Evolution of West Siberian Petroliferous in the Phanerozoic

Conditions for the formation of oil and gas pools in Tertiary volcanics in the western part of the Huimin sag, Shandong and their distribution have been studied based on the geological, seismic and well‐logging information. In this paper, the types and lithofacies of the volcanic rocks in the western part of the Huimin sag are described; the relationship between rocks and electrical properties, the seismic reflection structures, the development and distribution of the volcanic rocks are expounded; and the fourfold role of the volcanic activities in the formation of the oil and gas pools is also dealt with. It is considered by the authors that the volcanic activities were not destructive to the formation of oil and gas pools but a factor favourable to the accumulation of organic matters and their conversion to hydrocarbon. The volcanic rocks might have served as reservoir rocks and cap rocks, or as a synsedimentary anticline. The prerequisites and important factors for the formation of oil and gas pools and their distribution are pointed out in the paper.

Oil and gas pools: the fundamentals of formation, prospecting, and exploitation

Statistical analyses of size, orientation, and pressure measurements on Cretaceous and Jurassic oil and gas pools in Albeta reveal general predictable trends and some significant anomalies. The total oil and gas in place, and the plan areas of pools, appear to be lognormally distributed although this cannot be proved statistically. For major reservoirs showing a well-defined lognormal size-frequency distribution, the probability of future economic exploration success in that unit can be evaluated from the general trend. Notable deviations from the lognormal distribution pattern occur for Viking oil pools and Wabiskaw (Glauconitic) gas pools. The presence of two populations of pools (one of large pools and one of small pools) can explain the anomalous size-frequency distribution. The large, and therefore more profitable, oil pools in the Viking Formation occur in the Main Viking sand in areas of favourable hydrodynamics. For the gas pools in the Wabiskaw, a factor analysis indicates a relationship between the size of the pool and a combination of porosity and elevation of the reservoir. A map of factor loadings defines an area on the southwestern edge of the basin in which the large Wabiskaw pools are more likely to be found. For oil occurrences in Viking, Cardium, and Belly River reservoirs, the size of the pool can be predicted reliably from its plan area. Consequently, for these reservoirs the reserves potential of an exploration target can be estimated from the untested area. Gas reserves are generally less predictable from plan area. Diagrams showing the orientation of oil and gas accumulations in major reservoirs have both analytical and predictive applications. The orientations are caused by the original depositional conditions, and by later structural and hydrodynamic effects, and are used to identify the controlling features. A quantitative knowledge of the orientation directions of oil or gas pools in a particular reservoir will influence the extension of a new oil or gas discovery in that reservoir. Plots of pressure against depth for oil and gas pools reveal that the interconnected reservoir systems such as Gething Formation and Ellerslie (Basal Quartz) Member have well-defined pressure gradients close to hydrostatic. Groupings of pools on the Ellerslie Member plots, when mapped, define a western limit for the occurrence of oil in the Ellerslie. Maps showing the areal occurrence of oil and gas in Cretaceous and Jurassic reservoirs in Alberta delineate hydrocarbon-rich belts trending NW-SE. Some well-explored areas of the province have very small quantities of oil and gas discovered, apparently for lack of suitable reservoir units.

