Syntactic foam pressure housing
Systems and methods for forming and using a pressure housing to protect a downhole tool in a wellbore include machining an initial syntactic foam body into a pressure housing structure and post-curing the pressure housing structure in a programmable oven at a time-temperature program to produce a post-cured syntactic foam structure. Methods for protecting a downhole tool in a wellbore include containing the downhole tool in a post-cured syntactic foam structure, placing the structure in the wellbore and using the downhole tool contained in the post-cured syntactic foam structure in the wellbore, floating the post-cured syntactic foam structure containing the downhole to a surface location, and retrieving the post-cured syntactic foam structure containing the downhole tool. Systems for protecting a downhole tool in a wellbore include a post-cured syntactic foam structure positioned in the wellbore and a downhole tool pressure sealed within the post-cured syntactic foam structure.
1 . A method, comprising:
machining an initial syntactic foam body made of syntactic foam into an initial pressure housing structure; and
post-curing the initial pressure housing structure in a programmable oven at a time-temperature program to produce a post-cured syntactic foam structure in a form of a pressure housing, wherein the time-temperature program comprises the following steps:
heating the initial pressure housing structure in the programmable oven to a first temperature of about 30° C.;
holding at the first temperature for about 90 min;
heating for about 30 min to a second temperature of about 50° C.;
holding at the second temperature for about 150 min;
heating for about 60 min to a third temperature of about 95° C.;
holding at the third temperature for about 150 min;
cooling for about 180 min to a fourth temperature of about 25° C.; and
holding at the fourth temperature for about 10 min.
2 . The method of claim 1 , wherein the syntactic foam comprises:
a polymerized resin; and
a lightweighting additive.
3 . The method of claim 2 , wherein the syntactic foam further comprises at least one additional additive.
4 . The method of claim 3 , wherein the at least one additional additive comprises a catalyst.
5 . The method of claim 1 , wherein the time-temperature program includes heating the initial pressure housing structure to a maximum temperature of about 25° C. to about 35° C. below a rated temperature of the post-cured syntactic foam structure at a pressure of 5000 psi.
6 . The method of claim 1 , wherein the time-temperature program is a stepped heating schedule comprising a selected number of heat/hold steps, wherein each heat/hold step comprises:
a temperature increase, heating to a temperature over a ramp duration; and
a hold duration following the temperature increase, where the temperature is held for the hold duration.
7 . The method of claim 6 , wherein the ramp duration for at least two of the heat/hold steps is equal.
8 . The method of claim 6 , wherein the hold duration for at least two of the heat/hold steps is different.
9 . The method of claim 1 , wherein the time-temperature program comprises a step of heating the initial syntactic foam body at a maximum temperature for at least 150 min.
10 . The method of claim 1 , wherein the post-cured syntactic foam structure has a density of about 0.2 g/cc to about 0.8 g/cc.
11 . The method of claim 1 , wherein the post-cured syntactic foam structure has a rated temperature of at least 125° C. at a pressure of 5000 psi.
12 . A method, comprising:
machining an initial syntactic foam body made of syntactic foam into an initial pressure housing structure; and
post-curing the initial pressure housing structure in a programmable oven at a time-temperature program to produce a post-cured syntactic foam structure in a form of a pressure housing,
wherein the time-temperature program comprises heating the initial pressure housing structure in the programmable oven to a temperature of about 95° C. and then holding the initial pressure housing structure at about 95° C. for about 390 min.
13 . The method of claim 12 , further comprising:
enclosing a downhole tool in the pressure housing;
placing the pressure housing containing the downhole tool in a well;
using the downhole tool contained in the pressure housing in the well;
floating the pressure housing containing the downhole tool to a surface location; and
retrieving the pressure housing containing the downhole tool.
14 . The method of claim 1 , further comprising:
enclosing a downhole tool in the pressure housing;
placing the pressure housing containing the downhole tool in a well;
using the downhole tool contained in the pressure housing in the well;
floating the pressure housing containing the downhole tool to a surface location; and
retrieving the pressure housing containing the downhole tool.