Patent ID: 8838399

Claim:
A method for estimating a location of a leak in a pipeline, the method comprising the steps of: A) feeding a liquid of a known density into said pipeline at a first inlet pressure and shutting said pipeline downstream of said leak, such that, once said liquid achieves a substantially steady flow rate, the flow rate of liquid passing into the pipeline can be assumed to be equal to the flow of liquid from the leak; B) when said liquid achieves a substantially steady flow rate at said first pressure, recording the flow rate of the liquid passing into the pipeline; C) repeating steps A and B at a second, different, inlet pressure; and D) calculating, using a computer, an estimate of the leak location and the area of the leak by simultaneously solving a first and a second expression of the leak location relative to the flow rate recorded for each of said first and second inlet pressures, wherein at least one of said first and second expressions is represented by: Q L = C d ⁢ A L ⁢ 2 ⁢ g ⁡ [ P 1 ρ m ⁢ g + ( ρ m - ρ w ρ m ) ⁢ D - λ ⁡ ( x d ) ⁢ ( V 2 2 ⁢ g ) ] where Q L is the flow of liquid through the pipeline measured at the inlet; C d is the coefficient of discharge; A L is the area of the leak; g is gravitational acceleration; P 1 is the pressure at the pipeline inlet; ρ m is the liquid density in pipeline; ρ w is the density of seawater; D is the depth beneath the sea at the leak location; λ is the friction factor along the line; x is the leak location; d is the pipeline diameter; V is the liquid velocity, and wherein said first and second expressions comprise estimating the leak location and the area of the leak based on frictional energy losses of said liquid travelling through the pipeline to the leak location and relating this to the pressure in the pipeline at the leak and the flow rate of liquid from said leak.