US 2004O244977A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2004/0244977 A1 Luke et al. (43) Pub. Date: Dec. 9, 2004

(54) FLUID LOSSADDITIVES FOR CEMENT which is a continuation-in-part of application No. SLURRIES 10/727,370, filed on Dec. 4, 2003, which is a con tinuation-in-part of application No. 10/686,098, filed (76) Inventors: Karen Luke, Duncan, OK (US); on Oct. 15, 2003, which is a continuation-in-part of Russell M. Fitzgerald, Wauriha, OK application No. 10/623.443, filed on Jul. 18, 2003, (US); Robert S. Taylor, Calgary (CA); which is a continuation-in-part of application No. Keith A. Rispler, Red Deer (CA); Glen 10/315,415, filed on Dec. 10, 2002. C. Fyten, Red Deer (CA) Publication Classification Correspondence Address: CRAG W. RODDY (51) Int. Cl...... C04B 7/00; CO4B 16/00; HALLIBURTON ENERGY SERVICES C04B 16/02; CO4B 24/00; P.O. BOX 1431 E21B 33/13 DUNCAN, OK 73536-0440 (US) (52) U.S. Cl...... 166/292; 106/813; 106/805 (21) Appl. No.: 10/816,034 (57) ABSTRACT (22) Filed: Apr. 1, 2004 Methods for cementing in a Subterranean Zone, which use a cement composition that includes , cementitious Related U.S. Application Data material, proportioned fluid loSS control additives and a mixing fluid. Cement compositions containing proportioned (63) Continuation-in-part of application No. 10/795,158, fluid loSS control additives, and methods of making cement filed on Mar. 5, 2004, which is a continuation-in-part compositions containing proportioned fluid loSS control of application No. 10/738,199, filed on Dec. 17, 2003, additives. US 2004/0244977 A1 Dec. 9, 2004

FLUID LOSS ADDITIVES FOR CEMENT additives (FLAS), with a mixing fluid. The cement compo SLURRIES Sition is placed in the Subterranean Zone and allowed to Set therein. The base blend used in Such methods includes CROSS-REFERENCE TO RELATED Zeolite and at least one cementitious material, and the APPLICATIONS proportioned FLAS include at least a first fluid loss additive having a first molecular weight and at least one Second fluid 0001. This application is a continuation-in-part of prior loSS additive having a Second molecular weight that is leSS application Ser. No. 10/795,158 filed Mar. 5, 2004, the entire than the first molecular weight. The first fluid loss additive disclosure of which is incorporated herein by reference, will be hereafter referred to as the “high molecular weight which is a continuation-in-part of prior application Ser. No. FLA” and the second fluid loss additive will be hereafter 10/738,199 filed Dec. 17, 2003, the entire disclosure of referred to as the “low molecular weight FLA'. which is incorporated herein by reference, which is a con tinuation-in-part of prior application Ser. No. 10/727,370 0007 According to certain methods disclosed herein, the filed Dec. 4, 2003, the entire disclosure of which is incor proportionality of the FLAS can be described by a ratio. For porated herein by reference, which is a continuation-in-part example, the proportionality of the FLAS can be expressed of prior application Ser. No. 10/686,098 filed Oct. 15, 2003, as a ratio of the amounts of each FLA, where each amount the entire disclosure of which is incorporated herein by is expressed as a weight percent of the total weight of the reference, which is a continuation-in-part of prior applica base blend (%bwob). Thus, in certain examples described tion Ser. No. 10/623,443 filed Jul. 18, 2003, the entire herein, the proportionality of the FLAS can be described by disclosure of which is incorporated herein by reference, and a ratio of about 15:85, of a high molecular weight FLA to a which is a continuation-in-part of prior application Ser. No. low molecular weight FLA. In other examples, the amount 10/315,415, filed Dec. 10, 2002, the entire disclosure of of low molecular weight FLAS present in the base can be which is incorporated herein by reference. increased or decreased, with a complementary increase or decrease in the amount of high molecular weight FLAS. BACKGROUND According to one Such example, the amount of low molecu lar weight FLAS in the base blend decreases to about 0.75% 0002 The present embodiment relates generally to meth bwob, and the amount of high molecular weight FLAS ods and cement compositions for cementing in a Subterra increases to about 0.25% bwob. In such an example, the nean Zone, and more particularly, to cement fluid loSS control proportionality of the FLAS can be described by a ratio of additives, cement compositions containing the additives, about 25:75 of high molecular weight FLAS to low molecu and methods of using the cement compositions. lar weight FLAS. 0.003 Hydraulic cement compositions are commonly uti 0008. In another example, the proportionality of the lized in Subterranean well completion and remedial opera FLAS can be expressed as a ratio of the amount of high tions. For example, hydraulic cement compositions are used molecular weight FLA(s) to the amount of low molecular in primary cementing operations whereby Strings of pipe weight FLA(s), irrespective of the amount each type con Such as casings and liners are cemented in well bores. In tributes to the base blend. Thus, in certain examples performing primary cementing, a hydraulic cement compo described herein, the proportionality of the FLAS can be Sition is pumped into the annular space between the walls of described as a ratio of about 1:5.67, meaning that the amount a wellbore and the exterior Surfaces of a pipe String disposed of low molecular weight FLAS present in the base blend is therein. The cement composition is permitted to Set in the about 5.67 times the amount of high molecular weight FLAS annular space, thereby forming an annular sheath of hard present in the base blend. According to an example where ened Substantially impermeable cement therein, which Sup the amount of low molecular weight FLAS present in the ports and positions the pipe String in the well bore and bonds base blend has been decreased, such as to the 0.75% bwob the exterior Surfaces of the pipe String to the walls of the well described above, and the amount of high molecular weight bore. Hydraulic cement compositions are also utilized in FLAS has been increased, such as to 0.25% bwob described remedial cementing operations Such as plugging highly above, the proportionality of the FLAS can be described by permeable Zones or fractures in well bores, plugging cracks a ratio of about 1:3 of high molecular weight FLAS to low or holes in pipe Strings, and the like. molecular weight FLAS. 0004 Fluid loss control agents are used in cement com 0009. Yet another way to express the proportionality of positions to reduce fluid loSS from the cement compositions the FLAS as a ratio is in terms of their molecular weights. to the permeable formations or Zones into or through which According to certain methods, the high molecular weight the cement compositions are pumped. FLA has a molecular weight in the range of from about 800,000 atomic mass units to about 1,200,000 atomic mass DESCRIPTION units, and the low molecular weight FLA has a molecular weight in the range of from about 100,000 atomic mass units 0005. In carrying out certain methods disclosed herein, to about 300,000 atomic mass units. Thus, in certain cementing is performed in a Subterranean Zone by placing a examples, the proportionality of the FLAS can be described cement composition comprising a mixing fluid, Zeolite, as a ratio of about 12:1, meaning that the molecular weight cementitious material, and proportioned fluid loSS additives of the high molecular weight FLA would be about 12 times (FLAS) as described herein, into the Subterranean Zone and the molecular weight of the low molecular weight FLA. In allowing the cement composition to Set therein. other examples described herein, the proportionality is 0006 According to exemplary methods of sealing a well described as a ratio of about 4:1, meaning that the molecular bore, a cement composition is formed by mixing a cement weight of the high molecular weight FLA is about 4 times mix, which includes a base blend and proportioned fluid loSS the molecular weight of the low molecular weight FLA. In US 2004/0244977 A1 Dec. 9, 2004

