Type Curves of a Vertical Well Completed Within a Pair of Inclined Sealing Faults

Abstract

AbstractType curves come in handy when our pressure buildup and pressure drawdown analysis do not yield a straight line hence generating a master curve for wells completed within a pair of sealing faults. The type curves from an observed data is superimposed on the master curve to estimate reservoir system properties. A sealing fault creates image wells, which communicate with each other and the object well. As a result, object well performance can be affected by reservoir boundaries, and positioning of a well therefore must be strategic to ensure oil production for a long time. This is because pressure drop across the producing well is the addition of the pressure drop of the object well and the several image wells created because of the inclination. This is the principle of superposition. The inclination of a sealing fault influences the number of image wells, n, with the model n = (360/θ) -1. With different angles of inclination of the sealing faults, polygons are constructed to determine the distances between the object well and corresponding image wells.In this paper, both dimensionless pressure and dimensionless pressure derivatives type curves as functions of number of image wells, are produced assuming that a vertical well is completed within a pair sealing faults. Wellbore storage and skin effects are considered. The results provide distances for several angles of inclination. Object well design, image well distances and faults angle affect dimensionless pressure and dimensionless pressure derivative. Dimensionless pressure and dimensionless pressure derivative of 2.3026(n+1) per cycle and 0.5(n+1), respectively are observed.Generating dimensionless pressure derivative curves helps the engineer to identify the point where the hump expires and where the straight-line analysis begins. That is the right point for well test analysis.