Fang, Windsong et al.

Patent Trials and Appeals Board

Jan 7, 2020

13525488 - (D) (P.T.A.B. Jan. 7, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
13/525,488 06/18/2012 Windsong Fang 41307US 3215
85937 7590 01/07/2020
Boulware & Valoir
Tamsen Valoir
2603 Augusta Drive
Suite 1350
Houston, TX 77057
EXAMINER
SUE-AKO, ANDREW B.
ART UNIT PAPER NUMBER
3674
NOTIFICATION DATE DELIVERY MODE
01/07/2020 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
nseigel@boulwarevaloir.com
patent@boulwarevaloir.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________________
Ex parte WINDSONG FANG and THOMAS J. WHEELER
___________________

Appeal 2019-004186
Application 13/525,488
Technology Center 3600
____________________

Before PHILLIP J. KAUFFMAN, TARA L. HUTCHINGS, and
ALYSSA A. FINAMORE, Administrative Patent Judges.

KAUFFMAN, Administrative Patent Judge.

DECISION ON APPEAL
STATEMENT OF THE CASE
Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision to reject claims 1–20. Final Act. 2–12. We have
jurisdiction under 35 U.S.C. § 6(b).
We affirm in part.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42. Appellant identifies the real party in interest as
ConocoPhillips Company. Appeal Br. 3.
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CLAIMED SUBJECT MATTER
The claims are directed to the production of heavy oil or bitumen2
from a reservoir (formation). Spec. ¶ 34; Abstract. In order to extract heavy
oil and bitumen, it is necessary to lower their high viscosities. Spec. ¶¶ 4, 5.
The Specification describes a “steam-assisted production process” as a
viscosity reducing process that “utilize[s] steam to heat the formation to
reduce the viscosity thereof, thus increasing the production rate and
amount.” Spec. ¶ 24. One particular type of steam-assisted production
process is steam assisted gravity drainage (“SAGD”). Spec. ¶¶ 7, 8. As the
name implies, this process utilizes steam to reduce the viscosity of the heavy
crude oil or bitumen so that it may gravity drain into the lower wellbore.
Spec. ¶ 8.
Claims 1 and 7 are reproduced below.3
1. A method for improving production of heavy oil in a
steam-assisted production process that has at least one production well
in a hydrocarbon formation, comprising:
a) providing a horizontal target well for injecting recycled
carbon dioxide, wherein the target well is located at least 30 meters
horizontally away from at least one production well and into a top of a
pay zone in a bitumen or heavy oil reservoir wherein said pay zone is
a bitumen or heavy oil pay zone;
b) preparing the target well for injecting the recycled carbon
dioxide;
c) injecting the recycled carbon dioxide into said target
well and said pay zone at an initial pressure that is at least 1% higher
than an initial reservoir pressure, wherein said carbon dioxide
adequately penetrates the bitumen or heavy oil, said carbon dioxide
being significantly dissolved into the bitumen or heavy oil;

2 Colloquially known as “tar.” Spec. ¶ 4.
3 Italics added for emphasis.
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d) injecting the recycled carbon dioxide at an increased
pressure relative to reservoir pressure when a thermal front
approaches the production well;
e) the dissolved carbon dioxide making the bitumen or
heavy oil more readily drainable to the producer as the thermal front
approaches;
f) wherein some of the injected carbon dioxide remains in
the gas phase, said remaining gaseous carbon dioxide moving to the
top of the pay zone to provide an insulating benefit and reducing heat
loss to the over burden; and
g) recovering said heavy oil or bitumen from said at least
one production well.

