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The wellbore pressure response in naturally fractured reservoirs

Conference · · Soc. Pet. Eng. AIME, Pap.; (United States)
OSTI ID:5293288

Recently a new flow regime has been identified for pressure drawdown or buildup data obtained from a well producing a naturally fractured reservoir. During the time period corresponding to this new flow regime, a semilog plot of pressure versus time exhibits a semilog straight line with slope equal to m/2, where m is the slope of both the ''early and late time'' semilog straight lines predicted by the Warren and Root model. The identification of this intermediate time semilog straight line means that pressure data may exhibit as many as three semilog straight lines. A virtually complete analysis of well test pressure data is possible when the data exhibits two or more of the three possible straight lines. In this work we present type curves which can be used to obtain a virtually complete analysis of pressure data when only one of the three semilog straight lines is reflected by the data. Analytical work on the pressure response in a naturally fractured reservoir requires the assumption of a matrix-fracture geometry. One model that has frequently been used assumes that a naturally fractured reservoir is equivalent to a system of plane horizontal fractures. The use of this model suggests that the pressure response should be similar to the pressure response in a two-layer reservoir. In this work, the authors establish the conditions under which the pressure response in a two-layer reservoir with crossflow between the layers will be identical to the pressure response in a naturally fractured reservoir. The twolayer analogue provides information on the well response when the matrix feeds directly into the wellbore. In addition, the authors consider the economic feasibility of stimulating the ''matrix layer''.

Research Organization:
Univ. of Tulsa
OSTI ID:
5293288
Report Number(s):
CONF-8310121-
Journal Information:
Soc. Pet. Eng. AIME, Pap.; (United States), Journal Name: Soc. Pet. Eng. AIME, Pap.; (United States) Vol. SPE12012; ISSN SEAPA
Country of Publication:
United States
Language:
English