Hydrocarbon Generation Kinetics Research Articles

Difference of hydrocarbon generation between argillaceous dolomite and mudstone and its influence on oil source: A case study of the Es4 in the Leijia area, Liaohe depression

Argillaceous dolomite and mudstone are two terrestrial source rocks that commonly occur together, and the difference in hydrocarbon generation characteristics determines the oil accumulation mode. The fourth member of the Shahejie Formation (Es4) in the Leijia area was used as an example to study the hydrocarbon generation characteristics and the overpressure difference caused by oil generation between argillaceous dolomite and mudstone, using hydrocarbon generation kinetics. Furthermore, the source of oil in the argillaceous dolomite reservoir was analyzed by combining the biomarker characteristics. The results indicated that the hydrocarbon generation characteristics of argillaceous dolomite and mudstone are significantly different. Mudstone starts hydrocarbon generation later and has a shorter hydrocarbon generation cycle, while argillaceous dolomite starts hydrocarbon generation earlier and has a longer hydrocarbon generation period. Due to the difference in hydrocarbon generation characteristics, when the burial depth is below 3000 m (EasyRo <0.85%), the oil-generation overpressure in the mudstone is smaller than that in argillaceous dolomite, and the tight oil in the argillaceous dolomite reservoir is mainly generated by and stored in the argillaceous dolomite itself. However, when the burial depth exceeds 3000 m (EasyRo >0.85%), the oil-generation overpressure in the mudstone surpasses that in argillaceous dolomite, and the tight oil has mixed source characteristics. The biomarker characteristics observed in extracts and crude oil confirm the above view. Whether tight oil exploration in argillaceous dolomite reservoir requires attention to the hydrocarbon supply capacity of adjacent mudstone depends on the maturity of organic matter.

Hydrocarbon Source Rock Evaluation of the Lucaogou Shale in the Periphery of Bogeda Mountain (SE Junggar Basin, China) and Its Implications for Shale Oil Exploration: Insights from Organic Geochemistry, Petrology, and Kinetics Pyrolysis

Since the discovery of the vast Jimusaer shale oilfield in the southeastern Junggar Basin in 2012, there has been considerable interest in neighboring areas around Bogeda Mountain that have shale oil potential. The primary productive interval in the basin, the Middle Permian Lucaogou Formation (P2l), is well-developed in the areas of Qitai, Mulei, Shiqiantan, Chaiwopu, and Miquan. In this study, we conducted an assessment of the hydrocarbon generation potential of the P2l in these five areas and compared it with that of the P2l in the Jimusaer oilfield, which were determined by GC-MS, total organic carbon (TOC) and vitrinite reflectance (Ro) measurements, Rock-Eval pyrolysis, and organic petrology to investigate the type, origin, thermal maturity, hydrocarbon potential, and oil/gas proneness of organic matter in the P2l. Additionally, we applied open-system pyrolysis of hydrocarbon generation kinetics to explore differences in hydrocarbon generation and expulsion across various P2l mudstone/shale in the southeastern Junggar Basin. The findings of this study revealed that the P2l shale in Qitai and Miquan areas contains more abundant and lower thermally mature organic matter (early mature–mature stage), characterized by primarily Type II1–I kerogen, similar to that found in the P2l shale of the Jimusaer oilfield. Conversely, the P2l shale in Mulei, Shiqiantan, and Chaiwopu contains less abundant and more thermally mature organic matter (mainly mature–highly mature stage), dominated by Type II2–III kerogen. Consequently, shale in these areas is considerably less desirable for oil exploration compared to the Jimusaer shale. The semi-deep to deep lake facies in Miquan and Qitai exhibit the most promising exploration potential. This study can serve as a guide for shale oil exploration in the southeastern Junggar Basin.

