基于API极限工况下钻机结构安全性分析

Structural Safety Analysis of Drilling Rigs Based on API Extreme Conditions

以现场使用的某型号ZJ80钻机为研究对象,API设计验证为背景,结合现有对钻机井架力学特性的研究方法,提出一种结合稳定性研究的力学分析方法,旨在为井架设计安全性验证提供一种更为准确的分析方法。结合稳定性分析中的非线性屈曲分析研究方法,模拟井架及底座结构在受扰动及含缺陷状态下的失稳极限点,在此状态下分析结构强度及安全性。研究结果表明:在考虑井架及底座受到扰动及含缺陷时,各工况下井架及底座结构等效应力值均小于许用应力值,各工况计算UC值均小于1;其中当作业中存在钩载时,结构危险位置出现在天车梁处,无钩载状态下结构危险位置出现在底座转盘梁处;钻机井架在临近失稳状态时,结构综合强度依然满足设计需求。该计算方法及结果更符合现场作业情况,满足API规范要求。研究结果可为钻机井架结构改进提供理论支撑。

Taking an ZJ80-model drilling rig used in the field as an example, this paper develops a mechanical analysis method incorporating stability evaluation by combining the API design verification and the existing research methodology for mechanical characteristics of drilling derricks, in an attempt to provide a more accurate method for safety validation of derrick designs.The nonlinear buckling analysis method of stability analysis is introduced to simulate the critical instability point of the derrick and its substructure in the presence of both disturbance and defects and calculate the structural strength and safety in this state.The results show that when the derrick and substructure are subjected to disturbance and defects, the equivalent stresses of the derrick and substructure under each working condition are less than the allowable stress, and the unity check(UC) value calculated under each working condition is less than 1.Specifically, when the operating load involves the hook load, the risky position of the structure occurs at the crown block beam;when the operating load involves no hook load, the risky position of the structure is located in the rotary table beam of the substructure.The comprehensive strength of the structure still meets the design requirements, even though the structure approaches the the field operation conditions and meets the API specifications.The research results provide theoretical support for the structural optimization of drilling derricks.