ACIDIZING-WATER SHUTOFF"PROFILE CONTROL TEST IN WEICHENG OIL FIELD

A new technology test of controlling water absorption profile in water injec-tion well by combining ’acidizing-water shutoff" together was conducted in Weicheng oil fleld aiming at the reservoir characterlstics of high pressure, low permeability, high tempera-ture and high salinity of this field. By means of acidizing technology of acidizing before water shutoff, water shutoff before acidzing or adding precipitation reaction fluid, the plugging po-sition was removed away from nearby well bore, thus, not only water was inJected into for-mation, but also the problems of micro-fractures and fingering of injection water in high pressure well were settled. By doing so, water absorption profile of the water injection well was adjusted, water sweeping area was enlarged, water flooding development effect was im-proved. Among the 21 producers controlled by the 8 treated injectors, 17 producers became effective, the effective rate was 80. 9%. The average daily incremental oil of the well group was 2. 3 t, water decreased by 8. 6m’ every day. By the end of December 1997, the accumu-lated lncremental oil was 2894 t, water decreased by 1254m3 in total, the effective days were 158.