Geochemical characteristics of noble gases in natural gas and their application in tracing natural gas migration in the middle part of the western Sichuan Depression, China

Wang, Peng; Zhang, Shen; Liu, Sibing; Lv, Zhengxiang; Zhu, Tong; Gong, Yajun

doi:10.1007/s12182-013-0281-6

Cited by 6 publications

(4 citation statements)

References 19 publications

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“…These gases were derived from sedimentary organic matter and their characteristics also indicate oil-associated gases, which were produced in well CK1. These characteristics differ from those of the coal gases that originated from the Late Triassic Xujiahe Formation (Shen et al, 1995;Katz et al, 2008;Wang et al, 2013a) (Fig. 17).…”

Section: He-ne-ar Isotopesmentioning

confidence: 70%

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Characteristics and Natural Gas Origin of Middle–Late Triassic Marine Source Rocks of the Western Sichuan Depression, SW China

Sun

Luo

Qing

et al. 2020

Acta Geologica Sinica (Eng)

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A scientific exploration well (CK1) was drilled to expand the oil/gas production in the western Sichuan depression, SW, China. Seventy‐three core samples and four natural gas samples from the Middle–Late Triassic strata were analyzed to determine the paleo‐depositional setting and the abundance of organic matter (OM) and to evaluate the hydrocarbon‐generation process and potential. This information was then used to identify the origin of the natural gas. The OM is characterized by medium n‐alkanes (nC15–nC19), low pristane/phytane and terrigenous aquatic ratios (TAR), a carbon preference index (CPI) of ∼1, regular steranes with C29 > C27 > C28, gammacerane/C30hopane ratios of 0.15–0.32, and δDorg of −132‰ to −58‰, suggesting a marine algal/phytoplankton source with terrestrial input deposited in a reducing–transitional saline/marine sedimentary environment. Based on the TOC, HI index, and chloroform bitumen “A,” the algal‐rich dolomites of the Leikoupo Formation are fair–good source rocks; the grey limestones of the Maantang Formation are fair source rocks; and the shales of the Xiaotangzi Formation are moderately good source rocks. In addition, maceral and carbon isotopes indicate that the kerogen of the Leikoupo and Maantang formations is type II and that of the Xiaotangzi Formation is type II–III. The maturity parameters and the hopane and sterane isomerization suggest that the OM was advanced mature and produced wet–dry gases. One‐dimensional modeling of the thermal‐burial history suggests that hydrocarbon‐generation occurred at 220–60 Ma. The gas components and C–H–He–Ar–Ne isotopes indicate that the oil‐associated gases were generated in the Leikoupo and Maantang formations, and then, they mixed with gases from the Xiaotangzi Formation, which were probably contributed by the underlying Permian marine source rocks. Therefore, the deeply‐buried Middle–Late Triassic marine source rocks in the western Sichuan depression and in similar basins have a great significant hydrocarbon potential.

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Section: He-ne-ar Isotopesmentioning

confidence: 70%

“…17. Classification of the isotopic compositions of the He and Ar of the natural gases from well CK1 (Shen et al, 1995;Wang et al, 2013a).…”

Section: He-ne-ar Isotopesmentioning

confidence: 99%

Characteristics and Natural Gas Origin of Middle–Late Triassic Marine Source Rocks of the Western Sichuan Depression, SW China

Sun

Luo

Qing

et al. 2020

Acta Geologica Sinica (Eng)

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“…1) Deep inorganic CO 2 , desulfurization, atmospheric water leaching and NaHCO 3 -type water Wang et al (2013) studied the rare gas content and isotopes of He, Ne, and Ar in the tight sandstone gas of the Upper Triassic Xujiahe Formation in the western Sichuan Depression and confirmed that the Upper Triassic stratigraphic fluid in this area has no contribution from deep and mantle-derived materials. Therefore, the possibility of deep inorganic CO 2 entering the formation water to form NaHCO 3 -type water can be denied.…”

Section: Formation Water Typementioning

confidence: 83%

Geochemical Characteristics and Origin of Formation Water From the Upper Triassic Xujiahe Tight Sandstone in the Xiaoquan-Fenggu Structural Belt, Western Sichuan Depression, China

