| Along with the continual enlarge of the area of exploration and development, at the past few years, some non -homogeneous reservoirs with high porosity and high permeability have been found, especially in the offshore oil field. They have remarkable characters, such as extensive distribution, shallow hidden, thick oil pay zone, rich reserves, high porosity and high permeability but unconsolidated. Those make the formation damage easily during drilling and completion operation. Which causes low production. For enhancing production, and getting the investment back as quickly as possible, the formation is needed to be ACIDIZING for removing the damage. The representative example is the SZ36-1 oil field in the BOHAI BAY.SZ36-1 oil field is the biggest oil field with high porosity and high permeability which had been exploited, which have extensive distribution, shallow hidden, many series pay zone, thick oil pay zone, high porosity and high permeability, great different permeability between different zone, unconsolidated sand formation. It has a big scale of damage during operation of drilling and, completion and production. Aimed at the formation particularity of SZ36-1 oil field , combined the difficulty of offshore ACIDIZING, this paper presents the research of reservoir damage mechanism and types, the mechanism of stimulation, optimizing the acid fluid system, ACIDIZING technology, acid fluid diverting, optimizing the design and stimulation and real-time ACIDIZING monitoring and evaluation, and have fully understanding about ACIDIZING mechanism and the damage factor. The research accomplishment of ACIDIZING technology, acid fluid system and mathematical simulation not only formed practical sandstone ACIDIZING countermeasure and complex ACIDIZING technology and technique in BOHAI oil field, but also provided some experiences for the similar conditions in the whole world. The application of research accomplishments had gained a remarkable economic beneficial result.I through the research of the reservoir characters and geology conditions and sensible evaluation experiment, the objectivity of existing different kinds of potential damage factors was proven. The mechanism, scope, types and degree of the damage had been researched, the aim of ACIDIZING and removing plugging had been becoming clear.II According to the research of ACIDIZING the reservoir of high porosity and high permeability but unconsolidated, the results show the preferred acid fluid system should be deep penetrability, weak corrosion and stabilizing the framework, which consist of hydrochloric acid, mud acid and fluoboric acid. The ACIDIZING mechanism of fluoboric acid had been researched in detail. The research showed the temperature had little effect on the hydrolytic velocity of equilibrium constant, although it had effect on the hydrolytic velocity of fluoboric acid. The first hydrolytic process can expressed as the whole hydrolytic process at 80 C. So the at high temperature the reaction velocity of fluoboric acid was slower than mudacid ,it can get longer acid penetration distance. Because of its slow reaction velocityand weak removing plugging, this acid fluid system was appropriate to the reservoirwith high porosity and high permeability. Fluoboric acid had strong dissolubility and had the ability of stabilizing clay. Thereservoir handled by fluoboric acid can stabilize clay and prevent fine particlemigration, Optimizing mud acid-fluoboric acid sectional injecting technology as the bestACIDIZING technology. The acid fluid formula had been formed and the ACIDIZINGeffect evaluated and the best scope of the treatment parameters had been given.III The study on the diverting ACIDIZING technique experiment and diverting dynamic simulation. According to the character of many series of strata and thick oil layer and great difference between different layers, the reasonable diverting of acid fluid had been considered in the ACIDIZING technology. And based on the character of reservoir permeability and p...
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