Comparison of Scaling in Strong Alkali and Weak Alkali ASP Flooding Pilot Tests
H. Guo, Y. Q.Li, Y. Zhu, F. Y.Wang, D. B.Kong and R. C.Ma
Event name: IOR 2017 - 19th European Symposium on Improved Oil Recovery
Session: Poster Introductions 3
Publication date: 24 April 2017
Info: Extended abstract, PDF ( 1.19Mb )
Price: € 20
Scaling was proven great challenge to prevent ASP flooding going from laboratory to field especially in low oil price era. Both strong alkali ASP flooding (SASP) and weak alkali ASP flooding（WASP） tests were compared from perspective of scaling to help understand ASP technique. ASP field tests in Daqing indicated that scaling（Na2CO3） due to strong alkali（NaOH）was much more severe than weak alkali, which reflected by more pump stuck, higher pump checking rate and short pump checking time.Scaling type in WASP was different from SASP and the percentage of silicate scale difference distinguished WASP from SASP scale. WASP scaling samples composition was mainly carbonate scale, while a majority of scale from SASP composition was carbonate and silicate, and the proportion of silicate varied with injection stages. Different from WASP, SASP scaling included scaling and formation damage, thus it had greater influence on oil production in SASP than WASP. Scaling mechanism was different between WASP and SASP. Compared with SASP, WASP supersaturation was much lower and this made it uneasy to form new mineral particle. PH value was crucial to scale type. Different ASP blocks proved similar scale type at the same PH value, and as PH value increased, silicate scale content decreased.