Natural gas washing induces condensate formation from coal measures in the Pinghu Slope Belt of the Xihu Depression, East China Sea Basin: Insights from fluid inclusion, geochemistry, and rock gold-tube pyrolysis

Su, Ao; Chen, Honghan; Zhao, Jianxin; Zhang, Tong-wei; Feng, Yuexing; Wang, Cunwu

doi:10.1016/j.marpetgeo.2020.104450

Cited by 23 publications

(12 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Discussionmentioning

confidence: 99%

“…Gas components that are a large molar percentage of hydrocarbons are the keys to forming condensate gas reservoirs, and gas invasion is an important secondary transformation that causes a rapid increase in gas components. 69 Gas invasion leads to mixing between oil and gas, which not only changes the phase states but also the geochemical characteristics of the hydrocarbon molecular composition, isotopes, and biomarkers. 70−73 For example, some low-carbon n-alkanes of oil partially dissolve in natural gas and lead to a decrease in the molar percentage of low-carbon n-alkanes after gas invasion, resulting in the relationship between the molar percentage of n-alkanes and carbon number being no longer exponential in oil.…”

Section: Effects Of Gas Invasion On Hydrocarbon Phasementioning

confidence: 99%

See 1 more Smart Citation

Hydrocarbon Phase State Evolution and Accumulation Process of Ultradeep Permian Reservoirs in Shawan Sag, Junggar Basin, NW China

Xu,

Lei,

Zhang

et al. 2023

Energy Fuels

View full text Add to dashboard Cite

A large amount of oil and gas has been discovered in the ultradeep reservoirs in the Shawan Sag, Junggar Basin. However, the hydrocarbon phases in ultradeep reservoirs are complex, and the controlling factors and evolution have not been studied, which are important for exploration and development. This study determined the hydrocarbon phase states of the reservoirs in the Upper Wuerhe Formation (P3w) of Well Zheng 10 in the Shawan Sag via hydrocarbon components and a pressure–volume–temperature (PVT) phase diagram. We used 1D basin modeling to simulate the thermal maturity of the Lower Wuerhe (P2w) source rock, components of generated hydrocarbons, reservoir temperature and pressure, and hydrocarbon phase. The results show that the hydrocarbons in the P3w reservoir are secondary condensate gas. The source rock began to enter the threshold of hydrocarbon generation at the end of the Late Triassic, and the thermal maturity (Easy Ro%) of the P2w source rock in the P3w reservoir fetch area is approximately 1.5% at present. The reservoir experienced multiple periods of hydrocarbon charging and phase evolution. During the Late Triassic to the early Late Jurassic and the late Early Cretaceous to the Late Cretaceous, the hydrocarbons in the P3w reservoir were liquid. Since the Miocene, a large amount of gas has migrated to the P3w reservoir, leading to gas invasion, which is the key to the formation of a condensate gas reservoir. The hydrocarbons changed from liquid to condensate gas due to the increasing gas–oil ratio and reservoir temperature. This study provides a quantitative method to reconstruct the phase evolution process and establishes an accumulation model of condensate gas reservoirs.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Effects Of Gas Invasion On Hydrocarbon Phasementioning

confidence: 99%

Hydrocarbon Phase State Evolution and Accumulation Process of Ultradeep Permian Reservoirs in Shawan Sag, Junggar Basin, NW China

Xu,

Lei,

Zhang

et al. 2023

Energy Fuels

View full text Add to dashboard Cite

show abstract

“…In other words, Th measurement precision is ±1 °C. Fluid inclusion Th is commonly used to delineate the trapping time of oil and gas or the generation timing of alteration minerals in pores in reservoirs, even in the thermally overmature conditions [15][16][17]. Soft, reactive minerals such as deeply buried carbonate rocks are easily altered, and as a result, fluid inclusion Th may be prone to resetting [18].…”

Section: Fluid Inclusion Analysismentioning

confidence: 99%

Fluid Inclusion Evidence for Oil Charge and Cracking in the Cambrian Longwangmiao Dolomite Reservoirs of the Central Sichuan Basin, China

Xiao

Chen

et al. 2022

Geofluids

Self Cite

View full text Add to dashboard Cite

The Cambrian Longwangmiao gas reservoirs in the Moxi area of the Sichuan Basin have a complex associated gas accumulation history. Based on core and thin section examination, fluid inclusion analyses and 1-D burial-thermal modelling, the diagenetic evolution and hydrocarbon accumulation processes in the Longwangmiao Formation have been reconstructed. Various diagenetic events were identified, making up a complete pore fill sequence as follows: solid bitumen/dolomite→ nonfluorescent solid bitumen → dolomite → quartz/yellow fluorescent oily bitumen → residual hole. Analyses of oil inclusions and bitumen-bearing inclusions are key to the understanding of the hydrocarbon accumulation processes. The Th values of the aqueous inclusions that are contemporaneous with hydrocarbon inclusions range from 74.3 to 214.3°C. In conjunction with burial-thermal history modelling results, the results indicate that there were two stages of oil charge and three stages of natural gas accumulation in the Longwangmiao carbonate reservoirs. The two stages of oil charge occurred in the Late Silurian and Middle Triassic, respectively. Three gas accumulation events occurred in the Middle to Late Triassic, Middle Jurassic to Early Cretaceous, and Late Cretaceous, respectively.

