaimiro Formation (Eocene) coals are the chief sources of oils. Farther south, in the Kapuni and Kupe South fields, Farewell Formation (Paleocene) coals appear to be the main oil source rocks. Biomarkers suggest that the onset of oil expulsion from coals occurs at a maturity level corresponding to a vitrinite reflectance of ca. 0.8% Ro, and may be aided by the evolution of large volumes of carbon dioxide. The terrestrial influence on Paleogene source rocks diminishes to the north-northwest of the basin and increasing marin contributions to oils are observed. A late Paleocene marine black shale is the source of oil in the Kora volcanic structure. It is possible that shales interbedded with coals, reflecting periodic marine incursions of coastal flood plains, also contribute to oil generation throughout much of the basin.

Some sedimentological and geochemical characters of the late Triassic Noto formation, source rock in the Ragusa basin (Sicily)

In the Ragusa basin (southeastern Sicily), the late Triassic Noto formation is considered as the main oil source rock. We provide a detailed description of the sedimentary facies determined from core samples, and discuss geochemical results, obtained for both kerogens and chloroform extractable hydrocarbons from samples where sedimentary organic matter is immature. Two main sedimentary sequences were encountered: (i) layers of limestones and of marls (or shales) alternating at a metric scale, and (ii) laminites having various types and carbonate contents. The high petroleum potentials (S 2 up to 100 kg HC/t rock) are related to sedimentary lithologies that contain a minimum of clay. Two types of algal organic matter are probably mixed in the sediments studied. These two types can be distinguished by the oxygen content. They also do not have the same kinetic behavior in thermal evolution. Special attention has been paid to the possible use of bitumens and of pyrolysates obtained from kerogens for understanding “organic facies”. Bulk properties together with several biomarker distributions were examined through different facies. But most of the parameters measured or computed are more clearly related to the maturity of the sequences analyzed rather than to the intrinsic nature of the in situ organic matter. A modeling approach is proposed, taking into account geological and geochemical data. Different situations of the Noto source rock lead to different timings of oil formation. The importance of source rock heterogeneities at different scales in basin evaluation is underlined.

The geology of the Alpha oil shale deposit

Over the past forty-five years a total of 60 holes have been drilled in the vicinity of the Alpha oil shale deposit. This work has delineated an oil shale resource of at least 12 km long and 2.5 km wide. Two types of oil shale occur within the deposit; torbanite and cannel coal. Torbanite has resulted from the accumulation of algal remains and occurs as a lens confined to the northeastern portion of the resource. Cannel coal is more extensive and has resulted from the deposition of terrestrial plant material. The main source of oil in the torbanite is telalginite and oil yields range from 200–622 litres/tonne. Sporinite is the probable main source of oil derived during pyrolysis of the cannel coal which has a range of oil yields from 20–259 dm 3 tonne −1. The deposit contains an in situ inferred resource, Class 2, of between 10–100 million tonnes of oil shale 1. The cannel coal, although yielding less oil than torbanite, is far more extensive and accounts for at least 85 % of the deposit's known shale oil resource.

Oil Possibilities of Colombia

Colombia has an almost ideal situation with respect to the world's markets, being only a short distance from the Panama Canal and the West Indies. Thesailing distance from its Caribbean ports to New York is less than that fromTampico. Geographically, Colombia consists of three systems of broad mountain rangesseparated by two long narrow valleys. The Cauca River valley separates theWestern or Coastal range from the Central range. On the west side of theCoastal range are the Atrato and San Juan Rivers. The Central and Easternranges are separated by the Magdalena River valley. In the department ofSantander the Eastern range divides, one branch continuing northward as theCordillera of Perija, the other turning eastward across Venezuela as theCordillera of Merida. Between these ranges is the great basin occupied by LakeMaracaibo. These valleys consist mainly of long narrow reentrants or tongues ofTertiary sediments between the older rocks of the mountain ranges. The lateMiocene and younger sediments seem to have been deposited in separated basins, but the Cretaceous and possibly some earlier Tertiary strata were laid downmore or less continuously over a great part of Colombia and Venezuela. Thesestrata were subsequently folded into the present ranges. The deposition of theCretaceous and of some of the Tertiary was in a great sea, the main land massbeing in Brazil, with land probably along some of the cores of the presentmountain systems. The sediments, except the Lower Cretaceous, vary markedly incharacter and thickness. An illustration is seen in the massive series ofnon-marine conglomerates and sandstones of the upper Magdalena River valley, near Honda, which are almost wholly wanting in the coastal sections wheremarine sediments prevail. The oldest rocks bearing on the search for oil are the black carbonaceousand bituminous shales, limestones, and cherts of the upper part of the LowerCretaceous. These probably are the main source of oil in both Colombia andVenezuela. They include thick bodies of true "oil shale." Above thecarbonaceous and bituminous beds, lies a series of many thousand feet ofclastic sediments. The most noticeable and easily recognizable formation amongthese clastic sediments is the" coalbearing series," which may beeither upper Cretaceous or Eocene. AIME 068–71