Ex Parte Maus et al

Board of Patent Appeals and Interferences

Jul 22, 2003

09584526 (B.P.A.I. Jul. 22, 2003)

1 Claim 33 was amended and claims 15-18, 31 and 32 were canceled subsequent to the final
rejection (see Paper Nos. 8 and 9).
The opinion in support of the decision being entered today was not written
for publication and is not binding precedent of the Board.
Paper No. 18
UNITED STATES PATENT AND TRADEMARK OFFICE
____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________
Ex parte L. DONALD MAUS, TORNEY M. VAN ACKER and MARK E. EHRHARDT
____________
Appeal No. 2002-2203
Application No. 09/584,526
____________
ON BRIEF
____________
Before ABRAMS, STAAB and BAHR, Administrative Patent Judges.
BAHR, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the examiner's final rejection of claims 1, 12
and 13. Claims 2-11, 19-30 and 331 stand allowed and claim 14 stands objected to as
depending from a rejected claim. No other claims are pending in this application.
We AFFIRM-IN-PART.
Appeal No. 2002-2203
Application No. 09/584,526
Page 2
BACKGROUND
The appellants’ invention relates to a method for controlling the riser base
pressure in an offshore well and detecting well control problems, such as “kicks,” a
condition in which riser base pressure is not sufficient to prevent the influx of formation
fluids into the wellbore, or “lost circulation,” a condition in which the riser base pressure
exceeds the natural fracture pressure of the gradient, thereby possibly leading to a
blowout situation (specification, page 1). The objective of appellants’ method is to
maintain the hydrostatic pressure of the drilling fluid adjacent an exposed formation
above the formation’s pore pressure but below the formation’s fracture pressure. A
copy of the claims under appeal is set forth in the appendix to the appellants’ brief.
The examiner relied upon the following prior art references in rejecting the
appealed claims:
Dower 3,470,972 Oct. 7, 1969
Bruce et al. (Bruce) 3,815,673 Jun. 11, 1974
Calcar et al. (Calcar) 5,006,845 Apr. 9, 1991
Maus et al. (Maus), “Instrumentation Requirements for Kick Detection in Deep Water,”
August 1979.
Claim 1 stands rejected under 35 U.S.C. § 103(a) as being unpatentable over
Bruce in view of Dower.
Claim 12 stands rejected under 35 U.S.C. § 103(a) as being unpatentable over
Bruce in view of Calcar.
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Application No. 09/584,526
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Claim 13 stands rejected under 35 U.S.C. § 103(a) as being unpatentable over
Bruce in view of Calcar and Maus.
Rather than reiterate the conflicting viewpoints advanced by the examiner and
the appellants regarding the above-noted rejections, we make reference to the answer
(Paper No. 13) for the examiner's complete reasoning in support of the rejections and to
the brief and reply brief (Paper Nos. 12 and 15) for the appellants’ arguments
thereagainst.
OPINION
In reaching our decision in this appeal, we have given careful consideration to
the appellants’ specification and claims, to the applied prior art references, and to the
respective positions articulated by the appellants and the examiner. As a consequence
of our review, we make the determinations which follow.
We turn first to the rejection of claim 1 as being unpatentable over Bruce in view
of Dower. Bruce teaches that proper control of offshore wells requires that the riser
base pressure (the hydrostatic pressure exerted on the subsurface formation) be kept
at a sufficient level to overcome formation pressure without exceeding the natural
fracture gradient of the formation (column 1, lines 32-41). With this in mind, Bruce
discloses a method of pressure control comprising monitoring the riser base pressure
and adjusting the rate of lift gas injection into the riser to control the density of the fluid
in the riser to thereby adjust the riser base pressure. Bruce does not disclose using a
Appeal No. 2002-2203
Application No. 09/584,526
Page 4
2 It is elementary that to support an obviousness rejection, all of the claim limitations must be
taught or suggested by the prior art applied (see In re Royka, 490 F.2d 981, 984-85, 180 USPQ 580, 582-
83 (CCPA 1974)) and that all words in a claim must be considered in judging the patentability of that claim
against the prior art (In re Wilson, 424 F.2d 1382, 1385, 165 USPQ 494, 496 (CCPA 1970)).
throttling device at or near the top of the riser to adjust the mass flow rate out of the top
of the riser and the riser surface pressure to compensate for changes in the riser base
pressure, as called for in claim 1.
Dower discloses using a throttling device (casing pressure regulator 21) near the
top of the riser to control the flow of the return drilling fluid to thereby impose a back
pressure on the drilling fluid to reduce kicks. Dower, however, monitors riser surface
pressure using pressure gage 22 and adjusts the casing pressure regulator 21 in
response thereto.
We agree with the examiner that the combined teachings of Bruce and Dower
are sufficient to suggest use of a throttling device at or near the surface of Bruce’s riser
to adjust the mass flow rate out of the top of the riser and hence the riser surface
pressure. Dower, however, would have suggested adjustment of the throttling device to
compensate for changes in the riser surface pressure, not changes in the riser base
pressure, as called for in appellants’ claim 1. Thus, combination of the applied
references would not yield the invention recited in claim 1. It therefore follows that we
cannot sustain the rejection of claim 1.2
We turn next to the rejection of claim 12 as being unpatentable over Bruce in
view of Calcar. Calcar discloses a method of detecting kicks comprising predicting the
Appeal No. 2002-2203
Application No. 09/584,526
Page 5
density of the mud in the riser at a point just above the blowout preventer, locally
