Light Hydrocarbon Liquids Research Articles

Thiophene-functional hierarchical carbons for the removal of ionic and organic mercury in light hydrocarbon liquids: Synthesis, evaluation and adsorption mechanism

A simple synthesis of thiophene-functional zeolite-templated carbons (ZTCs) is proposed to remove ionic mercury (Hg2+) and organic mercury (Hgorg) from gasoline. Microporous zeolite (Beta) and mesoporous zeolite (MCM-41) were used to prepare porous carbon by impregnating with 2-thiophenemethanol (ThM) to explore the influence of template type on the quality of templated carbon. The amount of strong acidic sites in MCM-41 zeolite was more than Beta zeolite which promoted the catalytic polymerisation of the ThM in the pores structure of the zeolite and highly templated carbon was obtained. The impregnation concentration of ThM on the structure and functional groups of the samples was explored. It was found that increasing the concentration of ThM properly can promote the filling of zeolite pores by ThM and form more ordered templated carbons. In addition, the increased ThM promoted the formation of the S = O and C-O oxygen-containing functional groups. The optimal impregnation concentrations of ThM were 25% for B-Al (25%-B-Al-ZTC) and 75% for M−Al (75%-M−Al−ZTC). The 75%-M−Al−ZTC with sufficient S = O and C-O oxygen-containing functional groups showed excellent mercury adsorption capacity (617.49 μg/g) and a high intra-particle diffusion rate (294.10 h−1). The simultaneous adsorption of Hg2+ and Hgorg was also conducted and it was found that Hgorg had competitive adsorption for Hg2+ which led the total adsorption capacity to decrease. In addition, the 25%-B-Al-ZTC and 75%-M−Al−ZTC adsorbents had good regeneration ability and the adsorption capacity remained over 75% and 71% for Hg2+ and Hgorg after five desorption-sorption cycles, respectively. Thus, the new adsorbents with stable and efficient Hg removal performance have the potential for practical application by oil refineries.

Removing ionic and organic mercury from light hydrocarbon liquids by ordered zeolite-templated carbon doped with sulphur

Sulphur-doped, β-zeolite-templated carbons (S-β-ZTCs) were synthesized by chemical vapor co-deposition of hydrogen sulfide (H2S) and acetylene (C2H2) to remove ionic (Hg2+) and organic mercury (Hgorg) from gasoline. In situ doping of sulphur introduced aromatic thiols and thiophenes into the ZTC's framework that removed the mercury by forming Hg–S bonds. Notably, these covalently bonded sulphur groups exhibited better stability than physically deposited elemental sulphur, yielding less than 10% material loss after repeated adsorption-desorption tests. Thanks to these unique chemical properties, the adsorption capacity of S-β-ZTCs for Hg2+ in the gasoline (2660 μg/g) was at least an order of magnitude larger than that of common adsorbents. Moreover, simultaneous adsorption of Hg2+ and Hgorg on S-β-ZTCs proceeded independently when the total mercury concentration was in the range applicable to most natural gas condensate samples. Finally, Grand Canonical Monte Carlo (GCMC) method and Density Functional Theory (DFT) study were used to reveal the adsorption mechanism of ZTCs on Hg2+ and Hgorg. These findings provided a better understanding of the mercury sorption mechanism of S-β-ZTCs and have important practical significance for the clean production of the condensate processing industry.

Parametric study of catalytic hydropyrolysis of rice husk over a hierarchical micro-mesoporous composite catalyst for production of light alkanes, alkenes, and liquid aromatic hydrocarbons