Still other examples, the proportionality of the FLAS can be framework of SiO, and AIO in a tetrahedron, which creates described by a ratio of about 2.66:1, meaning that the a very high Surface area. Cations and water molecules are molecular weight of the high molecular weight FLA would entrained into the framework. Thus, all may be be about 2.66 times the molecular weight of the low molecu represented by the crystallographic unit cell formula: lar weight FLA 0010. In carrying out other methods disclosed herein, a 0015 where M represents one or more cations such as cement mix is prepared by forming a base blend comprising Na, K, Mg, Ca, Sr, Li or Ba for natural zeolites and NH, Zeolite and at least one cementitious material, and mixing CH-NH., (CH)NH, (CH), N, Ga, Ge and P for manmade the base blend with proportioned fluid loss additives as Zeolites; n represents the cation Valence; the ratio of bia is in described herein. a range of from greater than or equal to 1 to less than or 0.011 Thus, cement compositions and cement mixes as equal to 5; and X represents the moles of water entrained into disclosed herein include proportioned fluid loSS additives the Zeolite framework. (FLAS). In certain exemplary compositions and mixes, the 0016 Preferred Zeolites for use in the cement composi FLAS are non-ionic water based Soluble polymers. Accord tions prepared and used according to the present disclosure ing to other examples, the FLAS are hydrophobically modi include (hydrated Sodium aluminum Silicate), biki fied non-ionic water based Soluble polymers. In certain taite (lithium aluminum Silicate), brewsterite (hydrated examples described herein, the FLAS are unmodified Strontium barium calcium aluminum Silicate), chabazite hydroxyethylcelluloses. In still other examples, the FLAS (hydrated calcium aluminum Silicate), are hydrophobically modified hydroxyethylcelluloses. (hydrated Sodium aluminum Silicate), faujasite (hydrated 0012 Exemplary cement mixes include a base blend and Sodium potassium calcium magnesium aluminum Silicate), proportioned fluid loss additives. The base blend includes harmotome (hydrated barium aluminum silicate), heulandite Zeolite and at least one cementitious material. The propor (hydrated Sodium calcium aluminum Silicate), laumontite tioned fluid loSS additives are as described above, that is, at (hydrated calcium aluminum silicate), mesolite (hydrated least one high molecular weight FLA and at least one low Sodium calcium aluminum Silicate), natrolite (hydrated molecular weight FLA, and where the high molecular Sodium aluminum silicate), paulingite (hydrated potassium weight FLA and the low molecular weight FLA are present Sodium calcium barium aluminum Silicate), in the base blend in a ratio of about 1:5.67. According to (hydrated potassium Sodium calcium aluminum Silicate), certain examples, the high molecular weight FLA comprises Scolecite (hydrated calcium aluminum silicate), stellerite a hydroxyethylcellulose having a molecular weight in the (hydrated calcium aluminum Silicate), Stilbite (hydrated range of from about 800,000 atomic mass units to about Sodium calcium aluminum Silicate) and thomsonite 1,200,000 atomic mass units, and the low molecular weight (hydrated Sodium calcium aluminum Silicate). In exemplary FLA comprises a hydroxyethylcellulose having a molecular cement compositions prepared and used according to the weight in the range of from about 100,000 atomic mass units present disclosure, the Zeolite is Selected from the group to about 300,000 atomic mass units. consisting of analcime, bikitaite, brewsterite, chabazite, cli noptilolite, faujasite, harmotome, heulandite, laumontite, 0013) A variety of cementitious materials can be used in meSolite, natrolite, paulingite, phillipsite, Scolecite, Steller the present methods, mixes and compositions, including but ite, Stilbite, and thomsonite. According to Still other exem not limited to hydraulic cements. Hydraulic cements Set and plary cement compositions described herein, the Zeolite used harden by reaction with water, and are typically comprised in the cement compositions comprises clinoptilolite. of calcium, aluminum, Silicon, Oxygen, and/or Sulfur. Hydraulic cements include micronized cements, Portland 0017 According to still other examples, in addition to cements, poZZolan cements, gypsum cements, aluminous proportioned fluid loSS additives as described herein, the cements, Silica cements, and alkaline cements. According to cement compositions, cement mixes and base blends preferred embodiments, the cementitious material comprises described herein further comprise additives Such as Set at least one API Portland cement. As used herein, the term retarding agents and Set accelerating agents. Suitable Set API Portland cement means any cements of the type defined retarding agents include but are not limited to refined and described in API Specification 10, 5" Edition, Jul. 1, lignoSulfonates. Suitable Set accelerating agents include but 1990, of the American Petroleum Institute (the entire dis are not limited to Sodium Sulfate, Sodium carbonate, calcium closure of which is hereby incorporated as if reproduced in Sulfate, calcium carbonate, potassium Sulfate, and potassium its entirety), which includes Classes A, B, C, G, and H. carbonate. Still other additives Suitable for use in cement According to certain embodiments disclosed herein, the compositions comprising proportioned fluid loSS additives cementitious material comprises Class C cement. Those of as described herein include but are not limited to density ordinary skill in the art will recognize that the preferred modifying materials (e.g., Silica flour, Sodium Silicate, amount of cementitious material is dependent on the type of microfine Sand, iron oxides and manganese oxides), dispers cementing operation to be performed. ing agents, Strength retrogression control agents and Viscosi fying agents. 0.014) Zeolites are porous alumino-silicate minerals that may be either a natural or manmade material. Manmade 0018 Water in the cement compositions according to the Zeolites are based on the Same type of Structural cell as present embodiments is present in an amount Sufficient to natural Zeolites and are composed of aluminosilicate make a slurry of the desired density from the cement mix, hydrates having the same basic formula as given below. It is and that is pumpable for introduction down hole. The water understood that as used in this application, the term "Zeolite' used to form a slurry can be any type of water, including means and encompasses all natural and manmade forms of fresh water, unsaturated Salt Solution, including brines and Zeolites. All Zeolites are composed of a three-dimensional Seawater, and Saturated Salt Solution. According to Some US 2004/0244977 A1 Dec. 9, 2004 examples, the water is present in the cement composition in 0024 Sodium carbonate and sodium sulfate, in the an amount of about 22% to about 200% by weight of the amounts listed in Table 1A, where “% bwob' indicates a base blend of a cement mix. According to other examples, percentage based on the total weight of the base blend, were the water is present in the cement composition in an amount dry-mixed into the base blends of those compositions that of from about 40% to about 180% by weight of the base were to undergo fluid loSS testing at temperatures equal to or blend of a cement mix. According to Still other examples, the less than about 30° C. (i.e., Nos. 1, 4 and 7) to accelerate the water is present in the cement composition in an amount of Set of the cement at Such temperatures. from about 90% to about 160% by weight of the base blend of a cement mix. 0025 HR-5, which is the tradename for a retarder com prising a refined lignoSulfonate commercially available from 0019. The following examples are illustrative of the Halliburton Energy Services, was dry-mixed into the base methods and compositions discussed above. blends of cement composition Nos. 3 and 6 in the amount (% bwob) listed in Table 1A. The retarder served to slow the set EXAMPLE 1. time that would otherwise occur at the conditions (density 0020. The following describes exemplary cement com and fluid loss test temperature) of the compositions. positions comprising proportioned fluid loSS control addi 0026 Proportioned fluid loss additives (FLAS) were also tives as described herein, and the efficacy of Such propor dry-mixed into the base blends used for cement composition tioned fluid loSS control additives in Such compositions. Nos. 1-9. In the examples illustrated in Table 1A, the 0021 Nine cement compositions (Nos. 1-9) comprising proportioned fluid loss additives were Carbitron 20 and proportioned fluid loSS control additives were prepared from FWCA, which were dry-mixed into the base blend in the the ingredients described in Table 1A. amounts (% bwob) as listed in Table 1A. Carbitron 20 is an

