A Study on Alkali Consumption Regularity in Minerals of Reservoirs During Alkali(NaoH)/Surfactant/Polymer Flooding in Daqing Oilfield

Abstract

In the process of oil displacement of ASP (Alkali/ Surfactant/Polymer) flooding , when Alkali interacts with the fluid and minerals of the reservoir, the alkali is subject to be consumed. The consumption regularity is the key factor affecting ASP ingredient, injection plan, scaling regularity for production wells and oil displacement effectiveness. Therefore to study the alkali consumption is of great significance in guiding ASP ingredient, injection project design, and the analysis for oil displacement mechanism. In this paper, aiming at the main components of minerals in the reservoir in Daqing Oilfield, the laboratory study on static alkali consumption for five kinds of minerals (kaolinite, grundite, chlorite, feldspar and quartz) in ASP system and single component NaOH solution are done respectively. The alkali consumption regularities for five kinds of minerals in ASP and single component NaOH solution are concluded. The research indicates that the amount of alkali consumption for kaolinite, grundite, chlorite, feldspar and quartz is changing from larger to less accordingly, but is mainly caused by clay minerals; the average alkali consumption is 18.3% higher than that by matrix minerals. In single component NaOH solution, the alkali consumption styles of clay minerals and the matrix minerals take the chemical reaction as the lead, and the physical adsorption as the second. In ASP system solution, the alkali consumption style of clay minerals, takes the physical adsorption as the lead, and of matrix minerals takes the chemical reaction as the lead. In ASP solution, compared with single component solution, polymer and surfactant have the functions of restraint to alkali consumption in minerals of the reservoir, and the amount of alkali consumption decreases evidently.

Key words: Alkali; Surfactan; Polymer; ASPl; Oil displacement