Method of acquiring rock component content of stratum

Patent metadata

Field	Value
Publication number	US-10962679-B2
Application number	US-201815942356-A
Country	US
Kind code	B2
Filing date	Mar 30, 2018
Priority date	Nov 2, 2015
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

Disclosed is a method of acquiring the rock component content in a stratum, the method comprising: on the basis of acquired element capture spectroscopy logging data, performing normalization processing on each element yield in the stratum rock components; on the basis of an element yield curve obtained from the normalization processing and a pre-established stratum rock interpretation model, establishing a logging curve response equation set; and utilizing the established logging curve response equation set and an optimization algorithm, calculating the content of a rock component in a stratum. The method and device can directly process element yield data of element capture spectroscopy logging, and can improve the accuracy of calculating the rock component in a stratum.

First claim

The invention claimed is:

1. A method for acquiring stratum rock component contents, wherein the method comprising:
acquiring element capture energy spectrum well logging data by transmitting fast neutrons to a stratum from a chemical source;
performing normalization processing on all yields of elements in acquired element capture energy spectrum well logging data;
establishing a well logging curve response equation set according to the yields of the elements after the normalization processing and a pre-established stratum rock interpretation model; and
calculating stratum rock component contents using the established well logging curve response equation set and an optimization algorithm;
wherein performing normalization processing on all yields of elements comprises calculating the yields of the elements using the following equation:

ny
k

=

w
k

·

y
k

∑

l
=
1

ne

⁢

⁢

w
l

·

y
l

wherein ny k denotes a yield of a k-th element after the normalization processing; W k denotes a yield normalization coefficient of the k-th element; y k denotes a yield of the k-th element before the normalization processing; ne denotes the number of element types; w 1 and y 1 denote a yield normalization coefficient of an 1-th element and a yield thereof before the normalization processing, respectively.

2. The method according to claim 1 , wherein establishing a well logging curve response equation set according to the yields of the elements after the normalization processing and a pre-established stratum rock interpretation model comprises:
acquiring element yield curves and conventional well logging curves meeting a preset requirement according to the established stratum rock interpretation model;
establishing response equations each corresponding to the acquired element yield curves and conventional well logging curves.

3. The method according to claim 2 , wherein establishing response equations each corresponding to the acquired element yield curves and conventional well logging curves comprises establishing relational expressions between theoretical well logging response values each corresponding to the acquired element yield curves and conventional well logging curves and volume percentage contents of stratum rock components.

4. The method according to claim 3 , wherein the established relational expressions are represented as:

t

ck
,
1

=

∑

i
=
1

m

⁢

⁢

v
i

·

R
i

+

∑

j
=
1

f

⁢

⁢

v
j

·

R
j

t

ck
,
2

=

∑

i
=
1

m

⁢

⁢

(

v
i

·

ρ
i

·

R
i

)

/

∑

i
=
1

m

⁢

⁢

(

v
i

·

ρ
i

)

wherein t ck1 denotes a theoretical well logging response value corresponding to a k-th conventional well logging curve acquired; t ck2 denotes a theoretical well logging response value corresponding to a k-th element yield curve acquired; ν i and ν j denote volume percentage contents of each mineral component and fluid component of a stratum, respectively; R i and R j denote well logging response parameters of each mineral and fluid, respectively; ρ i denotes a density value of an i-th stratum mineral; m and f denote the number of the minerals and fluids in a stratum rock, respectively; i, j and k are all positive integers.

5. The method according to claim 4 , wherein the well logging response parameters are determined with a method that combines a rock element mineral experiment with a theoretical value calculation.

6. The method according to claim 1 , wherein calculating stratum rock component contents using the established well logging curve response equation set and an optimization algorithm comprises:
establish

Assignees

• Petrochina Co Ltd

Inventors

• Wu Hongliang
• Feng Zhou
• Li Ning
• Wang Kewen
• Feng Qingfu
• Zhang Gong

Classifications

• G01V5/101 Primary

  and detecting the secondary Y-rays produced in the surrounding layers of the bore hole · CPC title

• E21B49/00

  Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells · CPC title

• E21B49/08

  Obtaining fluid samples or testing fluids, in boreholes or wells · CPC title

• E21B49/02

  by mechanically taking samples of the soil · CPC title

• G01V99/005 Primary

  Physics · mapped topic