Page 20 - Fundamentals of Reservoir Engineering

CONTENTS XX

Fig. 7.4 Single rate drawdown test; (a) wellbore flowing pressure decline during the early
transient flow period, (b) during the subsequent semi-steady state decline
(Exercise 7.2) 159

Fig. 7.5 Dimensionless pressure as a function of dimensionless flowing time for a well
situated at the centre of a square (Exercise 7.4) 168

Fig. 7.6 Production history of a well showing both rate and bottom hole flowing pressure
as functions of time 169

Fig. 7.7 Pressure buildup test; (a) rate, (b) wellbore pressure response 171

Fig. 7.8 Multi-rate flow test analysis 172

Fig. 7.9 Horner pressure buildup plot for a well draining a bounded reservoir, or part of a
reservoir surrounded by a no-flow boundary 175

Fig. 7.10 Part of the infinite network of image wells required to simulate the no-flow
condition across the boundary of a 2 : 1 rectangular part of a reservoir in which
the real well is centrally located 176

Fig. 7.11 MBH plots for a well at the centre of a regular shaped drainage area 7
(Reproduced by courtesy of the SPE of the AIME) 178

Fig. 7.12 MBH plots for a well situated within; a) a square, and b) a 2:1 rectangle 7
(Reproduced by courtesy of the SPE of the AIME) 179

Fig. 7.13 MBH plots for a well situated within; a) a 4:1 rectangle, b) various rectangular
7
geometries (Reproduced by courtesy of the SPE of the AIME) 180
Fig. 7.14 MBH plots for a well in a square and in rectangular 2:1 geometries 7 181

Fig. 7.15 MBH plots for a well in a 2:1 rectangle and in an equilateral triangle 7
(Reproduced by courtesy of the SPE of the AIME). 181

Fig. 7.16 Geometrical configurations with Dietz shape factors in the range, 4.5-5.5 184

Fig. 7.17 Plots of ∆p wf (calculated minus observed) wellbore flowing pressure as a function
of the flowing time, for various geometrical configurations (Exercise 7.5) 186

Fig. 7.18 Typical Horner pressure buildup plot 190

Fig. 7.19 Illustrating the dependence of the shape of the buildup on the value of the total
production time prior to the survey 192

Fig. 7.20 Analysis of a single set of buildup data using three different values of the flowing
time to draw the Horner plot. A - actual flowing time; B - effective flowing time; C -
time required to reach semi-steady state conditions 194

Fig. 7.21 The Dietz method applied to determine both the average pressure p and the

dynamic grid block pressure p d 197