Abstract: At present, the formation pressure coefficient of SZ36-1 Oilfield is between 0.7~1.10 from the original normal 1.0 after years of water injection development, and the reservoir heterogeneity, contradiction between layers, high pressure and low pressure formation coexist. SZ36-1 Oilfield has become a complex pressure reservoir system, drilling and completion operations get more difficult. During adjustment development of the Oilfield, only 1.03~1.10 g/cm³ density completion fluids could be used, so completion fluid is leaked seriously and it needs a long time to flow back. In this respect, the clay free weak gel completion fluid system is proposed and applied, i.e. using it as the perforation fluid. The system will form the sealing zone in the perforation holes to improve the low pressure formation bearing pressure capacity, and prevent completion fluid from loss. After completion, broken-gel fluid is injected into to break the gel in the perforation holes, and the fluid flows back to the surface. Field application results show that the system could significantly reduce the completion fluid leakage rate higher than 90% in the complex pressure reservoir and shorten the flowback time, the formation protection effect is remarkable.

Key words: SZ36-1 Oilfield, high-porosity &, high-permeability formation, complex pressure reservoir, clay free weak gel completion fluid

摘要： 绥中36-1油田经多年注水开发,地层压力系数已由1.0变成了0.7~1.10,储层非均质性严重,层间矛盾突出,高压地层与压力衰竭地层共存,成为复杂压力油气藏系统,增加了后续钻完井作业的难度。在油田调整开发阶段,由于只能采用1.03~1.10 g/cm³密度的完井液,造成砾石充填完井时完井液漏失严重,返排时间长。为此,提出并应用了弱凝胶封堵性完井液体系,即,无固相弱凝胶射孔液,既可在射孔孔眼中形成弱凝胶封堵带,提高低压地层承压能力,又可阻止完井液漏失,完井后进行破胶和压差返排。现场应用表明,该体系能显著降低复杂压力油气藏完井液漏失速率90%以上,油井返排时间短,油气层保护效果显著。

关键词: 绥中36-1油田, 高孔高渗储层, 复杂压力油气藏, 弱凝胶封堵性完井