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Title: Analysis of Transient Pressure Tests Performed in Fractured Rock.

Abstract

Abstract not provided.

Authors:
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1266294
Report Number(s):
SAND2007-1435C
526818
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the Sandia INER-EEL Workshop held March 12-16, 2007 in Longtain, Taiwan.
Country of Publication:
United States
Language:
English

Citation Formats

Roberts, Randall Mark. Analysis of Transient Pressure Tests Performed in Fractured Rock.. United States: N. p., 2007. Web.
Roberts, Randall Mark. Analysis of Transient Pressure Tests Performed in Fractured Rock.. United States.
Roberts, Randall Mark. Thu . "Analysis of Transient Pressure Tests Performed in Fractured Rock.". United States. doi:. https://www.osti.gov/servlets/purl/1266294.
@article{osti_1266294,
title = {Analysis of Transient Pressure Tests Performed in Fractured Rock.},
author = {Roberts, Randall Mark},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}

Conference:
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  • The results from a large number of single-hole packer tests in crystalline rock from three test sites in Sweden have been analyzed statistically. Average hydraulic conductivity values for 25 m long test intervals along boreholes with a maximal length of about 700 m are used in this study. A comparison between steady state and transient analysis of the same test data has been performed. The mean value of the hydraulic conductivity determined from steady state analysis was found to be about two to three times higher compared to transient analysis. However, in some cases the steady state analysis resulted inmore » 10 to 20 times higher values compared to the transient analysis. Such divergence between the two analysis methods may be caused by deviations from the assumed flow pattern, borehole skin effects and influence of hydraulic boundaries.« less
  • This paper presents for the first time a technique for analyzing buildup data from wells produced at constant pressure with turbulent flow in the fracture. Two example applications, one each for buildup and drawdown, are included to demonstrate these methods which would find significant application in low permeability reservoirs that are generally produced at constant pressure.
  • Naturally fractured reservoirs that undergo waterflooding or steam injection or that are acid-stimulated frequently can be modeled as a composite naturally fractured reservoir with matrix skin. A new analytical solution is presented in Laplace space for such a model that includes wellbore storage and skin. Design and analysis methods for pressure-transient tests based on the pressure derivative are also presented. Correlating parameters have been found that ease test design and analysis. Practical methods to determine the size of the inner zone are given. These methods are based on a scaled deviation time from the semilog straight line. In this papermore » a field example for an acidized well is presented.« less
  • There are 5 basic techniques which can be used to analyze transient pressure data from hydraulically fractured wells: modified pseudo-radial flow (semi-log analysis), formation linear flow (square-root time analysis), bilinear flow (fourth-root time analysis), type curve analysis, and reservoir simulation history matching analysis. These techniques are applied to evaluate formation matrix permeability, created fracture half length, and fracture conductivity. Each technique has its advantages and disadvantages in estimating the above-mentioned parameters. Examples of transient pressure analysis for hydraulically fractured wells in the Western Tight Sands area have been used to demonstrate how the different techniques can provide a range ofmore » values for the above parameters. A representative example shows the matrix permeability calculations to range between 0.02 and 0.051 md as compared to the design parameter of 0.025 md. The fracture half length and conductivity estimates varied between 242 to to 1,425 ft and 56 to 253 md-ft compared to the design parameter of 500 ft and 200 md-ft, respectively. 35 references.« less
  • New ideas are presented for the interpretation of pressure transient tests for wells in naturally fractured reservoirs. This work is based on the transient matrix flow model formulated by de Swaan. The differences between this model and the Warren and Root model occur during the transition flow period. It is demonstrated that the behavior of a naturally fractured reservoir can be correlated by using three dimensionless parameters. It is established that regardless of matrix geometry the transition period might exhibit a straight line whose slope is equal to half the slope of the classical parallel semilog straight lines, provided themore » transient matrix linear flow is present. In addition, information is provided on the estimation of fracture area per unit matrix volume or matrix parameters from the transition period semilog straight line. It is shown that matrix geometry might be identified when pressure data are smooth. Field examples are included to illustrate the application and the validity of the theoretical results of this study.« less