PDF-HSD钻井液体系在渤海科学探索井的应用

Application of PDF-HSD drilling fluid in scientific exploitation well of Bohai Oilfield

针对BZ21-2-1井潜山储层特征和高温高压的钻井实际,研发了PDF-HSD抗高温无固相钻井液体系。该钻井液体系在潜山地层准152.4 mm井眼4 881.5~5 141.0 m井段应用成功,不仅有效地保护了潜山储层,而且较低的钻井液密度也有效预防了潜山裂缝性地层的恶性漏失。整个钻井过程中钻井液性能稳定,应用结果表明：PDF-HSD钻井液体系具有优良的抗温能力;钻井液滤液与煤油的油水界面张力低,具有较好的防水锁性能;渗透率恢复率大于85%,油气层保护效果显著;满足高温高压深井及低孔低渗型油藏的钻井作业和油气层保护需要。该体系的成功应用,为今后渤海油田类似高温高压及低孔低渗型储层钻井作业提供了技术保障。

This paper has researched the anti-high temperature and clay free drilling fluid which is named PDF-HSD according to the reservoir characteristics of buried hill and the actual drilling of deep well with high temperature and high pressure.The new drilling fluid has been applied successfully in the well intervals from 4,881.5 m to 5,141.0 m of Well BZ21-2-1,which protected the buried hill reservoir.The low density of drilling fluid prevented the vicious lost in buried hill fractured reservoir.The properties of drilling fluid were stable during the drilling.Application results show that PDF-HSD drilling fluid has excellent properties such as anti-high temperature,low interfacial tension and anti-water locking.The permeability recovery ratio is greater than 85% and the effect of reservoir protection is obvious.The PDF-HSD drilling fluid is completely satisfied with the needs of drilling operation and reservoir protection for the high temperature,deep well,low porosity and low permeability reservoir.The successful application of drilling fluid offers the technology security for the similar reservoir in Bohai Oilfield.