In this study, we compare the products of catalytic fast pyrolysis (CFP) and catalytic hydropyrolysis (CHP) of rice husk over an HZSM-5-based hierarchical catalyst. The results suggest that the addition of hydrogen inhibits polycondensation reactions, leading to a reduction of 2.3 wt% in coke yield at 400 °C and 35 bar. The presence of hydrogen increases the relative content of hydrocarbons in both liquid and gas products, with a more significant increase in CH4 and C2–C3 yield in the gas, suggesting that hydrodeoxygenation, decarbonylation, and decarboxylation reactions are promoted. Alkali-treatment of the HZSM-5 improves the catalytic activity and coking resistance of the catalyst. The addition of an extra external MCM-41 layer to the alkali-treated HZSM-5 further improves the catalytic activity, resulting in a relative hydrocarbon content of 48.9%, which is higher than that obtained with the alkali-treated HZSM-5 and pristine HZSM-5. We also report the effect of pressure on the products. As the pressure increases from 1 to 35 bar, the relative content of hydrocarbons increases from 39.9 to 48.9%, while the coke yield decreases from 3.4 to 1.9 wt%, and CH4 and C2–C3 yields decrease from 10.3 wt% and 5.1 wt% to 14.2 wt% and 6.7 wt%, respectively. As the temperature increases from 300 to 400 °C, the relative content of hydrocarbons increases from 38.2% to 48.9%. Both CH4 and C2–C3 yields reach the highest values of 14.2 wt% and 6.7 wt% at 400 °C and 35 bar.

Insights into catalytic effects of clay minerals on hydrocarbon composition of generated liquid products during oil cracking from laboratory pyrolysis experiments

Experiments were conducted to distinguish oil cracking in reservoir rock versus source rock. Oil and source rock samples were heated in pressure vessels at 380 °C for 72 h, which resulted in oil cracking to gas and pyrobitumen with some residual liquid. The oil samples were heated with different minerals (fine-grained quartz, calcium carbonate, montmorillonite, kaolinite and illite) employing different ratios of the oil to the mineral in each case. Heating oil with quartz or calcium carbonate was used to simulate oil cracking in reservoirs, while heating oil with clay minerals was used to simulate oil cracking within source rocks. Based on the experiments, oil cracking in reservoirs versus source rocks can be differentiated by relative concentrations of the prominent C7 hydrocarbons: n-heptane, methylcyclohexane and methylbenzene (toluene) in the liquid products. The light hydrocarbon distribution in the final cracking products is affected by the “matrix effect” from clay minerals and the surrounding medium in reservoirs and source rocks during oil cracking. No relationship between the types of marine source rock or total organic content (TOC) and the distribution of light liquid hydrocarbons generated by catalysis on clay minerals at high temperature was observed. Future studies are needed to evaluate different types of source rock (e.g., terrigenous versus marine, clastic versus calcareous), and the relationship between light liquid hydrocarbon yield and the quantity of each clay mineral.

STUDY OF THE PHYSICAL AND CHEMICAL PROPERTIES OF SYNTHETIC LIQUID HYDROCARBONS AND THEIR MIXTURES WITH CRUDE OILS

In this paper, the possibility of viscosity reducing of various high-viscosity and high-paraffin oils of the Timan-Pechora Oil and Gas Province (TPOGP) by adding synthetic liquid hydrocarbons (SLH) obtained from synthesis gas by the GTL method is investigated. The results of viscosity and density measurements are presented, as well as verification of compliance with the additivity rules of these physical quantities when mixing heavy oils with light and synthetic liquid hydrocarbons. Rheological studies on a rotary viscometer HAAKE VT-550 showed that at temperature 10 °C, the addition of 2 % of synthetic liquid hydrocarbons to the bituminous oil of the Yarega field reduces the viscosity by 1.6 times, at 6 % - by 4.0 times, and at 10 % - by 8.4 times. When added to the high-paraffin oil of the Kyrtayel field, the corresponding concentrations of SLH reduce the final viscosity by 1.5, 3.1 and 6.4 times. At 20 °C, the decrease in viscosity for these oils and these concentrations of SLH is slightly less. The component-group composition of synthetic liquid hydrocarbons has been studied by gas chromatography and IR-Fourier spectroscopy. Chromatographic analysis showed that the studied mixture of liquid synthetic hydrocarbons is similar in composition to the reforming catalysis performed under mild conditions on a catalyst of reduced activity. This is evidenced by the intermediate content of aromatic hydrocarbons (within 40 %) between platforming and Zeoforming, the pronounced predominance of isomeric alkanes over normal ones, the low residual content of naphthenes and the moderate content of olefins (within 3 %). The share of aromatic compounds in the composition of SLH is more than 36 % of the volume. Since they have the ability to effectively dissolve highmolecular hydrocarbon oils, it can be assumed that when adding SLH to real oil systems, aromatic hydrocarbons will contribute to the destruction (dissolution) of supramolecular asphalt-resinous formations, and, as a result, change the rheological characteristics of oils.

