Patent ID: 8225870

Claim:
A method for making gravel filters in oil wells having a casing coaxially mounted within a well bore and defining a space between said bore and said casing that is cemented to keep said casing in place, comprising the steps of: A) ascertaining a location, at the cemented casing in an oil well bore, adjacent to a producing formation where a gravel filter is to be built; B) cutting a portion of said casing adjacent to said producing formation; C) enlarging said bore's diameter where said portion was cut to create an enlarged annular space by removing the cemented space adjacent to said portion and beyond the bore's initial diameter; D) lowering and installing a producing tube having a distal end with an intake screen and being coaxially disposed within said casing and positioning said intake screen substantially adjacent to said casing portion which was removed; E) depositing an effective amount of gravel through said enlarged annular space and said gravel being delivered from above said screen at a first predetermined distance from said portion and exteriorly thereof between said screen and said casing, and the largest diameter of said gravel being limited by the separation between said casing and said screen; and F) locating sealing unit in said space between said screen and said casing at a second predetermined distance above said portion and below said first predetermined distance and said sealing unit being set after said gravel is deposited so that said sealing unit seals said annular space between said screen and said casing.