纳米复合聚合物凝胶阀压井新技术研究

Entire process underbalanced drilling is an advanced new technology of killing well, which plays important part in exploitation specific hydrocarbon resources. The technology of utilization of polymer gel valve enhanced by new type nanometer material on killing well is proposed in this project, aiming at solving issues in kill fluid used for underbalanced completion and other well workover processes. Nano-composite polymer gel with high mechanical strength and toughness which is low impact and adapted to killing operation is expected to be produced through polyacrylamide gel composited with nanometer materials with different property. Coupling agents with different structure are added in polymer gel to enhance the adhesion force between polymer gel and metal sleeve. On that basis, the compression strength of nano-composite polymer gel which is prepared under field environment is simulated. The atomic force microscope and self-designed adhesion force device are used for investigating the adhesion force between nano-composite polymer gel and the shell of pine and the results can provide the basis for the calculation and analysis of the compression strength of the gel in the annular tubes. These studies are expected to produce nano-composite polymer gel valve with high strength which is low impact can be directly utilized for killing well; meanwhile, the mechanisms of killing well by this kind nano-composite polymer gel valve is expected to be clarified in theoretical level, and the theoretical foundation of the practical application of nano-composite polymer gel valve is hoped to be established.

全过程欠平衡钻井技术作为一种新型的钻井技术，在开发特殊油气资源方面发挥着重要作用。本项目针对目前欠平衡完井及其它修井过程使用的压井液所存在问题，提出一种新型纳米材料增强的聚合物凝胶阀压井技术。通过将不同性能的纳米材料与聚丙烯酰胺凝胶进行复合，以期制备出高机械强度、高韧性的适应压井作业的低伤害纳米复合聚合物凝胶。研究在纳米复合聚合物凝胶中加入不同结构的偶联剂，以期增强聚合物凝胶与金属套管间的粘附力。在此基础上，模拟现场使用环境评价所制备的纳米复合聚合物凝胶阀的耐压强度。利用原子力显微镜及自行设计制作的粘附力测试装置研究纳米聚合物凝胶阀与管壁间的粘附力，为凝胶阀在圆形套管中抗压差分析计算提供依据。希望通过这些研究，一方面能够制备出高强度可直接用于压井的、低伤害的纳米复合聚合物凝胶阀，同时从理论上能够阐明这种纳米复合聚合物凝胶阀的压井机理，为纳米复合聚合物凝胶阀的实际应用奠定理论基础。

欠平衡钻完井及修井过程，需要利用压井液以平衡地层压力并封堵井筒防止油气泄漏来实现压井。本项目针对目前欠平衡完井及其它修井过程使用的压井液所存在问题，提出并发明了一种新型纳米材料增强的聚合物凝胶阀压井新技术。通过在常规聚合物凝胶（冻胶阀）体系内添加纳微米粒子（纳米二氧化硅、淀粉、蒙脱土、微球、纳米纤维素）制备出高机械强度的纳微米复合材料增强的冻胶阀，并利用电子万能试验机、流变仪和耐压测试装置研究了粒子的添加对复合凝胶的应力-应变性、粘弹性和耐压强度等机械性能的影响；采用X射线衍射、傅里叶变化红外光谱和差示扫描量热分析研究了增强剂粒子与聚合物的相互作用，并在此基础上通过环境扫描电镜和透射电镜观察增强剂粒子的分布及复合凝胶的微观形貌。. 首先建立了高机械强度、高韧性、高粘附力的纳米复合聚合物凝胶的制备方法。与常规凝胶相比，所制备的纳米二氧化硅复合凝胶的粘弹性模量及耐压强度均显著提高。淀粉的引入同样使得复合凝胶的机械强度得到了明显改善，且表现出良好的动力重构能力。鉴于纳米二氧化硅和淀粉的增强作用，本项目提出了一种“吸附-填充”机理阐述了纳微米粒子（二氧化硅和淀粉）在凝胶三维网络结构内的分布形式以解释此增强作用，即大部分粒子有选择性地吸附到凝胶骨架上，使增强的微观网络呈稳定的六边形，小部分粒子充填于网络孔洞内降低网络的孔隙度，以此分布形态增强复合凝胶的微观结构，进而改善复合体系宏观性能。蒙脱土也能显著改善复合凝胶的宏观机械性能。在此基础上，确定了纳米复合聚合物凝胶的耐压强度与其结构间所存在的内在关系。. 设计并建立了粘附力测量装置及方法，并测定了复合凝胶与不同接触基质间的粘附力。确定了纳米复合冻胶阀主要利用其自身机械强度及与井筒间的粘附力实现压井，即复合凝胶的耐压强度是凝胶机械强度和粘附力共同作用的结果，从而阐明了纳米复合聚合物凝胶阀的压井机理，为纳米复合聚合物凝胶阀的实际应用奠定了理论基础。