| Jack-up platform is widely used as important equipment in the exploration andexploitation of offshore oil and gas resources. In its life cycle, jack-up platformrequires move location many times. Retrieval of the platform’s legs and spudcanfootings is necessary before the platform move. The extraction process can be difficult,time consuming and costly with the reason of the complex geological conditions.Therefore, How to reduce the pull-out load effectively has become a problem thatneed to solve in marine engineering. The Chinese sea area is vast. The geologicalconditions in different seas may vary greatly. At present, our country has made a lot ofgeological exploration in different seas, and accumulated abundant geological data.The geological data are scattered because of these jobs belonging to different projects,and it has difficulty to consult these data. Therefore, developing a geological datainformation system for people to consult conveniently becomes a meaningful job.In this paper, the procedure of building the information system is describeddetailed, in which the geological data of Chengdao sea area are used as an example.The scattered geological data are collected and reorganized in advance. Then, we usethe HTML workshop software to build the geological information system. Thepreparatory work of building this system, creating a new project, contents, index andthe system setup in the final step are all introduced in detail. The geologicalinformation system can actualize data access and searching. In the future, it will speedup the work efficiency greatly. The procedure of building this information systemprovides a conception for the comprehensive geological information system includingall Chinese sea area in the approaching future.Water jetting systems, devised to ease spudcan extraction, are a common featureon modern jack-up units. However, their effectiveness in reducing the pull-out loadrequired is questioned by the offshore industry. In order to investigate the mechanismand efficiency of the water jetting system, the variation of jet parameters in differentgeological conditions and interaction among the parameters is introduced by singlenozzle test. To prove the efficiency of the watering jetting system in reducing pull-outload, the experiment of a reduced scale spudcan model with jets has been performed.The study demonstrates that jetting is efficient in facilitating spudcan extraction, as itreduces the required uplift load. This article provides the theoretical support for theapplication of water jetting system in practical engineering. The soil gravity on the spudcan, the soil friction around the spudcan and the soiladsorbability under the spudcan, which are needed to calculate the pull-out loadduring pile extracting, are given the derivation process and derived the simplifiedcalculation formula. The water jetting experiment is carried out by means of changinggeological conditions, water jetting pressure and the embedment depth of spudcan.The pull-out load may drop to30%-50%of original pull-out load when the waterjetting system is used on both side of the spudcan. The effect is very obvious throughthe analysis of the experiment result. On the other hand, the experiment proved thatwhen the jetting pressure of the water jetting system increased linearly, the pull-outload decreased at the first stage, then, it stabilized at the minimum value. Under idealconditions, the pull-out load can reach the minimum when the soil adsorbability underthe spudcan decreased to zero with the increase of jetting pressure. But, theseconditions need comprehensive consideration, because the increase of jetting pressurehas an impact on system life and security. |
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