measuring the density of the mud and comparing the predicted and measured density
values. If gas is present in the mud, thereby indicating a “gas kick,” the measured
density will be lower than the predicted value. Note the paragraph bridging columns 3
and 4. While Calcar focuses primarily on “kick” detection, Calcar also points out
(column 4, lines 8-10) that, in addition to gas kicks, “lost circulation conditions can be
determined using this invention.”
It is our opinion that the combined teachings of Bruce and Calcar are sufficient to
have suggested the subject matter of claim 12. Specifically, the combined teachings of
Bruce of adjusting lift gas flow rate to control the riser base pressure and of Calcar of
comparing measured riser mud density to a predicted density as an early indicator of a
kick or lost circulation situation would have suggested to one of ordinary skill in the art
at the time of appellants’ invention a method including predicting riser fluid density,
measuring the actual riser fluid density, comparing the predicted and measured values
to determine if either a kick or lost circulation situation exists, as taught by Calcar, and
increasing the lift gas flow rate, as taught by Bruce, if a lost circulation situation is
detected.
Appellants argue that the examiner’s combination of Bruce and Calcar is
improper because neither reference indicates a recognition that decreasing the rate of
injection of lift gas cannot provide sufficient control with regard to preventing the influx
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Application No. 09/584,526
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of formation fluids (brief, page 12). While appellants may be correct that neither
reference recognizes this fact, as long as some motivation or suggestion to combine the
references is provided by the prior art taken as a whole, the law does not require that
the references be combined for the reasons contemplated by the inventor. See In re
Beattie, 974 F.2d 1309, 1312, 24 USPQ2d 1040, 1042 (Fed. Cir. 1992); In re Dillon,
919 F.2d 688, 693, 16 USPQ2d 1897, 1901 (Fed. Cir. 1990), (en banc), cert. denied,
500 U.S. 904 (1991) and In re Kronig, 539 F.2d 1300, 1304, 190 USPQ 425, 427-428
(CCPA 1976). Calcar discloses a method of detecting “kick” or “lost circulation”
conditions but does not specify any means to correct or compensate for such
conditions. Bruce teaches adjustment of lift gas flow rate as a means to control riser
base pressure so as to prevent lost circulation conditions. It thus would have been
obvious to adjust lift gas flow rate as taught by Bruce with the method of Calcar to
correct for a lost circulation condition once it has been identified.
Appellants’ argument on page 13 of the brief that Bruce does not teach or
suggest the method of injecting boost mud to prevent an influx of formation fluids is not
commensurate in scope with the language of claim 12. Claim 12 does not require
adjustment of both lift gas flow rate and boost mud flow rate. Rather, claim 12 recites a
step of adjusting “one or both” of the boost mud flow rate and lift gas flow rate. This
limitation is met by the adjustment of lift gas flow rate only, which appellants concede is
taught by Bruce.
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Application No. 09/584,526
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For the foregoing reasons, we shall sustain the examiner’s rejection of claim 12.
In that appellant has not offered a separate argument as to the patentability of claim 13
but simply relies on the above arguments as to the combination of Bruce and Calcar
which we have not found persuasive, it follows that we shall also sustain the rejection of
claim 13 as being unpatentable over Bruce in view of Calcar and Maus. See In re
Young, 927 F.2d 588, 590, 18 USPQ2d 1089, 1091 (Fed. Cir. 1991); In re Wood, 582
F.2d 638, 642, 199 USPQ 137, 140 (CCPA 1978).
CONCLUSION
To summarize, the decision of the examiner to reject claims 1, 12 and 13 under
35 U.S.C. § 103(a) is affirmed as to claims 12 and 13 and reversed as to claim 1.
Appeal No. 2002-2203
Application No. 09/584,526
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No time period for taking any subsequent action in connection with this appeal
may be extended under 37 CFR § 1.136(a).
AFFIRMED-IN-PART
NEAL E. ABRAMS )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
LAWRENCE J. STAAB ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
JENNIFER D. BAHR )
Administrative Patent Judge )
JDB:svt
Appeal No. 2002-2203
Application No. 09/584,526
Page 9
APPENDIX
1. A method for controlling the pressure at the base of a gas-lifted riser during
drillling of an offshore well, said method comprising the steps of:
determining the rider base pressure (prb); and
using a throttling device located at or near the top of said riser to adjust the mass
flow rate out of the top of said riser (mo) and the riser surface pressure (prs)
to compensate for changes in the riser base pressure (prb).
12. A method for controlling the pressure at the base of a gas-lifted riser during
drilling of an offshore well, said method comprising the steps of:
determining a setpoint value for riser mix density (pmix);
determining the actual value of riser mix density (pmix);
adjusting one or both of the boost mud flow rate (qb) and the lift gas flow rate (qb)
to substantially minimize the difference between said setpoint value and said actual
value.
13. The method of claim 12, wherein said method further comprises the steps
of:
determining well return flow rate (qw) and drill string flow rate (qc); and
comparing the drill string flow rate (qc) to the well return flow rate (qw) to detect well
control problems such as kickers or lost circulation.
Appeal No. 2002-2203
Application No. 09/584,526
Page 10
Mr. Salvatore J Casamassima
Exxon Mobil Upstream Research Company
P O Box 2189
Houston, TX 77252-2189