Waste plastics-to-fuel using fly ash catalyst

Suitable disposal pathways of waste plastics and coal fly ash have yet not been established which is a matter of great environmental concern. Waste low-density polyethylene (LDPE) and high-density polyethylene (HDPE) were degraded using a semi-batch reactor along with acid or alkali modified fly ash catalyst. The high yield of liquid fuel product (about 87.24 wt%) was achieved for low-density polyethylene at a polymer and catalyst ratio of 25 w/w. About 96% conversion was found with very few amount of gaseous fuels. Both of the waste plastics were degraded at 400–450 °C. The liquid products were analyzed using Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H, 13C, and DEPT-135 NMR), and gas chromatography–mass spectrometry (GC–MS). Fly ash is an efficient catalyst to degrade waste plastic into light weight liquid (gasoline and kerosene) hydrocarbons. The NMR results accompanied by GC–MS data ensure that obtained fuels contain both aliphatic (saturated and unsaturated) and aromatic hydrocarbons. This plastic-to-fuel technology should be commercialized owing to be profitable and eco-friendly.

A Fe-Ca/SiO2 catalyst for efficient production of light aromatics from catalytic pyrolysis of biomass

In this study, the catalytic activity and selectivity of Fe-Ca/SiO2 catalyst systems for light hydrocarbon liquids (HCL) and gaseous products (GPs) were investigated in a fixed-bed reactor at N2 pressure 0.1 MPa, temperature 600–750 °C. A series of Fe-Ca/SiO2 catalysts were synthesized, characterized and evaluated for the oxygen transfer. The catalytic pyrolysis of biomass with catalysts (Fe/SiO2, Ca/SiO2, Fe-Ca/SiO2) was studied to identify the selective deoxygenation. With the addition of Fe/SiO2 catalyst, the oxygen was crucially removed in the form of CO2, and with Ca/SiO2 catalyst, more oxygen was removed in the form of H2O. In addition, the hydrogen content with Fe-Ca/SiO2 catalyst was higher than that of raw biomass. The hydrogen with Fe-Ca/SiO2 increased from 57.41 ml/g to 109.04 ml/g. It also effectively improved the aromatics in bio-oil with the addition of Fe-Ca/SiO2 catalyst during the pyrolysis process. It was found that the addition of Ca remarkable promoted the catalytic activity of Fe catalyst due to forming Ca2Fe2O5. A possible mechanism was proposed to be responsible for the high catalytic activity and deoxygenation in Fe-Ca/SiO2 catalyst systems.

Aquathermolysis of heavy oil in the presence of iron tallate and mineral components of reservoir rock

This study is devoted to conversion of heavy oil in sandstone, taken from the Ashalchinskoye field in Tatarstan, Russian Federation, in the presence of an oil-soluble catalyst precursor based on a transition metal of iron in water vapor. The mass content of a portion of the catalyst, in a hydrogen donor based solution totals 2.0 wt % of the oil extract in the rock sample. It was found that according to the results of the chemical composition study, the introduction of the catalyst ensures the conversion of resins (by 24 wt %) at 250°C and a significant conversion of asphaltenes at 300°C, the content of which decreases practically to “trace” amounts at this temperature. The intensification of the destructive processes of breaking heteroatom bonds in the molecules of resins and asphaltenes contributes to the generation of light liquid hydrocarbons.

