Quantitative simulation on pore evolution in diagenetic process of sandstone: A case study from Chang 8 oil reservoir set in Ansai area, Ordos Basin
Online published: 2014-10-20
The change of porosity in buried diagenetic process is a continuous process, which has important significance to hydrocarbon accumulation and regional reservoir evaluation. By using mathematical statistics and numerical simulation method, this paper carried out quantitative simulation of pore evolution during the whole burial diagenetic process of Chang 8 oil reservoir set in Ansai area. Based on analysis of petrologic characteristics, diagenetic features, burial history and diagenesis history, with current porosity as boundary constraint conditions, geological time and burial depth as variables, the whole pore evolution of Chang 8 oil reservoir set from initial burial until nowadays was divided into two independent processes: porosity decrease and porosity increase, for which two mathematical models were established respectively. The quantitative simulation result indicates that the porosity decrease model of mechanical compaction stage is a continuous function with burial depth as the independent variable, while that of ompactioncementation stages and porosity increase model under temperature window conditions and secondary porosity preservation (65~100 ℃) are continuous functions with geological time and burial depth as the variables. The whole pore evolution quantitative simulation built from the superimposition of porosity decrease and increase is a piecewise function with four sections. Finally, through the exemplification, it is verified that this approach works well in sandstone pore evolution simulation.
Key words: diagenesis; pore evolution; Xujiahe Formation; northeastern Sichuang Basin
HU Hao , L U Yao , TANG Qunying , WANG Min . Quantitative simulation on pore evolution in diagenetic process of sandstone: A case study from Chang 8 oil reservoir set in Ansai area, Ordos Basin[J]. Lithologic Reservoirs, 2014 , 26(5) : 15 -22 . DOI: 10.3969/j.issn.1673-8926.2014.05.004
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