An apparatus for generating and storing in a tank 22 a flowable slush 2 of frozen particles usable inter alia in Ice Pigging™ includes a control system 100 which is arranged to monitor an operating parameter OP of an agitator 23 in the storage tank. The control system initiates a slush comminution and separation or dewatering cycle when a control parameter CP based on the operating parameter OP reaches a threshold value CPt. The control parameter may represent a cumulative energy input to the storage tank 22. Comminution may be performed prior to separation, with the treatment cycle being terminated when a sensed rheometric parameter RP of the slush circulating in the treatment flowpath reaches a target value RPt.

A method of removing trapped hydrocarbons from pipework, the pipework comprising a through pipe (1) extending from an inlet to an outlet, and at least one up-pipe (2a, 2b) extending upwardly from the through pipe. The method comprises: flushing the through pipe with a water-based liquid (6) which has a density less than hydrocarbons; wherein the water-based liquid comprises a plurality of rigid containers, such as microspheres, the rigid containers each having a sealed void containing a gas. in this way, hydrocarbons in the up-pipes may be removed without hot-tapping them. The flushing may be performed by directing pipeline pigs (5a, 5b) in front of and behind the water-based liquid. The pigs may be a cross-linked gel, based pipeline pig with elastomeric properties. A kit of parts for such a method is also disclosed.

A method of removing trapped hydrocarbons from pipework, the pipework comprising a through pipe (1) extending from an inlet to an outlet, and at least one up-pipe (2a, 2b) extending upwardly from the through pipe. The method comprises: flushing the through pipe with a water-based liquid (6) which has a density less than hydrocarbons; wherein the water-based liquid comprises a plurality of rigid containers, such as microspheres, the rigid containers each having a sealed void containing a gas. in this way, hydrocarbons in the up-pipes may be removed without hot-tapping them. The flushing may be performed by directing pipeline pigs (5a, 5b) in front of and behind the water-based liquid. The pigs may be a cross-linked gel, based pipeline pig with elastomeric properties. A kit of parts for such a method is also disclosed.

A hydrophobic separating plug is used to separate and inhibit mixing between a first material and a second material. The plug may be formed of a hydrophobic material or may be formed of a plurality of pigs that are a solid or semi-solid material that may be hydrophobic or may have a hydrophobic or superhydrophobic surface. The plurality of pigs may be disposed within a hydrophobic fluid and the pigs may be neutrally buoyant in the hydrophobic fluid. The hydrophobic separating plug has dimensions sufficient to substantially fill the cross-section of pipe sections in which it is located and to define a leading edge and a trailing edge such that the leading edge is in contact with a first material and the trailing edge is in contact with a second material. Advantageously, mixing between the first material and the second material is inhibited by the plug.

A hydrophobic separating plug is used to separate and inhibit mixing between a first material and a second material. The plug may be formed of a hydrophobic material or may be formed of a plurality of pigs that are a solid or semi-solid material that may be hydrophobic or may have a hydrophobic or superhydrophobic surface. The plurality of pigs may be disposed within a hydrophobic fluid and the pigs may be neutrally buoyant in the hydrophobic fluid. The hydrophobic separating plug has dimensions sufficient to substantially fill the cross-section of pipe sections in which it is located and to define a leading edge and a trailing edge such that the leading edge is in contact with a first material and the trailing edge is in contact with a second material. Advantageously, mixing between the first material and the second material is inhibited by the plug.

The present invention relates to a new use of foaming products for the production of a compact foam pig, by means of the forced interaction of gas, water and product, capable of moving huge quantities of water accumulated in the gas production pipelines. The water removal takes place in very quick periods of time and allows an important decrease in the pressure drops with consequent quick increase in the produced gas quantities.

Method of purging and subsequently verifying a liquid-carrying conduit includes the steps of: providing a hydrogel comprising additive(s) selected from the group comprising: chloride ions, sulphate ions, nitrate ions fluorescein dye, carmine dye and cation salts; transporting the hydrogel along at least a portion of an offline liquid-carrying conduit to thereby purge the conduit; substantially or completely removing the hydrogel from the offline liquid-carrying conduit; flushing the offline liquid-carrying conduit with a volume of flushing water; and verifying removal of the hydrogel from the offline liquid-carrying conduit by checking the flushed water for detectable traces of the additive. The flushing step is repeated as often as necessary until the additive cannot be detected. The method may be employed to purge different types of liquid-carrying conduits, e.g. conduits for transporting potable water; conduits for transporting sewage; and oil pipelines.

An apparatus for generating and storing in a tank 22 a flowable slush 2 of frozen particles usable inter alia in ice pigging comprises a control system 100 which is arranged to monitor an operating parameter OP of an agitator 23 in the storage tank. The control system initiates a slush comminution and separation or dewatering cycle when a control parameter CP based on the operating parameter OP reaches a threshold value CPt. The control parameter may represent a cumulative energy input to the storage tank 22. Comminution may be performed prior to separation, with the treatment cycle being terminated when a sensed rheometric parameter RP of the slush circulating in the treatment flowpath reaches a target value RPt.

A polymer pipeline pig is provided for cleaning the interior of a pipeline capable of completely dissolving in a fluid including oil, water and/or gas over a time period of from 4 days to 24 days and over a temperature range of from 100 F. to 250 F. The polymer is selected from polylactic acid, polyglycolic acid, poly(lactic-co-glycolic acid) and combinations thereof The pipeline pig can be launched into the interior of the pipeline, allowed to move through the interior of the pipeline in a fluid including oil and water, and dissolved over a time period of from 4 days to 24 days and over a temperature range of from 100 F. to 250 F. Thus, no pig receiving facility is needed.

A method for detecting leaks in pipelines, particularly those transporting natural gas is disclosed. Leak sensitive particles are added either as soluble particles or in a nitrogen atmosphere which will transmit signals to an appropriate sensor when a leak condition is detected. The sensors can be located along the length of the pipeline or in a pig that will be transported through the pipeline along with the leak sensitive particles.