et al. 2021

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Formation water represents an important driving force and carrier for the migration and accumulation of oil and gas; thus, research on its origin is a hot spot in petroleum geology. The Upper Triassic Xujiahe Formation in the Xiaoquan-Fenggu Structural Belt in the western Sichuan Depression, China, has developed thick tight sandstone gas reservoirs. However, previous studies have provided different conclusions on the origin of the formation water in the Xujiahe tight sandstone reservoir. In this paper, the origin of the formation water in the Xujiahe Formation was determined based on the latest major and minor elemental concentration data, hydrogen and oxygen isotopes data of formation water, and carbon and oxygen isotope data of carbonate cements. The results show that the salinity of the formation water of the Xujiahe Formation in the study area is generally greater than 50 g/L. The water type is mainly the CaCl2 type, although a small proportion of NaHCO3 type water with high salinity is observed, which is related to hydrocarbon expulsion by overpressure. Moreover, the formation water in the sandstone of the Xujiahe Formation is obviously rich in Br, which is related to membrane infiltration, overpressured hydrocarbon expulsion of shale and diagenesis of organic matter. The composition of Cl− and Na+ ions in the formation water in the Xujiahe tight sandstone reservoir is consistent with the seawater evaporation curve, which deviates significantly from the freshwater evaporation curve. The hydrogen and oxygen isotopes of condensate water in the Xujiahe Formation tight sandstone are similar to those of atmospheric precipitation water, while the hydrogen and oxygen isotopes of the formation water in the Xujiahe Formation show that it is of seawater origin. Therefore, to use hydrogen and oxygen isotopes to determine the origin of formation water, condensate water must be accurately differentiated from formation water. Otherwise, if the condensate water is misjudged as formation water, then incorrect conclusions will be drawn, e.g., that the formation water of the Xujiahe Formation originated from fresh water. Affected by organic carbon, the carbon isotope Z value of the carbonate cements in the Xujiahe Formation is low (mainly distributed between 110 and 130). A Z value of less than 120 does not indicate that the ancient water bodies formed by cements were fresh water or mixed water bodies. However, Z values greater than 120 correspond to a formation temperature lower than 80 C, which indicates that carbonate cement was not affected by organic carbon; thus, the Z value can reflect the origin of ancient water bodies. The results of this study indicate that the formation water of the Xujiahe tight sandstone in the study area is of seawater origin. The determination of the origin of the formation water and seawater of the Xujiahe Formation provides strong evidence for the determination of the marine sedimentary environment of the Xujiahe Formation in the study area, and can provide scientific guidance for the search for high-quality reservoirs.

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“…As shown in Table 2, the 3 He/ 4 He value of CO 2 reservoirs in the Pingfangwang, Huagou, and Yangxin gas fields in the Jiyang Depression was high (3.55-4.49 9 10 -6 ), and R/Ra was 2.5-3.2, indicating a mixed He origin of mantle genesis and crust genesis (Wang et al 2013). The isotopic analysis of rare gases and CO 2 indicated that the highly concentrated CO 2 gas reservoir in the Jiyang Depression originated from magma-mantle degassing (Hunt et al 2012).…”

Section: Abiogenic Gasmentioning

confidence: 97%

Genetic types and geochemical characteristics of natural gases in the Jiyang Depression, China

Gao

Chun-yan

2015

Pet. Sci.

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Natural gases were widely distributed in the Jiyang Depression with complicated component composition, and it is difficult to identify their genesis. Based on investigation of gas composition, carbon isotope ratios, light hydrocarbon properties, as well as geological analysis, natural gases in the Jiyang Depression are classified into two types, one is organic gas and the other is abiogenic gas. Abiogenic gas is mainly magmatogenic or mantlederived CO 2 . Organic gases are further divided into coaltype gas, oil-type gas, and biogas according to their kerogen types and formation mechanisms. The oil-type gases are divided into mature oil-type gas (oil-associated gas) and highly mature oil-type gas. The highly mature oil-type gases can be subdivided into oil-cracking gas and kerogen thermal degradation gas. Identification factors for each kind of hydrocarbon gas were summarized. Based on genesis analysis results, the genetic types of gases buried in different depths were discussed. Results showed that shallow gases (\1,500 m) are mainly mature oil-type gases, biogas, or secondary gases. Secondary gases are rich in methane because of chromatographic separation during migration and secondary biodegradation. Secondary biodegradation leads to richness of heavy carbon isotope ratios in methane and propane. Genesis of middle depth gases (1,500-3,500 m) is dominated by mature oil-type gases.Deep gases (3,500-5,500 m) are mainly kerogen thermal degradation gas, oil-cracking gas, and coal-type gas.

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Geochemical characteristics of noble gases in natural gas and their application in tracing natural gas migration in the middle part of the western Sichuan Depression, China

Cited by 6 publications

References 19 publications

Characteristics and Natural Gas Origin of Middle–Late Triassic Marine Source Rocks of the Western Sichuan Depression, SW China

Characteristics and Natural Gas Origin of Middle–Late Triassic Marine Source Rocks of the Western Sichuan Depression, SW China

Geochemical Characteristics and Origin of Formation Water From the Upper Triassic Xujiahe Tight Sandstone in the Xiaoquan-Fenggu Structural Belt, Western Sichuan Depression, China

Genetic types and geochemical characteristics of natural gases in the Jiyang Depression, China

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