Patent ID: 7896080

Claim:
A method of removing fine particulate matter from a well gravel pack, placed in the well in between a tubular casing with perforations adjacent to a producing formation and a tubular screen, comprising the steps of: a) placing a tube in the well bore, the tube extending from a position near the earth's surface to a position just above or next to the gravel pack; b) pumping a solvent pre-flush into the well bore via the tube in sufficient volume to pre-flush the gravel pack, perforations, and a part of the producing formation that is next to the perforations; c) pumping a water based pre-flush into the well bore via the tube in sufficient volume to pre-flush the gravel pack, perforations, and a part of the producing formation that is next to the perforations; d) pumping an acid pre-flush into the well bore via the tube in sufficient volume to pre-flush the gravel pack, perforations, and a part of the producing formation that is next to the perforations; e) pumping an HF acid mixture into the well bore via the tube in sufficient volume to penetrate the gravel pack, perforations, and a part of the producing formation that is next to the perforations; f) pumping an overflush of fresh water treated with ammonium chloride or other clay protecting chemical, a water-wetting surfactant, and a non-emulsifying surfactant into the well bore via the tube in sufficient volume to flush HF acid mixture to a range of 3′ to 6′ into the formation matrix; g) pumping a solvent wash into the well bore via the tube in sufficient volume to fill the porosity of the gravel pack; h) wherein in steps “b” through “g”, injection rates for all fluids pumped into the gravel pack and the formation are a rate sufficiently slow to prevent initiation of a hydraulic fracture; and i) wherein steps “b” through “g” some of the fine particulate matter is dissolved and some of the fine particulate matter is physically dislodged from the gravel pack and carried into the formation.