The commercial oil and gas pools are on crests of closed anticlines and domes except in the General Petroleum field, where oil is found in variable shaly sandstone beds on a pitching anticline without structural closure. The oil sand of the G. P. field (G. P. sand) is not productive elsewhere even on closed structures. Commercial oil is found in the Mowry shale on the crests of the three sharpest folds-Little Lost Soldier, Wertz, and Ferris. It is not found in the Mowry shale on the gentler folds or elsewhere. Seemingly the maximum fracturing and other mechanical effects peculiar to the crests of sharp flexures are necessary to the formation of the shale oil pools or pockets. The productivity of the structures, other factors being equal, is in close relation to the extent to which they are fractured and faulted. Burial of the productive sand beneath a great thickness of shale is equivalent to diminution in faulting, since the faults may be sealed or may not persist to great depths. The more numerous and open the faults, the greater the tendency toward an oil pool or to barrenness through more or less complete leakage. The fewer and tighter the faults, the greater the tendency toward a gas pool or to barrenness through lack of migration and accumulation. With the Lost Soldier and many other oil and gas fields of the Rocky Mountain region as confirmatory evidence, it may be said that, in the post-Paleozoic strata of the region (i) water in an upper sand is not indicative of what is to be expected in lower sands, whether oil, water, or gas; (2) gas, as the predominant product in an upper sand, means that lower sands may be expected to be primarily gas sands; and (3) oil, as the predominant product in an upper sand, indicates that lower sands are likely to be primarily oil sands.13J. S. Irwin, “Faulting in the Rocky Mountain Region,” Bulletin Amer. Assoc. Petrol. Geol, Vol. 10 (1926), pp. 127-28.

The formation conditions and distribution regularities of oil-gas pools in volcanic rocks in western Huimin Depression have been studied in terms of geologic, seismic and well logging information. This paper discusses the types and lithofacies, development and distribution of Tertiary volcanic rocks in the area. The results demonstrate that volcanic activity occurred mainly during the period from the Sha-4 stage to the Guantao episode, i.e., before the oil-generating period (before the end of the Guantao episode and the Minghuazhen episode). The activity did not destroy oil and gas formation and accumulation, but was favourable for the concentration of organic matter and its conversion to hydrocarbons; besides, volcanic rocks can serve as reservoir rocks and cap rocks, playing a role very similar to that of a syndepositional anticline. The volcanic rocks are distributed near the margins of the oil-generating depression; there are many secondary interstices in the rocks, which are connected with each other. These are the leading conditions for the formation of oil-gas pools in volcanic rocks. The formation of volcanic rocks in high structural levels before the main oil-generating period and their self-sealing or good combination with other cap rocks are important factors for forming volcanic rock-hosted oil and gas pools. The oil-gas pools associated with volcanic rocks in western Huimin are mainly distributed around the deep oil-generating depression, in the central uplift or the high structural levels on the margins of the depression. In particular, the sites where several faults cross are usually locatons where high-yielding oil-gas pools in volcanic rocks are concentrated.

In the Shiwu fault depression, evolutionary history of formation pressure can be deduced on the basis of structural evolutionary history. Uplifting and denudation caused high pressure to evolve into low pressure. The main factors controlling the evolutions are (1) generation of fractures and release of high pressure, (2) temperature reduction and water-cooling pressure reduction, (3) desaturation and gas dissociation, and (4) diffusion and dissipation of gas. According to the pressure evolutionary history, the study area has had two pool-forming stages. During uplifting and denudation, fracture generation, and the transformation from high pressure to low pressure, the protogenic high-pressure oil and gas pools were transformed into low-pressure relic pools, and secondary pools with normal pressure formed above them. A predictor equation of the low pressure has been proposed on the basis of the balanced depth in the undercompaction zone, as well as the eroded thickness of the overlying strata. According to this equation, measured pressure data, well logs, and seismic interval velocity data, pressure prediction has been made in the study area by drawing on experience gained at key points. In the light of pressure evolutionary history and pool-forming history, it is regarded that the exploration potential of the low-pressure zonemore » is not as good as that of the hydrostatic-pressure zone. This has been verified by petroleum exploration activities.« less

