Evaluating Fault Sealing Using Geochemical Techniques

The fault sealing and reservoir continuity of different fault blocks is a very important issue for the study of oil filling histories and production. This study primarily considers the geochemical characteristics of petroleum reservoirs near faults, which can provide information about fault sealing in the geological record and hydrocarbons expulsion stage. Two research areas were chosen for the study of fault sealing in petroleum migration and reservoir continuity. One is in Weixinan sag, Beibuwan basin and the other is in Oulituozi region, Liaohe depression, Bohai Gulf basin. In the first locality, by analyzing geochemical chromatographic fingerprints, we found that a fault existed and was a major factor in poor reservoir continuity, although it is a small fault. The Oulituozi region geochemical and geological analysis shows that the oil pool near the fault has relatively high maturity and is abundant in pyrrolic nitrogen compounds. These results prove that the fault played an important role in petroleum migration. The two sites studied illustrate the advantages of geochemical techniques over other methods, in the study of fault sealing.