Patent Publication Number: US-2009239771-A1

Title: Swelling Inhibitors for Clays and Shales

Description:
TECHNICAL FIELD 
     The present invention concerns hydration inhibitors for clays and shales, i.e. chemicals that inhibit the swelling of clays and shales which come into contact with the water base fluids used in the oil industry during drilling and construction of oil and gas wells. 
     The clays and shales swelling inhibitors of the present invention are condensation products of dicarboxylic acids, having from 4 to 10 carbon atoms with alkanolamines, diamines or polyalkyleneamines. 
     During the rotary drilling of wells, a drilling fluid is circulated through the well, from the underground to the surface, to suspend the drill cuttings originating from the drilling process and to transport the cutting to the surface. 
     At the same time the drilling fluid cools and cleans the drill bit, reduces the friction between the drill pipe and the borehole walls and stabilizes the sections of the well that are not reinforced. 
     Normally the drilling fluids form a filter cake of low permeability which prevents leaking into the surrounding geological formations and avoids excessive losses of the liquid phase of the drilling fluid itself. 
     Drilling fluids can be classified according to the nature of their continuous liquid phase. There are oil base drilling fluids, in which the solids are suspended in a continues oleaginous phase and optionally water or a brine phase is emulsified into the oleaginous phase. 
     Alternatively, water base drilling fluids contain solids suspended in water or brine or solutions of silicates. 
     Various chemicals can be added to water base drilling fluids, deliberately or not: 
     A) organic colloids or clays, used to impart viscosity and fluid loss reduction; 
     B) insoluble inorganic minerals to increase the fluid density; 
     C) solids that originate from the drilling process. 
     The solids, which disperse into the fluid, include cuttings from the drilling operation and from the surrounding unstable geological formations. 
     When the formation yields solids, which are swellable clayey materials, they can compromise drilling time and increase costs. 
     There are different kinds of clays and shales that swell and they all can cause a number of problems. 
     The swelling increases the friction between the drill pipe and the borehole walls, causes drilling fluid losses and sticking between the drill pipe and the borehole walls. 
     For this reason the development of swelling inhibitors for clays and shales is important for the oil and gas industry. 
     The present invention works in this direction to solve these problems. 
     BACKGROUND ART 
     Many clays and shales inhibitors are known in the art, among which inorganic salts such as potassium chloride, which inhibits the swelling of clays and shales, are well known to those skilled in the art. 
     Many patents have been filed, which describe techniques or products that can be used to inhibit the swelling of clays and shales. Without having the ambition to exhaustively summarize the available patent literature and only by way of example, we cite the following swelling inhibiting compositions: 
     a) inorganic phosphates, described in U.S. Pat. No. 4,605,068 (Young et al.); 
     b) polyalkoxy diamines and their salts, in U.S. Pat. No. 6,484,821, 
     U.S. Pat. No. 6,609,578, U.S. Pat. No. 6,247,543 and US 20030106718, all by Patel et al.; 
     c) choline derivatives, as in U.S. Pat. No. 5,908,814 (Patel et al.); 
     d) oligomethylene diamines and their salts, in U.S. Pat. No. 5,771,971 (Horton et al.), and US 20020155956 (Chamberlain et al.); 
     e) the addition product of carboxymethy cellulose and an organic amine, in WO 2006/013595 (Li Bassi et al.) 
     f) 1,2-cyclohexanediamine and/or their salts, in WO 2006/013597 (Merli et al.); 
     g) salts of phosphoric acid esters of oxyalkylated polyols, in WO 2006/013596 (McGregor et al.); 
     h) the combination of a partially hydrolized acrylic copolymer, potassium chloride and polyanionic cellulose, in U.S. Pat. No. 4,664,818 (Halliday William S. et al.); 
     i) quaternary ammonium compounds, in U.S. Pat. No. 5,197,544 (Himes Ronald E.); 
     l) polymers based on dialkyl aminoalkyl methacrylate, in U.S. Pat. No. 7,091,159 (Eoff, Larry S. et al.); 
     m) aqueous solutions containing a polymer with hydrophilic and hydrophobic groups, in U.S. Pat. No. 5,728,653 (Audibert, Annie et al.); 
     n) the reaction product of a polyhydroxyalkane and an alkylene oxide, in U.S. Pat. No. 6,544,933 (Reid, Paul Ian et al.). 
     DISCLOSURE OF INVENTION 
     It has now been found that condensation products of dicarboxylic acids with 4 to 10 carbon atoms with alkanolamines, diamines or polyalkyleneamines are excellent clays and shales inhibitors for the oil industry, being capable of effectively inhibiting the swelling of clays and shales in subterranean formations. 
     These condensation products are amino-esters or amino-amides and can advantageously be prepared as solutions without a purification step. 
     It is therefore a fundamental object of the present invention a method to inhibit the hydration of clays and shales during drilling operations, which includes the use of a water base drilling fluid that contains as clays and shales inhibitor from 0.2 to 5% by weight of the condensation product of a dicarboxylic acid having 4 to 10 carbon atoms with alkanolamines, diamines or polyalkyleneamines of formula (I) R′″R″N—R′—XH 
