The aim of this work is to examine the well bore pressure behavior in reservoirs with single phase non-Darcy flow conditions produced at a constant sandface rate. The transient flow period is analyzed by means of results generated with a finite difference model. Analytical expressions of pressure drop and its semilog-arithmic slope are presented for the first time. These equations contain the laminar flow solution as a particular case and they provide means to evaluate the total skin factor. Another use of the analytical solution to the non-Darcy flow problem is to be able of identifying the presence of inertial effects by using a diagnostic plot which consists of graphing the derivative of the pressure data. versus the inverse of the square root of time on a cartesian paper. In this way, an analyst can easily predict the magnitude of the skin due to non-laminar flow under any condition of mechanical skin and rate. Furthermore, better stimulation jobs can be designed if non-Darcy flow conditions during a transient test are properly identified through the methodology presented in this study. The use of the methodology obtained in this work is illustrated with synthetic examples for homogeneous and naturally fractured reservoirs. Also, a field example of an undersaturated reservoir and a dry gas case (taken from the literature) show the application of this technique. For the case of naturally fractured reservoirs new insights are provided.

New analytical solutions for the response at a well intercepting a layered reservoir are derived. The well is assumed to produce at a constant rate or a constant pressure. We examine reservoir systems without interlayer communication and document the usefulness of these solutions, which enable us to obtain increased physical understanding of the performance of fractured wells in layered reservoirs. The influence of vertical variations in fracture conductivity is also considered. Example" applications of the approximations derived here are also presented.

The response of fractured wells producing noncommunicating layered reservoirs is the focus of this work. The conductivity of the fracture is assumed to be finite. The fracture length is assumed to vary from layer to layer. Two modes of production-constant wellbore pressure and constant rate-are considered.In the first part, the fractures are assumed to communicate only at the wellbore. The results given in this section are intended to provide engineers with analytical capabilities to examine responses in wells where the layers that have been stimulated are separated by considerable distances. Procedures to interpret the results of pressure buildup and/or production tests (draw down responses) in terms of layer properties are presented. Criteria to ensure maximum productivity are specified. The second part examines well responses when the fractures are in communication at points other than the wellbore. All other things being identical, we show that communication between fractures increases productivity.

A constant discharge Q was used in the simulation ran. For each time the radi• distance was varied in the definition of the dimensionless time factor u, which is related to the Boltzmann variable. We readily obse•e that a co,elation

The aim of this work is to examine the wellbore pressure behavior in reservoirs with single-phase non-Darcy flow conditions produced at a constant sandface rate. The transient flow period is analyzed by means of results generated with a finite difference model. Analytical expressions of pressure drop and its semilogarithmic slope are presented for the first time. These equations contain the laminar flow solution as a particular case, and they provide means to evaluate the total skin factor. Another use of the analytical solution to the non-Darcy flow problem is to identify the presence of inertial effects by using a diagnostic plot, which consists of graphing the derivative of the pressure data vs. the inverse of the square root of time on a Cartesian paper. In this way, an analyst easily can predict the magnitude of the skin owing to nonlaminar flow under any condition of mechanical skin and rate. Furthermore, better stimulation jobs can be designed if non-Darcy flow conditions during a transient test are properly identified through the methodology presented in this study.The use of the methodology obtained in this work is illustrated with synthetic examples for homogeneous and naturally fractured reservoirs. Also, a field example of an undersaturated reservoir and a dry gas case (taken from the literature) shows the application of this technique. For the case of naturally fractured reservoirs, new insights are provided.