Progress in Marine Oil Spill Optical Remote Sensing: Detected Targets,Spectral Response Characteristics,and Theories

Different oil spill pollution types could be produced in oil transport and weathering processes. Investigation of these pollution types is beneficial for oil spill recovery and processing. Optical remote sensing techniques play an important role in marine oil spill monitoring and have the ability to identify different oil spill pollution types. Recently, research on oil spill optical remote sensing has made much progress in detecting targets, identifying spectral response characteristics, and formulating theories. Floating black oil, oil slicks, and oil-water mixture in marine oil spill accidents are the main targets to be investigated by optical remote sensors. The visible spectral response differences of these targets are the base of oil spill optical remote sensing research. Bi-directional reflectance distribution function, light interference, absorption, and scattering of targets produce different spectra. Therefore, oil spill optical remote sensing could be used to identify the main oil spill pollution types and estimate oil spill volume.     

Utility of GOI,QGF, and QGF-E for interpreting reservoir geohistory and oil remigration in the Hudson oilfield,Tarim basin,northwest China

The physical mechanisms responsible for hydrocarbon migration in carrier beds are well understood. However, secondary migration is one of poorly understood facets in petroleum system. The Carboniferous Donghe sandstone reservoir in the Tarim Basin's Hudson oilfield is an example of a secondary (or unsteady) reservoir; that is, oil in this reservoir is in the process of remigration, making it a suitable geologic system for studying hydrocarbon remigration in carrier beds. Experimental methods including grains containing oil inclusions (GOI), quantitative grain fluorescence (QGF) and quantitative grain fluorescence on extract (QGF-E) -- together with the results from drilling, logging and testing data -- were used to characterize the nature of oil remigration in the Donghe sandstone. The results show that (1) significant differences exist between paleo- and current-oil reservoirs in the Donghe sandstone, which implies that oil has remigrated a significant distance following primary accumulation; (2) due to tectonic inversion, oil remigration is slowly driven by buoyancy force, but the oil has not entered into the trap entirely because of the weak driving force. Oil scarcely enters into the interlayers, where the resistance is relatively large; (3) the oil-remigration pathway, located in the upper part of the Donghe sandstone, is planar in nature and oil moving along this pathway is primarily distributed in those areas of the sandstone having suitable properties. Residual oil is also present in the paleo-oil reservoirs, which results in their abnormal QGF-E. A better understanding of the characteristics of oil remigration in the Donghe sandstone in the Hudson oilfield can contribute to more effective oil exploration and development in the study area.     

Generation,migration and accumulation of oil of El-Ayun Field,Gulf of Suez,Egypt

This study is an attempt to solve the problem of oil generation, migration and accumulation of oil in El-Ayun Field, Gulf of Suez. The organic carbon, hydrogen and organic matter contents in addition to the composition of kerogen are determined. The degree of transformation of organic matter to hydrocarbon and the level of thermal maturity of these sediments to yield hydrocarbons are deduced. The geothermal gradient mnd level of organic metamorphism (LOM) are determined by using the bottom hole temperature. The vitrinite reflectance values are used in this respect. The determined trace element contents for both crude oils and sediments clarifies the process of oil migration from possible source rocks to oil reservoirs.Recommendations, concerning exploratory testing of favourable sites for oil accumulation, laterally and vertically, are postulated on the basis of the achieved results.     

Petroleum accumulation in the deeply buried reservoirs in the northern Dongying Depression,Bohai Bay Basin,China: New insights from fluid inclusions,natural gas geochemistry,and 1-D basin modeling

