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AssigneeSchlumberger Technology Corporation
InventorsWendy Kneissl, Yan Kuhn De Chizelle
Estimating the term…
There is a method of determining properties relating to an underbalanced well, comprising inducing pressure variations in a fluid within a well, measuring the pressure variations, and calculating pore pressure of at least one fluid-producing formation. The pressure variations cause a change in flow rate from formations along a length of borehole, and as such a change in the production flow rate of the well. The variations in pressure are used to calculate the pore pressure. Variations in annular bottomhole pressure are induced by altering the flow rate of drilling fluid, or the density of drilling fluid or by acoustic pulsing downhole. The pore pressure, permeability and porosity of the formations is derived as a real time profile along the length of the borehole.
A method of calculating properties relating to a subterranean formation, comprising the steps of:
A method according to any of the preceding claims, wherein variations in pressure in the borehole are induced by altering the flow rate of drilling fluid.
A method according to any of the preceding claims, wherein data reflecting the measured pressures are communicated to the surface using mud-pulse telemetry.
A method according to any of the preceding claims, wherein the step of calculating comprises using a first relationship between the first flow rate and the first pressure, a second relationship between the second flow rate and the second pressure, and solving the first and second relationships to obtain a value for the property.
A method according to any of the preceding claims, further comprising obtaining a profile of formation properties along the length of a borehole.
A method according to any of the preceding claims, wherein the step of drilling is not interrupted during the measurement steps.
A system for calculating properties relating to a subterranean formation, comprising:
A method substantially as herein described with reference to, and as illustrated in, the accompanying drawings.
Dependencies are inferred from the claim text.