Discussion on Application Method of Rock Cuttings in the Fault Sealing of China Offshore Oilfield

Abstract

It is more and more important for offshore oil field to study the fault sealing after the oil spill occurred last year in Bohai Bay, China. Now every offshore oil field is asked for the analysis of fault sealing in China. However such basic geologic information as rock core of offshore oil field is very sparse. Many basic experimental study based on rock core can’t be done, which adds greatly to uncertainty of fault sealing result. Therefore rock cuttings are used to try to get some more information on fault sealing of offshore oil field for the first time. However the preliminary study shows that the depth uncertainty of rock cuttings can get even entirely different conclusions. Aiming at this problem, the idea of depth calibration is firstly put forward and the methodology of rock cuttings depth calibration is researched. With the idea and method of depth calibration, the key fault sealing layout on the Pd-Vsh*D chart of Q oil field is compilated, where Pd means displace pressure, Vsh is shale content and D is buried depth. The new plate shows that faults seal well in Q oil field. After depth calibration, the data has apparently good relativity. In the original plate, the high values of Vsh*D has 2 trends, while in the new plate this 2 trends amalgamated together. And the basic geologic information resource and study methods are greatly widen with the idea of using rock cuttings and method of depth calibration for rock cuttings.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018