TABLE 1A

No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7 No. 8 No. 9 Base Blend

Cement 60 60 60 60 60 60 60 60 60 (wt %) Zeolite 40 40 40 40 40 40 40 40 40 (wt %) Additive

Na,CO. 2.2 O O 2.2 O O 2.2 O O (%bwob) NaSO 4.4 O O 4.4 O O 4.4 O O (%bwob) HR-5 O O 1. O O 1. O O O (%bwob) Carbitron 20 O.85 O.85 O.85 O.85 O.85 O.85 O.85 O.85 O.85 (%bwob) FWCA O.15 O.15 O.15 O.15 O.15 O.15 O.15 O.15 O.15 (%bwob) Mixing Fluid Water 94.59 94.59 94.59 126.53 126.53 126.53 150.45 150.45 150.45 (%bwob) D-Air 300OL O.328 O.328 O.328 O.328 O.328 O.328 O.328 O.328 O.328 (1/sk) Density 15OO 15OO 15OO 1400 1400 1400 1350 1350 1350 (kg/m3)

0022 Cement composition Nos. 1-9 were prepared unmodified non-hydrophobic hydroxyethylcellulose (HEC) according to procedures described in API Specification RP having a molecular weight of about 225,000 atomic mass 10B, 22 edition, 1997, of the American Petroleum Institute, units, (amu), and is commercially available from Dow the entire disclosure of which is incorporated herein by Chemical. FWCA is an unmodified non-hydrophobic reference. Generally, the procedure involved preparing a hydroxyethylcellulose (HEC) having a molecular weight of base blend by dry-mixing a cementitious material and Zeo about 1,000,000 amu, and is commercially available from lite by hand in a glass jar. Halliburton Energy Services. 0023 The amount of Zeolite and cement comprising the 0027. The respective cement-Zeolite base blends, and any base blend is as described in Table 1 A, where “wt %' accelerating additives, retarders, and proportioned fluid loSS indicates the weight percent contributed to the total weight additives, comprised cement mixes from which cement of the base blend. The cementitious material used in each composition Nos. 1-9 were formed. base blend was Class C. Clinoptilolite, which is commer 0028. Each cement composition was formed by adding cially available from C2C Zeolite Corporation of Calgary, the cement mix to a mixing fluid being maintained in a Canada, was used as the Zeolite in each base blend. Waring blender at 4000 RPM. The cement mix was added to US 2004/0244977 A1 Dec. 9, 2004

