钻机井架安全承载能力评定方法研究

STUDY ON METHOD FOR EVALUATING SAFETY LOAD CAPACITY OF DRILLING MAST

钻井是石油天然气勘探与开发的一个重要环节,钻机井架作为钻井设备的关键部分,其承载性能直接关系到整套钻机系统的安全运行。为了准确评定出钻机井架的安全承载能力,提出了以测试应力为基准定量评定含损伤缺陷钻机井架安全承载能力的新方法。首先建立了以测试应力为基准的参考应力修正数学模型,其次推导出以截面锈蚀、杆件初弯曲、载荷偏心等主要损伤缺陷指标所确定的修正函数,得到真实反映含损伤缺陷钻机井架力学行为的数值修正模型,实现对安全承载能力的预测。对现场某型号钻机井架进行逐级加载试验,得到了载荷与应力的关系曲线;结合现场钻机井架实际的损伤缺陷状况修正数值模型,并进行了数值仿真模拟加载试验,实测值与仿真值误差在5%以内,验证了该数值模型的准确性。最后根据仿真预测结果对该井架安全承载性能进行了评定,为提高油气勘探开发过程中钻机系统的安全运行提供了参考。

Drilling is an important part during oil and gas exploration and development. As the key part of drilling equipment, the load capacity of the drilling mast is closely related to the safety of the whole drilling rig system. To accurately evaluate the safety load capacity of drilling mast already with damage and defects, a new quantitative evaluation method introduced herein is developed which is based on testing stress. First, the stress-corrected mathematics model is established based on testing stress; second, the function is deduced after corrected by the major damage or defect factors, including surface rusting, member bar bending deflection and eccentric loads, etc.; finally, the numerical correction model embodying the dynamic behaviors of the damaged or defective drilling mast is built to predict the safety load capacity of the drilling mast, which can really reflect the mechanical behavior of the drilling mast with damage and defects. A test of this method was carried out on one drilling mast in the field by applying loads in steps, getting a stress-load curve. After combining with the numerical correction model regarding the actual damage or defects on the drilling mast, a numerical simulation load test was conducted. The error between the simulation results and the actual measurements was within 5%, which proved the accuracy of this numerical model. Finally the safety load capacity of the drilling mast was evaluated according to the simulation results. It would provide reference data for safe operation of the drilling rig system during oil and gas exploration and development.