The deeply buried reservoirs (DBRs) from the Lijin, Shengtuo and Minfeng areas in the northern Dongying Depression of the Bohai Bay Basin, China exhibit various petroleum types (black oil-gas condensates) and pressure systems (normal pressure-overpressure) with high reservoir temperatures (154–185 °C). The pressure-volume-temperature-composition (PVTX) evolution of petroleum and the processes of petroleum accumulation were reconstructed using integrated data from fluid inclusions, stable carbon isotope data of natural gas and one-dimensional basin modeling to trace the petroleum accumulation histories.The results suggest that (1) the gas condensates in the Lijin area originated from the thermal cracking of highly mature kerogen in deeper formations. Two episodes of gas condensate charging, which were evidenced by the trapping of non-fluorescent gas condensate inclusions, occurred between 29-25.5 Ma and 8.6–5.0 Ma with strong overpressure (pressure coefficient, P_c = 1.68–1.70), resulting in the greatest contribution to the present-day gas condensate accumulation; (2) the early yellow fluorescent oil charge was responsible for the present-day black oil accumulation in well T764, while the late blue-white oil charge together with the latest kerogen cracked gas injection resulted in the present-day volatile oil accumulation in well T765; and (3) the various fluorescent colors (yellow, blue-white and blue) and the degree of bubble filling (F_v) (2.3–72.5%) of the oil inclusions in the Minfeng area show a wide range of thermal maturity (API gravity ranges from 30 to 50°), representing the charging of black oil to gas condensates. The presence of abundant blue-white fluorescent oil inclusions with high Grain-obtaining Oil Inclusion (GOI) values (35.8%, usually >5% in oil reservoirs) indicate that a paleo-oil accumulation with an approximate API gravity of 39–40° could have occurred before 25 Ma, and gas from oil cracking in deeper formations was injected into the paleo-oil reservoir from 2.8 Ma to 0 Ma, resulting in the present-day gas condensate oil accumulation. This oil and gas accumulation model results in three oil and gas distribution zones: 1) normal oil reservoirs at relatively shallow depth; 2) gas condensate reservoirs that originated from the mixture of oil cracking gas with a paleo-oil reservoir at intermediate depth; and 3) oil-cracked gas reservoirs at deeper depth.The retardation of organic matter maturation and oil cracking by high overpressure could have played an important role in the distribution of different origins of gas condensate accumulations in the Lijin and Minfeng areas. The application of oil and gas accumulation models in this study is not limited to the Dongying Depression and can be applied to other overpressured rift basins.     

溢油扩展、漂移及扩散预测技术研究进展

海上溢油灾害会严重破坏中国近海海洋环境,还会直接危害我国经济发展。因此,开展溢油预测预警技术研究是非常有必要的,能够为海上溢油应急响应提供技术支撑。本文综述了溢油扩展、漂移及扩散数值预测技术的发展过程及相关研究成果,包括溢油扩展模型、溢油漂移与扩散模型、溢油预测预警系统,为未来开展溢油应急工作提供了理论依据和参考。     

On the formation of short-lived,toxic, water-soluble compounds during illumination of crude oil on seawater

The toxicity of various oil extracts has been studied using cod eggs as test organisms. The most toxic effect was observed when the eggs were kept underneath the water/oil interface during irradiation. This supports the notion that toxic primary photoproducts with a short life-time are generated when oil on seawater is illuminated.     

Effects of oil cracking on fluorescence color,homogenization temperature and trapping pressure reconstruction of oil inclusions from deeply buried reservoirs in the northern Dongying Depression,Bohai Bay Basin,China

The effects of oil cracking on fluorescence color, homogenization temperature (T_ho) and trapping pressure (P_t) of oil inclusions from deeply buried reservoirs (DBRs) (3672–4359 m) in the northern Dongying Depression were determined based on fluorescence spectroscopy and homogenization temperatures of oil inclusions, kinetic modeling of crude oil cracking, and petroleum inclusion thermodynamics modeling.The modeling results demonstrate that fluorescence color, T_ho and predicted P_t have strong relationships with the transformation rate via cracking of oil to gas (T_r), and the formation temperature (T_f) that the inclusions experienced. The fluorescence color is hardly influenced at all during the initial stages of oil cracking (T_r < 13%, T_f < 160 °C), but fluorescence color begins to shift toward shorter wavelengths (blue shift) during progressive oil cracking (T_r < 24%, T_f < 190 °C). With further oil cracking, the fluorescence color may either experience no change or continue its blue shift. Eventually the fluorescence color will disappear as the aromatic compounds are completely cracked. The T_ho increases at first (T_r < 24%, T_f < 190 °C), but then decreases or even becomes negative during major oil cracking. The reconstructed P_t values show a corresponding reverse trend.Oil inclusions from DBRs and other shallow reservoirs in the Dongying Depression show an obvious blue shift in fluorescence color at a depth of approximate 4000 m (T_f = 160 °C) and generally contain solid bitumen below 4000 m, supporting the effect of oil cracking on fluorescence variation, consistent with the modeling result. The T_ho from DBRs in the Minfeng area increases with increasing burial depth (T_f < 190 °C), which is also consistent with the modeling results. However, the T_ho of oil inclusions with blue-white fluorescence from DBRs in the Shengtuo area did not show such a trend. Recent trapping, high trapping pressure and higher-maturity oil may have led to a low-degree of oil cracking, and thus less modification of T_ho in the Shengtuo area.Oil cracking results in consistent volume ratios of pyrobitumen to oil inclusions (F_vpy) in the same fluid inclusion assemblage, and the F_vpy value increases with oil cracking level, which can be used to recognize if oil cracking has occurred in oil inclusions and what level of oil cracking they have experienced.As the oil cracking model used in this study did not account for the role of pressure, it is more applicable for oil inclusions that were trapped under normally pressured conditions. Oil inclusions trapped under overpressured conditions will be less influenced by oil cracking.     

