Reservoir Quality and Controlling Mechanism of the Upper Paleogene Fine-Grained Sandstones in Lacustrine Basin in the Hinterlands of Northern Qaidam Basin, NW China

Gong, Lili; Gao, Xili; Qu, Futao; Zhang, Yongshu; Zhang, Guangya; Zhu, Jun

doi:10.1007/s12583-022-1701-6

Cited by 6 publications

(1 citation statement)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the generation of secondary porosity represents a significant diagenetic process that impacts reservoir quality (Bjørlykke & Jahren, 2012;Ehrenberg, 1991;Giles & De Boer, 1990;Li et al, 2020;Morad et al, 2010;. Grain dissolution can be initiated by various factors, including (1) low-molecularweight organic acids (LMWOA) (Meshri, 1985;Surdam et al, 1989), (2) CO 2 (Higgs et al, 2015), (3) meteoric water (Bjørlykke, 1982;Gong et al, 2023) and (4) dehydration of clay minerals (Bjørlykke, 1982). This study specifically examines the influence of LMWOA on grain dissolution and subsequent secondary porosity generation because there is no evidence of natural CO 2 gas accumulation and meteoric water in the study area .…”

Section: Introductionmentioning

confidence: 99%

Modelling diagenetic reactions and secondary porosity generation in sandstones controlled by the advection of low‐molecular‐weight organic acids

Li,

Black,

Hao

et al. 2024

Basin Research

View full text Add to dashboard Cite

Higher secondary porosity was observed in the centre of a sandstone unit in the Eocene Shahejie Formation fan delta front sandstones from the Bozhong Depression, Bohai Bay Basin. This differs from past studies showing secondary porosity mainly in the marginal parts of sandstones adjacent to shales. This study utilized reactive transport models involving low‐molecular‐weight organic acids (LMWOA) to discuss potential processes resulting in the contrary distribution of secondary porosity. An interface model simulating LMWOA diffusion from adjacent shales to the sandstone resulted in secondary porosity in sandstones adjacent to shales. In contrast, an advection model simulating advective transport of LMWOA parallel to the sandstone bedding successfully generated higher secondary porosity in the central part. The central part of the sandstone exhibited better grain sorting (greater depositional porosity) and significantly less early carbonate cements compared to the marginal sandstone parts. Consequently, the central part had greater porosity prior to the dissolution through LMWOA. The initially higher porosity in the central part allowed for a higher advective flux of LMWOA‐rich water and associated lower pH, resulting in decreased oligoclase saturation, higher oligoclase dissolution rates and ultimately higher secondary porosity. This study indicates that grain sorting during sediment deposition, early carbonate cementation, LMWOA production in adjacent shales, and advection processes collectively control the diagenetic reactions and the distribution of secondary porosity in sandstones.

show abstract