Dynamic Characteristic Research Of T-derrick On Floating Drilling Platform

With the exploitation and yield of land-based oil and gas decreased, people began to divert attention from land to the ocean, so the oil and gas field in deepwater will become an important source of oil and gas production in the future. The dynamic response of floating drilling platform which is the key platform about exploitation and exploration in marine oil and gas field will be taken more and more attention. Tower derrick is an important rig equipment in hoist system on the platform, which bears more complex loading conditions than land rigs. The loads not only contain working loads in regular, but also waves, currents, etc. The working circumstances of T-derrick is worse, and the strength and security of it are basic guarantee of working platform, therefore, the study about static and dynamic characteristics of T-derrick is necessary.According to preliminary investigation, the classifications of T-derrick on drilling platforms are listed. A single-derrick is selected as study object based on received material,and built a three-dimensional prototype and an one to ten scaled-down model of T-derrick. For the working environment of T-derrick, the loads is be divided,then the combination of loads would be calculated.Using the finite element analysis software-ABAQUS, the stress distribution and deformation are obtained by static analysis of T-derrick in various conditions, and the critical load is gained by the stability analysis. Through the modal analysis, the natural frequency and modes of vibration are attained. From the modal transient dynamic analysis under the making a trip, the dynamic response of T-derrick is studied. By introducing wave spectrum, it completes spectrum analysis and gets the varying values of response with frequencyIn older to complete the marine environment simulation experiment of drilling equipment, a set of test system is designed, which includes a six degree of freedom swing test-bed and model derrick, they can simulate the roll, pitch and heave movement of floating drilling platform. The strain gauge is pasted on the T-derrick and the strain variable data of T-derrick's thigh is gathered when the test-bed moving. In the hook load test, how will the size of loads impact on the dynamic strain and other parameters? The natural frequency of T-derrick is detected by hammer excitation. In order to obtain the size of heave displacement, a passive heave compensation system is assembling. Do dynamic simulation of the model, and compare test data with simulation results, then verify the simulation results.