Ultra High Viscosity Pill and Methods for Use with An Oil-Based Drilling System

Abstract

A fluid pressure transmission pill (FPTP) having an ultra-high viscosity for use in association with hydrocarbon drilling and exploration operations, particularly, managed pressure drilling (MPD) operations, is described. The ultra-high viscosity pill is a weighted pill composition that includes a hydrocarbon fluid, a thixotropic viscosifying agent, one or more activators, an emulsifier/wetting agent, a fluid loss control additive, and a weighting material. In accordance with selected aspects of the described fluid pressure transmission pill, the ratio of the amount of the thixotropic viscosifying agent to the activator is a ratio of about 7:1, and the weighting material is a barium-containing solid-phase material. Also described are methods of use of such FPTP products in subterranean operations, such as well killing operations during managed pressure drilling.

1 . A fluid pressure transmission pill (FPTP) for use in a managed pressure drilling (MPD) operation, the pill comprising:
 a fluid phase;   a thixotropic viscosifying agent;   an activator; and   a weighting material.   
     
     
         2 . The fluid pressure transmission pill (FPTP) of  claim 1 , wherein the fluid phase is an oleaginous fluid selected from the group consisting of diesel oil, mineral oil, synthetic oil such as polyolefins or isomerized polyolefins, ester oils, glycerides of fatty acids, aliphatic esters, aliphatic ethers, aliphatic acetals, and combinations thereof. 
     
     
         3 . The fluid pressure transmission pill of  claim 2 , wherein the fluid phase is a mineral oil. 
     
     
         4 . The fluid pressure transmission pill of  claim 3 , wherein the mineral oil is a low aromatic content mineral oil. 
     
     
         5 . The fluid pressure transmission pill of  claim 1 , wherein the thixotropic viscosifying agent is an organophilic clay. 
     
     
         6 . The fluid pressure transmission pill of  claim 5 , wherein the organophilic clay is present in an amount ranging from about 6 lb/bbl to about 16 lb/bbl. 
     
     
         7 . The fluid pressure transmission pill of  claim 1 , wherein the activator is a polar activator. 
     
     
         8 . The fluid pressure transmission pill of  claim 7 , wherein the activator is propylene carbonate. 
     
     
         9 . The fluid pressure transmission pill of  claim 1 , wherein the weighting material is a solid-phase material selected from the group consisting of anglesite, barite, calcite, celestite, crocoite, hematite, ilmenite, or combinations thereof. 
     
     
         10 . The fluid pressure transmission pill of  claim 9 , wherein the solid-phase material is barium sulfate or a barium-containing mineral having a weight average particle size diameter between about 5 μm and about 75 μm. 
     
     
         11 . The fluid pressure transmission pill of  claim 1 , wherein the pill has a mud weight ranging from about 7 lb/gal to about 20 lb/gal. 
     
     
         12 . An ultra-high viscosity pill for use in managed pressure drilling (MPD) operations, the pill comprising:
 a mineral oil;   an organophilic clay;   an activator;   an emulsifier and/or a wetting agent;   a fluid loss control additive; and   a weighting material.   
     
     
         13 . The ultra-high viscosity pill of  claim 12 , wherein the mineral oil is a low aromatic content mineral oil. 
     
     
         14 . The ultra-high viscosity pill of  claim 12 , wherein the organophilic clay is selected from the group consisting of bentonite, hectorite, montmorillonite, biedellite, saponite, and stevensite. 
     
     
         15 . The ultra-high viscosity pill of  claim 12 , wherein the organophilic clay is present in an amount ranging from about 6 lb/bbl to about 16 lb/bbl. 
     
     
         16 . The ultra-high viscosity pill of  claim 12 , wherein the organophilic clay has been treated with one or more oil-wetting agents. 
     
     
         17 . The ultra-high viscosity pill of  claim 16 , wherein the oil-wetting agent is a quaternary amine having from 6 to 20 carbon atoms. 
     
     
         18 . The ultra-high viscosity pill of  claim 12 , wherein the activator is selected from the group consisting of sodium silicate, sodium fluoride, sodium silicofluoride, magnesium silicofluoride, zinc silicofluoride, calcium carbonate, sodium carbonate, potassium carbonate, alkyl carbonates, calcium hydroxide, sodium hydroxide, potassium hydroxide, sodium sulfate, polar, aprotic compounds, and mixtures thereof. 
     
     
         19 . The ultra-high viscosity pill of  claim 18 , wherein the activator is present in an amount ranging from about 0.1 wt. % to about 30 wt. %, based on the total weight of the organophilic clay. 
     
     
         20 . The ultra-high viscosity pill of  claim 18 , wherein the activator is propylene carbonate, present in an amount relative to the organophilic clay in a ratio ranging from about 1:5 to about 1:10. 
     
     
         21 . The ultra-high viscosity pill of  claim 12 , wherein the emulsifier is a nitrogen-containing compound. 
     
     
         22 . The ultra-high viscosity pill of  claim 12 , wherein the fluid loss control additive is a styrene-butadiene rubber copolymer. 
     
     
         23 . The ultra-high viscosity pill of  claim 12 , wherein the weighting material is a barium-containing material. 
     
     
         24 . The ultra-high viscosity pill of  claim 23 , wherein the barium-containing material is barium sulfate. 
     
     
         25 . The ultra-high viscosity pill of  claim 12 , wherein the weighting material is a solid-phase material selected from the group consisting of anglesite, barite, calcite, celestite, crocoite, hematite, ilmenite, or combinations thereof. 
     
     
         26 . The ultra-high viscosity pill of  claim 25 , wherein the solid-phase weighting material is barite. 
     
     
         27 . A method of drilling a subterranean well using a fluid pressure transmission pill in conjunction with an oil-based drilling fluid, the method comprising:
 providing a fluid phase pressure transmission pill comprising:
 a fluid phase; 
 a thixotropic viscosifying agent; 
 an emulsifier and/or a wetting agent; 
 a fluid loss control additive; and 
 a weighting agent; and 
   using the oil-based drilling fluid to drill a well bore in a subterranean formation.   
     
     
         28 . The method of  claim 27 , wherein the fluid phase further comprises a brine solution. 
     
     
         29 . The method of  claim 27 , wherein the fluid phase has a mud weight ranging from about 7 lb/gal to about 20 lb/gal. 
     
     
         30 . The method of  claim 27 , wherein the composition further comprises an activator. 
     
     
         31 . The method of  claim 30 , wherein the activator is selected from the group consisting of sodium silicate, sodium fluoride, sodium silicofluoride, magnesium silicofluoride, zinc silicofluoride, calcium carbonate, sodium carbonate, potassium carbonate, alkyl carbonates, calcium hydroxide, sodium hydroxide, potassium hydroxide, sodium sulfate, polar, aprotic compounds, and mixtures thereof. 
     
     
         32 . The method of  claim 31 , wherein the activator is propylene carbonate. 
     
     
         33 . The method of  claim 27 , wherein the weighting agent is a material selected from the group consisting of anglesite, barite, calcite, celestite, crocoite, hematite, ilmenite, or combinations thereof. 
     
     
         34 . The method of  claim 33 , wherein the weighting agent is barite.