TITLE:
Structural Characteristics and Evolution Process of the Metamorphic Buried Hill: A Case of BZ Oilfield in Bohai Bay, China
AUTHORS:
Hua Zheng, Xuwei Bie, Xinfei Song, Yong Jiang, Wenchao Liu
KEYWORDS:
Bohai Bay, BZ Oilfield, Metamorphic Rock, Buried Hill, Tectonic Evolution, Stress
JOURNAL NAME:
International Journal of Geosciences,
Vol.13 No.1,
January
10,
2022
ABSTRACT: Bozhong oilfield which is abbreviated as BZ oilfield is the first oilfield
with deep metamorphic buried hill that is discovered reserves of billion-ton in
Bohai Bay. Affected by multi-stage tectonic movements, the distribution of fractures
is very complex in this area, therefore it is significant to study the evolution
of structures for understanding the distribution of fractures. In view of the complexity
on the tectonic evolution of the buried hill region in the study area, the influence
of tectonic movements on the formation of fractured reservoir is analyzed, and the
research results lay the foundation for the efficient development in this type of
the oilfield. The results show that main faults, which is formed during early Indosinian
and Yanshanian period, are mainly developed in the BZ oilfield area, and the fracture
strike has mainly east-west and north-east-east trend. Based on the analysis of
the relationship among tectonic evolution, regional stress field and fracture development,
it is considered that Indosinian extrusion is the main reason for the formation
of main direction faults in the study area. Yanshanian strike-slip transformation
and Himalayan reactivation further controlled the development of the fractured reservoirs
in the later stage, and formed the present fracture network system. Well block 5
is located in passive plate system during Indosinian period, it is affected by Himalayan
stretching and long-term activation of large faults in the later stage, so that
the effective fractures are relatively developed. The result plays an important
role in guiding the overall plan deployment of the BZ oilfield.