Method of gravel-packing a high-pressure well

Claim 2

Method oF gravel-packing a well that penetrates a highpressure formation, wherein said well contains weighted drilling mud to control said high pressure, and wherein said well has a tubing string suspended within a casing, which comprises: positioning a screen and washpipe with valve means for permitting only downward flow from said tubing through said washpipe and for controlling reverse flow upward into said tubing only near the lower end of said washpipe inside said screen adjacent to said formation, displacing said mud from said well adjacent to said formation while holding enough pressure to contain said high-pressure formation by circulating a wash fluid down said tubing string, and placing gravel to pack said well opposite said formation by reversing said wash fluid circulation to flow said gravel down the well annulus while continuing to hold said containment pressure, whereby an uncontaminated gravel pack of a high-pressure formation is obtained.

Claim 3

Method according to claim 1, which also comprises: squeezing said gravel into said formation by stopping said reverse circulation at the top of said tubing string after said gravel is in place and applying a predetermined squeeze pressure.

Claim 4

Method according to claim 2, which also comprises: producing said well through said tubing string after said gravel-packing has been squeezed into the formation.

Claim 5

Method according to claim 3, which also comprises: disengaging said washpipe from said screen to continue producing the well after the formation pressure has declined.

Claim 6

Method according to claim 1, which also comprises: producing said well through said tubing string after said gravel-packing is completed.

Claim 7

Method according to claim 5, which also comprises: disengaging said washpipe from said screen to continue producing the well after the formation pressure has declined.

Claim 8

Method of producing a well having formation pressure higher than that which can be controlled with unweighted fluid, said well having been completed with a casing head and a casing valve connection, comprising: making up an assembly of a slotted liner and washpipe therethrough with a washdown shoe at the bottom having a back-pressure check valve therein, said assembly also having a washpipe port and valve means near the lower end of said washpipe inside of said liner, running said assembly into said well at the bottom of a device until said assembly is opposite the producing formation, flanging said tubing up to said casing head, installing a christmas tree for controlling fluid flow in said tubing, displacing the drilling mud by pumping clear fluid down through said tubing while holding back-pressure at said casing valve connection to maintain control at said formation, reversing said clear fluid flow while holding back-pressure at said christmas tree and flowing gravel down said casing to place a gravel pack outside of said liner while said clear fluid returns through said washpipe valve means and up said tubing, squeezing said gravel pack by closing said christmas tree valve and increasing the pressure on said clear fluid, removing said squeeze pressure and producing said well through said gravel pack with said casing valve closed, and disengaging washpipe and tubing from said assembly and continuing to produce through said tubing after the formation pressure has declined to a safe level.

Claim 9

Method of producing a well having formation pressure higher than that which can be controlled with unweighted fluid, said well having been completed with a casing head and a casing valve connection, comprising: making up an assembly of a slotted liner and washpipe therethrough with a washdown shoe at the bottom having a back-pressure check valve therein, said assembly also having a washpipe port and valve means near the lower end of said washpipe inside of said liner, running said assembly into said well at the bottom of a device until said assembly is opposite the producing formation, flanging said tubing up to said casing head, installing a christmas tree for controlling fluid flow in said tubing, displacing the drilling mud by pumping clear fluid down through said tubing while holding back-pressure at said casing valve connection to maintain control at said formation, reversing said clear fluid flow while holding back-pressure at said christmas tree and flowing gravel down said casing to place a gravel pack outside of said liner while said clear fluid returns through said washpipe valve means and up said tubing, squeezing said gravel pack by closing said christmas tree valve and increasing the pressure on said clear fluid, removing said squeeze pressure and producing said well through said gravel pack with said casing valve closed, and disengaging washpipe and tubing from said assembly and continuing to produce through said tubing after the formation pressure has declined to a safe level.