Membrane Separation of Gaseous Hydrocarbons by Semicrystalline Multiblock Copolymers: Role of Cohesive Energy Density and Crystallites of the Polyether Block

The energy-efficient separation of hydrocarbons is critically important for petrochemical industries. As polymeric membranes are ideal candidates for such separation, it is essential to explore the fundamental relationships between the hydrocarbon permeation mechanism and the physical properties of the polymers. In this study, the permeation mechanisms of methane, ethane, ethene, propane, propene and n-butane through three commercial multiblock copolymers PEBAX 2533, PolyActive1500PEGT77PBT23 and PolyActive4000PEGT77PBT23 are thoroughly investigated at 33 °C. This study aims to investigate the influence of cohesive energy density and crystallites of the polyether block of multiblock copolymers on hydrocarbon separation. The hydrocarbon separation behavior of the polymers is explained based on the solution–diffusion model, which is commonly accepted for gas permeation through nonporous polymeric membrane materials.

Conditions of the Formation Gas Deposits in the Epart of the Dnieper-Donets Basin: Integration of Basin Modeling Data with Consequences of Strike-Slip Faulting Effects

Since 1950, when the megascale Shebelinka deposit was found in the north-eastern portion of the Dnieper-Donets basin (DDB) this district has been served as a heartland of the hydrocarbon extraction in Ukraine. Right now, this area is again facing a new wave of commercial interest. Most conventional hydrocarbon plays here contain natural gas and liquid gas accumulated in numerous clastic and fractured horizons throughout Carboniferous to Lower Permian successions. The numerical basin modelling in the Donbas segment indicated that organic-rich sediments are thermally mature in the deep levels of the basin. Our interpretation of the structural patterns within the study area suggests that the kinematic development of the fracture sets is consistent with the model of development of subsidiary structures within the dextral strike-slip zone. Nearly all gas and gas condensate fields in the eastern part of the DDB may be classified as naturally fractured reservoirs in fault-breached anticlinal traps associated with releasing jogs in strike-slip assemblages. Gaseous hydrocarbons generated in deep "gas window" compartments have escaped here via several fracture corridors forming "sweet spots " sites. The main objective of this contribution is to get an insight into the style and structural trends of formation structural traps of hydrocarbons which in concert with basin modeling technologies will ensure proper technical decisions for the efficient exploration and production of gas reservoirs. This research summarizes new insights into gas deposits formation in the eastern part of DDB based on a synthetic approach ascertaining a vital connection of basin modeling results with the spatial distribution of kinematically induced releasing jogs which facilitating magnified fluid-and-gas conductivity.

Differentiation of the Generation Potential of the Menilite and Istebna Beds of the Silesian Unit in the Carpathians Based on Compiled Pyrolytic Studies

The study of the source rocks was carried out with the use of various analytical methods in order to assess their generation potential and to predict the decomposition products of organic matter. The selected samples from the Menilite Beds from the Silesian and Dukla units, as well as the Istebna layers from the Silesian unit, which are classified as weak and medium source rocks in the Carpathian oil system, were examined. The generation potential and type of the products obtained from the pyrolysis of the analyzed source rocks, despite the often comparable overall content of organic matter, are significantly different. Menilite shale generated a higher abundance of hydrocarbons (alkanes, alkenes, and isoalkanes) by stage pyrolysis, which suggested that the organic matter of Menilite shale is different from the Istebna source rocks. Moreover, the thermogravimetric analysis showed a two-stage weight loss in the case of Menilite shales, while the Istebna shales were characterized by a one-stage weight loss at higher temperature. For the Istebna layers, n-alkanes from the C1–C5 range were detected as the main pyrolysis products, which proves the gas-forming type of the organic matter dispersed in these sediments. Rock-Eval analyses showed that the organic matter reached a degree of maturity corresponding to the early thermocatalytic processes (the initial oil window stage) and therefore was able to generate liquid and gaseous hydrocarbons. The comparison of the decomposition temperatures of the organic matter from the Rock-Eval and TG analyses allowed us to conclude that both measurements correlate well and can be equally used to assess the level of thermal transformations of organic matter.

Molecular and Stable Isotope Composition of Pollutants Emitted during Thermal Processes within the Rymer Coal Waste Dump (Upper Silesia, Poland)

Twenty-seven gases and sixteen rock wastes from the thermal active Rymer coal waste dump were collected. The composition and origin of gaseous, liquid, and solid pollutants emitted during the self-heating process and the development of these processes with time were established. Gases were subjected to determination of molecular and stable isotope (δ13C and δ2H) composition. Rock-Eval pyrolysis and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were applied for evaluation of the quantity and molecular composition of pyrolysates released during the heating of rocks in temperatures from 100 to 650 °C. The main products of Py-GC-MS are released between 350 and 650 °C, namely alkanes, aromatic hydrocarbons, and aromatic alcohols. These components were also recorded in Py-GC-MS products of samples collected from the dump surface. Besides the high-molecular-weight organic compounds, in emitted gases CO2, CO, gaseous hydrocarbons, and S-compounds were recorded. The stable isotope data indicated that methane was generated mainly during the low-temperature thermogenic process, but a share of the microbial-originated gas was visible. The source of the CO2 was the oxidation of organic matter. The gaseous S-compounds were products of high-temperature decomposition of sulphides and organic S-compounds. The hydrocarbon and CO contents of the emitted gases proved to be good indicators for tracking of the self-heating processes.

