7/29/2019 Some Problems in Pressure BUILD UP
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SOCIETY OF PETROLEUM ENGINEERS OF AIME6300 North Central
ExpresswayDallas, Tex.PAPER SP E - 1 4 5NUMBER
TRIS IS A PREPRINT - - - SUBJECT TO CORRECTION
SOME PROBLEMS IN PRESSURE BUILD-UP
ByWil+iam Hurst, Petroleum Consultant, Houston, Tex.Crville K.
Haynie, Christ ie , Mitchell and Mitchell Co, , Houston, 'I'ex
.Members AIME, andRichard N. Walker, Christ ie , Mitchell and
Mitchell Co., Houston, Tex ., Ju nio r Member AIME
Publication Rights ReservedThis paper i3 to be presented a t the
36th Annual Fall Meeting of the Society of Petroleum Enginof A:rnE
in Dallas, October 8-11, 1961,and is considered t he p rope rt y of
the Society of PetroleumEngineers. Permission to publish i s hereby
restr icted to an abstract of no t more than 300 words, witno i l
lustrations, unless the paper i s specifically released to th e p
ress by th e Edito r o f t he J ou rn aof Petroleum Technology or
the Executive Secretary. Such abstract should contain conspicuous
acknowedgment of where and by whom th e paper is p re sented. Pub
lic at io n elsewhere af ter publication in Jou0{ Petroleum
Technology or Society of Petroleum Engineers Journal is granted on
request, providingproper credit i s given that publication and the
original presentation of the papero
This paper deals with certain abnormalitiesas observed in pre
ssure build-up , b ut in ste ad ofabnormalities per se, these are
phenomena thatbegin to t e l l us something of the contiguousnature
of the formation further removed from th ewell. In a sense, this is
a broadening of thebasis of what pressure build-ups can mean
thatnow extend into the realm o subsurfaceinterpretat ions.
Discussion of this paper is invited. Three copies of any
discussion should be sent to th e Soc ieof Petroleum Engineers of
ice. Such discussion may be presented at the aboye meeting and
consideredfor publication in one o th e two SPE magazines with the
paperor--- . - - . - . - - - - - - - - -..--- . -- .
----------ABSTRACT van Everdingen4 for a constant-rate problem wita
fixed exterior pressure a t th e boundary. Thi
was purely an empirical correlation, and th e resul ts have more
than met the writers ' expectatias i t showed that build-up time
was a functiondrainage radius, and independent of wel l rad iusskin
effect . Thus, for the times in pressurebuild-up where these
abnormalities are observedoccur, yield drainage radi i for the main
sandbody that are i n sub st an ti al agreement with thoestablished
independently froro the lens problemThe problem t reated is an
actual assignmentin the study of the Atoka Conglomerate in
WiseCounty , Tex . Here i t has been observed a de parture from the
straight- l ine Lord Kelvin effect
o f p re ssure build-up to reveal two such brokenstraight-l
ines, one following th e other. Thishas been i n te rp ret ed a s
gas replenishment fromcontiguous lenses feeding into th e main
sandbody, for which mathematics have been formulated,based on the
series problem of unsteady-s ta t efluid flow.
To sustain this method by an ent i relydifferent application, a
radial drainage formulawas developed from work published by Hurst
andReferences and i l lustrat ions at end of, papero
There are associated problems connected withis study. One is
establishing t he d is tance oa gas cap over an o i l column, based
on this verdrainage formula; and the other is an estimatioof s ta t
ic bottom-hole pressure interpreted fromthe problem cited4 of these
ea rly invest iga to r swhere interference between wells
occur.INTRODUCTION
What this paper presents is some factualrepresentation o
abnormalities that appear inpressure build-up. However, these
should not baccepted as abnormal it ies per se, but rather
adeparture from th e accepted norm of what to expfor a pressure
build-up curve that begins toref lec t the contiguous nature of the
formation
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