Method of determining vertical permeability of a subsurface earth formation
First Claim
1. A method of determining vertical permeability of a subsurface earth formation comprising the steps of:
- perforating a production casing for an initial area less than a thickness of the subsurface earth formation;
measuring reservoir fluid flow and pressure through the initial area perforation in said production casing;
perforating said production casing for a production interval having an area greater than said initial area;
measuring reservoir fluid flow and pressure through the perforated production interval;
establishing a value corresponding to horizontal permeability from the measured reservoir fluid flow through the perforated production interval;
simulating pressure profiles using values of vertical permeability in combination with the established value of horizontal permeability; and
determining the simulated pressure profile which generally corresponds to a measured pressure profile from said initial area perforation.
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Abstract
A method of determining vertical permeability of a subsurface earth formation having the steps of perforating a production casing for an initial area less than a thickness of the subsurface earth formation, measuring reservoir fluid flow and pressure through the initial area perforation, perforating the production casing for a production interval of an area greater than the initial area perforation, measuring reservoir fluid flow and pressure through the perforated production interval, establishing a value corresponding to horizontal permeability from the measured reservoir fluid flow and pressure through the perforated production interval, simulating pressure profiles using values of vertical permeability in combination with the established value of horizontal permeability, and determining the simulated pressure profile which generally corresponds to a measured pressure profile from the initial area perforation. The method further includes the step of cementing through the perforated initial area to an exterior of the production casing so as to inhibit vertical fluid communication and reperforating the perforated initial area so as to allow reservoir fluid flow to enter the production casing.
25 Citations
18 Claims
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1. A method of determining vertical permeability of a subsurface earth formation comprising the steps of:
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perforating a production casing for an initial area less than a thickness of the subsurface earth formation; measuring reservoir fluid flow and pressure through the initial area perforation in said production casing; perforating said production casing for a production interval having an area greater than said initial area; measuring reservoir fluid flow and pressure through the perforated production interval; establishing a value corresponding to horizontal permeability from the measured reservoir fluid flow through the perforated production interval; simulating pressure profiles using values of vertical permeability in combination with the established value of horizontal permeability; and determining the simulated pressure profile which generally corresponds to a measured pressure profile from said initial area perforation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A process for determining vertical permeability of a subsurface earth formation comprising the steps of:
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perforating a production casing in an initial area within the subsurface earth formation; cementing through the perforated initial area to an exterior of said production casing so as to inhibit vertical fluid communication behind said production casing; reperforating the perforated initial area so as to allow reservoir fluid to enter said production casing from said subsurface earth formation; measuring reservoir fluid flow and pressure through the reperforated initial area into the production casing; perforating said production area for a production interval having an area greater than said initial area; measuring reservoir fluid flow and pressure through the perforated production interval; deriving a horizontal permeability value from the measured reservoir fluid flow and pressure through the perforated production interval; and simulating values of vertical permeability so as to create pressure profiles corresponding to a measured pressure profile from the reperforated initial area. - View Dependent Claims (13, 14, 15, 16)
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17. A process for determining vertical permeability of a subsurface earth formation comprising the steps of:
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perforating a production casing in an initial area positioned within the subsurface earth formation, said initial area being less than a thickness of the subsurface earth formation; measuring reservoir fluid flow and pressure through the initial area perforation in the production casing; perforating said production casing for a production interval having an area greater than the initial area perforation and generally corresponding to the thickness of the subsurface earth formation; measuring reservoir fluid flow and pressure through the perforated production interval; establishing a value corresponding to horizontal permeability from the measured reservoir fluid flow and pressure through the perforated production interval; simulating pressure profiles for the initial area perforation utilizing the established value of horizontal permeability and a plurality of vertical permeability values; and selecting the vertical permeability value from the pressure profile which corresponds most closely to a measured pressure profile from the initial area perforation. - View Dependent Claims (18)
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Specification