     where X is O or NR 0 , 
     R 0  is hydrogen or a linear or branched alkyl group having from 1 to 6 carbon atoms, 
     R′ is a linear or branched, aliphatic or cicloaliphatic alkylene group having from 2 to 10 carbon atoms, or 
     R′ is R″″(NH—R″″), where R″″ is ethylene or CH(CH 3 )CH 2 , n is a number from 1 to 6 and X is NR 0 ; 
     R″ and R′″ can be equal or different from one another and are hydrogen or a linear or branched alkyl group having from 1 to 6 carbon atoms, optionally substituted with a hydroxyl group. 
     It is another object of the present invention to provide a water base drilling fluid which comprises from 0.2 to 5%, preferably from 2 to 4% by weight, of the condensation product of a dicarboxylic acid having 4 to 10 carbon atoms with alkanolamines, diamines or polyalkyleneamines of formula (I). 
     It is still another object of the present invention a method to prepare a solution of a clays and shales inhibitor for water base drilling fluids that contains the condensation product of a dicarboxylic acid having 4 to 10 carbon atoms with alkanolamines, diamines or polyalkyleneamines of formula (I). 
     The condensation products of the present invention can be used in neutral form or as salt with organic or inorganic acids. 
     In a typical embodiment of the present invention the condensation product has the formula (II), R′″R″N—R′—X—C(═O)—R—C(═O)—X—R′—NR″R′″ 
     where R is an alkylene group, linear or branched, saturated or unsaturated, having from 2 to 8 carbon atoms or a phenylene group, and X, R 0 , R′, R″ e R′″ have the same meaning as in formula (I). 
     Preferably R is a linear saturated alkylene group. 
     Amino-esters of formula (II), where X is O, R is a tetramethylene or ethylene group, R′ is an ethylene group and R″ and R′″ can be equal or different and are hydrogen, methyl or hydroxyethyl groups, displayed excellent properties and are therefore preferred in the implementation of the present invention. 
     Amino-amides of formula (II), where X is NH, R is a tetramethylene or ethylene group, R′ is an ethylene group or R″″(NH—R″″) n  where R″″ is ethylene or CH(CH 3 )CH and n is a number from 1 to 4 and R″ and R′″ can be equal or different and are hydrogen, methyl or hydroxyethyl groups, are particularly preferred for use in high temperature environments because they offer, in addition to excellent performance, also a favorable thermal stability. 
     The clays and shales inhibitors of the present invention can be prepared through condensation by heating the alkanolamine or the diamine or the polyalkyleneamine of formula (I) and adding to it the dicarboxylic acid or the corresponding anhydride, under stirring without any solvent, at a temperature ranging from 100 to 180° C. and removing by distillation the water that is formed during the reaction. When the condensation reaction is completed, water and an acid, such as acetic acid or other organic or inorganic acid, can be added to prepare a ready for use aqueous solution of the ester or the amide. 
     The pH of the solution is normally adjusted to values of about 6-8; the concentration of the amino-ester or the amino-amide in the solution advantageously varies between 30 and 70% by weight. 
     Alternatively when the condensation reaction is completed, it is possible to dilute the product with an organic solvent, by way of example with ethylene glycol, propylene glycol or diethylene glycol, adjusting the concentration of the condensation product between 20 and 90% by weight. 
     The dicarboxylic acids and the anhydrides useful for the preparation of the clays and shales inhibitors of the present invention are commercially available and are, by way of example, succinic acid or succinic anhydride, adipic acid, sebacic acid, fumaric acid, maleic anhydride, phthalic anhydride, isophthalic anhydride or terephthalic anhydride. 
     Also, various alkanolamines, diamines and polyalkyleneamines of formula (I) are commercially available, and are for example triethanolamine, methylethanolamine, di-methylethanolamine, aminoethylethanolamine, ethylendiamine, isophoronediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine. 
     To obtain the amino-esters or the amino-amides of formula (II), the molar ration between the dicarboxylic acid and the alkanolamine or the diamine or the polyalkylene amine is about 1:2; higher molar ratios can be used, up to about 1:1, to obtain oligo amino-esters or amino-amides that are also useful to carry out the present invention. 
     The water base drilling fluid of the invention, in addition to the condensation products between a dicarboxylic acid having from 4 to 10 carbon atoms with alkanolamines, diamines or polyalkyleneamines of formula (I), also comprises the chemicals customarily used and well known to those skilled in the art, such as weighing agents, fluid loss reducers, corrosion inhibitors, defoamers and viscosifiers. 
     The continues water phase can be selected among: fresh water, seawater, brines, solutions of soluble organic compounds in water and their mixtures. 
     Useful weighing agents can be selected among barite, hematite iron oxide, calcium carbonate, magnesium carbonate, organic and inorganic magnesium salts, calcium chloride, calcium bromide, magnesium chloride, magnesium bromide, halides of zinc, and their mixtures. 
     The following examples illustrate the preparation of water solutions of useful clays and shales inhibitors following the invention; performance tests have been carried out to demonstrate their excellent properties as clays and shales inhibitors. 
    
