Method and apparatus for gravel packing wells

Claim 2

In a method of gravel packing a perforated liner opposite a subterranean formation in a well wherein a carrier liquid having gravel suspended therein is flowed downwardly along the outside of said liner to deposit said gravel around said liner, the improvement comprising: restricting the flow of said carrier liquid into said liner so as to maintain the minimum flow velocity of said carrier liquid along the outside of said liner that is necessary to prevent the premature settling of said gravel and the formation of gravel dunes near the upper portions of said liner.

Claim 3

The method as recited in claim 1 wherein said well is inclined.

Claim 6

The method as recited in claim 3 wherein said well is inclined.

Claim 7

The method as recited in claim 3 wherein said sealant is a fusible, heat-sensitive material with a melting point below the normal temperature of said formation where said liner is placed and wherein said sealant is removed by melting said sealant with formation heat.

Claim 8

The method as recited in claim 5 wherein said fusible material is wax.

Claim 9

The method as recited in claim 5 wherein said fusible material is a thermoplastic resin.

Claim 10

The method as recited in claim 5 wherein said fusible material is a low melting point alloy.

Claim 11

The method as recited in claim 3 wherein said sealant is a fusible, heat-sensitive material and wherein said sealant is removed by melting said sealant with a hot fluid injected into said liner.

Claim 12

The method as recited in claim 9 wherein said hot fluid is steam.

Claim 13

The method as recited in claim 9 wherein said fusible material is wax.

Claim 14

The method as recited in claim 9 wherein said fusible material is a thermoplastic resin.

Claim 15

The method as recited in claim 9 wherein said fusible material is a low melting point alloy.

Claim 16

The method as recited in claim 3 wherein said sealant is a dissolvable material and wherein said sealant is removed by extracting said sealant with a solvent.

Claim 17

The method as recited in claim 3 wherein said sealant is a decomposable material and wherein said sealant is removed by decomposing said sealant with a corrosive chemical.

Claim 18

The method as recited in claim 3 wherein the partial sealing of said liner reduces the total flow area by at least about 60 percent.

Claim 19

The method as recited in claim 16 wherein the flow area reduction is between about 67 and 83 percent.

Claim 20

In a method of gravel packing a perforated liner opposite a subterranean formation in a well wherein a carrier liquid having gravel suspended therein is flowed downwardly along the outside of said liner, said gravel being deposited around said liner, and said carrier liquid is then flowed through the perforations of said liner and upwardly through a return tube which extends substantially through the entire length of said liner, the improvement wherein said liner is provided with a plurality of temporary seals longitudinally spaced therealong to reduce the total flow area of said liner perforations and to thereby maintain sufficient flow velocity of said carrier liquid along the outside of said liner so that the premature settling of said gravel and the formation of gravel dunes near the upper portions of said liner is prevented, said temporary seal being fusible at the normal subsurface temperature of said formation.

Claim 21

In a method of gravel packing a perforated liner opposite a subterranean formation in a well wherein a carrier liquid having gravel suspended therein is flowed downwardly along the outside of said liner, said gravel being deposited around said liner, and said carrier liquid is then flowed through the perforations of said liner and upwardly through a return tube which extends substantially through the entire length of said liner, the improvement wherein said liner is provided with a plurality of temporary seals longitudinally spaced therealong to reduce the total flow area of said liner perforations and to thereby maintain sufficient flow velocity of said carrier liquid along the outside of said liner so that the premature settling of said gravel and the formation of gravel dunes near the upper portions of said liner is prevented, said temporary seal being fusible at the normal subsurface temperature of said formation.

Claim 22

Apparatus for gravel packing wells comprising: a perforated liner; and a removable sealant placed on or in said liner to partially seal said liner, said liner having unsealed perforations substantially throughout its entire length, said sealant being located to selectively seal perforations distributed along said liner to reduce the total flow area of said perforations by at least about 60 percent and to restrict the flow of fluids into said liner.

Claim 23

Apparatus for gravel packing wells comprising: a perforated liner; and a removable sealant placed on or in said liner to partially seal said liner, said liner having unsealed perforations substantially throughout its entire length, said sealant being located to selectively seal perforations distributed along said liner to reduce the total flow area of said perforations by at least about 60 percent and to restrict the flow of fluids into said liner.

Claim 24

Apparatus as defined in claim 19 wherein said sealant partially seals said liner at longitudinally spaced intervals.

Claim 25

Apparatus as defined in claim 19 wherein said sealant is a fusible, heat-sensitive material.

Claim 26

Apparatus as defined in claim 21 wherein said fusible material is wax.

Claim 27

Apparatus as defined in claim 21 wherein said fusible material is a thermoplastic resin.

Claim 28

Apparatus as defined in claim 21 wherein said fusible material is a low melting point alloy.

Claim 29

Apparatus as defined in claim 19 wherein said sealant is a solvent extactable material.

Claim 30

Apparatus as defined in claim 19 wherein said sealant is chemically decomposable material.

Claim 31

Apparatus as defined in claim 19 wherein between about 67 and 83 percent of said flow area is sealed.

Claim 32

Apparatus as defined in claim 19 wherein said sealant is placed so as to leave unsealed a plurality of narrow bands, said bands being evenly distributed along the length of said liner.

Claim 33

Apparatus for gravel packing wells comprising: a perforated liner; a removable sealant, said sealant partially sealing said liner at longitudinally spaced intervals to reduce the total flow area formed by the perforations of said liner so that the flow velocity about the outer periphery of said liner, of a carrier liquid having gravel suspended therein, is sufficiently maintained to prevent said gravel from prematurely settling out and forming gravel dunes near the upper portions of said liner; and a return tube which extends substantially through said liner and which is the return conduit for said carrier liquid.

Claim 34

Apparatus for gravel packing wells comprising: a perforated liner; a removable sealant, said sealant partially sealing said liner at longitudinally spaced intervals to reduce the total flow area formed by the perforations of said liner so that the flow velocity about the outer periphery of said liner, of a carrier liquid having gravel suspended therein, is sufficiently maintained to prevent said gravel from prematurely settling out and forming gravel dunes near the upper portions of said liner; and a return tube which extends substantially through said liner and which is the return conduit for said carrier liquid.