US 11,781,428 B1
Permeability evaluation method for hydrate-bearing sediment
Lanchang Xing, Qingdao (CN); Shuo Wang, Qingdao (CN); Huanhuan Zhang, Qingdao (CN); Bin Wang, Qingdao (CN); Zhoutuo Wei, Qingdao (CN); Xinmin Ge, Qingdao (CN); and Shaogui Deng, Qingdao (CN)
Assigned to CHINA UNIVERSITY OF PETROLEUM (EAST CHINA), Qingdao (CN)
Filed by CHINA UNIVERSITY OF PETROLEUM (EAST CHINA), Qingdao (CN)
Filed on Mar. 13, 2023, as Appl. No. 18/120,919.
Application 18/120,919 is a continuation of application No. PCT/CN2022/116966, filed on Sep. 5, 2022.
Claims priority of application No. 202210883799.8 (CN), filed on Jul. 26, 2022; and application No. 202210883800.7 (CN), filed on Jul. 26, 2022.
Int. Cl. E21B 49/08 (2006.01); E21B 41/00 (2006.01)
CPC E21B 49/088 (2013.01) [E21B 49/0875 (2020.05); E21B 41/0099 (2020.05)] 11 Claims
OG exemplary drawing
 
1. A non-transferrable computer readable storage medium storing computer instructions which are executable by a processor, wherein the computer instructions are configured to enable a computer to execute following steps of a permeability evaluation method for hydrate-bearing sediment:
a complex conductivity spectrum obtaining step of obtaining complex conductivity spectrum of the hydrate-bearing sediment;
a hydrate saturation calculating step of calculating hydrate saturation Sh from a frequency spectrum of a complex conductivity real part, from a complex conductivity imaginary part, or from equivalent relative permittivity; wherein the frequency spectrum of the complex conductivity real part, the complex conductivity imaginary part, and the equivalent relative permittivity are calculated from the complex conductivity spectrum;
a formation factor calculating step of when the hydrate-bearing sediment contains only three media of water, hydrate and quartz sand particles, calculating the formation factor based on Archie's first law; when the hydrate-bearing sediment contains not only the three media of the water, the hydrate and the quartz sand particles, but also clay mineral particles, calculating the formation factor from the complex conductivity real part, the complex conductivity imaginary part and a conductivity of pore water; and,
a permeability calculating step of when the hydrate-bearing sediment contains only the water, the hydrate, and the quartz sand particles, calculating the permeability of the hydrate-bearing sediment based on relaxation time in combination with the hydrate saturation and the formation factor, or based on polarization amplitude in combination with the hydrate saturation and the formation factor; when the hydrate-bearing sediment contains the water, the hydrate, the quartz sand particles, and the clay mineral particles, calculating the permeability of the hydrate-bearing sediment based on the relaxation time in combination with the hydrate saturation and the formation factor, or based on the polarization amplitude in combination with the hydrate saturation and the formation factor, or based on Cation Exchange Capacity in combination with the hydrate saturation; and when porous medium in the hydrate-bearing sediment has fractal characteristics and pore size satisfies a fractal scaling relation, calculating the permeability of the hydrate-bearing sediment based on pore radius and fractal dimension in combination with the hydrate saturation.