ABSTRACT
At present for conducting an interference well test a constant fl ow rate (at the “active” well) is utilized and the type-curve matching technique (where only values of several pressure drops are matched) is used to estimate the porosity-total compressibility product and formation permeability. For oil and geothermal reservoirs with low formation permeability the duration of the test may require a long period of time and it can be diffi cult to maintain a constant fl ow rate. In this study we present working equations which will allow processing fi eld data when the fl ow rate at the “active” well is a function of time (Kutasov et al. 2008). The shut-in period is also considered. As was mentioned in Chapter 7 the drawdown and buildup pressure well tests are used to determine the formation permeability and to estimate to what degree (expressed through skin factor) the drilling and production operations altered the permeability of formations near the wellbore. To process the fi eld data the formation porosity-total compressibility product should be known. These parameters cannot be determined from a pressure or fl ow test in a singular well. Only from interference tests (multiplewell tests) the necessary parameters can be estimated.
