US2015149089A1PendingUtilityA1
Determining reserves of a reservoir
Assignee: CESPEDES JORGE ARTURO ACUNAPriority: Nov 27, 2013Filed: Nov 19, 2014Published: May 28, 2015
Est. expiryNov 27, 2033(~7.3 yrs left)· nominal 20-yr term from priority
Inventors:Jorge Arturo Acuna Cespedes
E21B 47/06E21B 49/00G01V 2210/624G01V 1/50E21B 41/0092E21B 47/10
17
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Claims
Abstract
This disclosure provides embodiments of computer implemented methods, computing apparatuses, and other methods for determining reserves of a reservoir. For example, an embodiment of the computer implemented method includes receiving field data for a field that comprises a reservoir, wherein the field data includes pressure data and cumulative production data. The embodiment further includes generating normalized pressure values for a plurality of timestamps using time, the pressure data, and the cumulative production data. The embodiment further includes generating a normalized pressure graph, wherein the normalized pressure graph includes a normalized pressure curve of the generated normalized pressure values.
Claims
exact text as granted — not AI-modified1 . A computer implemented method of determining reserves of a reservoir, the method comprising:
receiving field data for a field that comprises a reservoir, wherein the field data includes pressure data and cumulative production data; generating normalized pressure values for a plurality of timestamps using time, the pressure data, and the cumulative production data; and generating a normalized pressure graph, wherein the normalized pressure graph includes a normalized pressure curve of the generated normalized pressure values.
2 . The method of claim 1 , wherein generating the normalized pressure values includes using an equation, wherein the equation is:
p
qB
=
4
π
p
QB
t
wherein QB is cumulative production at reservoir conditions, p i is initial reservoir pressure, p wf is is downhole flowing pressure, p=p i −p wf is reservoir pressure change, and t is time in units appropriate to make ratio QB/t have proper units of flow rate.
3 . The method of claim 1 , further comprising determining a slope and an intercept from the generated normalized pressure graph.
4 . The method of claim 3 , further comprising applying simple linear regression to obtain a best fit line to a linear portion of the generated normalized pressure graph, and wherein determining the slope and the intercept from the generated normalized pressure graph includes using the best fit line.
5 . The method of claim 4 , further comprising determining an end of linear flow from the generated normalized pressure graph using the best fit line.
6 . The method of claim 5 , wherein determining the end of linear flow from the generated normalized pressure graph includes determining when the normalized pressure curve deviates from the linear fit line using derivatives, a threshold, or both, wherein a deviation indicates the end of linear flow.
7 . The method of claim 3 , further comprising:
generating linear flow volume values for the timestamps using the determined slope and the determined intercept from the generated normalized pressure graph, and generating a linear flow volume graph, wherein the linear flow volume graph includes a linear flow volume curve of the generated linear flow volume values.
8 . The method of claim 7 , wherein generating the linear flow volume values includes using an equation, wherein the equation is:
LFV
=
QB
cp
(
1
+
b
m
t
)
wherein QB is cumulative production at reservoir conditions, p i is initial reservoir pressure, p wf is downhole flowing pressure, p=p i −p wf is reservoir pressure change, and t is time, m is a slope, b is an intercept, and c is compressibility.
9 . The method of claim 8 , further comprising:
generating a theoretical linear flow volume line for an infinite linear reservoir; and applying the theoretical linear flow volume line to the generated linear flow volume graph.
10 . The method of claim 9 , wherein generating the theoretical linear flow volume line for an infinite linear reservoir includes using an equation, wherein the equation is:
LFV
=
1.305
E
-
2
φ
μ
c
hn
f
X
f
k
t
=
t
6
π
m
c
wherein LFV is pore volume, t is time, m is a slope, c is compressibility, h is reservoir thickness, μ is viscosity, φ is porosity, k is permeability, n f is a number of fractures, and X f is a half-length of each of those fractures.
11 . The method of claim 9 , further comprising determining an end of linear flow from the generated linear flow volume graph using the theoretical linear flow volume line.
12 . The method of claim 11 , wherein determining the end of linear flow from the generated linear flow volume graph includes determining when the linear flow volume curve deviates from the theoretical linear flow volume line for the infinite linear reservoir using derivatives, a threshold, or both, wherein a deviation indicates the end of linear flow.
13 . The method of claim 11 , further comprising determining the reserves of the reservoir using a stimulated reservoir volume, wherein the stimulated reservoir volume equals the linear flow volume corresponding to the end of the linear flow from the generated linear flow volume graph.
14 . The method of claim 11 , further comprising using a shape of the linear flow volume curve after end of linear flow from the generated linear flow volume graph to facilitate determination of a type of boundary after the end of linear flow from the generated linear flow volume graph.
15 . A computing apparatus, the apparatus comprising:
At least one processor; and At least one computer readable medium including computer readable instructions, that when executed by the at least one processor, cause performance of a method of determining reserves of a reservoir, the method comprising:
receiving field data for a field that comprises a reservoir, wherein the field data includes pressure data and cumulative production data;
generating normalized pressure values for a plurality of timestamps using time, the pressure data, and the cumulative production data; and
generating a normalized pressure graph, wherein the normalized pressure graph includes a normalized pressure curve of the generated normalized pressure values.
16 . The apparatus of claim 15 , the method further comprising:
generating linear flow volume values for the timestamps using a determined slope and a determined intercept from the generated normalized pressure graph, and generating a linear flow volume graph, wherein the linear flow volume graph includes a linear flow volume curve of the generated linear flow volume values.
17 . The apparatus of claim 16 , the method further comprising:
determining the reserves of the reservoir using a stimulated reservoir volume, wherein the stimulated reservoir volume equals a linear flow volume corresponding to an end of the linear flow from the generated linear flow volume graph.
18 . A method of determining reserves of a reservoir, the method comprising:
identifying an end of the linear flow from a generated linear flow volume graph, wherein a stimulated reservoir volume equals linear flow volume corresponding to the end of the linear flow from the generated linear flow volume graph, and wherein the reserves of the reservoir are based on the stimulated reservoir volume, and wherein the generated linear flow volume graph is generated based on a slope and intercept from a generated normalized pressure graph that includes normalized pressure values for a plurality of timestamps using time, the pressure data, and the cumulative production data; and performing at least one field operation in response to the identified end of the linear flow from the generated linear flow volume graph.
19 . The method of claim 18 , further comprising identifying a type of boundary after the linear flow.Join the waitlist — get patent alerts
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