The invention relates to a high pressure separator or trap for separating sand and asphaltene from a high pressure stream of oil.
Much of the hydrocarbon reserves in Venezuela and other locations have a relatively large content of asphaltene which, if not addressed, can cause significant issues with respect to plugging of flow lines and equipment, inefficient flow properties and the like.
Various approaches are known for treating the crude oil, once it is produced, at facilities for removing or converting the asphaltene. Problems remain, however, with respect to flow of the produced crude oil from the well head to the facility for treatment and removal of asphaltenes.
It is therefore to be appreciated that an improvement in handling of sand and asphaltene in produced hydrocarbon streams is desirable.
In accordance with the present invention, a high pressure trap and separator is provided which allows for separation of sand and asphaltene from a stream of hydrocarbons at a very high pressure, for example, immediately after being produced from the well and prior to feeding to other surface flow equipment such as the shock box, which is a device for optimizing the flow of production flow in wells, and for optimizing the differential pressure to have less production of sand. This allows for efficient separation and removal of sand and asphaltene before the produced hydrocarbon is transported to facilities for further processing.
In accordance with the present invention, a high pressure trap for separating sand and asphaltene from a high pressure stream of oil is therefore provided, which comprises a vessel having a longitudinal axis arranged substantially vertically; an oil inlet for introducing a high pressure stream of oil with entrained sand and asphaltene into the vessel; an impact plate in the vessel and arranged at the inlet so that the high pressure stream of oil impacts the plate such that the entrained sand and asphaltene separate from the stream and collect in a bottom portion of the vessel; and a chemical inlet at the bottom portion for introducing chemicals to contact separated sand and asphaltene in the bottom portion to facilitate removal of the separated sand and apshaltene from the vessel.
In further accordance with the invention, a method for separating sand and asphaltene from a high pressure stream of oil is also provided, which comprises the steps of feeding a high pressure stream of oil to a high pressure trap for separating said sand and asphaltene entrained in the high pressure stream wherein the trap comprises a vessel having a longitudinal axis arranged substantially vertically; an oil inlet for introducing a high pressure stream of oil with entrained sand and asphaltene into the vessel; an impact plate in the vessel and arranged at the inlet so that the high pressure stream of oil impacts the plate such that the entrained sand and asphaltene separate from the stream and collect in a bottom portion of the vessel; and a chemical inlet at the bottom portion for introducing chemicals to contact separated sand and asphaltene in the bottom portion to facilitate removal of the separated sand and apshaltene from the vessel; whereby oil substantially free of entrained sand and asphaltene exits an oil outlet of the trap; injecting chemicals through the chemical inlet to treat asphaltenes collected in the bottom of the vessel; and removing sand and treated asphaltene from the bottom of the vessel.
Other objects, advantages and features will appear hereinbelow.
A detailed prescription of preferred embodiments follows, with reference to the attached drawings, wherein:
The invention relates to a high pressure trap for separating sand and asphaltene from a high pressure stream of oil.
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These materials can form agglomerates, and would otherwise plug any type of transportation or processing facility to which the stream of oil is transferred. In accordance with the present invention, oil from oil inlet 14 impacts plate 28 such that sand and asphaltene separate from the flow and collect in the lower end 22 of vessel 12 while oil which is now substantially free of these entrained materials passes around impact plate 28 and eventually exits vessel 12 through outlet 16.
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Base 20 should be sized sufficiently to provide stability for trap 10, taking into account the weight of fluids and forces to be exerted on plate 28, in accordance with the invention.
The chemical to be injected into outlet 24 during chemical injection is a dispersant of asphaltenes. The dispersant can be a solution of one or more surfactants, dissolved in a solvent such as a hydrocarbonate of aromatic character. The solvent promotes the dissolution of the asphaltene already precipitated through physico-chemical mechanisms of dispersing agents, and there is preferably no transformation of asphaltenes on-site, only removal of asphaltenes, followed by the disposal through any mechanism that may be desired.
Vessel 12 may preferably be designed to withstand internal pressures of at least about 5,000 psi and a typical high pressure stream of oil may be fed to vessel 12 at a pressure of between about 1500 and about 5200 psi, for example, about 3,200 psi, which is the pressure of a well where the apparatus of the invention may typically be used.
It should be appreciated that trap 10 according to the invention can advantageously be used by passing a produced stream of hydrocarbons with entrained asphaltenes and other undesirable particulates through the trap. The lower portion of the trap can either be continuously treated with asphaltene solvent to remove same from the vessel, or the lower portion can be monitored to determine when it is appropriate to remove accumulated materials from the vessel, at which time the lower portion of the vessel can be periodically treated with chemicals such as asphaltene solvent for removal of same.
It is to be understood that the invention is not limited to the illustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modification of form, size, arrangement of parts and details of operation. The invention rather is intended to encompass all such modifications which are within its spirit and scope as defined by the claims.