Patent ID: 6240787
Filing Date: 2001-06-05
Classification: E21B,G01F

Abstract:
A method of determining the rate of fluid flow into the wellbore of a well from a fluid-bearing reservoir, the wellbore forming a gas volume between a wellhead and the reservoir, there being a pressure differential between within and without the wellbore, and the wellhead having a port for fluid communication with the wellbore, the method comprising:(a) blocking the port to prevent fluid flow therethrough and measuring pressure and change in pressure in the wellbore adjacent the wellhead over time;(b) opening the port and measuring the flow of fluid therethrough, and measuring pressure and change in pressure in the wellbore over time, the duration of gas flow being insufficient to affect the reservoir;(c) determining the original gas volume and an original rate of gas flow in the wellbore as a function of the change of pressure and gas volume assuming all of the fluid inflow from the reservoir is gas and the original gas volume remains constant throughout steps (a) and (b);(d) flowing gas from the open port for a prolonged duration, while measuring the gas flow and measuring the pressure and the change in pressure in the wellbore over time, the duration of gas flow being sufficient to affect the reservoir;(e) determining the total rate of fluid inflow to the wellbore from the reservoir as a function of the change in pressure in the wellbore, the rate of flow through the port, and the original gas volume assuming the original gas volume remains constant throughout step (d); and(f) determining the incremental inflow rate of fluid from the reservoir as the difference between the total rate of fluid inflow less the original rate of gas flow.