    
     EXAMPLE 1 
     Preparation of the Amino-Ester of Succinic Anhydride with Triethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 186.8 g (1.252 moles) of triethanolamine are charged, heat is applied to reach 80° C. and 63.2 g (0.626 moles) of succinic anhydride are added; due to the exothermic reaction the temperature reaches 130° C. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. The water formed in the reaction is distilled off by heating to 160° C. in about one hour; after 2.5 hours 11.3 g of water have distilled and the acid number at the thymolphthalein end point is 5 mgKOH/g. The reaction mixture is cooled to 70° C. and 75 g of acetic acid and 210 g of water are added. 
     A solution of clays and shales inhibitor is obtained with a dry content of 49.1% by weight. 
     EXAMPLE 2 
     Preparation of the Amino-Ester of Adipic Acid with Triethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 201.4 g (1.35 moles) of triethanolamine are charged, heat is applied to reach 120° C. and 98.63 g (0.675 moles) of adipic acid are added. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. Heating is applied to reach 175° C. in about one hour. After 3 hours 23.5 g of water have distilled and the acid number is 5 mgKOH/g. The reaction mixture is cooled to 67° C. and 80 g of acetic acid and 250 g of water are added. 
     A solution of clays and shales inhibitor is obtained with a dry content of 44.37% by weight. 
     EXAMPLE 3 
     Preparation of the Oligo Amino-Ester of Adipic Acid with Triethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 181.5 g (1.217 moles) of triethanolamine are charged, heat is applied to reach 120° C. and 118.5 g (0.811 moles) of adipic acid are added. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. Heating is applied to reach 170° C. in about one hour. After 3 hours 29 g of water have distilled and the acid number is 5 mgKOH/g. The reaction mixture is cooled to 65° C. and 70 g of acetic acid and 250 g of water are added. 
     A solution of clays and shales inhibitor is obtained with a dry content of 45.97% by weight. 
     EXAMPLE 4 
     Preparation of the Amino-Ester of Sebacic Acid with Triethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 178.8 g (1.199 moles) of triethanolamine are charged, heat is applied to reach 100° C. and 121.2 g (0.599 moles) of sebacic acid are added. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. Heating is applied to reach 170° C. in about one hour. After 3 hours 21 g of water have distilled and the acid number is 10 mgKOH/g. The reaction mixture is cooled to 54° C. and 65 g of acetic acid and 250 g of water are added. 
     EXAMPLE 5 
     Preparation of the Amino-Ester of Fumaric Acid with Triethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 208.9 g (1.400 moles) of triethanolamine are charged, heat is applied to reach 60° C. and 77.4 g (0.675 moles) of fumaric acid are added. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. Heating is applied to reach 155° C. in about 4.5 hours. At this point 24 g of water have distilled and the acid number is 15 mgKOH/g. The reaction mixture is cooled to 80° C. and 90 g of acetic acid and 240 g of water are added. 
     EXAMPLE 6 
     Preparation of the Amino-Ester of Maleic Anhydride with Triethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 313.3 g (2.1 moles) of triethanolamine and 98.1 g (1.0 moles) of maleic anhydride are charged. Heat is applied to reach 80° C. and this temperature is kept for 0.5 hours. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. Heating is applied to reach 155° C. in 5 hours. At this point 18 g of water have distilled and the acid number is 15 mgKOH/g. The reaction mixture is cooled to 100° C. and 10 g of acetic acid and 350 g of water are added. 
     EXAMPLE 7 
     Preparation of the Amino-Ester of Adipic Acid with Methyldiethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 238.4 g (2.0 moles) of methyldiethanolamine are charged, heat is applied to reach 100° C. and 146.2 g (1.0 moles) of adipic acid are added. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. Heating is applied to reach 160° C. in 5 hours. At this point 36 g of water have distilled and the acid number is 10 mgKOH/g. The reaction mixture is cooled to 50° C. and 110 g of acetic acid and 320 g of water are added. 