Modeling and control of a Fischer-Tropsch synthesis fixed-bed reactor with a novel mechanistic kinetic approach

A modeling and dynamic control study for a Fischer-Tropsch synthesis fixed-bed reactor under the one-dimensional pseudohomogeneous scheme representation with integration of the cooling jacket dynamic approach has been developed. The proposed reactor model contemplates the use of a novel mechanistic kinetic model based on the Langmuir theory recently reported in the literature. To ensure a good thermal behavior and an improvement reactor performance a proportional-integral controller is implemented in the cooling jacket. The robustness of the controller, the dynamic model and the mechanistic kinetic approach are evaluated and validated against the use of four different sets of initial operating conditions of temperature, pressure and gas hourly space-velocity. The results indicate the reactor model potential under the proportional-integral controller action, since it allows to completely attenuate the typical hot-spot formation in fixed-bed reactors in which highly exothermic reactions are carried out. In addition, the mechanistic kinetic model represents to a great extent the Fischer-Tropsch synthesis reaction network in terms of the syngas conversion and the light gases and heavy liquid hydrocarbons selectivity.

Investigation of Ni─Ca binary catalystic activities for production of light aromatics from catalytic pyrolysis of brown coal

AbstractThe pyrolysis behavior of Ni─Ca‐loaded Yunnan brown coals (Shi Caoxing [SCX] and Guo Jiashan [GJS]) was studied in a fixed‐bed reactor to investigate the effects of Ni, Ca, and Ni─Ca loading on the yields of the obtained liquids and light aromatic hydrocarbons. Structural variations of the prepared coal chars were characterized by the scanning electron microscope–energy dispersion X‐ray, Fourier‐transform infrared spectroscopy, X‐ray diffractometer, Brunauer–Emmett–Teller analysis, and elemental analysis. The effects of the Ni, Ca, and Ni─Ca loadings on the tar yield and upgradation of pyrolysis tar were evaluated. The results revealed that the use of the Ni─Ca catalyst affords improved yields of the liquid products and tar. Furthermore, the light hydrocarbon liquids contents in the coal tar was improved with the use of the Ni─Ca catalyst. The heavy components and polycyclic aromatic hydrocarbons in the coal tar could be easy to convert into light hydrocarbon liquids (phenol, cresol, xylenols, and naphthalene) with the SCX brown coal pyrolysis. In contrast, the catalytic pyrolysis of GJS brown coal was inhibited by the Ni─Ca catalyst. The study revealed that the catalytic activity of the Ni─Ca catalyst greatly depends on the type of the coal substrate and was promoted or inhibited depending on the type of the brown coal.

The new Fischer-Tropsch process over ultrafine catalysts

Abstract TIPS RAS (Russia) has developed a new technology for high temperature three-phase Fischer-Tropsch synthesis. This technology is based on an original nanosized iron catalyst and a new reactor type. Producing light liquid hydrocarbons enriched with α-olefins (up to 50% wt) is the main distinction from industrial slurry-technologies. Yield of these products is about 140 g per 1 cubic meter of syngas. This technology is tested in a pilot plant with capacity of up to 2 liters of liquid hydrocarbons per day. Project indexes are CO conversion of about 80% (per pass), selectivity toward liquid products of 85%, and C5+ productivity of 600 g / h kgMe.

Origin of bitumen fractions in the Jurassic-early Cretaceous Vaca Muerta Formation in Argentina: insights from organic petrography and geochemical techniques

This paper investigates chemical functional groups of the two extracted bitumen fractions in shales of the Jurassic to early Cretaceous Vaca Muerta Formation of the Neuquén Basin in Argentina, South America. The results indicate that Bitumen I is strongly aliphatic and appears to be genetically related to fluorescent amorphous organic matter. In contrast, Bitumen II consists of highly condensed, aromatic hydrocarbons, and has some correspondence to nonfluorescent amorphous organic material. Comparison of Rock-Eval VI pyrolysis data (S1 and S2) with the bitumen yields suggests that Bitumen I relates to S1 but also to S2. In addition, Bitumen I has a positive correlation with light liquid hydrocarbons (C5–C29), but also partially with heavier hydrocarbons (above C30). This suggests that Bitumen I corresponds to the majority of lighter hydrocarbons up to C29 and some portion to heavier hydrocarbons. These results have implications for the assessment of the mobility of generated hydrocarbons and their availability for production.

