A Study On Further Water Flooding After Polymer Solution Slug For Eastnorth Area Of Lamadian Oilfield

On January 2001, the northeast block of Polymer region in La ma-dian oil field, the polymer amount used in entire area has reached 570PV ·mg/L of the project designed But because of the big thickness, high permeability of Pu 11-2 in this block, big change in plane growth and the spatial mop of oil layer, and the use of polymer flooding after more than 20 years water flooding development, the aeolotropism of oil layer in plane and longitudinal direction become more serious, such as using the conventional method to carry on the following water flooding, the water cut ascending velocity is faster, the remaining reserves have not obtained use well. Therefore, developing a research on the opportunity as well as the method of the follow-up water flooding of this block has a vital significance.This article evaluated the developing effect prior to the following water flooding after polymer slug of northern east block, analyzed the distribution of residual oil before the follow-up water flooding, in this foundation, determined the development opportunity of the follow-up water flooding, and proposed the effective methods, moreover, proceeded the technical economic evaluation to the follow-up water flooding effectOn the basis of the research results, an investigation on the opportunity and methods of follow-up water flooding was developed, considering that the opportunity that north east block polymer drive changes to the following water flooding was supposed to be the time when the water cut of oil well is bigger than 92% and the following water flooding should proceed according to the water cut of oil well. The proposed methods of following water flooding include: prior to following water flooding, suitable increase the polymer amount; in the later period of polymer injection, for those well groups whose water cut decrease relatively, on the base of best economic efficiency, develop the slug injection at different concentrations; in the period of the following water flooding, injection with low speed so as to control invalid injection-production; for injection well laying of permanent injector producer interval zone, production well blocks off high water cut zone, effectively governing invalid injection/production circulation; for internal residual oil, the measures on the depth of injection with "block and profile" and oil well with "deep block and profile" are used, increasing producing degree of poor reservoir; internal residual oil is produced, using the condition of high pressure and periodical injection in sequent water flooding phase; retention residual oil in well network is also produced through the regulation of...