Quantitative effect of kerogen type on the hydrocarbon generation potential of Paleogene lacustrine source rocks, Liaohe Western Depression, China

Kerogen types exert a decisive effect on the onset and capacity of hydrocarbon generation of source rocks. Lacustrine source rocks in the Liaohe Western Depression are characterized by thick deposition, high total organic carbon (TOC) content, various kerogen types, and a wide range of thermal maturity. Consequently, their hydrocarbon generation potential and resource estimation can be misinterpreted. In this study, geochemical tests, numerical analysis, hydrocarbon generation kinetics, and basin modeling were integrated to investigate the differential effects of kerogen types on the hydrocarbon generation potential of lacustrine source rocks. Optimized hydrocarbon generation and expulsion (HGE) models of different kerogen types were established quantitatively upon abundant Rock-Eval/TOC/vitrinite reflectance (Ro) datasets. Three sets of good–excellent source rocks deposited in the fourth (Es4), third (Es3), and first (Es1) members of Paleogene Shahejie Formation, are predominantly types I–II1, II1–II2, and II–III, respectively. The activation energy of types I–II2 kerogen is concentrated (180–230 kcal/mol), whereas that of type III kerogen is widely distributed (150–280 kcal/mol). The original hydrocarbon generation potentials of types I, II1, II2, and III kerogens are 790, 510, 270, and 85 mg/g TOC, respectively. The Ro values of the hydrocarbon generation threshold for type I–III source rocks gradually increase from 0.42% to 0.74%, and Ro values of the hydrocarbon expulsion threshold increase from 0.49% to 0.87%. Types I and II1 source rocks are characterized by earlier hydrocarbon generation, more rapid hydrocarbon expulsion, and narrower hydrocarbon generation windows than types II2 and III source rocks. The kerogen types also affect the HGE history and resource potential. Three types (conventional, tight, and shale oil/gas) and three levels (realistic, expected, and prospective) of hydrocarbon resources of different members in the Liaohe Western Depression are evaluated. Findings suggest that the Es3 member has considerable conventional and unconventional hydrocarbon resources. This study can quantitatively characterize the hydrocarbon generation potential of source rocks with different kerogen types, and facilitate a quick and accurate assessment of hydrocarbon resources, providing strategies for future oil and gas exploration.

Hydrocarbon generation kinetics of salinized lacustrine source rocks in the upper Cretaceous-Paleocene South Yellow Sea Basin, offshore eastern China

Saline lacustrine source rocks have different enrichments in organic matter and hydrocarbon generation processes as compared with source rocks formed in freshwater and marine basins. We investigated the hydrocarbon generation kinetics of saline lacustrine source rocks and the physical properties of petroleum using immature source rocks from the Upper Cretaceous Taizhou Formation and Paleocene Funing Formation in the South Yellow Sea Basin. The source rocks were analyzed using PhaseKinetics approach.Our main results are as follows. (1) Compared with source rocks from freshwater and marine basins, the source rocks in the South Yellow Sea Basin have the same organofacies (i.e., generating Paraffinic-Naphthenic-Aromatic low wax oils) and a lower bulk activation energy (frequency factors of A = 9.66 × 1012 and 4.61 × 1012 s−1, with a dominant activation energy at 51 and 50 kcal/mol), with oil window conditions of 128–155°C and 98–146°C). (2) Compositional kinetic modelling indicates that the generated gas consists mainly of C1, C2, and C3 compounds, while the liquid phase is dominated by C7-15 and C16-25 compounds. (3) The physical properties of the two suits of source rocks show that the saturation pressure, gas/oil ratio and formation volume factor vary with maturation. The pressure−temperature envelope of different maturities defined by these experiments allowed their phase behavior to be predicted, with a liquid phase being generated by the Taizhou Formation, and an oil−gas phase fluid being transiently generated by the Funing Formation.These results provide new insights into the hydrocarbon generation kinetics of saline lacustrine source rocks, which are relevant to regional shale oil exploration.