     EXAMPLE 8 
     Preparation of the Amino-Ester of Adipic Acid with Dimethylethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 196.3 g (2.2 moles) of dimethylethanolamine are charged, heat is applied to reach 50° C. and 146.2 g (1.0 moles) of adipic acid are added. Heating is applied so that the temperature of the distillation vapors do not exceed 105° C. After 6 hours the temperature of the reaction mixture reaches 190° C. 75.0 g of distillate are obtained, which contains 48 g of dimethylethanolamine and the acid number is 90 mgKOH/g, corresponding to a conversion degree of 75%. The reaction mixture is cooled to 50° C. and 125 g of acetic acid and 280 g of water are added. 
     EXAMPLE 9 
     Preparation of the Amino-Amide of Succinic Anhydride with Aminoethylethanolamine 
     In a 1 liter reaction vessel of volume equipped with stirrer, thermometer and distillation head 208.3 g (2.0 moles) of aminoethylethanolamine are charged, heat is applied to reach 50° C. and 100.1 g (1.0 moles) of succinic anhydride are added; due to the exothermic reaction the temperature increases to 150° C. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. This temperature is maintained for 2 hours, 18.0 g of distillate are collected and the amine number is 390 mgKOH/g. The reaction mixture is cooled to 90° C. and 120 g of acetic acid and 250 g of water are added. 
     The product has a dry content of 45.8% by weight and a pH value of 6.9. 
     EXAMPLE 10 
     Preparation of the Amide of Adipic Acid with Aminoethylethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 208.3 g (2.0 moles) of aminoethylethanolamine are charged, heat is applied to reach 110° C. and 146.2 g (1.0 moles) of adipic acid are added. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. Heating is applied to reach 160° C. After 4.5 hours the amine number is 360 mgKOH/g and the collected distillate is 35.5 g. The reaction mixture is cooled to 100° C. and 120 g of acetic acid and 280 g of water are added. 
     The product has a dry content of 47.0% by weight and a pH value of 6.84. 
     EXAMPLE 11 
     Preparation of the Amino-Amide of Sebacic Acid with Aminoethylethanolamine 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 152.2 g (1.462 moles) of aminoethylethanolamine and 147.8 g (0.7308 moles) of sebacic acid are charged; heating is applied to reach 155° C. Vacuum is applied to the reaction vessel to reach a residual pressure of about 20 mm Hg. The temperature is maintained for 5 hours. The amine number is 310 mgKOH/g and 25.5 g of distillate are collected. The reaction mixture is cooled to 90° C. and 87 g of acetic acid and 250 g of water are added. 
     The product has a dry content of 47.41% by weight and a pH value of 6.9. 
     EXAMPLE 12 
     Preparation of the Amino-Amide of Adipic Acid with Diethylenetriamine (DETA) 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 300.0 g (2.901 moles) of DETA are charged and heated to 60° C. under nitrogen atmosphere; 212.6 g (1.455 moles) of adipic acid are added and the temperature rises to 130° C., due to the formation of the salt; heating is applied to reach 160° C. and the distillation water is collected. After 6 hours the acidity number is 10, corresponding to a 97.1% conversion. 
     The reaction mixture is cooled to 66° C. and 163.5 g (2.18 moles) of 80% acetic acid and 290 g of water are added. 
     EXAMPLE 13 
     Preparation of the Amino-Amide of Terephthalic Acid with Diethylenetriamine (DETA) 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 300.0 g (2.901 moles) of DETA are charged and heated to 60° C. under nitrogen atmosphere; 241.7 g (1.4549 moles) of terephthalic acid are added and the temperature rises to 130° C., due to the formation of the salt; heating is applied to reach 178° C. and the distillation water is collected. After 6 hours the acidity number is 20, corresponding to a 94% conversion. 
     The reaction mixture is cooled to 90° C. and 163.5 g (2.18 moles) of 80% acetic acid and 320 g of water are added. 
     EXAMPLE 14 
     Preparation of the Amino-Amide of Adipic Acid with Triethylenetetramine (TETA) 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 400.0 g (2.7386 moles) of TETA are charged and heated to 60° C. under nitrogen atmosphere; 194.7 g (1.3323 moles) of adipic acid are added and the temperature rises to 131° C., due to the formation of the salt; heating is applied to reach 171° C. and the distillation water is collected. After 5 hours the acidity number is 2.4 corresponding to a 99% conversion. 
