Abstract:

Sealed coring is an important means of understanding the remaining oil distribution in high watercut oil field. Based on the sealed coring data of Quan4 Formation of Fuyu Oilfield at high water cut stage,this paper systematically demonstrates the qualitative and quantitative method to determine the water flooded situation of sealed coring well. The qualitative methods include: (1) observation with naked eyes; (2) microscope observation; (3) dripping test. The quantitative methods include: (1) determination of sealing condition of cores; (2) correction of oil and water saturation from core analysis; (3) calculation of original oil saturation; (4) determination of oil displacement efficiency of cores and its relationship with water production rate; (5) classification and discrimination criteria of water flooded extent. With this method, we analyzed 5 recent sealed coring wells and counted the waterflooded features of single well and all wells. Combined with the intralayer, interlayer and planar heterogeneity and the position relationship of the injection and production wells near the location of the sealed coring wells, key controlling factors of remaining oil distribution and water flooded condition were proposed, which play a fundamental role in the further mining of remaining oil.

Key words: sealed coring, waterflooded, remaining oil, heterogeneity, injectionproduction relation, key controlling factors