the mixing fluid over a 15 second period. When all of the example where the amount of low molecular weight FLAS cement mix was added to the mixing fluid, a cover was present in the base blend has been decreased, Such as to the placed on the blender and mixing was continued at about 0.75% bwob described above, and the amount of high 12,000 RPM for about 35 seconds. For each cement com molecular weight FLAS has been increased, Such as to position, the mixing fluid included water in the amounts as 0.25% bwob described above, the proportionality of the indicated in Table 1A. In certain compositions, the mixing FLAS can be described by a ratio of about 1:3 of high fluid also included D-Air 3000L as reported in Table 1A. The molecular weight FLAS to low molecular weight FLAS. amount of water is reported in Table 1A as a % bwob, and 0031 Yet another way to express the proportionality of the amount of D-Air 3000L is reported in “l/sk', which the FLAS is in terms of their molecular weights. Thus, in this indicates liters of D-Air 3000L per sack of cement compo Example 1, where the high molecular weight FLA comprises sition. D-Air 3000L is the tradename for a defoaming agent an unmodified non-hydrophobic hydroxyethylcellulose comprising polypropylene glycol, particulate hydrophobic (HEC) having a molecular weight of about 1,000,000 atomic Silica and a liquid diluent, which is commercially available mass units (amu) and the low molecular weight FLA com from Halliburton Energy Services, Duncan, Okla. The prises an unmodified non-hydrophobic HEC having a cement mix temperature and mixing fluid temperature were molecular weight of about 225,000 amu, the proportionality both 24° C. (75° F). of the FLAS can be described as a ratio of about 4:1, 0029 Cement composition Nos. 1-9 illustrate cement meaning that the molecular weight of the high molecular compositions comprising proportioned fluid loSS additives weight FLA(s) present in the base blend is about 4 times the (FLAS). The proportionality of the FLAS can be expressed as molecular weight of the low molecular weight FLA(s) in the a ratio of the amounts of each FLA, where each amount is base blend. In other examples, the molecular weight of the expressed as a weight percent of the total weight of the base low molecular weight FLAS can be in the range of from blend (%bwob). Thus, in this Example 1, the proportionality about 100,000 amu to about 300,000 amu, while the molecu of the FLAS, expressed as a ratio of the amounts (% bwob) lar weight of the high molecular weight FLA can be in the of each type of FLA, can be described by a ratio of about range or from about 800,000 amu to about 1,200,000 amu. 15:85, of a high molecular weight FLA to a low molecular Thus, according to an example where the high molecular weight FLA. In other examples, the amount of low molecu weight FLA has a molecular weight of about 1,200,000 amu lar weight FLAS present in the base can be increased or and the low molecular weight FLA about 100,000 amu, the decreased, with a complementary increase or decrease in the proportionality of the FLAS can be described by a ratio of amount of high molecular weight FLAS. According to one about 12:1, meaning that the molecular Weight of the high Such example, the amount of low molecular weight FLAS in molecular weight FLA is about 12 times the molecular the base blend decreases to about 0.75% bwob, and the weight of the low molecular weight FLA. In an example amount of high molecular weight FLAS increases to about where the high molecular weight FLA has a molecular 0.25% bwob. In such an example, the proportionality of the weight of about 800,000 amu and the low molecular weight FLA has a molecular weight of about 300,000 amu, the FLAS can be described by a ratio of about 25:75 of high proportionality of the FLAS can be described by a ratio of molecular weight FLAS to low molecular weight FLAS. about 2.66:1, meaning that the molecular weight of the high 0030 The proportionality of the FLAS can also be molecular weight is about 2.66 times the molecular weight expressed as a ratio of the amount of high molecular weight of the low molecular weight FLA. FLACs) to the amount of low molecular weight FLA(s), 0032 Referring now to Table 1B, rheological data and irrespective of the amount each type contributes to the base fluid loSS measurements of cement composition Nos. 1-9 are blend. Thus, in this Example 1, the proportionality of the reported.

TABLE 1B Rheological Data API. Fluid API Fluid Dial Readings (ep Loss Test Loss Temp. 600 300 200 100 60 3O 6 3 Temperature (mL/ No. (C) rpm rpm rpm rpm rpm rpm rpm rpm C. (F) 30 min) 1. 3O infa 196 145 89 65 47 34 32 30 (86) 84 2 50 245 175 131 84 62 43 21 18 50 (122) 76 3 8O 99 60 39 22 15 1O 7 6 80 (176) 1OO 4 3O 157 101 75 47 34 25 19 18 30 (86) 134 5 50 105 66 48 28 19 12 5 4 50 (122) 150 6 8O 57 38 23 12 7 5 4 2 80 (176) 176 7 3O 108 65 46 26 21 15 1O 8 30 (86) 227 8 50 57 36 25 15 1O 6 1. 0.5 50 (122) 243 9 8O 54 36 3O 25 17 11 8 7 80 (176) 364

FLAS can be described as a ratio of about 1:5.67, meaning 0033. The Theological data was determined using a Fann that the amount of low molecular weight FLAS present in the Model 35 viscometer. The visosity was taken as the mea base blend is about 5.67 times the amount of high molecular surement of the dial reading on the Farm Model 35 at the weight FLAS present in the base blend. According to an different rotational speeds as indicated in 600 to 3 RPM, and US 2004/0244977 A1 Dec. 9, 2004

