Early Stage Carbonate Scaling Characteristics in Dixie Valley Wellbores

Abstract

Carbonate scale in seven Dixie Valley wellbores has been logged, primarily with Schlumberger's multifinger caliper tool. The scale deposition rat is different of reach well and is primarily controlled by the preflash calcium content in the fluid, which varies considerably between wells. The deepest scale is found at the deepest flash point. Above this the scale rapidly increases in thickness and then gradually thins over total lengths up to 1700'. The minimum possible sale length at Dixie Valley is on the order of 600 to 800'. By varying wellhead pressure this length can be extended and the maximum thickness minimized. Estimated times between scale cleanouts will depend on how the wells are produced but will probably average 3 to 4 months for wells with 9 5/8" production casing and 6 to 12 months for wells with 13 3/8" production casing.