| Author's Name: HE Qiaolin 1,2 , WANG Ke 3 , HU Chunlei 1,2 , WANG Junpeng 3 , DENG Jianzhong 1,2 ,
ZHANG Zhiyuan 3 , SUN-JIN Jiajie 1,2 , HUANG Qingxuan 3 , LIU Yuan 1,2 |
| Structural fracture is an important condition for obtaining high gas yield from the deep tight glutenite reservoir
of the Cretaceous Yageliemu Formation in KT-1 gas reservoir of Kuqa Depression. To study the distribution and
effectiveness of structural fracture is conducive to favorable reservoir prediction of Yageliemu Formation. Based on core
and imaging logging data, the characteristics of structural fractures in Yageliemu Formation of KT-1 gas reservoir are
described, and the distribution of structural fractures is semi-quantitatively predicted by finite element method. The
effectiveness of structural fractures is evaluated from two aspects: time and space effectiveness. Finally, the numerical
simulation of structural fracture is carried out under the condition of constant horizontal stress and increasing gravity load
of overlying strata. The results show that the glutenite reservoir of Yageliemu Formation in KT-1 gas reservoir develops
tensile fractures and shear fractures, mainly at medium-high angles, and the dominant trend is NW-SE, which has a good
correspondence with the maximum paleotectonic stress orientation in the NNW direction. There are at least two stages of
fracture in Yageliemu Formation of KT-1 gas reservoir. The first stage of fracture is invalid, which was formed before the
depositional period of the Neogene Kangcun Formation. The second stage of fracture is effective formed in the
depositional period of the Pliocene Kuqa Formation-Quaternary (5 Ma until now), which has a good matching
relationship with natural gas charging, and is an important condition for the formation of large-scale natural gas reservoir.
The fracture spatial effectiveness is mainly controlled by the fracture density and fracture opening. The fracture density in
the high position of anticline of KT-1 gas reservoir is lower than that in the wing, but the fracture opening is larger and
the fracture permeability is significantly higher than that in the wing, which is an important reason why Well KT204
located in the wing has the highest fracture density but the lowest gas production. The numerical simulation results show
that in a certain depth range, with the increase of reservoir buried depth, the density of structural fractures decreases, but
the aperture and permeability increase significantly, and the effectiveness becomes significantly better, which is more
conducive to the efficient flow of natural gas in the reservoir. |