at the temperatures as indicated in Table 1B. There are a cations are intended to be included within the Scope of this number of theoretical models known to those of ordinary invention as defined in the following claims. skill in the art that can be used to convert the values from the dial readings at the different RPM's into viscosity (centi 1. A method of cementing in a Subterranean Zone com poises). In addition, different Viscometer models use differ prising: ent RPM values, thus, in Some instances, a measurement is not available at a particular RPM value. forming a cement composition by mixing a cement mix comprising a base blend and proportioned fluid loSS 0034. The Theological data was determined according to additives with a mixing fluid, which base blend com the procedures set forth in Section 12 of the API Specifica prises Zeolite and at least one cementitious material, tion RP 10B, 22nd Edition, 1997, of the American Petroleum and which proportioned fluid loSS additives comprise at Institute (the entire disclosure of which is hereby incorpo least a first fluid loSS additive having a first molecular rated as if reproduced in its entirety). The forgoing API weight and at least a Second fluid loSS additive having procedure was modified in that the initial reading at 300 a Second molecular weight, which Second molecular RPM was taken after 60 seconds continuous rotation at that weight is less than the first molecular weight, and speed. Dial readings at 200, 100, 60, 30, 6 and 3 were then which first fluid loss additive and second fluid loss recorded in descending order at 20-Second intervals. The additive are present in the base blend in a ratio of about final reading at 600 RPM was taken after 60 seconds 1:5.67; continuous rotation at that Speed. placing the cement composition into the Subterranean 0035. The fluid loss testing was conducted according to Zone; and procedures set forth in Section 10 of API Recommended Practice 10B, 22" Edition, 1997, of the American Petroleum allowing the cement composition to Set therein. Institute (the entire disclosure of which is hereby incorpo 2. The method of claim 1 wherein the Zeolite is repre rated as if reproduced in its entirety). sented by the formula: 0.036 The procedures followed were those for testing at Ma (AlO4), (SiO2).xH2O temperatures less than 1940F, with atmospheric pressure where M represents one or more cations Selected from the conditioning, and a Static fluid loSS cell. Generally, however, group consisting of Na, K, Mg, Ca, Sr, Li, Ba, NH, 475 cc of each composition was placed into the container of CH-NH., (CH)NH, (CH), N, Ga, Ge and P; in an atmospheric pressure consistometer commercially avail represents the cation Valence; the ratio of b:a is in a able from Howco. The temperatures of the compositions range from greater than or equal to 1 and less than or were adjusted to the test temperatures indicated in Table 1B, equal to 5; and X represents the moles of water (30, 50 and 80 C.). The test temperatures were arbitrarily entrained into the Zeolite framework. chosen, based on values that are often encountered as bottom 3. The method of claim 1 wherein the Zeolite is selected hole circulating temperatures (BHCTs) of a variety of types from the group consisting of analcime, bikitaite, brewsterite, of wells. chabazite, clinoptilolite, faujasite, harmotome, heulandite, 0037 After about 20 minutes, the composition to be laumontite, meSolite, natrolite, paulingite, phillipsite, Sco tested was stirred, and a 5 inch standard fluid loss cell, which lecite, Stellerite, Stilbite, and thomsonite. was prepared according to the aforemetioned Section 10 of 4. The method of claim 1 wherein the base blend com API Recommended Practice 10B, was filled. The test was prises from about 20 to about 60 weight percent Zeolite. Started within 30 Seconds of closing the cell by application 5. The method of claim 1 wherein the base blend com of nitrogen applied through the top valve. Filtrate was prises about 40 weight percent Zeolite. collected and the volume and time were recorded if blow out 6. The method of claim 1 wherein the first molecular occurred in less than 30 minutes or volume recorded at 30 weight is about twelve times as much as the Second molecu minutes if no blow out occurred. Thus, to determine the fluid lar weight. loSS data reported in Table 1B, Values were calculated as 7. The method of claim 1 wherein the first molecular twice the volume of filtrate multiplied by 5.477 and divided weight is about four times as much as the Second molecular by the Square root of time if blowout occurred, and as twice weight. the volume of filtrate if blowout did not occur within 30 8. The method of claim 1 wherein the first molecular minutes. weight is about 2.66 times as much as the Second molecular weight. 0038. The measured fluid loss values (mL of fluid lost/30 9. The method of claim 1 wherein the first molecular min) of cement composition Nos. 1-9 illustrate that propor weight is in the range of from about 800,000 atomic mass tioned fluid loss additives provide effective fluid loss control units to about 1,200,000 atomic mass units, and the fluid loss to cement compositions having a variety of densities, and at additive having the Second molecular weight comprises a temperatures at least up to 80° C. (176 F). In addition, the hydroxyethylcellulose having a molecular weight in the Theological data of cement composition Nos. 1-9 is within range of from about 100,000 atomic mass units to about acceptable parameters. 300,000 atomic mass units. 0039. Although only a few exemplary embodiments of 10. The method of claim 1 wherein the first molecular this invention have been described in detail above, those weight is about 1,000,000 atomic mass units and the second skilled in the art will readily appreciate that many other molecular weight is about 225,000 atomic mass units. modifications are possible in the exemplary embodiments 11. The method of claim 1 wherein the first fluid loss without materially departing from the novel teachings and additive is present in the cement mix in an amount of about advantages of this invention. Accordingly, all Such modifi 15% by weight of the base blend, and the second fluid loss US 2004/0244977 A1 Dec. 9, 2004