Comparison of methanol to gasoline conversion in one-step, two-step, and cascade mode in the presence of H-ZSM-5 zeolite

ABSTRACTIn this report, three technological modes for methanol-to-gasoline reaction in the presence of H-ZSM-5 catalyst are compared: (i) direct methanol transformation to hydrocarbons; (ii) two-step (methanol-dimethyl ether-hydrocarbons); and (iii) cascade pathway. Light hydrocarbon gases (methane, ethylene, propylene, and isobutene) and liquid aromatic hydrocarbons (benzene, toluene, xylene, cresol, durol, naphthalene, methylnaphthalene, ethyl naphthalene, isopropyl naphthalene, methyl isopropyl naphthalene, etc.) were found to be the main reaction products. The experimental results showed that the classical two-step methanol to gasoline (MTG) process nowadays remains the most effective for gasoline-range hydrocarbons production, while one-step and cascade schemes require further investigation and the development of reactor systems as well as the operating conditions. The product distribution of MTG synthesis after 120 h on stream in the case of two-step mode was found to be the following: liquid C6–C8 hydrocarbons – 23%; C1–C5 gaseous products – 65%; heavy C9–C12 hydrocarbons – 10%.

New Insight into the Kinetics of Deep Liquid Hydrocarbon Cracking and Its Significance

The deep marine natural gas accumulations in China are mainly derived from the cracking of liquid hydrocarbons with different occurrence states. Besides accumulated oil in reservoir, the dispersed liquid hydrocarbon in and outside source also is important source for cracking gas generation or relayed gas generation in deep formations. In this study, nonisothermal gold tube pyrolysis and numerical calculations as well as geochemical analysis were conducted to ascertain the expulsion efficiency of source rocks and the kinetics for oil cracking. By determination of light liquid hydrocarbons and numerical calculations, it is concluded that the residual bitumen or hydrocarbons within source rocks can occupy about 50 wt.% of total oil generated at oil generation peak. This implies that considerable amounts of natural gas can be derived from residual hydrocarbon cracking and contribute significantly to the accumulation of shale gas. Based on pyrolysis experiments and kinetic calculations, we established a model for the cracking of oil and its different components. In addition, a quantitative gas generation model was also established to address the contribution of the cracking of residual oil and expulsed oil for natural gas accumulations in deep formations. These models may provide us with guidance for gas resource evaluation and future gas exploration in deep formations.

Hydrocarbon evaporative loss from shale core samples as revealed by Rock-Eval and thermal desorption-gas chromatography analysis: Its geochemical and geological implications