Petroleum Generation Kinetics and Geological Implications for Jurassic Hydrocarbon Source Rocks, Hongqi Depression, Hailar Basin, Northeast China

AbstractA sample from the Jurassic Tamulangou Fm. and two comparison samples from the Cretaceous Fm. were used to document the hydrocarbon generation kinetics and phase behaviors at two heating rates using the confined gold tube system. The results show that the different heating rates affect the reaction rates, paths and levels of organic matter evolution. The average activation energy and dominant frequency activation energy of liquid hydrocarbon are significantly lower than those of gaseous. Moreover, igneous intrusion had a positive effect on the blooming, enrichment and preservation of organic matter, promoting a Ro increase of 0.09%–1.07% in the Jurassic Tamulangou Fm. Two models were used to simulate the normal and abnormal evolution caused by thermal events combined hydrocarbon generation kinetic parameters. Thermal simulation analysis shows that oil generation was initially slow and then increased rapidly until a burial depth of 1500 m was reached at ~128 Ma. The largest hydrocarbon expulsion began at ~120 Ma, corresponding to a burial depth of 2450 m. The maximum cumulative yield is 510 mg/g TOC, and it is still in the peak period of hydrocarbon generation, which demonstrates a favorable potential for hydrocarbon exploration.

Study on Pyrolysis Hydrocarbon Generation Kinetics and Shale Gas Formation Process of Marine Continental Transitional Rocks in Shanxi Formation, Ordos Basin

The marine continental transitional facies shale of Shan23 sub member of Shanxi Formation in Ordos Basin was selected, and the hydrocarbon generation kinetics of Shan 23 sub member marine continental transitional facies shale was studied through open system thermal simulation experiment. The experimental results show that the pre exponential factor of Shan 23 shale is 12.92*1015/s, and the activation energy is mainly concentrated in 52~82kcal/mole. On this basis, combined with petromod basin simulation software, the burial history, thermal evolution history and hydrocarbon generation history of Shanxi Formation shale are established, and the formation process of shale gas is clarified. Finally, using the genetic method, combined with the original TOC restored by Petromod basin simulation software and the hydrocarbon generation obtained from the open system thermal simulation experiment, the resources of the study area are calculated when the hydrocarbon expulsion efficiency is 50%. The calculation results show that the shale gas resource in the study area is 12.41*1012m3, which shows a good exploration potential of sea land transitional facies shale in the study area.

Impact of thermal maturity on the diagenesis and porosity of lacustrine oil-prone shales: Insights from natural shale samples with thermal maturation in the oil generation window

Shale diagenesis controls the generation, migration and accumulation of hydrocarbons through time and has become a frontier area of study in the fields of sedimentology and petroleum geology. There have been only a few studies on the generation of organic pores in lacustrine shale oil reservoirs during the oil generation thermal evolution stage. In this study, lacustrine organic-rich shale samples at various stages of maturity, from the first member of the Songliao Basin Qingshankou Formation were investigated, and a thermal transformation law of macerals was established, based on organic petrology. The diagenetic alteration styles and sequences were investigated using a high-resolution field emission scanning electron microscope, and cathode luminescence. Furthermore, automated pore extraction technology enabled the examination of the characteristics and genetic process of organic and inorganic pores under the influence of thermal maturation. The results indicate that a small quantity of pre-oil bitumen is generated during the early oil mature stage (Ro: 0.7% - 0.9%), and that the generation of a large quantity of post-oil bitumen that occurs following the peak oil generation stage (i.e., late oil mature stage, Ro: 1.1% - 1.4%), is controlled by the unimodal distribution of the activation energy of Type I kerogen. Compaction intensity certainly influences pore volume reduction. Siliceous cementation primarily occurs during peak oil generation maturity and the subsequent thermal evolution stage. The pores formed in the oil generation window primarily arise from mineral dissolution and organic matter polycondensation. Following peak oil generation, the pores undergo iron dolomitization, smectite illitization, and bitumen cracking. The degree of development of inorganic pores, the most common pore type in shale oil reservoirs, appears to have a significant impact on the total porosity of a reservoir shale. During thermal evolution, the inorganic pore volumes show a decreasing trend. There is a secondary pore development stage, reached when Ro exceeds 1.2%, closely related to the transformation of clay minerals. According to the hydrocarbon generation kinetics and compaction model, organic pore volumes increase gradually at 0.7%Ro, reach their peak at 1.1%Ro, and then steadily decrease due to compaction. The organic pores are relatively well developed when Ro is >0.85% (at the start of the oil window). The shale oil reservoir's most favorable thermal evolution stage is late oil maturity stage that follows the oil generation peak.