7. A method for enhanced oil recovery, comprising:
a) providing at least one horizontal producer well
near a bottom of a pay zone containing bitumen or heavy oil in a
hydrocarbon reservoir;
b) providing at least one horizontal steam injection
well in said pay zone above said producer well;
c) providing at least one horizontal target well for
injecting recycled carbon dioxide, wherein the target well is
located at a horizontal distance away from said production well
and said steam injection well and into a top of said pay zone;
d) injecting recycled carbon dioxide into said target
well at pressure that is at least 1% higher than the pressure of said
hydrocarbon reservoir, wherein said carbon dioxide adequately
penetrates the bitumen or heavy oil and said carbon dioxide is
significantly dissolved into the bitumen or heavy oil;
e) injecting steam into said steam injection well, the
dissolved carbon dioxide making the bitumen or heavy oil more
readily drainable to the producer as the thermal front approaches;
f) wherein some of the injected carbon dioxide
remains in the gas phase, said remaining gaseous carbon dioxide
moving to the top of the pay zone to provide an insulating benefit
and reduce heat loss to the over burden; and
g) collecting the bitumen or heavy oil produced in said
producer well.

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REJECTIONS4
I. Claims 1–6 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Horner, Rao, and Bandyopadhyay.5 Final Act. 3–7.
II. Claims 7–20 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Horner and Bandyopadhyay. Final Act. 7–12.

ANALYSIS

Claims 1–66
The Examiner concludes that the subject matter of independent claims
1–6 would have been obvious from the combined teachings of Horner, Rao,
and Bandyopadhyay. Final Act. 3–7.
The method recited in independent claim 1 includes the steps of:
(1) “injecting . . . recycled carbon dioxide into said target well and said pay
zone at an initial pressure that is at least 1% higher than an initial reservoir
pressure” (limitation (c)), and (2) “injecting the recycled carbon dioxide at
an increased pressure relative to reservoir pressure when a thermal front
approaches the production well” (limitation (d)). For the reasons that
follow, the combined teachings of Horner, Rao, and Bandyopadhyay would
not have resulted in both of these steps.

4 In the Final Office Action, the Examiner also rejected claims 1–6 under
35 U.S.C. § 112, first paragraph, for lack of written description. Final
Act. 2. The Examiner withdrew this rejection in the Answer. Ans. 3.

5 Horner (US 7,172,030 B2, issued Feb. 6, 2007); Rao (US 2006/0289157
A1, published Dec. 28, 2006); Bandyopadhyay (US 3,674,092, issued July
4, 1972).

6 Claims 2–6 depend from independent claim 1.
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Horner teaches a method for recovering hydrocarbons from a
formation that includes natural gas overlying, and in pressure
communication with, bitumen. Horner 6:6–10; 9:55–10:2; 10:59–11:12;
Fig. 7. The method produces natural gas by injecting Waste Gas that
includes carbon dioxide into the formation while either maintaining or
increasing the pressure within the formation; and the method produces
bitumen using SAGD. Horner 6:3–10; 11:53–12:8; Figs. 6, 7.
The Examiner correctly finds that Horner teaches “injecting Waste
Gas into the natural gas reservoir though the injection well(s) at a pressure
and rate that causes the pressure in the natural gas reservoir to be maintained
or increased notwithstanding the production of natural gas from the
reservoir.” Horner 11:63–67 (cited at Ans. 11); see also Horner 16:23–42
(claims 18, 20). However, we agree with Appellant that Horner does not
teach the separate step of “injecting the recycled carbon dioxide at an
increased pressure relative to reservoir pressure when a thermal front
approaches the production well.” See Reply Br. 3. Instead, as Appellant
points out, the cited passage is consistent with injecting Waste Gas at a
constant pressure sufficiently greater than the initial pressure of the natural
gas in the formation to increase the pressure acting on the bitumen. See
Appeal Br. 12. Horner makes no disclosure regarding the approach of a
thermal front. Nor are we persuaded by the Examiner’s reasoning that
Horner meets the limitation at issue because reservoir pressure may drop as
a thermal front approaches causing the injected Waste Gas to be at an
increased pressure relative to reservoir pressure. See Ans. 10–11. Again,
Horner says nothing about thermal fronts, and further, the Examiner’s
reasoning lacks evidentiary support.
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The Examiner relies on another passage in Horner. Final Act. 4
(citing Horner 10:5). This passage describes the transfer of heat from steam
injected into the reservoir during the SAGD process. The passage does not
describe a separate step of injecting recycled carbon dioxide at an increased
pressure relative to reservoir pressure when a thermal front approaches the
production well.
The Examiner does not rely upon Rao or Bandyopadhyay to remedy
the deficiency of Horner. See Final Act. 4–6.
Consequently, we do not sustain the rejection of claims 1–6 under
35 U.S.C. § 103(a) as unpatentable over Horner, Rao, and Bandyopadhyay.

