Methods for monitoring fluid flow and transport in shale gas reservoirs

Patent metadata

Field	Value
Publication number	US-10458894-B2
Application number	US-201515505412-A
Country	US
Kind code	B2
Filing date	Aug 12, 2015
Priority date	Aug 22, 2014
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

Methods for analyzing a reservoir in a formation containing hydrocarbon fluid are described. Information characterizing the formation is collected and applied to a formation simulator that is provided with a modified Darcy's law equation that accounts for at least one of gas adsorption/desorption, various modes of diffusive transport, and non-Darcy flow behavior, and the simulator is used to generate indications of the state of the reservoir and/or the state of production of hydrocarbon fluid from the reservoir. The modified Darcy's law equations are particularly useful in analyzing any type of formation containing any type of hydrocarbon fluid including shale formations containing hydrocarbon gases. According to one embodiment, a dual-porosity shape factor useful in a formation simulator is also provided.

First claim

What is claimed is:

1. A method for analyzing a reservoir in a formation containing hydrocarbon fluid, comprising:
collecting information characterizing the formation, said information collected from data obtained by at least one tool having interacted with the formation and processed to provide the information;
providing the information to a reservoir simulator incorporating a computational model of the formation that represents geological and fluid properties of the formation, the computational model including at least one equation representing transport of the hydrocarbon fluid through the formation using a permeability based on pore size and change in flow velocity over time; and
running the reservoir simulator to generate a solution for exploiting the formation, wherein the solution includes indications of at least one of the state of the reservoir and the state of the production of hydrocarbon fluid from the reservoir in the formation.

2. A method according to claim 1 , wherein:
the hydrocarbon fluid comprises hydrocarbon gas, and the formation comprises a shale matrix containing the hydrocarbon gas.

3. A method according to claim 2 , wherein:
the at least one equation accounts for transport of the hydrocarbon gas through the shale matrix according to a first relationship

∂
ω

∂
t

-

∇

·

(

κ
⁢

∇
ω

)

=
0

,

where ω=ϕρ g , t is a time index, ϕ is the porosity of the shale matrix, ρ g is the density of the hydrocarbon gas, and where κ is the effective diffusivity defined according to

κ
=

k
app

ϕ
⁢

⁢

c
t

⁢

μ
g

,

where c t is a total compressibility equal to a pore compressibility plus a gas compressibility, μ g is the viscosity of the hydrocarbon gas, and k m is a permeability defined according to

k
m

=

k
app

⁡

(

1
-

k
app

⁢

ρ
g

ϕμ
g

⁢
v

⁢

Dv
Dt

)

,

where ρ g is the density of the hydrocarbon gas, Dv/Dt is the change in flow velocity over time, and k app is an apparent permeability based on pore size.

4. A method according to claim 3 , wherein:
said apparent permeability k app is defined according to

k
app

=

k
⁡

[

1
+

16
⁢

⁢

D
g

⁢

μ
g

⁡

(

1
+

c
g

⁢
p

)

d
p
2

⁢
p

]

,

where c g is said gas compressibility, p is the fluid pressure of the hydrocarbon gas, k is the intrinsic permeability of the shale matrix, d p is the effective pore size and D g is the molecular diffusivity, corresponding to the random thermal motion of gas molecules between their consecutive collisions to each other.

5. A method according to claim 3 , wherein:
said apparent permeability k app is defined according to

k
app

=

k
⁡

[

W
A

⁡

(

Assignees

• Schlumberger Technology Corp

Inventors

• Xu Wenyue
• Diaz Campos Mery
• Kadayam Viswanathan Ravinath Kausik

Classifications

• G01N15/08 Primary

  Investigating permeability, pore-volume, or surface area of porous materials · CPC title

• E21B43/12

  Methods or apparatus for controlling the flow of the obtained fluid to or in wells (E21B43/25 takes precedence; valve arrangements E21B34/00) · CPC title

• G06G7/48

  Analogue computers for specific processes, systems or devices, e.g. simulators · CPC title

• G06F9/455

  Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines · CPC title

• E21B43/00 Primary

  Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells (applicable only to water E03B) · CPC title