Proximate composition of albacore tuna,Thunnus alalunga,from the temperate South Pacific and Tasman Sea

The proximate composition was determined of the white muscle of albacore tuna, Thunnus alalunga, caught by surface trolling along the Subtropical Convergence Zone east of the South Island of New Zealand ("Area 1"), and to the north and west of the North Island ("Area 2"). Fish from Area 1 were 70 ± 10 cm (mean ± s.d.) in fork length, and higher in oil content (4.6 ± 2.9%), than Area 2 fish which measured 55 ± 10 cm and contained 2.8 ±1.7% oil. The ash content of the white muscle of all fish sampled was 1.2 ± 0.1%, and the soluble carbohydrate content 0.36 ± 0.04%. Crude protein contents were calculated at c. 25%. Statistical relationships between moisture and oil contents of both white and red muscle were determined; they can be used to predict oil content from a known moisture content. Oil content was positively correlated with fork length, and negatively correlated with the sea surface temperature at time of capture. Oil levels in the fillet were highest in the muscle layer immediately below the skin and decreased logarithmically with depth. In fish with low white‐muscle oil content (below 5%), the corresponding red‐muscle oil content was higher; above 6% white muscle oil content the corresponding red‐muscle oil content was lower. The proximate composition of whole fish, the head, frame, skin, and viscera is presented.     

Northstar-Geology,Exploration History,and Development Status,Beaufort Sea,Alaska

Exploration for oil at Northstar has been long and costly. Northstar leases were first acquired in 1979 at a joint state and federal sale by Shell Oil, Amerada Hess, and Texas Eastern. The Northstar Unit is 6 mi offshore and about 4 mi northeast of the Point McIntyre Field. Oil was first discovered in Shell's Seal Island 1 in 1983. Five additional appraisal wells were drilled (1983-1986) from two man-made gravel islands in 40 ft of water. Early engineering estimates put the cost of development at $ 1.6 billion. In February 1995, BP Exploration (Alaska) acquired a 98 % interest in the Northstar Unit from Amerada Hess and Shell Oil. When developed by BP, Northstar will be the first oil produced from federal leases in Alaska. To date, the oil industry has invested in excess of $ 140 million in exploration and appraisal operations. An additional $ 90 million was spent on lease bonus bids. The giant Prudhoe Bay and Kuparuk Fields lie along the Barrow Arch. This arch is bounded to the north by a rift margin that deepens into the present-day offshore region. Northstar is located among a series of down-stepping faults off this northern rift margin of the Prudhoe Kuparuk high. The structure is a gently south-dipping northwest-trending faulted anticline. The crest of the structure is located near 10,850 ft subsea. The primary reservoir is the Ivishak Formation (325 ft thick) of the Sadlerochit Group. This is the same primary reservoir at Prudhoe Bay, approximately 12 mi to the south. At Northstar the Ivishak is a high-energy, coarse-grained conglomeratic facies of the Ivishak Formation. The primary lithology is a pebbly chert to quartz conglomerate with occasional sandstone. This very high net to gross reservoir appears to contain no regionally continuous permeability barriers. Cementation has reduced primary porosity to less than 15 %. Accurate porosity estimates are difficult to make due to the coarse-grained nature of the lithology and the presence of kaolinite and microporous chert. Permeability is highly variable, but averages 10 to 100 mDarcies. Oil is a very light and volatile 42 API crude with approximately 2,100 ft3 of gas per stock tank barrel of oil. This oil is very different from the heavier oils (26) found to the south in Prudhoe Bay. Estimated recoverable oil reserves range from 100 to 160 million barrels. A free-standing drilling rig is required at Northstar because the reserves are beyond extended-reach drilling techniques from shore-based facilities. The current development plan is to expand the existing Seal Island to about 5 acres. This is significantly less than Endicott's 40-acre island. The proposed drilling and produc tion island will be accessed by summer barges and winter ice roads. Oil, gas, and water will be processed at a stand-alone facility and then sent to shore via a subsurface pipeline. Northstar will have the first Arctic subsea pipeline in Alaska to transport oil to shore facilities (TAPS). Preliminary tests in Spring 1996 were very successful in demonstrating the technology to successfully bury a subsea pipeline safely in the Arctic.     

