Jack-up units are extensively playing a successful role in drilling engineering around the world, and their safety and efficiency take more and more attraction in both research and engineering practice. An accurate pr...Jack-up units are extensively playing a successful role in drilling engineering around the world, and their safety and efficiency take more and more attraction in both research and engineering practice. An accurate prediction of the spudcan penetration depth is quite instrumental in deciding on whether a jack-up unit is feasible to operate at the site. The prediction of a too large penetration depth may lead to the hesitation or even rejection of a site due to potential difficulties in the subsequent extraction process; the same is true of a too small depth prediction due to the problem of possible instability during operation. However, a deviation between predictive results and final field data usually exists, especially when a strong-over-soft soil is included in the strata. The ultimate decision sometimes to a great extent depends on the practical experience, not the predictive results given by the guideline. It is somewhat risky, but no choice. Therefore, a feasible predictive method for the spudcan penetration depth, especially in strata with strong-over-soft soil profile, is urgently needed by the jack-up industry. In view of this, a comprehensive investigation on methods of predicting spudcan penetration is executed. For types of different soil profiles, predictive methods for spudcan penetration depth are proposed, and the corresponding experiment is also conducted to validate these methods. In addition, to further verify the feasibility of the proposed methods, a practical engineering case encountered in the South China Sea is also presented, and the corresponding numerical and experimental results are also presented and discussed.展开更多
The structural failures of jack-up rigs were mostly found in leg structures,due to cracks in way of connections between tubular members of leg structures.Although,stress calculations of leg structures can be made by u...The structural failures of jack-up rigs were mostly found in leg structures,due to cracks in way of connections between tubular members of leg structures.Although,stress calculations of leg structures can be made by using“finite element techniques”,it takes a lot of time to complete the calculations for the full cases of all working conditions because of many tubular members.Therefore,a simple method for the stress calculations for design purposes is strongly desired.This paper desribes a simple stress calculaiton method of leg structures and shows a satisfactory results as compared with the results obtained by a detailed calculation method.展开更多
基金supported by the National High Technology Research and Development Program of China(863 Program,Grant No.2008AA092701-3)
文摘Jack-up units are extensively playing a successful role in drilling engineering around the world, and their safety and efficiency take more and more attraction in both research and engineering practice. An accurate prediction of the spudcan penetration depth is quite instrumental in deciding on whether a jack-up unit is feasible to operate at the site. The prediction of a too large penetration depth may lead to the hesitation or even rejection of a site due to potential difficulties in the subsequent extraction process; the same is true of a too small depth prediction due to the problem of possible instability during operation. However, a deviation between predictive results and final field data usually exists, especially when a strong-over-soft soil is included in the strata. The ultimate decision sometimes to a great extent depends on the practical experience, not the predictive results given by the guideline. It is somewhat risky, but no choice. Therefore, a feasible predictive method for the spudcan penetration depth, especially in strata with strong-over-soft soil profile, is urgently needed by the jack-up industry. In view of this, a comprehensive investigation on methods of predicting spudcan penetration is executed. For types of different soil profiles, predictive methods for spudcan penetration depth are proposed, and the corresponding experiment is also conducted to validate these methods. In addition, to further verify the feasibility of the proposed methods, a practical engineering case encountered in the South China Sea is also presented, and the corresponding numerical and experimental results are also presented and discussed.
文摘The structural failures of jack-up rigs were mostly found in leg structures,due to cracks in way of connections between tubular members of leg structures.Although,stress calculations of leg structures can be made by using“finite element techniques”,it takes a lot of time to complete the calculations for the full cases of all working conditions because of many tubular members.Therefore,a simple method for the stress calculations for design purposes is strongly desired.This paper desribes a simple stress calculaiton method of leg structures and shows a satisfactory results as compared with the results obtained by a detailed calculation method.
