Method to determine frictional pressure losses from fluid flow through wells, pipes, and perforations from analysis of water hammer
View Patent ↗A method for determining flowing fluid pressure loss in a well includes moving fluid through a well pipe and perforations in a well pipe at a first rate. A pressure of the fluid moving at the first rate is measured. The rate of moving fluid is changed to a second rate. The rate is changed so as to induce tube waves in the well. Pressure of the fluid moving at the second rate is measured. The measured pressures are used to determine frictional fluid pressure loss in the well pipe and frictional and fluid pressure loss through the perforations. The measured pressures and determined frictional fluid pressure losses are used to determine a fluid pressure outside the perforations.
1 . A method for determining flowing fluid pressure loss in a pipe, comprising:
moving fluid through the pipe at a first rate;
measuring a pressure of the fluid moving at the first rate;
changing the rate of moving fluid to a second rate, the rate changed so as to induce tube waves in the pipe;
measuring pressure of the fluid flowing at the second rate; and
using the measured pressure flowing at the first rate and at the second rate to determine frictional fluid pressure loss in the pipe, wherein the determining fluid pressure loss in the pipe comprises determining a pipe friction factor based on pressure change with respect to time after the changing flow rate and prior to a reflected tube wave reaching a position of the measuring pressure.
2 . The method of claim 1 wherein the changing rate comprises decreasing the flow rate.
3 . The method of claim 1 wherein the determining pipe friction factor comprises initializing a value of the friction factor, modeling the pressure change with respect to time based on the pipe friction factor, comparing the modeled pressure change to the measured pressure change, and adjusting the pipe friction factor and repeating the modeling until a difference between the modeled pressure change and the measured pressure change falls below a selected threshold.
4 . The method of claim 1 , further comprising using the measured pressure flowing at the first rate and at the second rate to determine frictional fluid pressure loss in fluid flowing through perforations in the pipe; and using the measured pressures and the determined frictional fluid pressure losses to determine a fluid pressure outside the perforations.
5 . The method of claim 4 wherein the determining frictional fluid pressure loss in the perforations comprises determining a friction coefficient of the perforations.
6 . The method of claim 5 wherein the determining the friction coefficient of the perforations comprises initializing a value of the friction coefficient of the perforations, modeling a pressure with respect to time of a reflected tube wave in the pipe, comparing the measured pressure to the modeled reflected tube wave pressure, adjusting the friction coefficient of the perforations and repeating modeling the reflected tube wave pressure until a difference between the modeled tube wave pressure and a change in measured pressure from the reflected tube wave falls below a selected threshold.
7 . The method of claim 4 wherein the fluid pressure outside of the perforations comprises fluid pressure at a mouth of a fracture in a reservoir formation.
8 . The method of claim 1 wherein the flowing fluid at the first rate and at the second rate comprises pumping a hydraulic fracture treatment.
9 . The method of claim 1 wherein the pipe comprises a well pipe.
10 . A non-transitory computer readable medium having stored thereon a computer program, the computer program having logic operable to cause a programmable computer to perform acts, comprising:
accepting as input to the computer measurements of a pressure in a pipe of fluid moving at a first rate through the pipe;
after changing the rate of moving fluid to a second rate, the rate changed so as to induce tube waves in the pipe, accepting as input to the computer measurements of pressure of the fluid flowing at the second rate;
in the computer, using the measured pressures at the first rate and at the second rate, determining frictional fluid pressure loss in the pipe, wherein the determining fluid pressure loss in the pipe comprises determining a pipe friction factor based on pressure change with respect to time after the changing flow rate and prior to a reflected tube wave reaching a position of the measuring pressure.
11 . The non-transitory computer readable medium of claim 10 , wherein the changing rate comprises decreasing the flow rate.
12 . The non-transitory computer readable medium of claim 10 , wherein the determining pipe friction factor comprises initializing a value of the friction factor, modeling the pressure change with respect to time based on the pipe friction factor, comparing the modeled pressure change to the measured pressure change, and adjusting the pipe friction factor and repeating the modeling until a difference between the modeled pressure change and the measured pressure change falls below a selected threshold.
13 . The non-transitory computer readable medium of claim 10 wherein the flowing fluid at the first rate and at the second rate comprises pumping a hydraulic fracture treatment.
14 . The non-transitory computer-readable medium of claim 10 further comprising logic operable to cause a programmable computer to perform using the measured pressure flowing at the first rate and at the second rate to determine frictional fluid pressure loss in fluid flowing through perforations in the pipe; and using the measured pressures and the determined frictional fluid pressure losses to determine a fluid pressure outside the perforations.
15 . The non-transitory computer readable medium of claim 14 , wherein the determining frictional fluid pressure loss in the perforations comprises determining a friction coefficient of the perforations.
16 . The non-transitory computer readable medium of claim 15 , wherein the determining the friction coefficient of the perforations comprises initializing a value of the friction factor of the perforations, modeling a pressure with respect to time of a reflected tube wave in the pipe, comparing the measured pressure to the modeled reflected tube wave pressure, adjusting the friction coefficient of the perforations and repeating modeling the reflected tube wave pressure until a difference between the modeled tube wave pressure and a change in measured pressure from the reflected tube wave falls below a selected threshold.
17 . The non-transitory computer readable medium of claim 14 wherein the fluid pressure outside of the perforations comprises fluid pressure at a mouth of a fracture in a reservoir formation.
18 . The non-transitory computer readable medium of claim 10 wherein the pipe comprises a well pipe.