show abstract

“…In addition, the ECSSB can be divided into three secondary building units: western geotectogene, central uplift belt, and eastern geotectogene from west to east. Among them, the eastern geotectogene can be classified into Diaobei Sag, Xihu Sag, and Fujiang Sag from south to north [1][2][3][4][5]33] (Figure 1B). The Xihu Sag is located northeast of the ECSSB and belongs to a secondary sag of the western geotectogene.…”

Section: Geological Settingmentioning

confidence: 99%

“…However, there have been few studies on the pyrolysis experiments of coal-measure source rocks of the Pinghu Formation in the Xihu Sag. In the closed simulated system, based on the methods of fluid inclusion analysis, petroleum geochemistry, and rock gold-tube pyrolysis on the condensates in the Pinghu slope belt of the Xihu Sag, Su found that coal was evaluated as source rock and inclined to gas and oil generation at moderate maturity [33]. In an open simulated system, Zhu used the Rock-Eval pyrolysis method to analyze the organic geochemical and petrographic characteristics of Paleogene coals and organic-rich mudstones in the Xihu Sag and found that two different regions had fair to excellent hydrocarbon generative potential but varied in the hydrocarbon phase [34].…”

Section: Introductionmentioning

confidence: 99%

Evidence from the Changing Carbon Isotopic of Kerogen, Oil, and Gas during Hydrous Pyrolysis from Pinghu Formation, the Xihu Sag, East China Sea Basin

Cao

et al. 2021

Energies

View full text Add to dashboard Cite

Semi-open hydrous pyrolysis experiments on coal-measure source rocks in the Xihu Sag were conducted to investigate the carbon isotope evolution of kerogen, bitumen, generated expelled oil, and gases with increasing thermal maturity. Seven corresponding experiments were conducted at 335 °C, 360 °C, 400 °C, 455 °C, 480 °C, 525 °C, and 575 °C, while other experimental factors, such as the heating time and rate, lithostatic and hydrodynamic pressures, and columnar original samples were kept the same. The results show that the simulated temperatures were positive for the measured vitrinite reflectance (Ro), with a correlation coefficient (R2) of 0.9861. With increasing temperatures, lower maturity, maturity, higher maturity, and post-maturity stages occurred at simulated temperatures (Ts) of 335–360 °C, 360–400 °C, 400–480 °C, and 480–575 °C, respectively. The increasing gas hydrocarbons with increasing temperature reflected the higher gas potential. Moreover, the carbon isotopes of kerogen, bitumen, expelled oil, and gases were associated with increased temperatures; among gases, methane was the most sensitive to maturity. Ignoring the intermediate reaction process, the thermal evolution process can be summarized as kerogen0(original) + bitumen0(original)→kerogenr (residual kerogen) + expelled oil (generated) + bitumenn+r (generated + residual) + C2+(generated + residual) + CH4(generated). Among these, bitumen, expelled oil, and C2-5 acted as reactants and products, whereas kerogen and methane were the reactants and products, respectively. Furthermore, the order of the carbon isotopes during the thermal evolution process was identified as: δ13C1 < 13C2-5 < δ13Cexpelled oil < δ13Cbitumen < δ13Ckerogen. Thus, the reaction and production mechanisms of carbon isotopes can be obtained based on their changing degree and yields in kerogen, bitumen, expelled oil, and gases. Furthermore, combining the analysis of the geochemical characteristics of the Pinghu Formation coal–oil-type gas in actual strata with these pyrolysis experiments, it was identified that this area also had substantial development potential. Therefore, this study provides theoretical support and guidance for the formation mechanism and exploration of oil and gas based on changing carbon isotopes.

show abstract

Natural gas washing induces condensate formation from coal measures in the Pinghu Slope Belt of the Xihu Depression, East China Sea Basin: Insights from fluid inclusion, geochemistry, and rock gold-tube pyrolysis

Cited by 23 publications

References 43 publications

Hydrocarbon Phase State Evolution and Accumulation Process of Ultradeep Permian Reservoirs in Shawan Sag, Junggar Basin, NW China

Hydrocarbon Phase State Evolution and Accumulation Process of Ultradeep Permian Reservoirs in Shawan Sag, Junggar Basin, NW China

Fluid Inclusion Evidence for Oil Charge and Cracking in the Cambrian Longwangmiao Dolomite Reservoirs of the Central Sichuan Basin, China

Evidence from the Changing Carbon Isotopic of Kerogen, Oil, and Gas during Hydrous Pyrolysis from Pinghu Formation, the Xihu Sag, East China Sea Basin

Contact Info

Product

Resources

About