Investigation on hydrocarbon generation and expulsion potential by deep learning and comprehensive evaluation method: A case study of Hangjinqi area, Ordos Basin

The Hangjinqi area is a significant gas exploration area from the northern Ordos Basin, an important petroliferous basin in China. Although a considerable amount of achievements has been made in the natural gas exploration field, the controversy about the hydrocarbon generation characteristics of source rocks has raged unabated for ten years. In addition, few studies have systematically investigated hydrocarbon expulsion potential in the Hangjinqi area.In this paper, we adopted a series of new approaches to assess the hydrocarbon generation and expulsion potential of source rocks in Hangjinqi. Specifically, we analyzed the rock pyrolysis, kerogen composition, and biomarker data and applied Convolution Neural Network (CNN) in the field of deep learning to determine organic matter abundance, type, maturity and depositional environment. Then, two techniques, the hydrocarbon generation kinetics method and the hydrocarbon generation potential method, were implemented to obtain both the hydrocarbon generation and expulsion quantity. The results reveal that the new technique CNN is suitable for TOC prediction, and the performance is improved largely compared to traditional methods, e.g., Back Propagation neural network (BP) and △log R. Rock pyrolysis data, kerogen macerals and biomarker data reveal that the source rocks are gas-prone and dominated by type Ⅲ. By the integrating hydrocarbon generation potential method and hydrocarbon generation kinetics method, the hydrocarbon generation quantity of the study area is 20.35 × 1012m3. The results of the hydrocarbon potential method indicate that about 23.7 × 108t and 0.74 × 108t hydrocarbons were expulsed from coal and mudstone, respectively. According to comprehensive analysis, the hydrocarbon generation and expulsion quantities in the Hangjinqi area are extensive, indicating good prospects for natural gas exploration. These findings have significant implications for the understanding of natural gas resources potential and the distribution of favorable natural gas areas.

The key parameter of shale oil resource evaluation: Oil content

The United States has become the world's largest oil producer of shale oil. China has abundant shale oil resources, but its resource potential has not yet been exploited. The core of the evaluation is the selection of parameters and their reliability. By combining the parameters of the shale oil resource evaluation, we investigated the key parameters in the evaluation model and reviewed the research results. The adsorption and retention of heavy hydrocarbons, loss of light hydrocarbons, and original oil saturation are key in the evaluation of shale oil resources. The adsorption and retention of heavy hydrocarbons can be determined by the pyrolysis, FID curve, and hydrocarbon generation kinetics of shale before and after extraction. The loss of light hydrocarbons mainly occurs in coring (change in temperature and pressure), sample treatment, which can be evaluated using the GC spectrum, rock pyrolysis, crude oil volume coefficient, mass balance, component hydrocarbon generation kinetics, and other methods. The original oil saturation evaluation includes indirect, direct, logging, and simulation methods. The most reliable parameters can be obtained by using the sealed or pressure-maintained coring immediately after thawing (without crushing), and the recovery of light hydrocarbon loss is critical for the resource evaluation of medium to high mature shale. Therefore, the experimental determination of shale oil content and the study of the influencing factors of the parameters should be strengthened.

