Reservoir Descriptions Via Pulse Testing: A Technology Evaluation

ABSTRACT Implementation of pulse testing technology as a tool to obtain reservoir descriptions has been limited to only certain types of reservoir heterogeneities. An integrated approach to evaluate pulse testing as a means of obtaining reservoir descriptions for multilayer heterogeneous reservoirs is presented in this paper. A method is developed to simulate pulse tests using a gridded model. Pulse test responses in multilayer heterogeneous reservoirs are investigated for unequal layer pressures, vertical layer heterogeneities, and wellbore storage effects both at the active and observation wells. The integrated approach is applied to a pulse test pilot completed in a San Andres reservoir. The usefulness of pulse testing is found to be highly reservoir specific. Pulse test data alone are not sufficient to derive reservoir descriptions for multilayer heterogeneous reservoirs and must be used in conjunction with geological, petrophysical, and single well pressure transient data. Pulse testing may not provide an adequate definition of vertical layer heterogeneities for tertiary miscible gas performance predictions and can be used only to refine the definition of high speed layers which control gas cycling in a tertiary miscible gas process. The pulse test derived reservoir description may be adequate for waterflooding predictions under certain situations. For primary depletion predictions, single well pressure transient data are sufficient when coupled with geological and petrophysical data. The integrated approach to evaluate pulse testing is recommended before actually conducting pulse tests in the field.