The S1 peak generated by Rock-Eval analysis of source rock and reservoir interval core and cuttings samples has been routinely employed for in-place hydrocarbon resources assessment by petroleum geochemists, geologists and even engineers. Significant evaporative loss of gaseous and light hydrocarbons (up to C10) can occur during core and cuttings collection and storage, and subsequent sample preparation in the laboratory before instrumental analysis. Consequently a correction to the S1 values is needed in order to obtain a more accurate estimate of the resources. To investigate the effect of evaporative loss on both the amount and the composition of the hydrocarbons retained in shale, a time-series of Rock-Eval and thermal desorption-gas chromatography (TD-GC) analyses have been carried out on an organic-rich Devonian Duvernay Formation shale core sample from the Western Canada Sedimentary Basin (WCSB) and an organic-lean Ordovician Lotbinière Formation shale core sample from Quebec, Canada. The results suggest that the content of total organic carbon (TOC) may play an important role in retaining and preserving light hydrocarbons in sedimentary rocks. A total loss of gaseous and light liquid hydrocarbons up to C9 is shown to take place within 21 h of sample preparation for the low TOC (<1%) Ordovician Lotbinière shale when the powdered sample was left exposed to the open air, accounting for a 38% decrease in its Rock-Eval S1 peak. The Rock-Eval S1 peak can be reduced by 29% even if the powdered sample has been stored in a sealed container for just over a week. In contrast, the volatile loss has been found to occur at a much slower rate for the high TOC (>11%) Devonian Duvernay shale core sample. After 360 h of exposure to the open air, the powdered Duvernay shale sample shows only 15% decline in its Rock-Eval S1 peak, and still contains high relative concentrations of C7–C9 hydrocarbons. In addition, the evaporative loss of some isomers of C5–C7 hydrocarbons from the organic-rich shale is not fully in agreement with their GC retention/elution behavior, but appears to be partially controlled by their adsorption/desorption on the organic matter and mineral matrix. This suggests that the C5–C8 gasoline range hydrocarbon parameters should be used with caution for oil–oil correlation for unconventional shale and tight petroleum systems. While the findings in this study validate the current industrial practice that targets organic-rich and mature shale intervals for unconventional shale gas and oil exploration because of their large hydrocarbon storage capacity, the results also have an important implication that high TOC content may adversely affect the production efficiency of shale and tight hydrocarbon reservoirs due to the strong adsorption of hydrocarbons by the high maturity organic matter.

Effect of calcium additive on product yields in hydrogasification of nickel-loaded Chinese sub-bituminous coal

Hydrogasification of Chinese sub-bituminous coal was performed in a fixed-bed reactor to study the effects of Ni and Ni+Ca dual catalysts on the yields of light hydrocarbon liquids (HCL) and gaseous products (GPs). In the presence of calcium, a high yield of HCL and GPs was obtained. The main components in tar were light aromatic hydrocarbons (LAHs) such as BTX and naphthalene. The product yields strongly depended on the amount of co-loaded calcium. The maximum yields of LAHs and GPs were achieved to be 2.15wt% (0.85wt% of BTX and 0.7wt% of naphthalene) and 51.51wt% (CH4, CO, CO2 and C2–C3), respectively, when using 5% Ni+1% Ca dual catalysts at 750°C and 1.0MPa. The addition of Ca promoted the conversion of oxygen-containing species and aromatics to H2O, CO, CO2, CH4 and BTX.

An improved viscosity model based on Peng–Robinson equation of state for light hydrocarbon liquids and gases

Recently, a PRμ viscosity model was developed by Fan et al. It is applicable to both the liquid and gas hydrocarbons, but some large deviations might be obtained when applied to some multi-component mixtures. This short communication proposes an improvement method to enhance the accuracy of this model. The method replaces the universal critical compressibility factor in the original model with each component's real critical compressibility factor. The experimental viscosity data of pure methane, pure propane and thirteen light liquid hydrocarbon mixtures were adopted to validate the improved model. The results show the improved model is suitable to both the light hydrocarbon liquids and gases with satisfactory accuracy. The average ARD of the PRμ model was enhanced 4.78% when applied to thirteen hydrocarbon mixtures. Additionally, when applied to five complicated Qatari synthetic natural gas mixtures, the improved PRμ model is essentially comparable in predictability to five other viscosity prediction models.

Suggestion of mixing rule for parameters of PRμ model for light liquid hydrocarbon mixtures

Our aim is to improve the predictions for the viscosities of selected light liquid hydrocarbon mixtures by using a reliable model based on Peng-Robinson equation of state (PR EOS). Therefore, a viscosity model on the basis of the similarity between PvT and Tμ(viscosity) P has been applied. Based on the volume-translated Peng-Robinson equation of state (VTPR EOS), a correction has been used for viscosity to improve the results of model. The viscosity model can be extended to mixtures by using an appropriate mixing rule for the parameters of the PR model. For a better description of viscosity and improvement of some calculation results, a mixing rule has been proposed for the parameters of the model. The results of the model show that the agreement between experimental and the calculated viscosities is reasonably good and noticeable improvements can be seen in the results of some calculations.

