Laboratory Experimental Study Of Polymer-surfactant Flooding In Cha 30 Fault Block Reservoir With High-temperature And High-salinity

Cha 30 fault block reservoir is typical high-temperature (90℃) and highsalinity(31516mg/L) reservoir with significant heterogeneity (inhomogeneitycoefficient is more than 0.795) which development situation is not very good,especially when the water flooding recovery of Cha 30 fault block reservoir is only22.4%. So, it is of great importance to study the tertiary oil recovery techniques andmethods of Cha 30 fault block. According to the situation of Cha 30 fault block and incombination with enhanced oil recovery methods, the article introduced polymer/surfactant compound system oil displacement methods to enhance the oil and gasrecovery. Using oil/water interfacial tension (IFT) up to 10-2mN/m as a selecting factor,experiments and appraisal has been made about surfactant. The experiments resultsshowed that when the density of surfactant CDS-1 is between 0.01% and 0.05%, theIFT could reach 10-2mN/m, especially when the density of CDS-1 is 0.01%, the IFTdropped to 0.0424mN/m which reduced the usage of surfactant and cost of compoundsystem. Then by using the compound of CDS-1, polymer and cross-linking system, westudied the relationship between polymer density, surfactant density and apparentviscosity, and has came to the conclusion that association polymer HNT201-3(0.05%CDS-1/1250mg/L)and 0.05%CDS-1 /CDS-1 weak gel cross-linkingsystem(polymer HLD-1 800mg/L, hydroxyphenol with density of50mg/L,methenamine with density of 115 mg/oxalic acid with density of 180 mg/L) isbetter than other compounds. And with further stable and static adsorptionexperiments were the possibility of combination flooding in the oilfield. Thedisplacement experiment has proved that these two compounds systems have highersweep efficiency and oil displacement efficiency). The enhanced oil recovery is21%OOIP when using 1250mg/L HNT201-3/0.05% CDS-1 with complex system slugin 0.33PV. And the enhanced oil recovery is 22%OOIP when using weak gel flooding)in mixed-phase with slug in 0.3PV.Polymer/ surfactant compound system were used in Cha 30 block field and S/Pflooding oil displacement microscopic mechanisms using S/P flooding in ultra lowdensity were studied, so as to provide technical support for the use of polymer/surfactant compound system in oilfield with high-temperature, high salinity and serious heterogeneity.