additive is present in the cement mix in an amount of about proportioned fluid loSS control additives, which propor 85% by weight of the base blend. tioned fluid loss additives comprise at least a first fluid 12. The method of claim 1 wherein the first fluid loss loSS additive having a first molecular weight and at additive is present in the cement mix in an amount of about least a Second fluid loSS additive having a Second 25% by weight of the base blend, and the second fluid loss molecular weight, which Second molecular weight is additive is present in the cement mix in an amount of about less than the first molecular weight, and which first 75% by weight of the base blend. fluid loss additive and second fluid loss additive are 13. The method of claim 1 wherein the first fluid loss and present in the base blend in a ratio of about 1:5.67; and the second fluid loss additive are present in the base blend at least one accelerating additive in an amount of about in a ratio of about 1:3. 0.5% to about 10% by weight of the base blend. 14. The method of claim 1 wherein the proportioned fluid 30. The method of claim 29 wherein the accelerating loSS additives comprise non-ionic water based Soluble poly additive is present in the cement mix in an amount of from CS. about 2% to about 8% by weight of the base blend. 15. The method of claim 1 wherein the proportioned fluid 31. The method of claim 1 wherein the Zeolite is selected loSS additives comprise hydrophobically modified non-ionic from the group consisting of analcime (hydrated Sodium water based Soluble polymers. aluminum Silicate), bikitaite (lithium aluminum silicate), 16. The method of claim 1 wherein the proportioned fluid brewsterite (hydrated Strontium barium calcium aluminum loSS additives comprise hydroxyethylcelluloses. Silicate), chabazite (hydrated calcium aluminum Silicate), 17. The method of claim 1 wherein the proportioned fluid clinoptilolite (hydrated Sodium aluminum Silicate), faujasite loss additives comprise hydrophobically modified hydroxy (hydrated Sodium potassium calcium magnesium aluminum ethylcelluloses. Silicate), harmotome (hydrated barium aluminum Silicate), 18. The method of claim 1 wherein the first fluid loss heulandite (hydrated Sodium calcium aluminum Silicate), additive comprises a hydroxyethylcellulose having a laumontite (hydrated calcium aluminum silicate), mesolite molecular weight in the range of from about 800,000 atomic (hydrated Sodium calcium aluminum silicate), natrolite mass units to about 1,200,000 atomic mass units, and the (hydrated Sodium aluminum Silicate), paulingite (hydrated Second fluid loSS additive comprises a hydroxyethylcellulose potassium Sodium calcium barium aluminum Silicate), phil having a molecular weight in the range of from about lipsite (hydrated potassium Sodium calcium aluminum sili 100,000 atomic mass units to about 300,000 atomic mass cate), Scolecite (hydrated calcium aluminum Silicate), stel units. lerite (hydrated calcium aluminum silicate), stilbite 19. The method of claim 18 wherein the first molecular (hydrated Sodium calcium aluminum Silicate) and thomso weight is about 1,000,000 atomic mass units and the second nite (hydrated Sodium calcium aluminum Silicate). molecular weight is about 225,000 atomic mass units. 32. A method for preparing a cement mix comprising: 20. The method of claim 1 wherein the mixing fluid comprises water. mixing Zeolite and at least one cementitious material to 21. The method of claim 1 wherein the water is present in form a base blend for the cement mix; a range of about 22% to about 200% by weight of the base mixing the base blend with proportioned fluid loss addi blend. tives, which proportioned fluid loSS additives comprise 22. The method of claim 1 wherein the water is present in at least a first fluid loSS additive having a first molecular a range of about 40% to about 180% by weight of the base weight and at least a Second fluid loSS additive having blend. a Second molecular weight, which Second molecular 23. The method of claim 1 wherein the water is present in weight is less than the first molecular weight, and a range of about 90% to about 160% by weight of the base which first fluid loss additive and second fluid loss blend. additive are present in the base blend in a ratio of about 24. The method of claim 20 wherein the mixing fluid 1:567. further comprises a defoaming agent. 33. The method of claim 32 wherein the Zeolite is 25. The method of claim 1 wherein the base blend represented by the formula: comprises at least one cementitious material Selected from the group consisting of micronized cement, Portland cement, Ma (AlO4), (SiO2).xH2O poZZolan cement, gypsum cement, aluminous cement, Silica where M represents one or more cations Selected from the cement, and alkaline cement. group consisting of Na, K, Mg, Ca, Sr, Li, Ba, NH, 26. The method of claim 1 wherein the cement compo CH-NH., (CH)NH, (CH), N, Ga, Ge and P; in sition formed has a density in a range of from about 1350 represents the cation Valence; the ratio of b:a is in a kg/m to about 1500 kg/m. range from greater than or equal to 1 and less than or 27. The method of claim 1 wherein the cement compo equal to 5; and X represents the moles of water Sition further comprises at least one accelerating additive. entrained into the Zeolite framework. 28. The method of claim 27 wherein the at least one 34. The method of claim 32 wherein the Zeolite is selected accelerating additive is Selected from the group consisting of from the group consisting of analcime, bikitaite, brewsterite, Sodium Sulfate, Sodium carbonate, calcium Sulfate, calcium chabazite, clinoptilolite, faujasite, harmotome, heulandite, carbonate, potassium Sulfate, and potassium carbonate. laumontite, meSolite, natrolite, paulingite, phillipsite, Sco 29. The method of claim 1 wherein the cement mix lecite, Stellerite, Stilbite, and thomsonite. comprises: 35. The method of claim 32 wherein the Zeolite is selected from the group consisting of analcime (hydrated Sodium a base blend comprising Zeolite and at least one cemen aluminum Silicate), bikitaite (lithium aluminum silicate), titious material; brewsterite (hydrated Strontium barium calcium aluminum US 2004/0244977 A1 Dec. 9, 2004

