LABORATIORY STUDY AND FIELD APPLICATION OF WATER TREATMENT RESIDUE LIME SLUDGE PROFILE CONTROL AGENT
PED, 1997, 24(4):75-79Zhao Puchun (No. 3 Oil Production Co., Zhongyuan Petroleum Exploration Burean, Henan, 252434)
Zhongyuan oil field is a complex oil field with many small fault blocks and shallow and quite heterogeneous reservoirsThrough high rate production by high pressure water injection, the oil field has entered its high water-cut production period,and secondary large porous channels created, making water plugging and profile control difficult. Many kinds of profile control agent were applied before 1996, resulting in varying degrees of benefit. In 1996, lime sludge profile control agent was developed, and broadly applied, 51 jobs were completed with the success ratio of 98%. The lime sludge profile control agent,containing CaCO3, MgCO3, CaSO4, FeS, Ca(OH)2 and so on, is a grey suspension with a density of 1.08g/cm3. Laboratory experiments indicate that the lime sludge profile control agent has high plugability high flush resistance and long term validity. For field application, the water treatment residue with 20%-30% lime sludge can be transported to well sites, and injected into target zones through workstrings. In the field tests, the profile control agent increased the actuating pressure and water injection pressure of water injectors, and decreased apparent water injectivity index, significantly improved water intake profile, lengthened average validity term of water injectors, and thereby increased the oil production of the oil wells and lowered their water production.