Palaeo-carbonate seep structures above an oil reservoir, Gryphon Field, Tertiary, North Sea

Petrographic and geochemical analyses performed on a North Sea core from the Gryphon Field reveal the presence of palaeo-degassing features surrounded by injected sandstones in the Eocene interval. The injected sandstones are oil-stained and poorly cemented by carbonate and quartz. ¹⁸O isotope analyses indicate that carbonate cementation occurred during shallow burial (likely less than about 300 m). Depleted ¹³C (around –30 V-PDB) carbonate cement suggests that bicarbonate was derived from the microbial oxidation of oil and gas. Late quartz overgrowths enclose oil present in the injected units. The tubular degassing conduits are composed of zoned cements and have ¹⁸O and ¹³C isotope values similar to the injected sandstones, indicating that oil and gas seepage induced the precipitation of authigenic carbonate in the shallow subsurface. Oil inclusions in inter- and intra-crystal cement sites in both injected sandstones and degassing conduits indicate that oil seepage was an ongoing feature at shallow burial. A proposed model involves oil and gas seepage and the formation of the degassing conduits, followed by a sand injection phase. It seems likely that oil and gas continued to leak towards the seabed by exploiting the network of permeable injected sandstones and the horizons of porous degassing features.     

Charging of oil fields surrounding the Shaleitian uplift from multiple source rock intervals and generative kitchens,Bohai Bay basin,China

This paper discusses origin and charging directions of oil fields on the Shaleitian Uplift, Bohai Bay basin. The Shaleitian Uplift is a footwall uplift surrounded by three sags containing mature source rocks. The origins of the four oil fields on the Shaleitian Uplift, both in terms of source rock intervals and in terms of generative kitchens, were studied using biomarker distributions for 61 source rock samples and 27 oil samples. Hierarchical cluster analysis using 12 parameters known to be effective indicators of organic matter input and/or depositional conditions allowed the identification of six oil types or classes. These six oil classes could then be linked to three distinct source rock intervals ranging in age from 43.0 Ma to 30.3 Ma. The third member (43.0–38.0 Ma in age) and first member (35.8–32.8 Ma) of the Eocene Shahejie Formation, and the third member of the Oligocene Dongying Formation (32.8–30.3 Ma) each sourced one class of oil. The other three classes represent mixtures of oil generated from multiple source rock intervals. Traps on the Shaleitian Uplift were charged in the east by oil generated from the Eocene Shahejie Formation in the Bozhong Sag, in the southeast by oil generated from the Eocene Shahejie and then Oligocene Dongying formations in the southwestern part of the Bozhong Sag and/or in the eastern part of the Shanan Sag, and in the southwest by oil generated from the Eocene Shahejie Formation in the western part of the Shanan Sag. The estimated migration distances range from less than 5 km to about 20 km. The compositional heterogeneity within fields and multiple-parameter comparisons between oils from nearby wells in different fields have proven to be a powerful tool to determine the in-filling histories of oil fields in cases where multiple source rock intervals and multiple generative kitchens exist.     