Silicate), chabazite (hydrated calcium aluminum Silicate), having a molecular weight in the range of from about clinoptilolite (hydrated Sodium aluminum Silicate), faujasite 100,000 atomic mass units to about 300,000 atomic mass (hydrated Sodium potassium calcium magnesium aluminum units. Silicate), harmotome (hydrated barium aluminum Silicate), 49. The method of claim 48 wherein the first molecular heulandite (hydrated Sodium calcium aluminum Silicate), weight is about 1,000,000 atomic mass units and the second laumontite (hydrated calcium aluminum silicate), mesolite molecular weight is about 225,000 atomic mass units. (hydrated Sodium calcium aluminum silicate), natrolite 50. The method of claim 32 wherein the base blend (hydrated Sodium aluminum Silicate), paulingite (hydrated comprises at least one cementitious material Selected from potassium Sodium calcium barium aluminum Silicate), phil the group consisting of micronized cement, Portland cement, lipsite (hydrated potassium Sodium calcium aluminum sili poZZolan cement, gypsum cement, aluminous cement, Silica cate), Scolecite (hydrated calcium aluminum Silicate), Stel cement, and alkaline cement. lerite (hydrated calcium aluminum Silicate), Stilbite 51. The method of claim 32 further comprising: (hydrated Sodium calcium aluminum Silicate) and thomso nite (hydrated Sodium calcium aluminum Silicate). mixing the base blend with at least one accelerating 36. The method of claim 32 wherein the first molecular additive Selected from the group consisting of Sodium weight is about twelve times as much as the Second molecu Sulfate, Sodium carbonate, calcium Sulfate, calcium lar weight. carbonate, potassium Sulfate, and potassium carbonate. 37. The method of claim 32 wherein the first molecular 52. A cement composition comprising: weight is about four times as much as the Second molecular a mixing fluid; weight. 38. The method of claim 32 wherein the first molecular a base blend comprising Zeolite and cementitious mate weight is about 2.66 times as much as the Second molecular rial; and weight. proportioned fluid loSS control additives, which propor 39. The method of claim 32 wherein the first fluid loss tioned fluid loss additives comprise at least a first fluid additive comprises a hydroxyethylcellulose having a loSS additive having a first molecular weight and at molecular weight in the range of from about 800,000 atomic least a Second fluid loSS additive having a Second mass units to about 1,200,000 atomic mass units, and the molecular weight, which Second molecular weight is Second fluid loSS additive comprises a hydroxyethylcellulose less than the first molecular weight, and which first having a molecular weight in the range of from about fluid loss additive and Second fluid loss additive are 100,000 atomic mass units to about 300,000 atomic mass present in the base blend in a ratio of about 1:5.67. units. 53. The cement composition of claim 52 wherein the 40. The method of claim 32 wherein the first molecular Zeolite is represented by the formula: weight is about 1,000,000 atomic mass units and the second molecular weight is about 225,000 atomic mass units. 41. The method of claim 32 wherein the first fluid loss where M represents one or more cations Selected from the additive is present in the cement mix in an amount of about group consisting of Na, K, Mg, Ca, Sr, Li, Ba, NH, 15% by weight of the base blend, and the second fluid loss CH-NH., (CH)NH, (CH), N, Ga, Ge and P; in additive is present in the cement mix in an amount of about represents the cation Valence; the ratio of b:a is in a 85% by weight of the base blend. range from greater than or equal to 1 and less than or 42. The method of claim 32 wherein the first fluid loss equal to 5; and X represents the moles of water additive is present in the cement mix in an amount of about entrained into the Zeolite framework. 25% by weight of the base blend, and the second fluid loss 54. The cement composition of claim 52 wherein the additive is present in the cement mix in an amount of about Zeolite is Selected from the group consisting of analcime, 75% by weight of the base blend. bikitaite, brewsterite, chabazite, clinoptilolite, faujasite, har motome, heulandite, laumontite, meSolite, natrolite, paul 43. The method of claim 32 wherein the first fluid loss ingite, phillipsite, Scolecite, Stellerite, Stilbite, and thomso additive and the Second fluid loSS additive are present in the nite. base blend in a ratio of about 1:3. 55. The cement composition of claim 52 wherein the base 44. The method of claim 32 wherein the proportioned blend comprises from about 20 to about 60 weight percent fluid loSS additives comprise non-ionic water based Soluble Zeolite. polymers. 56. The cement composition of claim 52 wherein the base 45. The method of claim 32 wherein the proportioned blend about 40 weight percent Zeolite. fluid loss additives are comprise hydrophobically modified 57. The cement composition of claim 52 wherein the first non-ionic water based Soluble polymers. molecular weight is about twelve times as much as the 46. The method of claim 32 wherein the proportioned Second molecular weight. fluid loSS additives comprise hydroxyethylcelluloses. 58. The cement composition of claim 52 wherein the first 47. The method of claim 32 wherein the proportioned molecular weight is about four times as much as the Second fluid loss additives comprise hydrophobically modified molecular weight. hydroxyethylcelluloses. 59. The cement composition of claim 52 wherein the first 48. The method of claim 32 wherein the first fluid loss molecular weight is about 2.66 times as much as the Second additive comprises a hydroxyethylcellulose having a molecular weight. molecular weight in the range of from about 800,000 atomic 60. The cement composition of claim 52 wherein the first mass units to about 1,200,000 atomic mass units, and the fluid loSS additive comprises hydroxyethylcellulose having a Second fluid loSS additive comprises a hydroxyethylcellulose molecular weight in the range of from about 800,000 atomic US 2004/0244977 A1 Dec. 9, 2004

