Research method and its application to effectiveness of time matching of source-fault-caprock

Key words:  source-fault-caprock  time matching  effectiveness  research method

Abstract:

In order to study the oil-gas distribution patterns in lower generation-upper accumulation source rock-reservoir-cap rocks in oil-gas bearing basins, a set of research methods for the effectiveness of time matching of source-fault-caprock were established. The methods were derived based on influence factors and the effectiveness of time matching of source-fault-caprock, and by determining the transporting hydrocarbon period of source-fault configuration and the period of sealing ability of oil and gas formed of fault-caprock configuration. The new methods were then used to research study the effectiveness of time matching of source-fault-caprock of the reservoir in the 2nd member of Dongying Formation in Nanpu Depression of Bohai Bay basin. The results show that the period of sealing ability of gas formed of closed type fault-caprock configuration of the reservoir in the 2nd member of Dongying Formation in Nanpu Depression is the early deposition of lower member of Minghuazhen Formation and that for the unclosed type is the early deposition of upper member of Minghuazhen Formation. They are both later older than the transporting gas period of source-fault configuration during the deposition of the 1st member of Dongying Formation, which is unfavorable for gas accumulation. The period of sealing ability of gas formed of closed type fault-caprock configuration is the early deposition of lower member of Minghuazhen Formation. It is soon earlier than the transporting gas period of source-fault configuration during from the deposition of Minghuazhen Formation to Quaternary, which is favorable for gas accumulation. The period of sealing ability of gas formed of unclosed type fault-caprock configuration is the early deposition of upper member of Minghuazhen Formation. It is the corresponding period with the transporting gas period of source-fault configuration during from the deposition of Minghuazhen Formation to Quaternary, which is also favorable for gas accumulation, and the effectiveness of time matching of source-fault-caprock is relatively good. The results are coincident with that the oil and gas which has been found in the reservoir in the 2nd member of Dongying Formation in Nanpu Depression, and suggest that the method is feasible to be applied in researching the effectiveness of time matching of source-fault-caprock.