Diagenesis of sandstone reservoir of Chang 9 oil reservoir set in Longdong area, Ordos Basin
Online published: 2014-02-05
Chang 9 oil reservoir set is one of the potential hydrocarbon exploration targets in Longdong area, Ordos Basin, while its reservoir features are not clear and became a constraint on the efficient exploration and development of Chang 9 oil reservoir set. Based on the data of thin section, SEM, vitrinite reflectance and physical properties, this paper studied the reservoir features of Chang 9 oil reservoir set. The results show that the favorable rock types comprise medium to fine-grained lithic arkoses and feldspathic sandstones of underwater distributary channel microfacies, and they are the foundation for the reservoir development. Mechanical compaction and cementation of calcites, quartz, illite/smectite, illite, kaolinite and laumontite occluded the pores in different degrees, and they are the main causes for the reduced porosity and permeability. Early authigenic chlorite rim and illite/smectite rim cements enhanced the capacity of compaction resistance, inhibited quartz cementation, and saved large numbers of primary intergranular pores. Hydrothermal dissolution by deep organic acid has greatest contributions to improve the porosity and permeability of the reservoirs by producing secondary pores, and it is crucial for the development of the high quality reservoirs.
ZHONG Haiquan , ZHOU Junjie , LI Yingchuan , PU Hao , TAN Yan . Diagenesis of sandstone reservoir of Chang 9 oil reservoir set in Longdong area, Ordos Basin[J]. Lithologic Reservoirs, 2014 , 26(1) : 1 -9 . DOI: 10.3969/j.issn.1673-8926.2014.01.001
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