Episodic petroleum fluid migration in fault zones of the northwestern Junggar Basin (northwest China): Evidence from hydrocarbon-bearing zoned calcite cement

AAPG Bulletin ◽  
2008 ◽  
Vol 92 (9) ◽  
pp. 1225-1243 ◽  
Author(s):  
Zhijun Jin ◽  
Jian Cao ◽  
Wenxuan Hu ◽  
Yijie Zhang ◽  
Suping Yao ◽  
...  
Keyword(s):  
Junggar Basin ◽  
Northwest China ◽  
Fault Zones ◽  
Fluid Migration ◽  
Calcite Cement ◽  
Petroleum Fluid

scholarly journals Chemically Active Elements of Reservoir Quartz Cement Trace Hydrocarbon Migration in the Mahu Sag, Junggar Basin, NW China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Linjun Huang ◽  
Yin Liu ◽  
Baoli Bian ◽  
Yongping Ma ◽  
Hailei Liu ◽  
...  
Keyword(s):  
Organic Geochemistry ◽  
Petroleum Reservoirs ◽  
Junggar Basin ◽  
Northwest China ◽  
Fluid Migration ◽  
Hydrocarbon Migration ◽  
Geochemical Study ◽  
Migration Pathways ◽  
Quartz Grains

Element exchange and enrichment during fluid-rock interactions are common, providing potentially novel proxies to trace hydrocarbon migration in addition to the traditional organic geochemistry tracers. However, the processes, mechanisms, and geological and geochemical fingerprints of these interactions are complex, hampering the applications of hydrocarbon migration tracers. To investigate such interactions, we conducted a petrological, mineralogical, and in situ and bulk geochemical study of authigenic quartz and whole-rock samples from the Mahu Sag, northwestern Junggar Basin, northwest China. We found that dissolution, clay and chlorite formation, and overgrowth occurred on quartz grains in hydrocarbon fluid migration pathways, suggestive of strong fluid-rock interactions. In situ quantitative elemental analysis of quartz grains revealed elemental enrichment (e.g., Mn, Fe, Al, Sr, and W) in quartz overgrowth rims compared with their cores, indicating that migration of hydrocarbon-bearing fluids in reservoirs may promote elemental exchange between fluids and minerals. Whole-rock geochemical analysis showed that decreasing contents of some elements may reflect the direction of hydrocarbon-bearing fluid migration and can be monitored with three geochemical proxies, which are the MnO contents and MnO/Zr and Y/Ho ratios. Our data provide new constraints on fluid-rock interactions in petroleum reservoirs and have implications for using inorganic geochemical methods to trace hydrocarbon migration.

scholarly journals Permeability Calculation of Sand Conglomerate Reservoirs Based on Nuclear Magnetic Resonance (NMR)

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
You Zhou ◽  
Songtao Wu ◽  
Zhiping Li ◽  
Rukai Zhu ◽  
Shuyun Xie ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Junggar Basin ◽  
Northwest China ◽  
Free Fluid ◽  
Iteration Parameters ◽  
Nuclear Magnetic

The concept of an intermingled fractal unit (IFU) model was first proposed by Atzeni and Pia in 2008, and their model has since been successfully applied to predict thermal conductivity, electrical conductivity, and the mechanical properties of porous media materials. This paper, based on the Pia IFU model, fits the pore size distribution spectrum to quantitatively characterize the Triassic Karamay Formation conglomerate reservoirs in the Mahu region, in the Junggar Basin of Northwest China, and makes permeability predictions using the free fluid T 2 spectrum according to the nuclear magnetic resonance (NMR) experimental data. The results show that the accuracy of the IFU model is significantly higher than that of the classic Coates and SDR models for conglomerate reservoirs with complex pore structures, indicating that this is an effective method to calculate permeability based on NMR. In addition, preliminary discussions are entered into regarding the intermingled fractal expression of the Kozeny-Carman equation and the relative permeability, in order to widen the application of the IFU model in reservoir physics. The derived expressions appear complicated in form but are straightforward to calculate and apply using computer programming since their iteration parameters are definite. The findings set out in this paper provide a valuable reference for further research of the IFU model in reservoir physics.

scholarly journals The Distribution and Origin of Carbonate Cements in Deep-Buried Sandstones in the Central Junggar Basin, Northwest China

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Wang Furong ◽  
He Sheng ◽  
Hou Yuguang ◽  
Dong Tian ◽  
He Zhiliang
Keyword(s):  
Fluid Pressure ◽  
Junggar Basin ◽  
Isotopic Analysis ◽  
Northwest China ◽  
Petrographic Analysis ◽  
Burial Depth ◽  
Depth Range ◽  
High Porosity ◽  
Carbonate Cements ◽  
And Migration

Extremely high porosities and permeabilities are commonly discovered in the sandstones of the Xishanyao Formation in the central Junggar Basin with the burial depth greater than 5500 m, from which hydrocarbons are currently being produced. High content of carbonate cements (up to 20%) is also observed in a similar depth range. Our study aimed to improve our understanding on the origin of carbonate cements in the Xishanyao Formation, in order to provide insights into the existence of high porosity sandstones at greater depths. Integrated analyses including petrographic analysis, isotopic analysis, fluid-inclusion, and core analysis were applied to investigate the distribution and origin of carbonate cements and the influence of high fluid pressure on reservoir quality. Textural evidences demonstrate that there are two generations of carbonate cements, precipitated at the temperature of 90°C and 120°C, respectively. The carbonate cements with low δCPDB13 ranging from −19.07 to -8.95‰ dominantly occurred near the overpressure surface and especially accumulated at approximately 100 m below the surface. Our interpretation is that high content of carbonate cements is significantly influenced by early carbonate cements dissolution and migration under overpressure. Dissolution of plagioclase resulted in the development of internal pores and porosities of as much as 10% at 6500 m depth presumably.

Sign in / Sign up

Export Citation Format

Share Document