Canada has played a prominent role in the development of horizontal drilling technology. To date, over 1,400 "grassroots" and "re-entry" wells have been drilled. Although other countries have experienced greater numbers of wells, the number of different types, varieties, and formations tested with this technology in Canada is unparalleled. Due in part to the exponential growth of horizontal well applications since the mid-1980's, coiled tubing CCT) technology in Canada has been adapted and evolved for more traditional uses such as horizontal well stimulation, evaluation, workovers, and clean-outs. The principal nontraditional aspect of CT is its use in drilling operations. This paper will deal with the current state and recent advances in CT horizontal drilling in Canada, A brief historical perspective will be presented that highlights Canada's presence as a pioneer in CT drilling and documents its evolution from vertical re-entries dating back to 1974, grassroots vertical wells in 1976, to the industry's current efforts at vertical and horizontal CTD. The principal Canadian service companies are reviewed in terms of present capabilities in CTO applications and the perceived driving forces that are stimulating the development of this emerging technology. The key factors such as diameter and fatigue life of the coil, length limitations, bottom hole assemblies, surveying methods and the economic and market factors affecting CTO relative to more conventional drilling techniques are reviewed. Finally, the future technological, market and economic developments necessary for the successful implementation of CTO for grassroots vertical and horizontal well re-entry projects are suggested. Introduction The exponential growth in the number of horizontal well applications in Canada and internationally over the past eight years has led to a relatively rapid development of both personnel and equipment to enhance the horizontal drilling method of exploiting existing oil and gas pools. In Canada, there are an estimated 70,000 producing wells: 40,000 gas wells and 30,000 oil wells. Recently, the National Energy Board (NEB) presented a study on horizontal oil wells and their impact on future crude oil supply in Canada. They estimated that there is a potential market of over 12,000 horizontal wells that can be economically drilled within 1,800 oil pools at a market price of $20 US/Bbl. Of these 12,000 wells, 5,000 were believed to be grassroots in nature (1 I 100 have been drilled to date) while 7,000 were horizontal re-entries through existing cased wells (300 have been drilled to date). Of the 6,700 remaining re-entries, the competition for services will be between slim hole (less than or equal to 6–1/4 in. hole size) conventional drilling systems using drilling rigs or modified service rigs and coiled tubing drilling (CTD) technology. Add to this potential market vertical deepenings, horizontal lengthenings and grassroots wells coupled with increasing interest in horizontal exploitation of gas pools, and the development of CTD appears to be poised for exponential growth in Canada over the next five years. Some of the questions that will be addressed during the course of this paper are:

The pore size of the chabazite structure is exceptionally suitable for the methanol to olefins (MTO) reaction. The reaction has an induction period required for the formation of a hydrocarbon pool (HP), usually composed of aromatic compounds of different sizes. HP is alkylated by methanol and afterward cracked, leading to the formation of olefins. Despite the importance of HP, its formation and growth in size are exceedingly dependent on the porosity of the catalyst. The ideal is that the formed HP remains stable throughout the reaction because the growth in its size causes blockage of the small catalyst pores, decreasing its capacity. Herein we studied chabazite zeolites with different porosity and structure, caused by variation in the particle size and pores’ volume. Porosity influenced the formation of HP species in quantity (as revealed by thermogravimetric analysis (TGA)) and polymerization degree (gas chromatography coupled with mass spectrometer (GC-MS) analysis) and, consequently, the MTO reaction’s performance.

The Middle Caspian offshore is one of a few provinces of Russian shelf with not only explored and proved petroleum resources but also where active production is taking place. Main oil and gas bearing complexes are Jurassic terrigenous-carbonate and Cretaceous terrigenous. Jurassic deposits contain 88% of petroleum resources within the Sarmat-Kvalyn anticline zone which is a part of Prikum-Central-Caspian system of anticlines and troughs. Current level of exploration gives reasonable level of confidence to identify large and medium structures. New profitable prospects are believed to be found in structural-tectonic and nonanticline traps. Due to good seismic coverage, irregular distribution of drilled wells, long distances between some of zones and lateral changes of thickness and lithology of Jurassic deposits application of sequence-stratigraphy analysis is necessary. With application of this method Jurassic deposits were divided into sequences of 2nd and 3rd order and parasequences for the first time in area of Middle Caspian. Identification of system tracts allowed to describe character of sedimentation in Jurassic basin and to define reservoirs and potential seals and their distribution.

