非常规油气田微小井眼钻井连续管滑动遇阻牵引机理研究

The Coiled Tubing (CT) Microhole Drilling can improve development benefit and cost cutting for the maturing field, shale gas, coal seam gas, tight gas, three low reservoirs (low pressure,low permeability, low-yield), inaccessible reservoirs and other unconventional oil and gas resources. It can reduce reservoir pollution, protect the environment and have a very wide application prospects in China. However its wellbore diameter is very small, the CT drill string cannot revolute in the microhole, friction resistance of CT sliding drilling is so seriously that it is difficulty to run back into the well. This has directly influenced the application and popularization of the CT sliding Microhole Drilling technology in the exploration of unconventional oil and gas resources. So the subject is studied on the based of the research on the major sliding resistance factors of CT string in microhole in the way of various artificial simulation and experimental study by the Fluent, Protel, UG and other software. Fristly,the CT sliding resistance mechanism will be studied to establish the parameter prediction model of sliding resistance to optimize hydraulic source and hydraulic drive circuit in the CT Microhole Drilling. Secondly, the tractor control model is established to reveal its mechanism and to optimize control system. Thridly,the three-dimensional simulation model of microhole tractor is built to optimize the experiment prototype of microhole tractor to make its performance to meet the practical requirements. All these lay the foundation for solving the CT sliding resistance bottleneck technology in Microhole Drilling, which will promote development of Microhole CT Drilling technology in the exploration of unconventional oil and gas resources.

微小井眼连续管（CT）钻井技术在提高老油田，页岩气、煤层气及致密气，"低压、低渗、低产"三低油气藏等非常规油气藏的开发效益，降低成本，减少油层污染等方面优势突出，在中国应用前景广泛。但因微小井眼直径小，不旋转的CT在井眼中滑动遇阻严重，影响微小井眼CT滑动钻井技术的应用与推广。因此在对CT在微小井眼中的主要遇阻因素进行研究的基础上，拟采用模拟仿真与实验研究相结合的方法，运用Fluent、Protel、UG等软件，先后构建微小井眼钻井CT滑动遇阻参数预测模型，研究CT滑动遇阻机理；构建牵引液压驱动模型，揭示CT遇阻牵引液压驱动机理，优化液压驱动管路；构建牵引器控制模型，揭示CT遇阻牵引控制机理，优化控制系统；构建牵引器三维仿真模型，优化并加工牵引器实验样机，使其性能达到应用要求，为解决非常规油气藏微小井眼钻井CT滑动遇阻大的瓶颈问题奠定理论基础，推动非常规油气田微小井眼CT钻井技术的发展。

微小井眼CT滑动钻井技术在提高老油田，页岩气、煤层气及致密气等非常规气藏的开发效益，降低成本，保护环境等方面优势突出，在中国应用前景广泛。但因井眼直径小，CT强度低、在井眼中不旋转、滑动遇阻严重、管柱送进困难、沿程循环压耗大，严重影响微小井眼CT滑动钻井技术的应用与推广，因此分析微小井眼CT滑动摩阻、钻井液循环压差等因素，研究牵引器的牵引机理，设计微小井眼CT钻井牵引器，对推动微小井眼CT钻井技术的发展有重要意义。. 1.围绕微小井眼CT钻井牵引器牵引力参数设计，研究井下CT管柱载荷模型，计算分析不同直径CT分别在φ89mm微小井眼的斜直井井段、弯曲井段、水平井段中的临界屈曲和接触、摩阻载荷，研究牵引力与轴向力、CT牵引长度、井眼直径、CT直径、井斜角等参数的关系，确定微小井眼CT滑动钻井牵引器牵引力参数的设计范围。. 2.针对微小井眼CT钻井循环系统的特点，研究循环压耗模型，计算微小井眼CT钻井液在卷筒上和井下的CT水眼内、以及井眼环空的沿程循环压耗，分析水力参数对牵引器的液压驱动性能的影响，优选微小井眼钻井CT，设计CT牵引器的水力参数。. 3.研究牵引器的牵引机理，设计了依靠钻井液循环压差驱动的电控液压驱动牵引器，分析工作原理，建立牵引器主要零部件的受力模型和运动模型，确定主要部件的性能参数，优化牵引器主要零部件的设计。. 4.围绕电控液压驱动牵引器的总体结构方案，设计牵引器的液压循环驱动系统和对应的电子控制系统，研究电控液压驱动牵引器的液压驱动工作原理与电子控制原理，解决了牵引器动力驱动与控制的问题，为牵引器后期生产开发奠定理论基础。. 通过该项目的研究，它将解决微小井眼CT井下作业遇阻的科学问题，推动微小井眼CT钻井技术的快速发展与广泛应用，提高老油田、三低油气藏等难动用油气藏的开发效益，尤其是在我国非常规油气藏的勘探开发方面，有着广泛的应用前景。