     The reaction mixture is cooled to 68° C. and 256.7 g (4.11 moles) of 80% acetic acid and 270 g of water are added. 
     EXAMPLE 15 
     Preparation of the Amino-Amide of Terephthalic Acid with Triethylenetetramine (TETA) 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 292.2 g (2.0 moles) of TETA are charged and heated to 60° C. under nitrogen atmosphere; 166.2 g (1.0 moles) of terephthalic acid are added and the temperature rises to 135° C., due to the formation of the salt; heating is applied to reach 190° C. and the distillation water is collected. After 5 hours the acidity number is 8 corresponding to a 97% conversion. 
     The reaction mixture is cooled to 88° C. and 225 g (3.0 moles) of 80% acetic acid and 190 g of water are added. 
     EXAMPLE 16 
     Preparation of the Amino-Amide of Terephthalic Acid with Tetraethylenetetramine (TEPA) 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 300 g (1.5848 moles) of TEPA are charged and heated to 50° C. under nitrogen atmosphere; 125.4 g (0.7545 moles) of terephthalic acid are added; heating is applied to reach 196° C. and the distillation water is collected. After 6 hours the acidity number is 9 corresponding to a 96% conversion. 
     The reaction mixture is cooled to 75° (and 226.4 g (3.0 moles) of 80% acetic acid and 166 g of water are added. 
     EXAMPLE 17 
     Preparation of the Amino-Amide of Adipic Acid with Tetraethylenepentamine (TEPA) 
     In a 1 liter reaction vessel equipped with stirrer, thermometer and distillation head 300 g (1.5848 moles) of TEPA are charged and heated to 50° C. under nitro-en atmosphere; 110.4 g (0.7554 moles) of adipic acid are added; heating is applied to reach 188° C. and the distillation water is collected. After 3 hours the acidity number is 3 corresponding to a 98.5% conversion. 
     The reaction mixture is cooled to 57° C. and 226.4 g (3.0 moles) of 80% acetic acid and 157 g of water are added. 
     Performance Testing 
     Performance tests have been carried out to determine the ability of the clays and shales inhibitors of the present invention to inhibit the swelling of a bentonite in a water base fluid. 
     The following method has been used, where ppb means “pounds per barrel”: 
     350 ml tap water and 8 g (8 ppb) of clays and shales inhibitor (calculated on 100% active substance) are charged into a clean glass beaker. 
     10 g of bentonite (10 ppb) are added and the mixture (the mud) is mixed with a Hamilton Beach Mixer for 30 minutes. 
     Additional 10 grams of bentonite are added and the mud is mixed for additional 30 minutes; the procedure is repeated until a total of 40 ppb of bentonite have been added. The rheology of the mud is measured by means of a rotational viscometer Fann mod. 35 at 25° C. The mud is then aged in special cells, which are kept rolling in a special heated rolling oven at 65° C. for 16 hours, and the rheology is again measured after the aging. 
     The additions of 10 g of bentonite and the heat aging are repeated until the mud becomes too viscous to be measured. 
     The performance tests have been carried out as described here above on the clays and shales inhibitors of the present invention as prepared in the Examples 1 to 17, on diethanolamine (DEA) and on triethanolamine (TEA); the theological data (Yield Point) are reported in Table 1 and in Table 2, where the first column reports the ppb of bentonite added before the measurement, “AHR” means “after hot rolling”. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Ex. 1 
                 Ex. 2 
                 Ex. 3 
                 Ex. 4 
                 Ex. 5 
                 Ex. 6 
                 Ex. 7 
                 Ex. 8 
                 Ex. 9 
                 Ex. 10 
                 Ex. 11 
                 DEA 
                 TEA 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 40 
                 18 
                 25 
                 31 
                 32 
                 12 
                 5 
                 5 
                 9 
                 4 
                 3 
                 10 
                 330 
                 90 
               