Evaluation method of hydrocarbon yield of source rocks in open, semiopen, and closed systems: A case study on the K1qn Formation, northern Songliao Basin, China

Hydrocarbon yield of source rocks is an important parameter in the evaluation of oil and gas resources, and its value determines the potential of conventional and unconventional oil and gas resources. There is no oil cracking into gas in the thermal pyrolysis experiment data of an open system, whereas kerogen cracking into oil in a closed system is involved in the calculation of oil cracking into gas. However, most source rocks in sedimentary basins are a process of hydrocarbon generation and hydrocarbon expulsion, which could lead to insufficient understanding of hydrocarbon yield of source rocks. Based on the multiple thermal pyrolysis experiment data, three hydrocarbon generation kinetic models, and actual geologic data (burial history, thermal history, and hydrocarbon generation threshold), we established the evaluation method and chart of hydrocarbon yield of source rocks under open, semiopen, and closed systems by using the hydrocarbon generation kinetics method. The concept of degree of openness was proposed. From a closed system to an open system, the degree of openness increases gradually, and its value changes from 0 to 1. Taking the K1qn Formation in the northern Songliao Basin as an example, the hydrocarbon expulsion efficiency of the K1qn Formation source rock is approximately 70%, and it can be approximated as the degree of openness. Based on our method for evaluating hydrocarbon yield of source rocks, the charts of hydrocarbon yield of source rocks under open system, semiopen system with a degree of openness of 0.7, and closed system of the K1qn Formation in the northern Songliao Basin were established. The oil and gas yields of the K1qn Formation source rocks in a semiopen system with a degree of openness of 0.7 are approximately 540 and 105 mgHC/gTOC at a burial depth of 2000 m, respectively. Our results indicate that the hydrocarbon yield of source rocks in a semiopen system is closer to the hydrocarbon yield of source rocks under geologic condition. We use the thermal pyrolysis experiment data, hydrocarbon generation kinetics model, and geologic data to propose a very valuable evaluation method of hydrocarbon yield of source rock, which has a solid theoretical basis and strong applicability.

Analysis of Controlling Effect of Temperature–Pressure Conditions on Hydrocarbon Generation of Source Rocks

The thermal evolution of source rocks and the generation of oil and gas were not isolated reactions of kerogen pyrolysis but were comprehensively controlled by many influencing factors. In this study, using Permian source rock samples from Junggar Basin, a large number of high-temperature thermal simulation experiments were carried out to study the characteristics of kerogen, for example, thermal evolution degree and hydrocarbon yield, and their influences under the open system, closed system, and different temperature–pressure conditions. The results show that the hydrocarbon yield under the low heating rate is higher than that under the high heating rate, and the hydrocarbon generation reaction can be fully carried out under the low heating rate, which is more favorable for hydrocarbon generation; with the increase in pressure in the reaction system, the dominant frequency of activation energy of hydrocarbon generation gradually decreases. In terms of the hydrocarbon yield, the oil yield is higher in a high-pressure environment, especially the yield of C6-14 component in hydrocarbons is obviously increased, while there is a relatively small difference between the C14+ components. The result of this research provides a scientific evidence for evaluating the evolution process, hydrocarbon generation kinetics, and hydrocarbon resource potential of source rocks under different temperature–pressure conditions.

Hydrocarbon generation history constrained by thermal history and hydrocarbon generation kinetics: A case study of the Dongpu Depression, Bohai Bay Basin, China

With the increasing exploration and development of typical hydrocarbon-rich depressions, such as the Dongpu Depression, the exploitation difficulty of shallow formations is increasing. There is an urgent need to clarify the hydrocarbon generation mode and hydrocarbon generation histories in deep formations. In this study, a gold tube-autoclave closed system was used to simulate the hydrocarbon generation processes and establish the hydrocarbon generation mode of different types of kerogen. Then, constrained by the thermal history and hydrocarbon generation kinetics, hydrocarbon generation histories were modeled. The results show that hydrocarbon generation evolution can be divided into five stages, and the maturity of each stage is different. The hydrocarbon generation history of the source rocks of the Shahejie 3 Formation mainly dates from the early depositional period of the Shahejie 1 Formation to the middle depositional period of the Dongying Formation. Hydrocarbon generation history constrained by thermal history and hydrocarbon generation kinetics is more in line with actual geological conditions. Moreover, this research can provide important hydrocarbon generation parameters for deep oil and gas exploration and exploitation of the Shahejie 3 Formation in the Dongpu Depression.

