RU2016349C1 - Pre-repair procedures for main pipeline - Google Patents

Abstract

FIELD: repair of pipelines. SUBSTANCE: faulty section is shut off on both ends. Part of liquid of pumped out of faulty section to adjacent serviceable section. Pumping-out is made at closest lower points of pipeline route located on either side of repair site. Discharge of liquid being pumped out is determined from equation given in description of invention. EFFECT: facilitated procedure. 2 dwg

Description

 The invention relates to the main transport of liquids, mainly gas-saturated oils, unstable gas condensate, and can be used in the repair of the pipeline.

 A known method of preparing the main pipeline for repair, including closing the faulty section above the damage and moving the fluid from the faulty section to the next serviceable one, while draining the liquid into the tank at a lower section of the pipeline for temporary storage [1].

 The disadvantage of this method is that in order to displace the liquid from the faulty section, it is necessary to install aeration taps and an external source of compressed air or inert gas, however, the introduction of an additional amount of gas leads to depressurization of the pipeline, degassing of the gas-saturated liquid, its gravitational separation and, as a result, pressure increase on the repaired area.

 All these measures reduce the safety of subsequent repair and fire works, lead to significant losses of gas transported with oil.

 There is a method of preparing a main pipeline for repair, including overlapping a faulty section of the pipeline from two sides, moving fluid from the faulty section to an adjacent serviceable section using a pump and pumping the liquid from the pipeline into a tank or temporary storage barn [2].

 The disadvantage of this method is that after partial emptying of the pipeline from gas-saturated oil, its gravitational separation occurs, increasing pressure and reducing the safety of subsequent welding and installation and firing works. In addition, the pump-free discharge of a gas-saturated liquid into a container or barn for temporary faceting leads to significant losses of oil gas.

 The purpose of the invention is the exclusion of pressure increase during gravitational separation of partially degassed gas-saturated oil, ensuring the safety of subsequent welding and installation and firing operations, reducing oil gas losses.

(sinα_i)^0,57(1-γ)², где V_∞ - скорость всплытия одиночного газового пузырька в бесконечном объеме жидкости;
γ - истинное газосодержание нефти;
Ω - площадь сечения трубы;
α _i - угол наклона i-го участка трубопровода;
n - число восходящих и нисходящих участков в ремонтируемой секции.This goal is also achieved by the fact that according to the method, which includes shutting down the faulty section from two sides, pumping part of the liquid from the pipeline using pumps of oil pumping stations to the tank farm and at the same time moving the liquid from the faulty section to an adjacent operational one from the nearest lower points of the pipeline route, located on both sides of the repair site, using a connected pump and pump-free discharge of the degassed liquid into a container for temporary storage, at ohm flow rate of the pumped liquid is determined by the formula q≥ 0.57 · V

(sinα _i ) ^0.57 (1-γ) ² , where V _∞ is the ascent velocity of a single gas bubble in an infinite volume of liquid;
γ is the true gas content of oil;
Ω is the cross-sectional area of the pipe;
α _i - the angle of inclination of the i-th section of the pipeline;
n is the number of ascending and descending sections in the repaired section.

 The method and procedure for emptying the emergency section of the main pipeline to prepare for repair avoids increasing the pressure in the repaired section due to gravitational separation of the gas-saturated liquid. This allows you to increase the safety of subsequent welding and installation and firing work, to reduce the loss of oil gas and to reduce the volume of fluid discharged into a temporary tank.

 In FIG. 1 shows a schematic diagram of a trunk pipeline for implementing the method of preparation for repair; in FIG. 2 - element of the emergency section of the pipeline with linear sectioning valves.

 The scheme contains pumping stations 1 with reservoir parks 2, a main pipeline 3, linear shutoff (sectioning) valves 4, bypass lines 5 with valves at stations 1, connecting the pressure and discharge lines to reservoir parks 2, discharge lines 6 connected in adjacent to the place repair of reduced sections of pipeline 3 using a connected pump 7, a discharge line 8 with a valve for emptying the emergency section into a container (earthen barn) 9 for temporary storage of the transported product during the repair period sec ii conduit and the peeling pipe 10 with valve for pumping product from the container 9 into the conduit 3 after the repair.

 Emptying and preparation for repair of the emergency section of the main pipeline is as follows.

 Close the linear stop valves 4, sectioning the main pipeline 3 from two sides in the area requiring emptying and repair, to the discharge lines 6 located at the nearest lower points of the pipeline route on both sides of the repair place, connect the pump 7, which connects the repair section with a working pipeline 3, at the same time using the main pumps of the pumping stations 1, a part of the liquid is pumped out from a working pipeline 3 to the tank farm 2 through bypass lines 5. As a result of pumping the liquid, we Wasp 7 from the emptied area partially degasses the gas-saturated liquid in the area being prepared for repair, which is discharged via discharge line 8 into a container 9 in an amount sufficient to release the damaged area.

 The liquid poured into the container (or barn) 9 after preparing the pipeline for repair using the stripping pipe 10 and the connected pump 7 is pumped into a serviceable section of the main pipeline 3.

 The exclusion of pressure increase during gravitational separation of a gas-saturated liquid at the site of repair work can improve their safety and significantly reduce the loss of oil gas.

Claims (1)

METHOD FOR PREPARING A MAIN PIPELINE FOR REPAIR, including blocking the faulty section from two sides, pumping part of the fluid from the faulty section to an adjacent serviceable one using a connected pump, characterized in that the fluid is pumped out at the nearest lower points of the pipeline route located on both sides of the repair and the flow rate of the pumped liquid is determined by the formula
q≥ 0.57V

(sinα _l ) ^1,57 · (1-γ) ² ,
× (1 - γ) ² ,
where v _∞ is the ascent rate of a single gas bubble in an infinite volume of liquid;
γ is the true gas content of oil;
Ω is the cross-sectional area of the pipe;
α _i - the angle of inclination of the i-th section of the pipeline;
n is the number of ascending and descending sections in the repaired section.

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