文档介绍：Performance Methods(储量预测方法英文课件)
Performance Reserves Estimation Methods
Rate versus time.
Log of percent oil cut versus cumulative oil production.
Percent water cut versus cumulative oil production.
Oil rate versus cumulative oil production.
Log of water-oil-ratio (WOR) versus cumulative oil production.
Decline Curve Analysis (DCA)
Basis Assumptions:
Past performance data are sufficient to establish a trend with reasonable certainty.
The operational practices will continue in the same manner in the future.
There is an established economic limit.
Economic Limits
Rate.
Abandonment pressure.
Maximum % water cut.
Minimum % oil cut.
WOR – water oil ratio.
Given:
% – WC 96%.
Corresponding.
% OC 4%.
WOR = 96/4 = 24.
Economic Limits –(cont’d)
Three types of rate-time monly accepted in the industry
Exponential
Hyperbolic
Harmonic
Exponential decline, the nominal (instantaneous) decline rate is constant and takes the form:
Where d = nominal decline rate
q1 = initial producing rate
q2 = producing rate at time 2
t = period between rate q2 and qi
a. Hyperbolic decline has the form:
The term n is the curvature or shape factor and is constant with time.
b. Harmonic decline is a special type of hyperbolic where:
n = 1
Exponential Decline
Time
Oil Rate
Hyperbolic Decline
Time
Oil Rate