ESTIMATING WELL DELIVERABILITY BY CALCULATING CHANGES IN DELIVERABILITY EXPONENT IN THE SIMPLIFIED ANALYSIS EQUATION

• Main Author: Lubis, Tabrani
• Format: Theses
• Language: Indonesia
• Subjects: Pertambangan dan operasi berkaitan
• Online Access: https://digilib.itb.ac.id/gdl/view/86782
• Institution: Institut Teknologi Bandung

An earlier known well deliverability test was the back pressure test popularized by Rawlins and Schellhardt (1935). When the flow rate (qg) and pressure difference (Pr2-Pwf2) data are plotted on a logarithmic scale, the general form of the simplified analysis equation is obtained. C (deliverability coefficient) is the intercept while n (deliverability exponent) is the inverse slope of the graph. To minimize the testing time of the back pressure test, which is considered quite long for low permeability (tight gas) reservoirs, other test methods have been introduced such as the isochronal test, modified isochronal test and optimized isochronal test. These three tests also use simplified analysis equation to calculate absolute open flow value. Although all methods use C values that change over time, determining the value of n for each method is quite different. The back pressure test and optimized isochronal test assume a constant n value, the isochronal test uses the initial n value of the test, while the modified isochronal uses the average value of n tests. Seeing these differences, the research will try to observe changes in the n value from transient conditions to pseudo pseudo-steady state conditions so that it can produce more accurate absolute open flow value.