Enrichment and distribution of shale oil in the Cretaceous Qingshankou Formation,Songliao Basin,Northeast China

The Songliao Basin is a large-scale petroliferous basin in China. With a gradual decline in conventional oil production, the exploration and development of replacement resources in the basin is becoming increasingly important. Previous studies have shown that the Cretaceous Qingshankou Formation (K₂qn) has favorable geological conditions for the formation of shale oil. Thus, shale oil in the Qingshankou Formation represents a promising and practical replacement resource for conventional oil. In this study, geological field surveys, core observation, sample tests, and the analysis of well logs were applied to study the geochemical and reservoir characteristics of shales, identify shale oil beds, build shale oil enrichment models, and classify favorable exploration areas of shale oil from the Cretaceous Qingshankou Formation. The organic matter content is high in shales from the first member of the Cretaceous Qingshankou Formation (K₂qn¹), with average total organic carbon (TOC) content exceeding 2%. The organic matter is mainly derived from lower aquatic organisms in a reducing brackish to fresh water environment, resulting in mostly type I kerogen. The vitrinite reflectance (Ro) and the temperature at which the maximum is release of hydrocarbons from cracking of kerogen occurred during pyrolysis (T_max) respectively range from 0.5% to 1.1% and from 430 °C to 450 °C, indicating that the K₂qn¹ shales are in the low-mature to mature stage (Ro ranges from 0.5% to 1.2%) and currently generating a large amount of oil. The favorable depth for oil generation and expulsion is 1800–2200 m and 1900–2500 m, respectively as determined by basin modeling. The reserving space of the K₂qn¹ shale oil includes micropores and mircofractures. The micropore reservoirs are developed in shales interbedded with siltstones exhibiting high gamma ray (GR), high resistivity (Rt), low density (DEN), and slightly abnormal spontaneous potential (SP) in the well-logging curves. The microfracture reservoirs are mainly thick shales with high Rt, high AC (acoustic transit time), high GR, low DEN, and abnormal SP. Based on the shale distribution, geochemical characteristics, reservoir types, fracture development, and the process of shale oil generation and enrichment, the southern Taikang and northern Da'an are classified as two favorable shale oil exploration areas in the Songliao Basin.     

厦门港刘五店航道海域溢油扩散数值模拟

利用MIKE 21 HD模块建立了厦门湾二维水动力模型,经2008年最新实测资料,验证了模型的可靠性和适用性,模拟结果为厦门湾刘五店航道二维溢油模型的建立提供水动力基础数据.利用MIKE21 SA模块建立厦门湾刘五店航道二维溢油模型,应用"油粒子"模型模拟输移、风化和热量迁移等过程,对刘五店航道一期工程溢油泄露事故进行...     

Geochemical evidence for coal-derived hydrocarbons and their charge history in the Dabei Gas Field, Kuqa Thrust Belt, Tarim Basin, NW China

Large to middle-scale thrust structures are important reservoir plays for coal-derived hydrocarbons in the foreland basins of NW China, with both gas and some accompanying oil. In the Dabei Gas Field of the Kuqa Thrust, however, the oil and gas pools are vertically distributed in a quite unique way: (1) liquid oil and some dissolved gas are present in the Dawanqi Anticline with the reservoir at 300-700 m depth, forming the only oil field in the Kuqa Thrust; (2) gas and minor accompanying oil are found in the deep reservoir of the Dabei-1 and Dabei-2 thrust traps around 5000-6000 m depth; (3) an extremely dry gas pool is found in the Dabei-3 thrust trap where the depth of the reservoir is over 7000 m. Geochemical data suggest that the hydrocarbons in the Dawanqi Anticline and the Dabei thrust traps originated from a similar source, i.e. the underlying Jurassic coal measures, with some contribution from Jurassic lacustrine shales. The Jurassic source rocks did not start to generate oil until the Miocene (around the Kangcun Stage), and extended into the Pliocene (the Kuche Stage) with the main gas generation period in the Pliocene (the Kuche Stage) and the Quaternary. Because the traps formed relatively early, the Dabei-1 and Dabei-2 thrusts could trap some of the early generated oils, but most of the early charged oil was redistributed to the shallower Dawanqi Anticline during the Kuche Stage. The Dabei-3 thrust trap formed concurrently with major gas generation and thus could not trap liquid hydrocarbons. The difference in the vertical distribution of the hydrocarbon accumulations in the Dabei Gas Field resulted from a complex interplay of source variability, structural evolution of the basin and thermal maturation.     