Claims 7, 11–15, and 18–20
The Examiner concludes that the subject matter of claims 7, 11–15,
and 18–20 would have been obvious from the combined teachings of Horner
and Bandyopadhyay. Because Appellant does not present separate
arguments for the patentability of claims 7, 11–15, and 18–20, we select
claim 7 as representative. 37 C.F.R. § 41.37(c)(1)(iv).
Claim 7 recites steps of “providing at least one horizontal producer
well near a bottom of a pay zone containing bitumen or heavy oil in a
hydrocarbon reservoir” (limitation (a)); and “providing at least one
horizontal target well for injecting recycled carbon dioxide, wherein the
target well is located . . . into a top of said pay zone” (limitation (b)).
Appellant argues that these steps require injection directly into oil, and
further contends that Horner fails to teach or suggest these steps. Appeal
Br. 8–10.
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The Examiner correctly interprets the phrase “into a top of said pay
zone” as sufficiently broad to encompass injection into natural gas overlying
bitumen within a reservoir. Ans. 5. The Examiner defines a “pay zone” as a
“reservoir or portion of a reservoir that contains economically producible
hydrocarbons.” Id. (quoting Schlumberger Oilfield Glossary,
https://www.glossary.oilfield.slb.com/en//Terms/p/pay.aspx); see also Rao
¶ 9 (defining a “pay zone” as “rock in which oil and gas are found in
exploitable quantities”). Horner describes “production” of both natural gas
and bitumen from a reservoir in which the natural gas overlies the bitumen.
Horner 9:55–10:2; 10:59–11:12. Therefore, giving the phrase “pay zone” its
broadest reasonable interpretation, the reservoir described by Horner defines
a pay zone containing both bitumen and natural gas. Ans. 6. Because
Figure 7 of Horner depicts the target well as extending into an upper portion
of the reservoir, that is, into the carbon dioxide overlying the bitumen, the
Examiner correctly finds that Horner describes injection “into a top of said
pay zone.”
Appellant contends that Rao fails to teach certain limitations and that
the Examiner’s proposal to combine the teachings of Horner and Rao is
improper. Appeal Br. 10–12. These contentions are unpersuasive because
the Examiner does not rely on Rao.
Appellant contends that Horner fails to teach or suggest a separate
step of injecting recycled carbon dioxide at an increased pressure relative to
reservoir pressure when a thermal front approaches the production well.
Appeal Br. 12–13. Representative claim 7 mentions the thermal front only
once, in connection with the timing with which carbon dioxide dissolves into
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the heavy oil or bitumen.7 Claim 7 does not recite injecting at an increased
pressure when the thermal front approaches. Therefore, Appellant’s
contention is not commensurate with the scope of claim 7.
Appellant has not shown error in the Examiner’s conclusion that the
subject matter of representative claim 7 would have been obvious from the
combined teachings of Horner and Bandyopadhyay. Consequently, we
sustain the rejection of claims 7, 11–15, and 18–20 under 35 U.S.C. § 103(a)
as unpatentable over Horner and Bandyopadhyay.

