METHOD OF ELIMINATING PARAFFIN-CRYSTAL HYDRATE PLUG IN WELLS Russian patent published in 2001 - IPC

FIELD: oil producing industry. SUBSTANCE: method includes performance of electric insulating work in well provided with casing, tubing, sucker-rod pump, sucker-rod string with polished rod and X-mass tree. Metal electrical connections between polished rod and pumping unit, polished rod and X-mass tree in stuffing box, X-mass tree and flow line, well and grounding circuit are broken. Electric power is applied to polished rod and picked off from surface ground conductor. Used for elimination of paraffin-crystal hydrate plug is two-electrode conductive coupling. Electrodes are used in the form of electrically insulated well and near located grounding device in the form, for instance, neighboring well. Paraffin-crystal hydrate plug is eliminated by intervals. First, freed from plug is heated part of sucker-rod string which is unscrewed and lifted from well. Then lowered into well is auxiliary sucker-rod string with electrically insulated external surface whose rods are solid or hollow with left-hand thread with electrical resistance lower than that of stuck sucker-rod string, for instance, from aluminum-copper-magnesium alloy. Sucker-rod string is equipped with dielectric centralizers. Auxiliary sucker-rod string is connected with stuck sucker-rod string. Combined polished rod is installed in the form of dielectric, current-conducting contact and current-conducting insulated surfaces. Applied to polished rod is electric power. Prior to supply of electric power, electric insulating works are additionally performed on two neighboring wells of well cluster. Insulating works are similar to those performed on the first well. Electric power is supplied, first, to all electrically insulated wells of cluster. In this case, conductive coupling is used in the form of three-electrode conductive coupling supplied from three-phase mains. After retrieval of heated part of sucker-rod string, dielectric fluid is injected into tubing. Further interval-by-interval elimination of paraffin-crystal hydrate plug is carried out separately on each well with use of two-electrode conductive coupling with power supply from single-phase mains. Dielectric fluid is used as a commercial oil. EFFECT: higher efficiency and reduced time for elimination of paraffin-crystal hydrate plugs on well cluster. 2 cl, 3 dwg