The origin and charging directions of Neogene biodegraded oils: A geochemical study of large oil fields in the middle of the Shijiutuo Uplift,Bohai Sea,China

Two large oil fields (QHD32-6 and QHD33-1), located in the middle part of the Shijiutuo Uplift, have generally suffered mild biodegradation. Based on multivariate statistical analysis of the biomarker parameters, this study discussed the origin and charging directions for these two oil fields.In contrast to Ed₃-derived oil, all available oil samples from these two large oil fields displayed low C₁₉/C₂₃, C₂₄/C₂₆ and high G/H and 4-MSI, which are attributed to the mixtures of oils derived from the Shahejie (Es₁ and Es₃) source rocks. Oils in QHD32-6, which contain relatively more Es₃-derived oil, are called Group I oils, and most oils in QHD33-1, which share relatively more Es₁-derived oil, are called Group II oils. Our mixed oil experiments reveal the predominant Es₃- and Es₁-derived oil contribution for Group I and Group II oil groups, respectively; however, the selection of end member oils warrants further research.Based on comparisons of biomarker parameters, the QHD32-6 oil field was mainly charged in the north by oil generated from Shahejie formation source rocks in the Bozhong depression. However, oils from the north of QHD32-6 field display a remarkable difference to the oils in the south of this field, which may indicate that a charging pathway exists from the QHD33-1 field. Considering the variations in biomarker compositions in the west to -east and northwest to -southeast sections across the QHD33-1 and QHD32-6 oil fields, it can be deduced that Es₃-sourced oil migrated westward to the QHD32-6 traps, and then charging by Es₁ oil from the Bozhong Sag resulted in the QHD33-1 oil field being characterized by the mixture of Es₃- and Es₁-sourced oil. Moreover, migration of Es₁-derived oil from the Qinnan Sag was not identified, implying that the QHD33-1 oil field is mainly charged from the northeast of the Bozhong Sag.     

Retrospective analysis: bile hydrocarbons and histopathology of demersal rockfish in Prince William Sound,Alaska, after the Exxon Valdez oil spill

Demersal rockfish are the only fish species that have been found dead in significant numbers after major oil spills, but the link between oil exposure and effect has not been well established. After the 1989 Exxon Valdez oil spill in Prince William Sound, Alaska, several species of rockfish (Sebastes spp.) from oiled and reference sites were analyzed for hydrocarbon metabolites in bile (1989-1991) and for microscopic lesions (1990 and 1991). Biliary hydrocarbons consistent with exposure to Exxon Valdez oil were elevated in 1989, but not in 1990 or 1991. Significant microscopic findings included pigmented macrophage aggregates and hepatic megalocytosis, fibrosis, and lipid accumulation. Site differences in microscopic findings were significant with respect to previous oil exposure in 1991 (P=0.038), but not in 1990. However, differences in microscopic findings were highly significant with respect to age and species in both years (P<0.001). We conclude that demersal rockfish were exposed to Exxon Valdez oil in 1989, but differences in microscopic changes in 1990 and 1991 were related more to age and species differences than to previous oil exposure.     

Properties and shale oil potential of saline lacustrine shales in the Qianjiang Depression,Jianghan Basin,China

