The generation and its sealing condition of natural gas in the Tadong area  

作　　者：HU GuoYi1,2,3,LI Jin3,CUI HuiYing3,RAN QiGui3,ZHANG Li3,WANG XiaoBo3 & WANG YiFeng3 1 Research Institute of Petroleum Exploration and Development,PetroChina,Beijing,100083,China 2 College of Resources and Environment,China University of Petroleum,Beijing 102249,China 3 Research Institute of Petroleum Exploration and Development-Langfang Branch,PetroChina,Langfang 065007,China 

出　　处：《Science China Earth Sciences》2009年第S1期96-105,共10页中国科学（地球科学英文版）

基　　金：Supported by PetroChina Foundation Project (Grant No. 07-01C-01-07);Na-tional Basic Research Program of China (Grant No. 2007CB209503)

摘　　要：Focusing on the two natural gas exploration geological problems with abundant source of oil cracking gas in the late stage and the sealing condition of the oil cracking gas reservoir,the kinetics of oil cracking gas and the evaluation parameters of gas cap rock are adopted to the study on the natural gas accumulation conditions in the Tadong area. Both the study on the kinetics of oil cracking gas and the statistical results of reservoir bitumen reveal that the geological formation of oil cracking gas in the Tadong area is located in the top of Cambrian. Two kinds of oil cracking gas geological models at least,namely well Mandong-1's early rapid generation model(Middle Ordovician-end Silurian) and peak cracking model(with the natural gas conversion rate >90%) ,namely well Yingnan-2's two-stage generation model of oil cracking gas,have been set up. The oil cracking gas of Yingnan-2 in the late stage is very significant in the evaluation of natural gas exploration in the Tadong area. The evaluation results of the cap rock show that the microscopic parameters of cap rock from the lower assemblage of Cambrian-Ordovician are better than those from the upper assemblage. The former has strong capillary sealing ability and higher cap rock breakthrough pressure than the upper assemblage,with strong sealing ability,so that natural gas dissipates mainly by diffusion. According to the above investigations,the lower assemblage Cambrian-Ordovician natural gas of Kongquehe slope,Tadong low uplift and Yingjisu depression in the Tadong area prospects well.Focusing on the two natural gas exploration geological problems with abundant source of oil cracking gas in the late stage and the sealing condition of the oil cracking gas reservoir,the kinetics of oil cracking gas and the evaluation parameters of gas cap rock are adopted to the study on the natural gas accumulation conditions in the Tadong area. Both the study on the kinetics of oil cracking gas and the statistical results of reservoir bitumen reveal that the geological formation of oil cracking gas in the Tadong area is located in the top of Cambrian. Two kinds of oil cracking gas geological models at least,namely well Mandong-1's early rapid generation model(Middle Ordovician-end Silurian) and peak cracking model(with the natural gas conversion rate >90%) ,namely well Yingnan-2's two-stage generation model of oil cracking gas,have been set up. The oil cracking gas of Yingnan-2 in the late stage is very significant in the evaluation of natural gas exploration in the Tadong area. The evaluation results of the cap rock show that the microscopic parameters of cap rock from the lower assemblage of Cambrian-Ordovician are better than those from the upper assemblage. The former has strong capillary sealing ability and higher cap rock breakthrough pressure than the upper assemblage,with strong sealing ability,so that natural gas dissipates mainly by diffusion. According to the above investigations,the lower assemblage Cambrian-Ordovician natural gas of Kongquehe slope,Tadong low uplift and Yingjisu depression in the Tadong area prospects well.

关 键 词：Tadong area oil CRACKING GAS GAS generation GEOLOGICAL model SEALING CONDITION evaluation 

分 类 号：P618.13[天文地球—矿床学]