# US 11,078,401 B2 · Rare earth oxide as a weighting and bridging agent > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,078,401 B2 - Document ID: US11078401B2 - Status: Granted - Kind: B2 - Application number: 16/467,346 - Filed: 2018-07-19 - Published: 2021-05-27 - Granted: 2021-08-03 - Earliest claimed: 2018-07-19 - Assignees: Halliburton Energy Services, Inc. - Applicants: Halliburton Energy Services, Inc. - Inventors: Sandeep Chavan - Web page: https://patentgrep.com/patent/US11078401B2 ## CPC - C09K 8/504: Compositions based on water or polar solvents (C09K8/502 takes precedence) - C09K 8/5045: {containing inorganic compounds} - E21B 21/003: {Means for stopping loss of drilling fluid (plastering the borehole wall E21B33/138)} - E21B 33/138: Plastering the borehole wall; Injecting into the formation - E21B 37/00: Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence) - E21B 37/08: cleaning in situ of down-hole filters, screens, {e.g. casing perforations,} or gravel packs (E21B37/06 takes precedence) - C09K 2208/18: Bridging agents, i.e. particles for temporarily filling the pores of a formation; Graded salts - E21B 21/065: {Separating solids from drilling fluids} - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract Methods of treating a subterranean formation and treatment fluids are discussed herein. The methods generally include treating the subterranean formation with a rare earth oxide by providing a first treatment fluid having a density of at least about 10 pounds per gallon including a rare earth oxide; and introducing the first treatment fluid into the subterranean formation. ## Claims ### Claim 1 A method of treating a subterranean formation, comprising: providing a first treatment fluid having a density of at least about 10 pounds per gallon (ppg) comprising samarium oxide; introducing the first treatment fluid into the subterranean formation; allowing the first treatment fluid to deposit a filter cake on the subterranean formation; introducing an acid or acid precursor into the subterranean formation; and allowing the acid or an acid generated from the acid precursor to dissolve the filter cake. ### Claim 2 (depends on 1) The method of claim 1, further comprising re-using the samarium oxide in a second treatment fluid. ### Claim 3 (depends on 2) The method of claim 2, wherein re-using the samarium oxide comprises: precipitating dissolved samarium in the acid-dissolved filter cake; separating the precipitated samarium from the acid-dissolved filter cake; and calcining the separated samarium to yield recycled samarium oxide. ### Claim 4 (depends on 3) The method of claim 3, further comprising mixing the recycled samarium oxide with a second treatment fluid. ### Claim 5 (depends on 1) The method of claim 1, wherein the samarium oxide is present in the first treatment fluid in an amount in a range of from about 1% to about 70% by weight of the first treatment fluid. ### Claim 6 (depends on 5) The method of claim 5, wherein the samarium oxide is present in the first treatment fluid in an amount in a range of from about 5% to about 70% by weight of the first treatment fluid. ### Claim 7 (depends on 1) The method of claim 1, wherein the density of the first treatment fluid is in a point in a range of from about 10 ppg to about 35 ppg. ### Claim 8 (depends on 7) The method of claim 7, wherein the density of the first treatment fluid is about 10 ppg. ### Claim 9 (depends on 7) The method of claim 7, wherein the density of the first treatment fluid is in a point in a range of from about 20 ppg to about 25 ppg. ### Claim 10 (depends on 1) The method of claim 1, wherein the first treatment fluid further comprises a weighting and bridging agent. ### Claim 11 A method of preventing fluid loss in a subterranean formation, comprising: providing a first treatment fluid having a density of at least about 10 pounds per gallon (ppg) comprising samarium oxide; introducing the first treatment fluid to a first location of the subterranean formation; allowing the first treatment fluid to form a filter cake to prevent fluid loss from the first location to a second location of the subterranean formation; introducing hydrochloric acid or nitric acid into the subterranean formation; and allowing the hydrochloric acid or nitric acid to dissolve the filter cake. ### Claim 12 (depends on 11) The method of claim 11, further comprising re-using the samarium oxide in a second treatment fluid. ### Claim 13 (depends on 12) The method of claim 12, wherein re-using the samarium oxide comprises: precipitating dissolved samarium in the acid-dissolved filter cake with a hydroxide or an oxalate; separating the precipitated samarium from the acid-dissolved filter cake; and calcining the separated samarium to yield recycled samarium oxide. ### Claim 14 (depends on 13) The method of claim 13, further comprising mixing the recycled samarium oxide with a second treatment fluid. ### Claim 15 (depends on 11) The method of claim 11, wherein the samarium oxide is present in the first treatment fluid in an amount in a range of from about 1% to about 70% by weight of the first treatment fluid. ### Claim 16 (depends on 15) The method of claim 15, wherein the samarium oxide is present in the first treatment fluid in an amount in a range of from about 5% to about 70% by weight of the first treatment fluid. ### Claim 17 (depends on 11) The method of claim 11, wherein the density of the first treatment fluid is in a point in a range of from about 10 ppg to about 35 ppg. ### Claim 18 (depends on 17) The method of claim 17, wherein the density of the first treatment fluid is about 10 ppg. ### Claim 19 (depends on 17) The method of claim 17, wherein the density of the first treatment fluid is in a point in a range of from about 20 ppg to about 25 ppg. ### Claim 20 (depends on 11) The method of claim 11, wherein the first treatment fluid further comprises a weighting and bridging agent.