# US 8,541,346 B2 · Methods of degrading subterranean filter cakes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,346 B2 - Document ID: US8541346B2 - Status: Granted - Kind: B2 - Application number: 12/786,767 - Filed: 2010-05-25 - Published: 2010-09-16 - Granted: 2013-09-24 - Earliest claimed: 2003-09-17 - Assignees: Halliburton Energy Services, Inc. - Applicants: Bradley L. Todd; Trinidad Munoz, Jr. - Inventors: Bradley L. Todd; Trinidad Munoz, Jr. - Web page: https://patentgrep.com/patent/US8541346B2 ## CPC - C09K 8/5045: {containing inorganic compounds} - C09K 8/03: Specific additives for general use in well-drilling compositions - C09K 8/06: Clay-free compositions (containing inorganic compounds only C09K8/05) - C09K 8/508: macromolecular compounds {(C09K8/512 takes precedence)} - C09K 8/52: Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning - C09K 2208/18: Bridging agents, i.e. particles for temporarily filling the pores of a formation; Graded salts - Y10T 428/2982: Particulate matter [e.g., sphere, flake, etc.] - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention relates to bridging agents for use in subterranean formations, to well drill-in and servicing fluids comprising such bridging agents, and to methods of using such bridging agents and well drill-in and servicing fluids in subterranean drilling operations. An example of a well drill-in and servicing fluid of the present invention comprises a viscosified fluid, a fluid loss control additive, and a bridging agent comprising a degradable material. ## Claims ### Claim 1 A method of degrading a self-degrading filter cake in a subterranean formation, comprising the step of: placing in the subterranean formation a bridging agent comprising a degradable material wherein the degradable material is selected from the group consisting of: anhydrous sodium tetraborate, anhydrous boric acid, a chitin, a chitosan, a protein, an orthoester, an aliphatic polyester, a poly(glycolide), a poly(lactide), a poly(ε-caprolactone), a poly(hydroxybutyrate), a polyanhydride, an aliphatic polycarbonate, a poly(orthoester), a poly(amino acid), a poly(ethylene oxide), a polyphosphazene, and combinations thereof; and, contacting the degradable material with water, releaseable water, or a combination thereof for a period of time such that the degradable material is dissolved thereby; wherein the filter cake was deposited within the subterranean formation by a well drill-in and servicing fluid and wherein at least a portion of the bridging agent is incorporated into the filter cake while the filter cake is deposited. ### Claim 2 (depends on 1) The method of claim 1 wherein the bridging agent further comprises a degrading agent. ### Claim 3 (depends on 1) The method of claim 1 wherein a degrading agent is supplied by the well drill-in and servicing fluid. ### Claim 4 (depends on 1) The method of claim 1 wherein the releaseable water is provided by a water containing compound selected from the group consisting of sodium acetate trihydrate, sodium borate decahydrate, sodium carbonate decahydrate, or a combination thereof. ### Claim 5 (depends on 1) The method of claim 1 wherein the degradable material further comprises a plasticizer. ### Claim 6 (depends on 1) The method of claim 1 wherein the degradable material comprises a stereoisomer of a poly(lactide). ### Claim 7 (depends on 1) The method of claim 1 wherein the degradable material comprises poly(lactic acid) and a compound chosen from the group consisting of sodium borate, boric oxide, calcium carbonate, and magnesium oxide. ### Claim 8 (depends on 7) The method of claim 7 wherein the poly(lactic acid) is present in the degradable material in a stoichiometric amount. ### Claim 9 (depends on 1) The method of claim 1 wherein the degradable material has a particle size distribution in the range of from about 0.1 micron to about 1.0 millimeter. ### Claim 10 (depends on 1) The method of claim 1 wherein the bridging agent comprising the degradable material is present in the well drill-in and servicing fluid in an amount sufficient to create a desirable number of voids in the filter cake. ### Claim 11 (depends on 1) The method of claim 1 wherein the bridging agent comprising the degradable material is present in the well drill-in and servicing fluid in an amount of about 0.1% to about 30% by weight. ### Claim 12 (depends on 1) The method of claim 1 wherein the well drill-in and servicing fluid comprises a viscosified fluid and a fluid loss control additive; wherein the viscosified fluid comprises xanthan in an amount in the range of from about 0.13% to about 0.16% by weight; wherein the fluid loss control additive comprises starch and is present in the well drill-in and servicing fluid in an amount in the range of from about 1% to about 1.3% by weight; wherein the bridging agent comprising the degradable material is present in the well drill-in and servicing fluid in the range of from about 1% to about 5% by weight; and wherein the degradable material comprises poly(lactic acid) and a compound selected from the group consisting of: calcium carbonate, magnesium oxide, and combinations thereof. ### Claim 13 A method of degrading a self-degrading filter cake in a subterranean formation, comprising the step of: placing in the subterranean formation a bridging agent comprising a degradable material wherein the degradable material is selected from the group consisting of: an orthoester, a poly(orthoester), and combinations thereof; and, contacting the degradable material with water, releaseable water, or a combination thereof for a period of time such that the degradable material is dissolved thereby; wherein the filter cake was deposited within the subterranean formation by a well drill-in and servicing fluid and wherein at least a portion of the bridging agent is incorporated into the filter cake while the filter cake is deposited. ### Claim 14 (depends on 13) The method of claim 13 wherein the bridging agent further comprises a degrading agent. ### Claim 15 (depends on 13) The method of claim 13 wherein the degradable material further comprises a plasticizer. ### Claim 16 (depends on 13) The method of claim 13 wherein the degradable material further comprises a compound chosen from the group consisting of: sodium borate, boric oxide, calcium carbonate, magnesium oxide, and combinations thereof. ### Claim 17 (depends on 13) The method of claim 13 wherein the degradable material has a particle size distribution in the range of from about 0.1 micron to about 1.0 millimeter. ### Claim 18 (depends on 13) The method of claim 13 wherein the bridging agent comprising the degradable material is present in the well drill-in and servicing fluid in an amount of about 0.1% to about 30% by weight. ### Claim 19 (depends on 13) The method of claim 13 wherein the well drill-in and servicing fluid comprises a viscosified fluid and a fluid loss control additive; wherein the viscosified fluid comprises xanthan in an amount in the range of from about 0.13% to about 0.16% by weight; wherein the fluid loss control additive comprises starch and is present in the well drill-in and servicing fluid in an amount in the range of from about 1% to about 1.3% by weight; wherein the bridging agent comprising the degradable material is present in the well drill-in and servicing fluid in the range of from about 1% to about 5% by weight; and wherein the degradable material further comprises a compound selected from the group consisting of: calcium carbonate, magnesium oxide, and combinations thereof.