Insulating fluid and methods for preparing and insulating concentric piping

Abstract

The present inventions include an insulating fluid comprising a non-particulate viscosifying polymer, a water or brine, a cross-linking agent, and insulating particulates. The insulating fluid may be produced by performing the following steps in any order: adding a non-particulate viscosifying polymer to a brine, adding a cross-linking agent, adding insulating particulates, and optionally adding a solvent. The insulating fluid may be injected into an annulus surrounding a pipe such as production tubing, casing, surface pipelines, subsea pipelines, or risers.

1 . A method for insulating a length of pipe within an annulus, comprising injecting into the annulus an insulating fluid,
 wherein the insulating fluid comprises a non-particulate viscosifying polymer, a water or brine, a cross-linking agent, and insulating particulates.   
   
   
       2 . The insulating fluid of  claim 1  wherein the insulating particulates are selected from the group consisting of microspheres, glass beads, and fibers. 
   
   
       3 . The method of  claim 1  wherein the pipe is production tubing, casing, surface pipelines, subsea pipelines, or risers. 
   
   
       4 . The insulating fluid of  claim 1  wherein the cross-linking agent is selected from the group of consisting of borate, zirconium, titanium and organic complexed metals. 
   
   
       5 . The method of  claim 1  wherein the insulating fluid further comprises a solvent. 
   
   
       6 . The insulating fluid of  claim 5  wherein the solvent is an ether. 
   
   
       7 . The insulating fluid of  claim 6  wherein the ether is selected from the group consisting of ethylene glycol ethers, propylene glycol ethers, and polyols. 
   
   
       8 . The insulating fluid of  claim 1  wherein the non-particulate viscosifying polymer is selected from the group consisting of cellulose, xanthan, starch, guar gum and a derivatives thereof. 
   
   
       9 . The insulating fluid of  claim 8  wherein the a non-particulate viscosifying polymer is selected from the group consisting of hydroxyl propryl guar, carboxymethyl hydroxypropyl, and carboxymethyl-cellulose. 
   
   
       10 . The insulating fluid of  claim 1  wherein the cross-linking agent is present in a quantity of 0.01% to 5% by weight. 
   
   
       11 . The insulating fluid of  claim 1  wherein the non-particulate viscosifying polymer is present in a quantity of 0.1% to 5% by weight. 
   
   
       12 . The insulating fluid of  claim 1  wherein the insulating particulates are present in a quantity of 0.1% to 30% by weight.