Quicklook Prestimulation Well Test

Abstract

In this paper, the authors present a technique that allows one to perform a computerized short term oil or natural gas well test. The short duration of the test results in reasonably good estimates of formation permeability, skin factor, and reservoir pressure. The technique, referred to as Quicklook, requires pressure measurement at the surface and downhole. After perforation, the formation is subjected to an instantaneous-rate drawndown or injection for a couple minutes. The instantaneous-rate period is followed by a shut-in period of sufficient duration to achieve the desired radius of investigation. Three interpretation plots are made to perform the analysis: a derivative type plot for flow-regime identification and type-curve analysis, a specialized plot (rate-convolved Horner (RCH) analysis) for certain flow parameter calculations, and a system-verification plot. A desirable feature of the technique is that the testing and perforating can be performed during the same trip. Two field examples from low-permeability wells illustrate the technique and data interpretation.