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• Linear Flow: <br /> 1. May result from flow in a channel, parallel faults, or a highly conductive fracture <br /> 2. Characterized by a half slope on both the log-log plot pressure and semilog <br /> derivative curves with the derivative curve approximately 1/3 of a log cycle lower <br /> than the pressure curve and a straight line on the square root of time plot. <br /> 3. The log-log plot derivative of the pressure vs square root of time plot is flat <br /> • Hydraulically Fractured Well: <br /> 1. Multiple flow regimes present including wellbore storage, fracture linear flow, <br /> bilinear flow, pseudo-linear flow, formation linear flow, and pseudo-radial flow <br /> 2. Fracture linear flow is usually hidden by wellbore storage <br /> 3. Bilinear flow results from simultaneous linear flows in the fracture and from the <br /> formation into the fracture, occurs in low conductivity fractures, and is <br /> characterized by a quarter slope on both the pressure and semilog derivative <br /> curves on the log-log plot and by a straight line on a pressure versus quarter root <br /> of time plot <br /> 4. Formation linear flow is identified by a half slope on both the pressure and <br /> semilog derivative curves on the log-log plot and by a straight line on a pressure <br /> versus square root of time plot <br /> 5. Psuedo-radial flow is analogous to radial flow in an unfractured well and is <br /> characterized by flattening of semilog derivative curve on the log-log plot and a <br /> straight line on a semilog pressure plot <br /> • Naturally Fractured Rock: <br /> 1. The fracture system will be observed first on the falloff test followed by the total <br /> system consisting of the fractures and matrix. <br /> 2. The falloff analysis is complex. The characteristics of the semilog derivative <br /> trough on the log-log plot indicate the level of communication between the <br /> fractures and the matrix rock. <br /> • Layered Reservoir: <br /> 1. Analysis of a layered system is complex because of the different flow regimes, <br /> skin factors or boundaries that may be present in each layer. <br /> 2. The falloff test objective is to get a total tranmissibility from the whole reservoir <br /> system. <br /> 3. Typically described as commingled (2 intervals with vertical separation) or <br /> crossflow(2 intervals with hydraulic vertical communication) <br /> Semilog Plot <br /> • The semilog plot is a plot of the pressure versus the log of time. There are typically four <br /> different semilog plots used in pressure transient and falloff testing analysis. After <br /> plotting the appropriate semilog plot, a straight line should be drawn through the points <br /> located within the equivalent radial flow portion of the plot identified from the log-log <br /> plot. . <br /> A-8 <br />