mass units to about 1,200,000 atomic mass units, and the (hydrated Sodium aluminum Silicate), bikitaite (lithium alu Second fluid loSS additive comprises a hydroxyethylcellulose minum Silicate), brewsterite (hydrated Strontium barium having a molecular weight in the range of from about calcium aluminum Silicate), chabazite (hydrated calcium 100,000 atomic mass units to about 300,000 atomic mass aluminum silicate), clinoptilolite (hydrated Sodium alumi units. num silicate), faujasite (hydrated Sodium potassium calcium 61. The cement composition of claim 52 wherein the first magnesium aluminum Silicate), harmotome (hydrated molecular weight is about 1,000,000 atomic mass units and barium aluminum Silicate), heulandite (hydrated Sodium the second molecular weight is about 225,000 atomic mass calcium aluminum Silicate), laumontite (hydrated calcium units. aluminum Silicate), mesolite (hydrated Sodium calcium alu 62. The cement composition of claim 52 wherein the first minum Silicate), natrolite (hydrated Sodium aluminum sili fluid loss additive is present in an amount of about 15% by cate), paulingite (hydrated potassium Sodium calcium weight of the base blend, and the second fluid loss additive barium aluminum Silicate), phillipsite (hydrated potassium is present in an amount of about 85% by weight of the base Sodium calcium aluminum silicate), Scolecite (hydrated cal blend. cium aluminum silicate), Stellerite (hydrated calcium alumi 63. The cement composition of claim 52 wherein the first num Silicate), Stilbite (hydrated Sodium calcium aluminum fluid loss additive is present in an amount of about 25% by Silicate) and thomsonite (hydrated Sodium calcium alumi weight of the base blend, and the second fluid loss additive is present in an amount of about 75% by weight of the base num Silicate). blend. 76. A cement mix comprising: 64. The cement composition of claim 52 wherein the first a base blend comprising Zeolite and at least one cemen fluid loss additive and the second fluid loss additive are titious material; and present in the base blend in a ratio of about 1:3. 65. The cement composition of claim 52 wherein the proportioned fluid loSS additives, which proportioned proportioned fluid loSS control additives comprise non-ionic fluid loss additives comprise at least a first fluid loss water based Soluble polymers. additive having a first molecular weight and at least a 66. The cement composition of claim 52 wherein the Second fluid loSS additive having a Second molecular proportioned fluid loSS control additives comprise hydro weight, which Second molecular weight is less than the phobically modified non-ionic water based soluble poly first molecular weight, and which first fluid loss addi CS. tive and Second fluid loSS additive are present in the 67. The cement composition of claim 52 wherein the base blend in a ratio of about 1:5.67. proportioned fluid loSS control additives comprise hydroxy 77. The cement mix of claim 76 wherein the Zeolite is ethylcelluloses. represented by the formula: 68. The cement composition of claim 52 wherein the proportioned fluid loSS control additives comprise hydro Ma (AlO4), (SiO2).xH2O phobically modified hydroxyethylcelluloses. where M represents one or more cations Selected from the 69. The cement composition of claim 52 wherein the first group consisting of Na, K, Mg, Ca, Sr, Li, Ba, NH, fluid loSS additive comprises a hydroxyethylcellulose having CH-NH., (CH)NH, (CH), N, Ga, Ge and P; in a molecular weight in the range of from about 800,000 represents the cation Valence; the ratio of b:a is in a atomic mass units to about 1,200,000 atomic mass units, and range from greater than or equal to 1 and less than or the Second fluid loSS additive comprises a hydroxyethylcel equal to 5; and X represents the moles of water lulose having a molecular weight in the range of from about entrained into the Zeolite framework. 100,000 atomic mass units to about 300,000 atomic mass 78. The cement mix of claim 76 wherein the Zeolite is units. Selected from the group consisting of analcime, bikitaite, 70. The cement composition of claim 69 wherein the first brewsterite, chabazite, clinoptilolite, faujasite, harmotome, molecular weight is about 1,000,000 atomic mass units and heulandite, laumontite, meSolite, natrolite, paulingite, phil the second molecular weight is about 225,000 atomic mass lipsite, Scolecite, Stellerite, Stilbite, and thomsonite. units. 79. The cement mix of claim 76 wherein the Zeolite is 71. The cement composition of claim 52 wherein the Selected from the group consisting of analcime (hydrated cement composition has a density in a range of from about Sodium aluminum silicate), bikitaite (lithium aluminum sili 1350 kg/m to about 1500 kg/m. cate), brewsterite (hydrated Strontium barium calcium alu 72. The cement composition of claim 52 wherein the minum Silicate), chabazite (hydrated calcium aluminum cement composition further comprises at least one acceler Silicate), clinoptilolite (hydrated Sodium aluminum Silicate), ating additive Selected from the group consisting of Sodium faujasite (hydrated Sodium potassium calcium magnesium Sulfate, Sodium carbonate, calcium Sulfate, calcium carbon aluminum Silicate), harmotome (hydrated barium aluminum ate, potassium Sulfate, and potassium carbonate. Silicate), heulandite (hydrated Sodium calcium aluminum 73. The cement composition of claim 72 wherein the Silicate), laumontite (hydrated calcium aluminum Silicate), accelerating additive is present in an amount of about 0.5% mesolite (hydrated Sodium calcium aluminum Silicate), to about 10% by weight of the base blend. natrolite (hydrated Sodium aluminum Silicate), paulingite 74. The cement composition of claim 72 wherein the (hydrated potassium Sodium calcium barium aluminum sili accelerating additive is present in the cement mix in an cate), phillipsite (hydrated potassium Sodium calcium alu amount of from about 2% to about 8% by weight of the base minum silicate), Scolecite (hydrated calcium aluminum sili blend. cate), Stellerite (hydrated calcium aluminum Silicate), 75. The cement composition of claim 52 wherein the Stilbite (hydrated Sodium calcium aluminum Silicate) and Zeolite is Selected from the group consisting of analcime thomsonite (hydrated Sodium calcium aluminum silicate). US 2004/0244977 A1 Dec. 9, 2004

80. The cement mix of claim 76 wherein the first molecu 89. The cement mix of claim 76 wherein the proportioned lar weight is about twelve times as much as the Second fluid loss additives comprise hydrophobically modified non molecular weight. ionic water based Soluble polymers. 81. The cement mix of claim 76 wherein the first molecu 90. The cement mix of claim 76 wherein the proportioned lar weight is about four times as much as the Second fluid loSS additives comprise hydroxyethylcelluloses. molecular weight. 82. The cement mix of claim 76 wherein the first molecu 91. The cement mix of claim 76 wherein the proportioned lar weight is about 2.66 times as much as the Second fluid loss additives comprise hydrophobically modified molecular weight. hydroxyethylcelluloses 83. The cement mix of claim 76 wherein the first molecu 92. The cement mix of claim 76 wherein the first fluid loss lar weight is in the range of from about 800,000 atomic mass additive comprises a hydroxyethylcellulose having a units to about 1,200,000 atomic mass units, and the second molecular weight in the range of from about 800,000 atomic fluid loSS additive comprises a hydroxyethylcellulose having mass units to about 1,200,000 atomic mass units, and the a molecular weight in the range of from about 100,000 Second fluid loSS additive comprises a hydroxyethylcellulose atomic mass units to about 300,000 atomic mass units. having a molecular weight in the range of from about 84. The cement mix of claim 76 wherein the first molecu 100,000 atomic mass units to about 300,000 atomic mass lar weight is about 1,000,000 atomic mass units and the units. second molecular weight is about 225,000 atomic mass units. 93. The cement mix of claim 92 wherein the first molecu 85. The cement mix of claim 76 wherein the first fluid loss lar weight is about 1,000,000 atomic mass units and the additive is present in the cement mix in an amount of about second molecular weight is about 225,000 atomic mass 15% by weight of the base blend, and the second fluid loss units. additive is present in the cement mix in an amount of about 94. The cement mix of claim 76 wherein the base blend 85% by weight of the base blend. comprises at least one cementitious material Selected from 86. The cement mix of claim 76 wherein the first fluid loss the group consisting of micronized cement, Portland cement, additive is present in the cement mix in an amount of about poZZolan cement, gypsum cement, aluminous cement, Silica 25% by weight of the base blend, and the second fluid loss cement, and alkaline cement. additive is present in the cement mix in an amount of about 95. The cement mix of claim 76 further comprising: 75% by weight of the base blend. 87. The cement mix of claim 76 wherein the first fluid loss at least one accelerating additive Selected from the group additive and the Second fluid loSS additive are present in the consisting of Sodium Sulfate, Sodium carbonate, cal base blend in a ratio of about 1:3. cium Sulfate, calcium carbonate, potassium Sulfate, and 88. The cement mix of claim 76 wherein the proportioned potassium carbonate. fluid loSS additives comprise non-ionic water based Soluble polymers.