宝北Ⅲ_2低渗透油藏合理压力保持水平研究

Study on Rational Pressure Maintenance Level in Baobei Ⅲ_2 Low Permeability Reservoir

宝浪油田宝北区块Ⅲ2层系油层孔隙度12.8％，空气渗透率16.8×10-3μm2，地层原油饱和压力19．92MPa，地饱压差仅4．74MPa，气油比250m3／t，原油收缩率38．38％．开发过程中,地层压力保持水平合理与否直接关系到开发的成败．本文通过注来节点分析、油井脱气半径计算，认为：地层压力保持在90％时，在满足注采平衡的条件下，采油井井底流压18MPa，井口油压3．65MPa，注水井井底流压46．66MPa，井口注入压力241.6MPa，注采关系比较协调；油井脱气半径仅1．7m，油井产量不会因此而明显下降．因此，确定Ⅲ2层系合理压力保持水平为原始地层压力的90％。

In strata scries Ⅲ2 of Baobei block, Baolang oilfield, oil reservoir porosity is 12.8%, air- permeability 16.8 ×10-3μm2, formation saturation pressure diffcrence 4.47 MPa, gas -oil ratio 250m3/t, and crude oil shrinkage ratio 38.38％. Whether or not formation pressuremaintenance level is rational is of vital importance to development.Injection-production nodal point analysis and oil well degasification radius calculation show that when formation pressure maintaining at 90％ andinjection - production being under balanced conditions,bottomhole flowing pressure in producers is 18MPa, wellhead oil pressure 3.65MPa; bottomhole flowing pressure in injectors is 46.68MPa, wellhead injecting pressure 24.16MPa, and injection - production relationship is harmonious;degassed radius of oil well is only 1 .7m, but oil rate do not decline grcatly. It is concluded that rational pressure maintenance level in layer Ⅲ2 should be 90°of the original formation pressure.