Paleotemperatures and paleofluids recorded in fluid inclusions from calcite veins from the northern flank of the Ponta Grossa dyke swarm: Implications for hydrocarbon generation and migration in the Paraná Basin

The Paraná Basin, southern Brazil, has an atypical thermal and fluid history due to the occurrence of an episodic continental flood volcanism during the Early Cretaceous. So far, there are few data about the influence of this volcanic event on the paleotemperatures and paleofluids of the Paraná Basin sedimentary rocks. The Teresina Formation in the northern flank of the Ponta Grossa dyke swarm hosts high concentration of subsurface igneous rock bodies (sills and dykes), besides its covering by a hundreds meter thick volcanic rock cap. In this study, we used fluid inclusion analysis performed in horizontal and vertical calcite veins from the Teresina Formation and from a Late Cretaceous basic dyke to estimate paleotemperatures and to characterize the composition of diagenetic paleofluids. Homogenization temperatures of requilibrated fluid inclusions show that the Teresina Formation reached temperatures above 200 °C. Horizontal parallel bedding calcite veins from the Teresina Formation record low to high salinity (2–26 wt.% NaCl eq.) aqueous paleofluids. The prevalence of high salinity fluid inclusions associated with light hydrocarbon fluid inclusions indicates deep buried fluids. Fluid inclusions in vertical calcite vein from basic dyke comprise only low salinity aqueous fluids (0–3 wt.% eq.NaCl) interpreted as dominated by meteoric water. The recorded paleotemperatures are attributed to the heating by the Paraná volcanic event during the Early Cretaceous, with the thermal effect of the volcanic rock cap surpassing the effect of nearby sills and dykes. Estimated paleotemperatures higher than 200 °C would allow the generation of light liquid and gaseous hydrocarbons. Overpressured compartments in the Teresina Formation allowed the expulsion of buried pore fluids (high salinity aqueous fluids and hydrocarbons) to fracture systems, where they mixed with meteoric water. The input of meteoric water through fracture systems connected with the surface favored hydrocarbons degradation in the early stages of source rock maturation during the Early Cretaceous.

Light volatile liquid and gas shale reservoir potential of the Cretaceous Shaftesbury Formation in northeastern British Columbia, Canada

The geologic controls on reservoir properties and potential hydrocarbon (volatile, low-molecular-weight liquid and gas) resources of the Cretaceous Shaftesbury Formation in northeastern British Columbia have been investigated. Maturity varies from the oil to dry gas window (Tmax = 429–486C), with increasing maturity and depth of burial toward the south. The Tmax, in degrees Celsius, is the oven temperature at the peak generation of S2 during pyrolysis. Total organic carbon (TOC) content ranges between 0.64 and 8.0 wt. %, with an average of 2.2 wt. %. The TOC content distribution mirrors the trends in maturity, with lower TOC content in areas of high maturity. Kerogen is characterized as either type II-III or type III. The quartz content ranges between 33 and 66%, with higher quartz content in areas with lower TOC content and greater maturities. Porosity ranges between 4.5 and 14.6%, with higher porosities observed within shallower wells, low quartz content, or maturities, or a combination of all three. The porosity is reduced in high-maturity samples by mechanical compaction and silica cementation. Total gas capacities range between 4.5 and 24.8 cm3/g, and gas-in-place (GIP) estimates are between 0.98 and 3.39 bcf/(section meter). The calculated hydrocarbon generation is less than 3.6 bcf/(section meter), with light liquid generation between 3.7 and 516.2 MMBO. Present-day depths and organic maturity have strong influences on the hydrocarbon capacity more so than TOC content. Deeper, higher maturity samples in the south have the largest total gas capacity and GIP estimates (0.98–3.39 bcf/[section meter]). Maturity is within the dry gas window in the southern one-third of the study area. Highest volumes of light liquid hydrocarbons are found within the less mature northern part of the study area.