Hydrocarbon generation kinetics and in-situ conversion temperature conditions of Chang 7 Member shale in the Ordos Basin, China

In-situ conversion technology has been more popular lately as an effective way to realize the industrial development of extensive medium- and low-mature shale oil/oil shale resources in China. The Ordos Basin has been recognized as the main basin containing the largest in-situ conversion recoverable resources of China. Researchers have revealed the hydrocarbon generation kinetics of low mature oil shales in the 7th Member of the Yanchang Formation (Chang 7 Member). However, the kinetics of medium mature shales may be different from those of low mature shales, and they can also be used as potential targets for in-situ conversion. At present, there is a lack of research on the in-situ hydrocarbon generation kinetics of medium- and low-mature shale oil/oil shale. In this paper, open system pyrolysis experiments were carried out on natural shales and shale samples derived from semi-open system pyrolysis with different maturities in the Chang 7 Member of the Ordos Basin respectively. Using the parallel first-order reaction theory, the frequency factor of low-mature shale was calculated to be 5.47 × 1010 s−1, and the distribution of activation energy ranged from 38 kcal/mol to 61 kcal/mol. The main peak of activation energy was 49 kcal/mol, and accounted for 66.91% of all shales. With the increase in maturity, the average activation energy becomes higher, and therefore more in-situ conversion energy is needed. At the same time, the hydrocarbon generation potential characterized by S2 peak of pyrolysis decreases during the maturation process. The activation energy is divided into three groups according to its distribution characteristics: low, main peak and high activation energy groups, representing <47 kcal/mol, ranging from 47 kcal/mol to 52 kcal/mol and >52 kcal/mol respectively. The proportion of low and high activation energy groups increased with the increase in maturity, while the proportion of main peak activation energy groups decreased. When the kinetic parameters are extrapolated to the condition of in-situ conversion, it is better to choose shales with low maturity (RO <1 .0%) and fully transform them by rapid heating to the main hydrocarbon generation stage, and different conversion temperature ranges should be set for different maturity samples.

Hydrocarbon Generation Kinetics of Salinized Lacustrine Source Rocks in the Upper Cretaceous-Paleocene South Yellow Sea Basin, Offshore Eastern China

Hydrocarbon Generation Kinetics of Salinized Lacustrine Source Rocks in the Upper Cretaceous-Paleocene South Yellow Sea Basin, Offshore Eastern China

Hydrocarbon generation history in the Chagan Depression, Inner Mongolia, northern China: constraints of hydrocarbon generation kinetics and thermal history

Hydrocarbon generation history in the Chagan Depression, Inner Mongolia, northern China: constraints of hydrocarbon generation kinetics and thermal history

Hydrocarbon generation kinetics and expulsion models of the Triassic Chang 9 lacustrine shales, Ordos Basin, China: Implications for the tight sandstone oil occurrence