Organic and Isotopic Geochemistry of Evaporites and Shales of the Santana Group (Araripe Basin, Brazil): Clues on the Evolution of Depositional Systems and Global Correlation during the Lower Cretaceous

Even being the more studied of the interior basins of Northeast Brazil, the Araripe Basin still lacks research in organic geochemistry designed to support interpretations of depositional systems and conditions of formation. This work aims to investigate the organic behavior of evaporites and shales from the Santana Group (Lower Cretaceous), as well as discuss their role in the evolution of its depositional systems. A total of 23 samples, 17 shales and six evaporites, were collected in outcrops and quarries. Analyses of Total Organic Carbon (TOC), Total Sulfur (TS), Rock Eval pyrolysis, and the δ34S isotope ratio were performed. The TOC results revealed high organic content for seven intervals, of which only five had high TS content. From the Rock Eval pyrolysis, dominance of the Type I kerogen was verified, thus corresponding to the best type of organic matter (mainly algal) for the generation of liquid and gaseous hydrocarbons. The Lower Cretaceous (probably Aptian) response to the progressive evolution in redox conditions is linked to a remarked Oceanic Anoxic Event (OAE-1a). The TOC/TS ratio suggests variable palaeosalinity, indicating most of the shales were formed under brackish waters with saline influence, yet tending to increase the salinity upwards where hypersaline conditions dominate in the Ipubi Formation. The isotope data also suggest the occurrence of marine ingressions in the depositional systems even prior to the well-documented event of the Romualdo Formation.

Phase Behavior Identification and Formation Mechanisms of the BZ19-6 Condensate Gas Reservoir in the Deep Bozhong Sag, Bohai Bay Basin, Eastern China

Significant developments have been observed in recent years, in the field of deep part exploration in the Bozhong Sag, Bohai Bay Basin in eastern China. The BZ19-6 large condensate gas field, the largest gas field in the Bohai Bay Basin, was discovered for the first time in a typical oil-type basin. The proven oil and gas geological reserves in the deeply buried hills of the Archean metamorphic rocks, amount to approximately 3 × 10 8 tons of oil equivalent. However, the phase behavior and genetic mechanisms of hydrocarbon fluids are still unclear. In this study, the phase diagram identification method and various empirical statistical methods, such as the block diagram method, φ 1 parameter method, rank number method, and Z -factor method were implemented to comprehensively identify the phase behavior types of the BZ19-6 condensate gas reservoir. The genetic mechanism of the BZ19-6 condensate gas reservoir was investigated in detail through analyses of physical properties of the fluid at high temperatures and pressures, organic geochemical characteristics of condensate oil and gas, and regional tectonic background. Consequently, this study is shown as follows: (1) The BZ19-6 condensate gas reservoir is a part of a secondary condensate gas reservoir with oil rings, formed synthetically since the Neogene period due to multiple factors, such as retrograde evaporation from deep burial and high temperature, inorganic CO2 charging from the deep mantle, and late natural gas invasion. (2) The hydrocarbon accumulation process of the BZ19-6 condensate gas reservoir is as follows: First, a large amount of oil is accumulated at the end of the lower Minghuazhen deposition (5 Ma BP); second, a large amount of natural gas is generated in the deep-source kitchen and mantle-derived inorganic CO2 charged into the early formed oil reservoirs at the end of the upper Minghuazhen deposition (2 Ma BP). As a result, the content of gaseous hydrocarbons in the hydrocarbon system of the reservoir increased, which led to large amounts of liquid hydrocarbons dissolved in gaseous hydrocarbons and significantly reduced the critical temperature of the hydrocarbon system. Therefore, existing secondary condensate gas reservoirs are formed when the critical temperature is lower than the formation temperature and it enters the critical condensate temperature range.

Elements of regional organic geochemistry and separate prediction of oil and gas content of regions

The article considers the elements of organic geochemistry in the regional aspect, which aims to separate quantitative prediction of oil and gas content of regions. The principles and results of balance calculations of generation and emission of liquid and gaseous hydrocarbons for different facies-genetic types of organic matter and methods for calculating the scale of hydrocarbon emission are considered. Finally, a list of the main regularities of organic geochemistry is given.