NEW WORK GROUP Revision of Starch Specifications in API 13 A Saleh Al-Ammari Saudi Aramco June 29 th, 2010

Starch or amylum is a carbohydrate consisting of a largecarbohydrate number of glucose units joined together by glycosidic bonds.glucoseglycosidic bonds This polysaccharide is produced by all green plants as anpolysaccharideplants energy store. It is contained in potatoes, wheat, maize (corn),potatoeswheatmaize ricerice, and cassava.cassava What is Starch?

Drilling Fluid Materials API SPECIFICATION 13A 11.1 Description a. Drilling grade starch can be manufactured from several kinds of native starches. The starch should be made cold water hydratable (pregelatinized) and may be treated further in such a way that it is suitable for use as a filtrate reducing agent in water-base drilling fluids. b. Drilling grade starch should be free-flowing and free from lumps. Drilling grade starch shall be deemed to meet this specification if a composite sample representing no more than one day's production conforms to the physical requirements of Table 11.1, represents the product produced, and is controlled by the manufacturer. SECTION 11 STARCH

Table STARCH PHYSICAL REQUIREMENTS Requirement Specification Suspension Properties: Viscometer Dial Reading at 600 rpm in 40 g/L Salt Water 18, maximum in Saturated Salt Water 20, maximum Filtrate Volume in 40 g/L Salt Water 10 cm 3, maximum in Saturated Salt Water 10 cm 3, maximum Residue Greater than 2000 micrometers No residue Drilling Fluid Materials API SPECIFICATION 13A

Formulation and order of addition: (one barrel) Average Fluid Properties: Waterbbl:0.97Densitylb/ft 3 :66 XC-Polymerlb:1.0PVcp:10 Starchlb:4.0YPlb/100ft 2 :14 Limelb:0.510 sec gellb/100ft 2 :3 CaCO 3 “fine”lb: min gellb/100ft 2 :6 Filtrateml/30min:10 pH:9.5 Example 1 – Clay free mud

Formulation and order of addition: (one barrel) Average Fluid Properties: Waterbbl:0.97Densitylb/ft 3 :66 XC-Polymerlb:1.0PVcp:10 Starchlb:4.0YPlb/100ft 2 :14 Limelb:0.510 sec gellb/100ft 2 :3 CaCO 3 “fine”lb: min gellb/100ft 2 :6 Filtrateml/30min:NC pH:9.5 Example 1 – Clay free mud

Formulation and order of addition: (one barrel) Average Fluid Properties: Waterbbl:0.92Densitypcf:80 Bentonitelb:10.0PVcp:18 Limelb:0.5YPlb/100ft 2 :16 Starchlb:4.0Gelslb/100ft 2 :3/6 Baritelb:122Filtrateml/30 min:8 pH: Example 2 – Bentonite mud

Formulation and order of addition: (one barrel) Average Fluid Properties: Waterbbl:0.92Densitypcf:80 Bentonitelb:10.0PVcp:18 Limelb:0.5YPlb/100ft 2 :16 Starchlb:10.0Gelslb/100ft 2 :3/6 Baritelb:122Filtrateml/30 min:8 pH: Example 2 – Bentonite mud

Formulation and order of addition: (one barrel) Average Fluid Properties: Waterbbl:0.67Densitylb/ft 3 :89 Defaomergal:0.01PVcp:16 XC-Polymerlb:1.0YPlb/100ft 2 :20 Starchlb:6.010 sec gellb/100ft 2 :4 Limelb:0.510 min gellb/100ft 2 :8 CaCl 2 lb245Filtrateml/30min:6 CaCO 3 “fine”lb:22.0pH:9.5 Chloridemg/l:357k Example 3 – CaCl 2 mud

Formulation and order of addition: (one barrel) Average Fluid Properties: Waterbbl:0.67Densitylb/ft 3 :89 Defaomergal:0.01PVcp:16 XC-Polymerlb:1.0YPlb/100ft 2 :20 Starchlb: sec gellb/100ft 2 :4 Limelb:0.510 min gellb/100ft 2 :8 CaCl 2 lb245Filtrateml/30min:6 CaCO 3 “fine”lb:22.0pH:9.5 Chloridemg/l:357k Example 3 – CaCl 2 mud

1.Increase in concentration 2.Thermal degradation at lower temperature 3.Use of expensive fluids loss additives 4.Encounter more operational problems 5.Face interrupted inventories 6.Difficulty in controlling the quality 7.Ineffective API monogram Conclusions

1.Improve the suspension properties 2.Specify more particles size distributions 3.Include temperature limitation 4.Introduce classifications 5.Develop analytical methods 6.Standardize nomenclature Suggestions

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