Investigation of Fault Permeability in Sands with Different Mineral Compositions (Evaluation of Gas Hydrate Reservoir)

Energies

Hiroaki Kaneko¹  Sho Kimura¹  Hideki Minagawa¹  Takuma Ito¹ 

[1] Reservoir Modeling Team, Methane Hydrate Research Centre,National Institute of Advanced Industrial Science and Technology (AIST),2-17-2-1 Tsukisamu-Higashi, Toyohira-ku, Sapporo 062-8517, Japan;

关键词: permeability;    fault;    porosity;    normal stress;    mineralogy;    grain size;    ring-shear;   

DOI  :  10.3390/en8077202

来源: DOAJ

【 摘 要 】

We used a ring-shear apparatus to examine the perpendicular permeability of sands with different mineral compositions to evaluate fault behavior around gas hydrate reservoirs. The effect of effective normal stress on the permeability of two sand types was investigated under constant effective normal stresses of 0.5–8.0 MPa. Although Toyoura sand and silica sand No. 7 mainly comprise quartz, silica sand No. 7 contains small amounts of feldspar. For Toyoura sand, the permeability after ring-shearing dramatically decreased with increasing effective normal stress up to 3.0 MPa, then gradually decreased for stresses over 3.0 MPa, whereas the permeability after ring-shearing of silica sand No. 7 rapidly decreased with increasing effective normal stress up to 2.0 MPa. Although the relationships between the permeability after ring-shearing and effective normal stress for both sands could be expressed by exponential equations up to 3.0 MPa, a more gradual change in slope was shown for Toyoura sand. The permeabilities of both sands were almost equal for effective normal stresses over 3.0 MPa. The mineralogical properties of the small amount of feldspar in the sample indicate that both mineralogy and original grain size distribution affect the fault permeability and shear zone formation.

【 授权许可】

Unknown