Ordos Basin, a large lacustrine basin in the Triassic, possesses amounts of conventional and unconventional petroleum. In the basin, the Chang 7 shales have been studied extensively. Recent studies suggested that the crude oils accumulated in the Triassic Chang 9–8 should be mainly sourced by the Chang 9 shales [including the delta plain shale (DPS), delta front shale (DFS), and deep lake shale (DLS)]. The source rock (SR) potential, hydrocarbon generation (HG), and hydrocarbon expulsion (HE) characters of the Chang 9 shales should be analysed to make a comprehensive source rock evaluation. The shales are evaluated as excellent source rock potential, and the DLS is evaluated as the best potential. The HG–HE of the shales are analysed by utilizing two (closed and open systems) pyrolysis experiments. The DLS activation energy (Ea) shows the narrowest distribution and has the lowest average value of 219.00 kJ/mol. The HG onsets and total amounts of the DFS, DPS, and DLS have been determined (165 Ma and 200 × 103 t/km2, 157 Ma and 305 × 103 t/km2, 154 Ma and 430 × 103 t/km2), and the peak generation of the shales happened at 125–117 Ma, 127–100 Ma, and 125–100 Ma, respectively. The Chang 9 DFS, DPS, and DLS have reached the HE threshold at depths of 2,250, 2,500, and 2050 m, respectively, indicating large amounts of hydrocarbons have been expelled into the Lower Yanchang Formation (LYF). The tight sandstone oil reservoirs (TSORs) are mainly located in the areas where the organic‐rich shales are developed, especially in the northeastern study area. The areas between high‐value zones of source rock properties (e.g., thickness, Ro, total organic carbon, HG–HE intensity) are the sweet spots.

Hydrocarbon generation and gasification study of Valia lignite, Gujrat, India

ABSTRACT In the present investigation, an attempt was made on the Valia lignite, Surat, Gujarat, based on different analysis to determine the hydrocarbon generation, kerogen type, mineralogical characterization and CO2 gasification kinetics. Hydrocarbon generation is estimated by FTIR analysis and kerogen type have concluded by proximate and ultimate analyses data, SEM and EDX analysis were used to determine various mineral associated with coal. Isothermal CO2 gasification implemented by TGA at three different gasification temperature range of 900°C, 950°C, and 1000°C. Value of “A” (0.668) and “C” (0.502) factors concluded that the sample has the lowest aromaticity showed the highest hydrocarbon generation potential, which also validated by the Van Krevelen’s diagram. The results of FE-SEM and EDX of coal sample reveal several metals in various minerals form like sulfate, kaolinite, albite, mullite, Illite, hematite, hercynite, and pyrite. Alkali/alkaline earth metal oxides also found in ash. Kinetic parameters and activation energy of the sample were calculated by three kinetic models, such as the volumetric model (VM), grain model (GM), random pore model (RPM), and the Arrhenius equation. The CO2 gasification VM model showed a lower activation energy (E a ) value of 128.44 kJ/mol than the GM and RPM model value 130.31 kJ/mol and 133.98 kJ/mol, respectively, for the temperature range from 900°C, 950°C, and 1000°C. The overall study concludes that Valia lignite has sufficient potential for hydrocarbon generation and its suitability for clean coal technology such as CO2 gasification.

Pyrolysis experiment and hydrocarbon generation potential of the Bayingebi 2 Formation in the Hari Sag, Yingen-Ejiqi Basin, China

The Bayingebi 2 Formation of the Hari Sag is a typical self-generating and self-preserving reservoir, and the exploration degree of this reservoir is low. Mainly from the unclear understanding of hydrocarbon generation kinetics model, its hydrocarbon generation potential and resources cannot be accurately evaluated. The hydrocarbon generation history is an important index used to evaluate reservoirs and can be determined by software BasinMod 1D based on Tissot’s hydrocarbon generation kinetics models. The results show that the maximum oil and gas generated mass of the bottom of the Bayingebi 2 Formation are 288.71 and 12.11 mg/g TOC, respectively, while the exploration obtained a high-production gas and oil flow. To enhance the geochemical source rock characterization and predict hydrocarbon phases and generation accurately, we improved the traditional method. One sample from the Hari Sag was selected for a kerogen pyrolysis experiment, and the software KINETICS 2000 was used to establish the hydrocarbon generation kinetics model in the Hari sag. The hydrocarbon generation history was redetermined, and the results show that the translation rate of the bottom of Bayingebi 2 Formation was 84.36%, with maximum oil and gas generated mass of 214.91 mg/g TOC and 83.85 mg/g TOC, respectively. Compared with the traditional method, the results obtained by our improved method match the actual exploration situation better, which shows that the establishment of hydrocarbon generation kinetic models through pyrolysis experiments is crucial to accurately evaluate the hydrocarbon generation potential of the reservoir, and shows that the Hari sag has good oil and gas potential.