               
                 40 Ahr 
                 7 
                 9 
                 10 
                 14 
                 7 
                   
                 9 
                 7 
                 1 
                 −1 
                 2 
                   
                 195 
               
               
                 50 
                 15 
                 17 
                 21 
                 22 
                 23 
                 2 
                 20 
                 22 
                 2 
                 1 
                 5 
                   
                 330 
               
               
                 60 
                 32 
                 33 
                 38 
                 41 
                 115 
                 27 
                 35 
                 44 
                 6 
                 9 
                 13 
               
               
                 60 Ahr 
                   
                   
                   
                   
                 61 
                 132 
                   
                 13 
               
               
                 70 
                 57 
                 60 
                 65 
                 63 
                   
                 109 
                 67 
                 99 
                 14 
                 21 
                 29 
               
               
                 70 Ahr 
                   
                   
                   
                   
                   
                   
                 69 
                 108 
                 15 
                 26 
                 30 
               
               
                 80 
                 106 
                 110 
                 112 
                 120 
                   
                   
                 142 
                   
                 41 
                 75 
                 86 
               
               
                 80 Ahr 
                 85 
                 77 
                 91 
                 125 
                   
                   
                 134 
                   
                 66 
                 98 
                 142 
               
               
                 90 
                 143 
                 138 
                 172 
                 330 
                   
                   
                 330 
                   
                 153 
                 330 
                 330 
               
               
                 90 Ahr 
                 147 
                 176 
                 320 
                   
                   
                   
                   
                   
                 178 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Ex. 12 
                 Ex. 13 
                 Ex. 14 
                 Ex. 15 
                 Ex. 16 
                 Ex. 17 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 40 
                 15 
                 1 
                 2 
                 −1 
                 0 
                 1 
               
               
                 40 Ahr 
                 330 
                 0 
                 2 
                 1 
                 0 
                 1 
               
               
                 50 
                   
                 6 
                 12 
                 6 
                 5 
                 6 
               
               
                 60 
                   
                 9 
                 16 
                 12 
                 8 
                 10 
               
               
                 60 Ahr 
                   
                 330 
                 20 
                 6 
                 4 
                 4 
               
               
                 70 
                   
                   
                 88 
                 5 
                 5 
                 2 
               
               
                 70 Ahr 
                   
                   
                 330 
                 2 
                 3 
                 0 
               
               
                 80 
                   
                   
                   
                 33 
                 36 
                 22 
               
               
                 80 Ahr 
                   
                   
                   
                 51 
                 48 
                 21 
               
               
                 90 
                   
                   
                   
                 330 
                 330 
                 160