The effect of Meso-Cenozoic tectonic processes on the formation of Upper Jurassic and Cretaceous hydrocarbon pools in the north of the Aleksandrov arch (West Siberia)

Structural superimposition and conjunction and its effects on hydrocarbon accumulation in the Western Sichuan Depression

Ethylene dehydroaromatisation (EDA) was investigated at 700 °C under 1 bar of ethylene (5 mol% in N2) over a micro-(M) and a nano-sized (N) H-ZSM-5. On the M zeolite an induction period followed by deactivation was observed, which could be related to the presence of long diffusion path lengths in this sample, leading to mass transfer resistance. During the induction step, the aromatics yield increases, despite a significant loss of the acid site concentration as a result of coking. This induction period corresponds to the formation of an active hydrocarbon pool (HCP) composed of units of 2 to 5 aromatic rings with a molecular weight ranging from 130 to 220 g mol−1 (light coke). A kinetic study revealed that the developing HCP species is two times more active than Brønsted acid sites in the fresh zeolite. Diffusion limitations yet impact the product desorption by promoting coke growth and, therefore the deactivation of the HCP and hence of the catalyst. From MA-LDI/LDI-TOF MS (Matrix Assisted Laser Desorption Ionization—Time of Flight Mass Spectroscopy) characterisation was deduced that even after complete catalyst deactivation, the as-deposited coke continues growing at the external surface of the zeolite by condensation reactions, thus leading to heavy coke composed of more than 100 carbon atoms and a molar mass exceeding 1300 g mol−1. Unlike the micro-sized zeolite, the nano-scaled zeolite features a short diffusion path length and promotes fast formation of the active HCP. As a result, higher activity and selectivity into benzene were observed, whilst catalyst deactivation was significantly mitigated.

The generation and storage capacities of Neocomian and Jurassic sediments of the northern part of Western Siberia are evaluated. Variants of biogenic and abiogenic methanogenesis are considered. Tectonic and hydrothermal mechanism of the formation of gas pools in Cenomanian sediments is proposed. The youngest Cenomanian gas pools are predicted to be widespread northward under the Arctic Ocean bed. The method of seismic data integration and tectonophysical modelling based on it is proposed in order to search for hydrocarbon accumulations.

