Page 18 - Fundamentals of Reservoir Engineering

CONTENTS XVIII

Fig. 2.3 Application of PVT parameters to relate surface to reservoir hydrocarbon
volumes; below bubble point pressure 47

Fig. 2.4 Producing gas oil ratio as a function of the average reservoir pressure for a
typical solution gas drive reservoir 47

Fig. 2.5 PVT parameters (B o, R s and B g), as functions of pressure, for the analysis
presented in table 2.4; (p b = 3330 psia). 49

Fig. 2.6 Subsurface collection of PVT sample 52

Fig. 2.7 Collection of a PVT sample by surface recombination 54

Fig. 2.8 Schematic of PV cell and associated equipment 56

Fig. 2.9 Illustrating the difference between (a) flash expansion, and (b) differential
liberation 56

Fig. 3.1 Volume changes in the reservoir associated with a finite pressure drop ∆p; (a)
volumes at initial pressure, (b) at the reduced pressure 72

Fig. 3.2 Solution gas drive reservoir; (a) above the bubble point pressure; liquid oil, (b)
below bubble point; oil plus liberated solution gas 78

Fig. 3.3 Oil recovery, at 900 psia abandonment pressure (% STOIIP), as a function of the
cumulative GOR, R p (Exercise 3.2) 82

Fig. 3.4 Schematic of the production history of a solution gas drive reservoir 84

Fig. 3.5 Illustrating two ways in which the primary recovery can be enhanced; by downdip
water injection and updip injection of the separated solution gas 85

Fig. 3.6 Typical gas drive reservoir 87

Fig. 3.7 (a) Graphical method of interpretation of the material balance equation to
determine the size of the gascap (Havlena and Odeh) 88

Fig. 3.7 (b) and (c); alternative graphical methods for determining m and N (according to
the technique of Havlena and Odeh) 90

Fig. 3.8 Schematic of the production history of a typical gascap drive reservoir 91

Fig. 3.9 Trial and error method of determining the correct aquifer model (Havlena and
Odeh) 93

Fig. 3.10 Schematic of the production history of an undersaturated oil reservoir under
strong natural water drive 95

Fig. 3.11 (a) Triaxial compaction cell (Teeuw); (b) typical compaction curve 95

Fig. 3.12 Compaction curve illustrating the effect of the geological history of the reservoir
on the value of the in-situ compressibility (after Merle) 97

Fig. 4.1 Schematic of Darcy's experimental equipment 101