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k=permeability, and µ,,=viscosity of the historic waste plume at reservoir conditions, cp ct=total system compressibility, psi' • The time should be plotted on both the log-log and semilog plots to see if this time corresponds to any changes in the derivative curve or semilog pressure plot. If the time estimated to exit the waste front occurs before the start of radial flow,the assumption that the pressure transients were propagating through the reservoir fluid during the radial flow period was correct. Therefore,the viscosity of the reservoir fluid is the appropriate viscosity to use in analyzing the well test. If not,the viscosity of the historic waste plume should be used in the calculations. If the mobility ratio is extreme between the wastestream and formation fluid, adequate information should be included in the report to verify the appropriate fluid viscosity was utilized in the analysis. Reservoir Thickness • The thickness used for determination of the permeability should be justified by the operator. The net thickness of the defined injection interval is not always appropriate. • The permeability value is necessary for plume modeling, but the transmissibility value, kh/µ, can be used to calculate the pressure buildup in the reservoir without specifying values for each parameter value of k, h, and µ. • Selecting an interval thickness is dependent on several factors such as whether or not the injection interval is composed of hydraulically isolated units or a single massive unit and wellbore conditions such as the depth to wellbore fill. When hydraulically isolated sands are present, it may be helpful to define the amount of injection entering each interval by conducting a flow profile survey. Temperature logs can also be reviewed to evaluate the intervals receiving fluid. Cross-sections may provide a quick look at the continuity of the injection interval around the injection well. • A copy of a SP/Gamma Ray well log over the injection interval,the depth to any fill, and the log and interpretation of available flow profile surveys run should be submitted with the falloff test to verify the reservoir thickness value assumed for the permeability calculation. Use of Computer Software • To analyze falloff tests, operators are encouraged to use well testing software. Most software has type curve matching capabilities. This feature allows the simulation of the entire falloff test results to the acquired pressure data. This type of analysis is particularly useful in the recognition of boundaries, or unusual reservoir characteristics, such as dual porosity. It should be noted that type curve matching is not considered a substitute, but is a compliment to the analysis. • All data should be submitted on a CD-ROM with a label stating the name of the facility, the well number(s), and the date of the test(s). The label or READ.Me file should include A-14