Analysis And Experimental Study On Support System Of Super-Long-Hole Seafloor Drill

The deep-sea drilling rig is the key technical equipment necessary for carrying out the scientific research of seabed geology,the exploration of marine mineral resources and the exploration of seabed engineering geology.It is necessary to develop a super-long-hole seafloor drill machine with deeper depth and drilling depth,larger core diameter,higher automation and reliability for Distribution of mineral resources in order to explore deep geology and marine scientific research.As an important part of the super-long-hole seafloor drill,the support leveling system is very important for the stability and reliability of the super-long-hole seafloor drill.In this paper,according to the sampling technical requirements of the super-long-hole seafloor drill,a kind of support system which can be used to level the seabed slope within 20° is designed and relevant research is carried out.The main contents of this paper is as follows:Analyzes the current research status of the leveling system of the deep-sea seafloor drilling rig at home and abroad,and according to the practical needs of the super-long-hole seafloor drill developed by the project team,which has a working depth of more than 2000 meters and a drilling depth of more than 200 meters,and needs to show stable support on the uneven sea bottom to carry out the deep sea drilling aggressive core operation,the overall design and research of the support system of the deep sea ultra deep drilling rig are carried out.Put forward a support system for the super-long-hole seafloor drill,which is convenient for the stable support of the seabed and the retraction and release of the drilling rig,the support system adopts the form of three leveling support legs driven by the oil cylinder.According to the overall design scheme of the support system of the super-long-hole seafloor drill,the design scheme of the support system and key components of the super-long-hole seafloor drill is determined,and some key components such as the support legs,the support leg oil cylinder,the support leg connecting rod and the hinge point are calculated and analyzed.Through the kinematic analysis of the support leg of the support system,a series of motion equations of the support leg cylinder are established.Based on the force analysis of the support system,the equation of the change of the thrust of the support leg cylinder with the expansion length of the cylinder and the equation of the support force of the drilling rig support leg under the condition of inclined seabed are established.Through the design and calculation of the main parameters of the leg cylinder,the main parameters of the support leg hydraulic cylinder of the super-long-hole seafloor drill machine are obtained.Designed and analyzed the structural forms of the key parts of the support system,such as leg connecting rod,support plate and hinge point of the support system.Aiming at the problem that the super-long-hole seafloor drill may capsize in the leveling process of the inclined sea floor,the stability analysis of the support is carried out.Based on the analysis of the three situations of the rig body support,the support system support and the single leg support due to misoperation,proposed the stability coefficient of the seafloor rig,The calculation formula of the stability coefficient is derived,and the parameters affecting the stability performance,such as the position of the mass center,the length of the chassis,the length of the support leg,the height of the support leg and the length of the support leg,are found out and verified,and proposed the design domain of each parameter.After verification,the stability coefficient of the support system of the super-long-hole seafloor drill is 1.42 when it is supported by the body,2.41 when it is supported by the support system,and 1.02 when it is supported by a single leg due to misoperation.The stability of the designed support system is verified.It is proposed to open the support system in advance before the drilling rig is lowered to the seabed,so that the support legs are parallel to the bottom of the frame,so as to increase the support area to reach the highest stability coefficient.The stress and strain of the whole support system and the key components of the support system are analyzed with the finite element method.The results show that:The support system can meet the requirements of strength and rigidity of support leveling;And The best selection range of seabed inclination is within 15 °;Under the premise of ensuring the strength and rigidity performance of the support leg link and the safety factor is greater than 3,the structural optimization of the supporting link is carried out through the Workbench,the weight of the optimized support leg link is66.884 kg,which is 81.044 kg less than that before optimization.Produce the support system of the super-long-hole seafloor drill,and carry out the support leveling test on the support system.The verification results show that the developed support system of the super-long-hole seafloor drill meets the expected technical performance requirements,and the leveling and supporting effect of each leg is good,which will lay the foundation for the sea test of the super-long-hole seafloor drill.