How TOC affects Rock-Eval pyrolysis and hydrocarbon generation kinetics: an example of Yanchang Shale (T3y) from Ordos Basin, China

Rock-Eval pyrolysis and kinetics are widely used to evaluate hydrocarbon generations. Due to heterogeneity of shale, even a series of samples come from the same drill core rock will have a wide range of total organic carbon (TOC). It is important to select propriate TOC samples to acquire Rock-Eval and kinetic parameters. However, influence of different TOC levels to Rock-Eval and kinetics are still not well known. In this study, different samples with different TOC of 3.87%, 13.59%, 18.17%, 23.93%, 25.93% and 35.35% taken from one drill core were selected and analysed. And all samples are prepared to 4mm grain-size samples for Rock-Eval pyrolysis to reflect hydrocarbon generation and expulsion in realistic conditions. The results show that generation rate gradually decreases from 0.0064 to 0.0053 mg/g·s−1 when TOC increase from 13.59 to 35.35%. And the samples with 35.35% and 25.53% TOC show highest transformation ratio, while the samples with 3.87% show the lowest transformation ratio. In addition, the samples with 3.87% TOC only shows one main activation energy peak (56Kcal/mol). Yet the samples with 35.35% TOC shows three activation energy peaks (53, 54, 56Kcal/mol). With increasing of TOC levels of samples, percentage of main activation energy decrease from 69.43 to 25.96 and 29.62%. Therefore, generation rate of high TOC shale will decrease and transformation ratio will increase. And hydrocarbon generation and expulsion of high TOC samples need lower action energies.

Kinetics of hydrocarbon generation from the marine Ordovician Goldwyer Formation, Canning Basin, Western Australia

Pyrolysis and bulk kinetic studies were used to investigate the hydrocarbon generation potential and source rock organofacies variability of marine organic-rich rocks from the Middle Ordovician (Darriwilian) Goldwyer Formation in the Canning Basin, Western Australia. Rock-Eval pyrolysis results for the analysed immature to mid-mature calcareous mudstones imply that the upper Goldwyer Sequence I contains oil-prone type I kerogen, while the lower Goldwyer Sequence III contains type II/III oil- and gas-prone kerogen. This is supported by pyrolysis gas chromatography (Py-GC) results that show the presence of homogenous organofacies in the Goldwyer Sequence I having aliphatic molecular signatures, possibly due to selective preservation of lipids derived from Gloeocapsomorpha prisca (G. prisca). The heterogeneous organofacies of the Goldwyer Sequence III contain aromatic moieties in similar abundance to the aliphatic compounds. The calcareous claystones of the Goldwyer Sequence I have the capacity to generate low wax paraffinic oil, whereas the Goldwyer Sequence III has potential for paraffinic-naphthenic-aromatic (P-N-A) low wax oils, gas, and condensate.The temperature for hydrocarbon generation for the type I kerogen, assuming a constant geological heating rate of 3 °C/my, is estimated to occur over a narrow interval between 145 °C and 170 °C for the Goldwyer Sequence I samples. Generation from the type II/III kerogen occurs from 100 °C to 160 °C in the Goldwyer Sequence III samples which are significantly less thermally stable than the Goldwyer Sequence I samples. The kinetic results for both sequences were used in standard thermal and burial history plots to evaluate their transformation ratio and hydrocarbon generative potential. This provided basin-specific kinetic inputs for burial history modelling and better constraint on kerogen transformation and hydrocarbon generation on the Broome Platform.