Competing Against 3D With Energy Mapping and Related Well Testing Issues

Abstract A Shockwave Front Exists Coincident with the Traditional Radius of Investigation = 2 (η*t)1/2. It Becomes the Boundary Condition for the Cone of Influence During the Transient Phase. The Capillary Forces that Give Rise to the Shockwave also Constrain Flow through Radial Capillary Pathways that Have Finite Strength. The Combination of Radial Pathways and the Shockwave Boundary Condition Produce Discrete Responses at the Well Bore that are the Result of First and Second Law Requirements for Joule Thomson Hydraulic Power Dissipation through Heat Generation. To reduce the capillary model to the traditional diffusion potential model one only has to declare that all initiating pressures have broken down. A theory or physical model is only as good as its performance. Experiment is the traditional approach to test a model. Every well test should be treated as an experiment. Blind testing compared with a standard is the traditional path to advancing technology. This requires a model to be run against geologic maps and geophysical images. In the case of a reservoir model, it must be judged against geology and a track record established. Introduction The outermost or Primary Capillary Shockwave propagates in a manner that is coincident with the traditional radius of investigation. This paper is confined to a description of the Primary Capillary Shockwave that is the basis for a more complete transient model developed byWAVEXSM, Inc. to describe the expansion of the cone of influence as it initiates flow through porous media. As the capillary shockwave encounters an order of magnitude decrease in fluid mobility, the cone of influence responds within the constraints of the system of capillaries of which it is composed. Normally, a choke is used at the well head to maintain constant flow rate. The loss of growth at a sealing boundary results in the formation of a secondary cone of influence bounded by its own Secondary Capillary Shockwave discontinuity boundary. OBSERVATION OF A CONE OF INFLUENCE A unique experimental opportunity presented itself about ten years ago to observe the growth of a cone of influence from the vantage point of the well bore of the producing well and two offset wells at 2000 ft. and 4000 ft. distance. The following data plot depicts the pressure response in the static observation well at a distance of 2000 ft. The producing well was completed in a 500 Md. sandstone and flowing dry gas at 17 Mmscfd. The time scale originates at the same time that the producing well was opened to flow. The observation well was not affected by the offset producing well for the first 28 hours of flow. The double image plot is due to a thermistor cycling between temperature outputs by.1 degree Fahrenheit. The pressure response begins, not asymptotically as we expect from traditional diffusion theory assumptions, but as a step pressure drop followed by a small half sine wave dynamic. There were a number of pressure step discontinuities followed by abrupt changes in the semi log slope.