Online pigging system and method

Abstract

The disclosure provides a heat transfer system having a tubing coil for heating fluid flowing therein, where the tubing coil can be pigged (descaled) while operationally online, instead of offline. The online system uses an assembly of valves and associated equipment to connect to a pig launcher and pig receiver while the system is online. A valve opens and the pig launches into the flow stream under pressure through the valve and travels along the tube with the fluid. The system continues to produce heated fluid with the pig in the flow path. A pig receiver receives the pig after the pigging, and then is isolated from the flow path of the heated fluid by another valve. The pig launcher, pig receiver, and pig are removed, and this process is repeated for any other passes in the tubing coil.

1 . A heat transfer system, comprising:
 a heat source coupled to a chamber having a tubing coil disposed therein, the heat source adapted to heat at least a portion of a fluid in the tubing coil into a heated fluid by providing heat to the tubing coil, the tubing coil having an inlet and an outlet, the inlet adapted to receive the fluid for flowing through a flow path in the tubing coil and the outlet adapted to allow the heated fluid to exit the tubing coil;   a first inlet connection coupled to the inlet for coupling with a supply line to supply the fluid into the tubing coil;   a second inlet connection coupled to the inlet and fluidicly independent of the first inlet connection;   an inlet valve coupled to the second inlet connection;   a third inlet connection coupled to the inlet valve;   a pig launcher coupled to the third inlet connection, the pig launcher adapted to launch a pig into the tubing coil through the inlet valve;   a first outlet connection coupled to the outlet and adapted to allow the heated fluid to exit therethrough;   a second outlet connection coupled to the outlet and fluidicly independent of the first outlet connection;   an outlet valve coupled to the second outlet connection;   a third outlet connection coupled to the outlet valve; and   a pig receiver coupled to the third outlet connection, the pig receiver adapted to receive the pig from the tubing coil through the outlet valve.   
     
     
         2 . The system of  claim 1 , wherein the heat transfer system comprises a steam generator, the fluid in the tubing coil comprises feedwater, and the heated fluid comprises steam. 
     
     
         3 . The system of  claims 2 , wherein the steam generator comprises a once-through steam generator, and the heat source comprises a burner. 
     
     
         4 . The system of  claim 2 , wherein the steam generator comprises a once through heat recovery steam generator, and the heat source comprises a gas turbine, a burner, or a combination thereof. 
     
     
         5 . The system of  claim 1 , wherein the fluid comprises feedwater, the heated fluid comprises steam, and further comprising;
 a steam pipeline coupled to the outlet of the tubing coil and disposed in a geologic stratum having hydrocarbons, the steam pipeline having an injection portion with openings to allow the steam to be injected into the geologic stratum;   a collection pipeline disposed in the geologic stratum and having a collection portion with openings to allow heated hydrocarbons from the steam to flow into the collection pipeline; and   a processor adapted to process the heated hydrocarbons after collection.   
     
     
         6 . The system of  claim 1 , wherein one or more of the pig launcher, inlet valve, and second inlet connection and third inlet connection are longitudinally aligned with a longitudinal axis of the tubing coil adjacent the inlet. 
     
     
         7 . The system of  claim 6 , wherein the first inlet connection is nonaligned with the longitudinal axis of the tubing coil adjacent the inlet. 
     
     
         8 . The system of  claim 1 , wherein one or more of the pig receiver, outlet valve, and second outlet connection and third outlet connection are longitudinally aligned with a longitudinal axis of the tubing coil adjacent the outlet. 
     
     
         9 . The system of  claim 8 , wherein the first outlet connection is nonaligned with the longitudinal axis of the tubing coil adjacent the outlet. 
     
     
         10 . The system of  claim 1 , wherein the tubing coil comprises multiple tubing passes, and wherein at least two of the tubing passes each have an inlet and an outlet and an inlet valve coupled to the inlet and an outlet valve coupled to the outlet for coupling each of the at least two tubing passes to the pig launcher and the pig receiver. 
     
     
         11 . A method of pigging a heat transfer system, the system having a heat source coupled to a chamber having a tubing coil disposed therein, the tubing coil having one or more tubing passes, the heat source adapted to heat at least a portion of the fluid in the tubing coil into a heated fluid by providing heat to the tubing coil, the tubing coil having an inlet and an outlet, the inlet adapted to receive the fluid for flowing through a flow path in the tubing coil, and the outlet adapted to allow the heated fluid to exit the tubing coil,
 the heat transfer system further having: a first inlet connection coupled to the inlet for coupling with a supply line to supply the fluid into the tubing coil; an inlet valve coupled to the inlet fluidicly independent of the first inlet connection; a pig launcher coupled to the inlet valve, the pig launcher adapted to launch a pig into the tubing coil through the inlet valve; a first outlet connection coupled to the outlet and adapted to allow the heated fluid to exit therethrough; an outlet valve coupled to the outlet fluidicly independent of the first outlet connection; and a pig receiver coupled to the outlet valve, the pig receiver adapted to receive the pig from the tubing coil through the outlet valve, the method comprising:   maintaining operation of the heat transfer system by continuing to supply fluid through the first inlet connection into the tubing coil;   opening the inlet valve;   launching the pig into a tubing pass of the tubing coil through the inlet valve and into a flow path of the fluid;   descaling tubing surfaces of the tubing pass while continuing to generate the heated fluid in the tubing pass;   opening the outlet valve;   ejecting the pig through the outlet valve into the pig receiver; and   flowing the heated fluid generated upstream and downstream of the pig in the tubing pass through the outlet independent of the outlet valve.   
     
     
         12 . The method of  claim 11 , further comprising closing the inlet valve and the outlet valve and continuing to flow the fluid into the inlet and the heated fluid out of the outlet. 
     
     
         13 . The method of  claim 11 , wherein the tubing coil comprises multiple tubing passes, and wherein at least two of the tubing passes each have an inlet and an outlet and an inlet valve coupled to the inlet and an outlet valve coupled to the outlet, and further comprising removing the pig launcher and the pig receiver from a first tubing pass and assembling the pig launcher and pig receiver to an inlet valve and an outlet valve on a second tubing pass. 
     
     
         14 . The method of  claim 13 , further comprising pigging the second tubing pass while maintaining operation of the second tubing pass. 
     
     
         15 . The method of  claim 11 , wherein the fluid comprises feedwater, the heated fluid comprises steam, and the outlet is coupled to a steam pipeline disposed in a geologic stratum containing hydrocarbons, and further comprising injecting the steam through the steam pipeline into the geologic stratum to heat the hydrocarbons and collecting at least a portion of the heated hydrocarbon into a collection pipeline. 
     
     
         16 . The method of  claim 11 , wherein the pig launcher is longitudinally aligned with a longitudinal axis of the tubing coil adjacent the inlet, and further comprising launching the pig from the pig launcher in alignment with the longitudinal axis of the tubing coil. 
     
     
         17 . The method of  claim 11 , wherein the pig receiver is longitudinally aligned with a longitudinal axis of the tubing coil adjacent the outlet, and further comprising receiving the pig into the pig receiver in alignment with the longitudinal axis of the tubing coil.