Link for citation: Raudina T.V., Smirnov S.V., Istigechev G.I., Pokrovsky O.S. Photochemical transformation of dissolved organic matter and behavior of metals in the waters of the southern taiga bog complex, Western Siberia. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 182-193. In Rus. The relevance. Dissolved organic matter is one of the largest biologically available sources of carbon in terrestrial and aquatic ecosystems, and its dynamics are critical to local and global carbon cycles. Destruction of organic matter during migration determines the biological cycle of elements and their stability. Important processes that lead to the transformation or removal of the dissolved organic matter are bio- and photodegradation. To date, enough research has been carried out to study the composition of humic substances, forms of metals, and the processes of migration of organo-mineral compounds in natural waters of the taiga zone, Western Siberia. Work is underway to study the dissolved organic carbon bioavailability, but the mechanisms of its photochemical transformations in different seasons of the year have not been studied. At the same time, photochemical mineralization of dissolved organic compounds largely regulates the biogeochemical cycles of elements by changing their bioavailability, the intensity of carbon dioxide emission from surface waters into the atmosphere, and the removal of dissolved trace elements through precipitation and coagulation. The main aim is to assess changes in the chemical composition and the rate of the dissolved organic matter and dissolved metals removal in the waters of the southern taiga bog complex (Western Siberia) under the sunlight exposure on a spatio-temporal scale. Objects: soil waters within different bog landscapes (open sedge-sphagnum fen, tall ryam (pine-shrub-sphagnum phytocenosis with high pine trees), and waterlogged mixed forest) of the Bakchar bog complex located in the southeastern part of the Ob-Irtysh interfluves, the Vasyugan plain. The waters were taken at a depth by digging a pit (40´40 cm area, 40 cm depth), which allowed the surrounding gravitational water to fill it up to the depth of 10–20 cm. The sampling took place during two field period in 2020 (June and October). Methods. pH, water temperature, specific conductivity (Cond) and dissolved oxygen were measured using a multiparameter instrument (WTW MULTI 3430 SET). The dissolved organic carbon was measured by a high-temperature thermic oxidation method using a Shimadzu TOC-LCPN analyzer, with an uncertainty of 2 %. The absorbance was measured at wavelengths up to 800 nm, 1 nm step using quartz 10 mm cuvette on a Cary-50 spectrophotometer. Major cations (Ca, Mg, Na, K), Si, and trace metals were determined with an ICP-MS Agilent CE 7500 with In and Re as internal standards and three various external ones. In the photodegradation experimental design, we followed the methodology which is sunlight exposure of sterile filtered (0,2 μm) samples in quartz reactors in the outdoor pool. Results. The authors revealed the influence of photodegradation on the qualitative and quantitative composition of dissolved organic substances and the behavior of metals in water samples of bog landscapes of the taiga zone of Western Siberia on spatiotemporal scales. It was established that from 3 to 30 % of the dissolved organic carbon can be removed from soil water under the influence of sunlight with maximum values in early June. At the same time, in autumn, despite the decrease in the amount of solar radiation, the photodegradable DOC can also reach 10–12 %. In general, there is a decrease in the percentage of the dissolved organic carbon loss in the waters in the row fen>ryam>forest. The dissolved organic carbon removal can be associated both with the transition of a part into an inorganic form, and with the destruction of high-molecular organic substances. A significant change (p<0.05) in the optical parameters is noted, which is consistent with the behavior of the dissolved organic matter during photolysis. In addition, under the influence of insolation, the transformation of organo-mineral compounds occurs, which leads to a change in the forms of metals. The greatest losses relative to control were observed for rare earth elements (Y, La, Ce, Pr, Nd), as well as Ti, V, which in some cases reach 70 % (more significant in fen waters). These trace elements show behavior similar to dissolved organic carbon, Al and Fe, which confirms the importance of organic and organo-Fe-Al-colloids determining the behavior of most elements in acidic waters with a high content of organic matter.

Pastoral areas are the key difficulty in China’s pursuit of common prosperity and a key region for China to build the northern ecological safety barrier and to realize the Two Centenary Goals. It is of great significance to scientifically evaluate the quality of rural life (QRL), measure the relative poverty level (RPL), and identify the relatively poor areas, making it possible to dock poverty elimination with rural revitalization. Based on the socio-economic data of 18 pastoral areas in Inner Mongolia, this paper draws on spatial layout theory to evaluate QRL and measures RPL by the natural breakpoint method and then identifies the relatively poor areas in Inner Mongolia. The results show that (1) the QRLs of pastoral areas in Inner Mongolia were unbalanced and highly polarized. The mean score of QRLs was 0.2598. Eleven (61.11%) of the counties/banners had a QRL smaller than the mean score. On the spatial layout of QRLs, the western areas were stronger than the central areas. High QRL counties/banners are mainly concentrated in the western region. In the central region, the QRLs were very fragmented, falling onto all five levels. (2) The pastoral areas in Inner Mongolia differed significantly in RPL. The mean score of RPL stood at 0.3788. Nine counties/banners (50%) had an RPL greater than the mean. Contrary to the spatial layout features of QRLs, the central pastoral areas in Inner Mongolia had stronger RPLs than the eastern ones. High RPL counties/banners are mostly clustered in the central region. The spatial layout of RPLs is relatively reasonable in the central region: the RPLs decreased gradually from Dorbod Banner. (3) Nearly 45% of the pastoral areas in central and western Inner Mongolia face serious relative poverty and a high risk of returning to poverty. Eight counties/banners (45%) were identified as high composite relative poverty areas. From spatial layout, the composite relatively poor counties/banners clustered clearly, mainly in the western region. Finally, this paper establishes a warning mechanism against large-scale returning to poverty, aiming to lower composite RPL. The research results provide empirical reference and implementation path for consolidating the results of poverty eradication and facilitating rural revitalization.