The geochemical and petrographic characteristics of saline lacustrine shales from the Qianjiang Formation, Jianghan Basin were investigated by organic geochemical analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and low pressure nitrogen adsorption analysis. The results indicate that: the saline lacustrine shales of Eq3 member with high oil content are characterized by type I and type II oil-prone kerogen, variable TOC contents (1.0–10.0 wt%) and an early-maturity stage (R_o ranges between 0.41 and 0.76%). The mineral compositions of Eq3 saline shale show strong heterogeneity: brittle intervals with high contents of quartz and carbonate are frequently alternated with ductile intervals with high glauberite and clay contents. This combination might be beneficial for oil accumulation, but may cause significant challenges for the hydraulic stimulation strategy and long-term production of shale oil. The interparticle pores and intraparticle pores dominate the pore system of Eq3 shale, and organic matter hosted pores are absent. Widely distributed fractures, especially tectonic fractures, might play a key role in hydrocarbon migration and accumulation. The pore network is contributed to by both large size inorganic pores and abundant micro-factures, leading to a relatively high porosity (2.8–30.6%) and permeability (0.045–6.27 md) within the saline shale reservoir, which could enhance the flow ability and storage capacity of oil. The oil content (S₁ × 100/TOC, mg HC/g TOC and S₁, mg HC/g rock) and brittleness data demonstrate that the Eq3^3x section has both great potential for being a producible oil resource and hydraulic fracturing. Considering the hydrocarbon generation efficiency and properties of oil, the mature shale of Eq3 in the subsidence center of the Qianjiang Depression would be the most favorable zone for shale oil exploitation.     

Numerical simulation of the thermal maturation, oil generation and migration in the Songliao Basin, Northeastern China

The discovery of the giant Daqing oil field in the Songliao Basin led to the realisation of the significant petroleum potential of non-marine basins. In order to reconstruct the basin evolution and oil formation, an integrated organic geochemical-basin modelling study along a regional transect across the Songliao Basin was conducted. It provided a regional heat flow evolution model, and revealed post-orogenic or late syn-orogenic maturation in the Central Depression and pre-orogenic maturation in the Southeast Uplift Zone. Kinetic parameters of petroleum generation for the lacustrine source formations are the basis for the simulation of oil generation and migration in the Songliao Basin. Using the principle activation energy peaking at 54 kcal/mol and a pre-exponential factor of about 4.2·10²⁷ Ma⁻¹, the simulation obtained a relatively good match with the measured transformation ratios. The Qingshankou Formation in the West and East Central Depressions constituted the major source in the basin. Major oil generation, migration and accumulation occurred during the Early Tertiary. In the West Central Depression, the generated oils migrated upwards into the Yaojia Formation followed by the updip migration into the Daqing Anticline and towards the local structural high along the West Slope. In contrast, the oil migration in the East Central Depression was dominated by the downward movement from the lower member of the Qingshankou Formation followed by the updip migration towards the Caoyang Anticline. The simulated oil accumulations are in good agreement with discovered oil fields, implying a potential application of the model for prediction and evaluation of new exploration targets in the basin.     

Some dynamics of spilled oil in a fractured ice field in Buzzards Bay, Massachusetts

A spill of #2 fuel oil occurred 28 January 1977 in a dynamic ice field in BBuzzards Bay, Massachusetts. An oil budget study revealed that within four days after the spill occurred, approximately 60% of the oil was incorporated into the fractured ice zones and onto the ice surface. The movement of the oil (initially spilled under the ice) into the fracture zones appears to be the result of water current below the ice and buoyancy spreading mechanisms. Areas of fracture zones and leads provided a surface outlet for the less dense oil as it moved under the ice. When the leads closed, the oil was trapped into tools on top of the ice at the floe edges. The further spread of the oil onto the surface of the ice floes appears to have been caused by the wind.     

UK onshore oil exploration, 1930–1964

The earliest attempts to find oil in Britain, dating from 1918–1922, based on anticlines flanking the Pennines, were largely unsuccessful. Renewal of exploration in the 1930s, aimed at a broader range of prospects, met with much criticism but went ahead after nationalization of the unknown and undiscovered oil resources (1934). The south of England ranked as first priority but the initial drilling of the new campaign carried out in 1935–1937 yielded only minor quantities of oil and gas. Attention was transferred in 1938 to Upper Palaeozoic prospects in the Midlands and north, resulting in small gas and oil discoveries in Scotland and Yorkshire, and discovery of a series of commerical oilfields in the Upper Carboniferous of Nottinghamshire. In the 1950s the first commercial discovery in the Jurassic was made at Kimmeridge in Dorset. Further Carboniferous discoveries were made in Nottinghamshire and Lincolnshire, and a series of fresh objectives defined by seismic reflection were drilled in the Mesozoic basin of southern England. This phase of exploration was terminated at the end of 1964 by adverse fiscal changes. Continuation of effective exploration operations remained uneconomic until the oil price rise in 1973.