油基泡沫钻井流体技术研究

针对水基泡沫钻井流体在水敏性地层易造成泥页岩水化膨胀，气体钻井遇到地层出水时即转换成水基泡沫钻井流体，在此过程中易造成井壁坍塌等问题，开展了油基泡沫钻井流体技术研究。研制出以油基发泡剂DRI-YF-1和油基稳泡剂DRI-YW-1为主要组分的油基泡沫钻井流体，进行了发泡体积、半衰期、流变性、抗高温和抗污染等性能评价实验。实验结果表明，油基泡沫钻井流体密度范围为0.17～0.38 g/cm³，其发泡体积和半衰期比国外同类产品高，流变性好，抗高温、抗污染能力较强。并观察了油基泡沫和油包水泡沫微观结构，提出了水进入油基泡沫前后的油基泡沫微观结构的假设模型。

A study on the oil-based foam drilling fluid technique

In order to solve drilling problems, such as the shale hydration expansion caused by using water-based foam in water sensitivity formations, the hole collapse caused by the conversion of gas drilling to a water-based foam drilling in the formation when water flows into the well，and others, an oil-based foam drilling fluid composed mainly of the DRI-YF-1 foamer and DRI-YW-1 foam stabilizing agent was studied and developed. Moreover, performances characteristic of its foaming volume, half-life, rheologic properties, high temperature resistance and contamination resistance were experimentally evaluated. The experimental results showed that the density range of the oil-based foam drilling liquid is 0.17～0.38 g/cm³, and both the foaming volume and half-life are superior to that of the similar imported products，so are the rheologic properties, high temperature resistance and contamination resistance characteristics. Furthermore,microstructures of the oil-based foam and oil-water foam were investigated and hypothetical models were proposed for microstructures of the oil-based foam drilling liquid before and after water flew into the oil-based foam.