7 Appellant cites Mahmoud as teaching that “the amount of CO2 that will
dissolve at the interface is insignificant.” Appeal Br. 9 n.1 (citing
Mahmoud, Range of Operability of Gas-Assisted Gravity Drainage Process,
SPE 113474 (presented at the 2008 SPE/DOE Improved Oil Recovery
Symposium, Tulsa, OK, Apr. 19–23, 2008). This assertion is not persuasive.
As the Examiner correctly finds, Horner teaches that carbon dioxide injected
into natural gas overlying bitumen will “be dissolved in bitumen, thereby
reducing the viscosity.” Ans. 7 (quoting Horner 11:44–52). Against this
teaching, Mahmoud says that the slower recovery rate in a water-alternating-
gas (“WAG”) recovery process as opposed to a GAGD process “can be
attributed to the time period of CO2 gas injection where CO2 gas has just
travelled to the top without making any contribution to production.”
Mahmoud 10. Mahmoud teaches that “WAG could be performed with both
miscible and immiscible models.” Id. Nevertheless, because alternating
water and carbon dioxide injections in a WAG recovery process produce
hydrocarbons by displacing the hydrocarbons from the reservoir (Rao ¶ 5), it
is not clear that the authors of Mahmoud are referring to the dissolution of
injected carbon dioxide into the hydrocarbon in this sentence. Therefore, the
teachings of Horner persuade us that, where the carbon dioxide is injected
prior to the steam in Horner’s process (see Horner 12:31–34), “[the] carbon
dioxide [will make] the bitumen or heavy oil more readily drainable to the
producer as the thermal front approaches,” as recited in claim 7. Ans. 7.
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Claims 8–10, 16, and 17
Claim 8 recites the “method of claim 7, wherein said [horizontal
distance said target well is away from said production well and said steam
injection well] is at least 30 meters away from said at least one producer
well.” Claims 9 and 10 recite similar limitations. Claim 16 recites the
“method of claim 12, wherein there are a plurality of oil production wells
and wherein said [horizontal distance said target well is away from said
steam injection well and said production wells] is at least 25 meters away
from said plurality of oil production wells.” Claim 17 recites the “method of
claim 12, wherein said [horizontal distance said target well is away from
said steam injection well and said production well] is 30–50 meters away
from said oil production well and said steam injection.”
The Examiner concludes that the subject matter of claims 8–10, 16,
and 17 would have been obvious from the combined teachings of Horner
and Bandyopadhyay. The Examiner concludes that it would have been
obvious to optimize the position of the target well relative to the positions of
the production and steam injection wells in such a way as to satisfy the
limitations of claims 8–10, 16, and 17. Final Act. 10–12 (citing In re Aller,
220 F.2d 454, 456 (CCPA 1955)).
The Examiner has not adequately explained why optimization of the
distance between the target well, on the one hand, and the production and
steam injection wells, on the other, in Horner’s process would have resulted
in the distances, or distance ranges, recited in claims 8–10, 16, and 17. As
Appellant correctly points out, the Examiner’s findings and analysis are not
persuasive because the Specification and Horner teach recovery processes
based on different principles. Appeal Br. 13. Horner teaches using Waste
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Gas injection not only to provide carbon dioxide to reduce the viscosity of
the bitumen, but also to provide a horizontal sweep of the natural gas from
the pay zone. Appeal Br. 13–14; Horner, Fig. 7. The Specification does not
appear to describe using the injected carbon dioxide to perform any similar
sweep of the bitumen or heavy oil reservoir. See, e.g., Spec. ¶ 20.
Therefore, we do not sustain the rejection of claims 8–10, 16, and 17 under
35 U.S.C. § 103(a) as unpatentable over Horner and Bandyopadhyay.

CONCLUSION
In summary:
Claims
Rejected
35 U.S.C. § Reference/Basis Affirmed Reversed
1–6 103(a) Horner, Rao,
Bandyopadhyay
1–6
7, 11–15,
18–20
103(a) Horner,
Bandyopadhyay
7, 11–15,
18–20

8–10, 16, 17 103(a) Horner,
Bandyopadhyay
8–10, 16, 17
Overall
Outcome
7, 11–15,
18–20
1–6, 8–10,
16, 17

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C. F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(1)(iv) (2011).

AFFIRMED IN PART