A Method for “Punch-Through” Proof Design for Independent Leg Jack-Ups

1985 ◽  
Vol 22 (01) ◽  
pp. 50-63
Author(s):  
Sobhan Sengupta ◽  
John O'R. Breeden
Keyword(s):  
Operating Parameters ◽  
Offshore Drilling ◽  
Systematic Method ◽  
Analysis And Design ◽  
Jack Up ◽  
Important Design ◽  
Limiting Values

"Punch-through" is one of the most common types of failure affecting independent leg self-elevating-type mobile offshore drilling units (jack-ups), and existing rules do not provide any guidelines to design for "punch-through" induced forces. This paper presents a systematic method for analysis and design of independent leg jack-ups for such forces, identifying the important design and operating parameters and evaluating their effects. The method can be used to design the jack-up legs for a given set of operating parameters, or for an existing unit it can be used to define the limiting values of these parameters. Based on these limitations, operating procedures can be developed to eliminate or minimize the chances of leg damage due to punch-through. A realistic example is worked out to demonstrate the application of the method.

scholarly journals PENGEBORAN LEPAS PANTAI

2012 ◽  
Vol 16 (3) ◽  
pp. 113
Author(s):  
Budi Utomo
Keyword(s):  
Reinforced Concrete ◽  
Crude Oil ◽  
Oil Wells ◽  
Bridge Structure ◽  
Offshore Drilling ◽  
Drilling Equipment ◽  
Key Word ◽  
Jack Up ◽  
Structure Plate

Budi Utomo, in this paper explain that offshore drilling carried out to obtain crude oil through the oil wells. The means that must exist in the operation of offshore drilling is a bridge structure (plate form) as a place to put the drilling equipment. Known two kinds of platforms, that is platforms permanent (fixed) which stands on the feet of reinforced concrete, and the bridge is not fixed like swamp barges, drilling ship (floaters) and jack-up rig. Jack up rig is one of the offshore rigs that have the ability to elevation in accordance with a sea depth of drilling. Drilling equipment is a range of equipment that is prepared in such a way, so that such a drill rod, and all this equipment has a hole inside that allows for fluid or mud circulation.   Key word: Drilling equipment

Effect of Spudcan Sliding on Structure and RPD of Jack-Up Platform

2020 ◽  
Author(s):  
Jie Gao ◽  
Menglan Duan
Keyword(s):  
Bearing Capacity ◽  
Phase Difference ◽  
Critical Distance ◽  
Offshore Platforms ◽  
Offshore Drilling ◽  
Symmetrical Structure ◽  
Sea Area ◽  
Jack Up ◽  
The Relationship ◽  
Sliding Distance

Abstract In the same sea area, with the increase of the number of operations, the situation of jack up offshore drilling platform carrying out secondary or multiple Jack-up leg embedment operations in the vicinity, or even in the same location will increase year by year. Therefore, the operation of jack up offshore drilling platform makes the sea area “step on the footprints” The problems become more and more frequent, and have a significant impact on the operation safety of offshore platforms. During the “footprint” process of jack-up drilling platform, the spudcan will slide transversely along the direction of Jack-up leg pits to varying degrees. If the sliding distance is too large, the leg or platform structure will be damaged. Based on the symmetrical structure of the three-leg jack-up offshore platform, the bow and the starboard spudcan are slided along x-axis at different angles, respectively. According to the critical bearing capacity of the platform legs, the critical distance of spudcans sliding is calculated. Finally, the relationship between the sliding distance of spudcan in different directions and RPD (Rack phase difference) is obtained by monitoring the RPD value of legs. It provides meaningful guidance for platform designers and operators.

SUPERELSO 690CR

Alloy Digest ◽  
2007 ◽  
Vol 56 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Yield Strength ◽  
Tensile Properties ◽  
Heat Treating ◽  
High Yield ◽  
Offshore Drilling ◽  
High Yield Strength ◽  
Jack Up

Abstract Superelso 690CR, also known as SE 690CR, is a high yield strength, quenched-and-tempered alloy for jack-up legs of offshore drilling platforms. This datasheet provides information on composition and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SA-577. Producer or source: Industeel USA, LLC.

Optimal Preliminary Selection of Mobile Offshore Drilling Units

1982 ◽  
Vol 19 (04) ◽  
pp. 341-349
Author(s):  
Crane E. Zumwalt
Keyword(s):  
Decision Making ◽  
Operating Time ◽  
Quantitative Information ◽  
Offshore Drilling ◽  
Systematic Method ◽  
General Series ◽  
Key Points ◽  
Drilling Unit ◽  
Qualitative Decision ◽  
Selection Of

A comprehensive, systematic method tor selecting a mobile offshore drilling unit is presented. Going beyond the normal, simplistic cost analysis, the procedure includes the unit's performance capabilities and operating time as criteria. The analysis evaluates the suitability of the broad classes of units and/or specific units for the intended operating program. At key points in the analysis subjective decisions are made by the evaluator in keeping with his specific perspective and drilling program needs. Thus the selection utilizes both the quantitative information available on the units and planned drilling program as well as the qualitative decision-making ability of the evaluator. As an example, an evaluation of a general series of units for a multiple-location, multiple-well North Sea drilling program is presented.

Analysis and Design of Dye Sensitized Solar Cells

2010 ◽  
Author(s):  
Karthik Nithyanandam ◽  
Ranga Pitchumani
Keyword(s):  
Solar Cells ◽  
Low Cost ◽  
Dye Sensitized Solar Cells ◽  
Electricity Production ◽  
Attractive Alternative ◽  
Operating Parameters ◽  
Analysis And Design ◽  
Dye Sensitized ◽  
Wide Range ◽  
Sensitized Solar Cells

Dye sensitized solar cells (DSC) are an attractive alternative to the conventional photovoltaic cell because of their low cost electricity production from solar radiation. The advantages of a DSC include the ability to generate power without emitting pollutants and requiring no fuel. While modeling of the physical and transport phenomena in DSC has been widely reported in the literature, a thorough analysis to quantitatively determine the optimal design and operating configuration in installation is lacking. The present study incorporates a model of the DSC coupled with a model to predict global irradiance on a terrestrial surface to analyze the hourly, daily, monthly and annual performance of a DSC installation over a wide range of design and operating parameters. Optimum design and operating parameters are derived from the analysis.

Nonlinear RPD Analysis of Jack-Up Rigs Including Material Plasticity

2016 ◽  
Author(s):  
Partha Chakrabarti ◽  
Abhijeet Chawan
Keyword(s):  
Lateral Displacement ◽  
3D Analysis ◽  
The Past ◽  
Lateral Offset ◽  
The Many ◽  
Reserve Strength ◽  
Jack Up ◽  
Important Design ◽  
Very High ◽  
Displacement Effects

Rack Phase Difference or RPD may occur during the installation phase of a jack-up rig when it is jacking up at a location. Instances of failure of leg members of a jack-up have been reported in the past. Therefore, this is an important design issue. Among the many causes of high RPD, important ones are when one of the jack-up spudcans becomes eccentrically supported on the bottom or has lateral offset due to preexisting soft spots in the soil during installation. The resulting moment and shear on the leg is carried essentially by the horizontal guide reactions that may induce high stresses leading to failure of a diagonal brace in extreme cases. In a previous OMAE paper written by the authors [1] the importance of a 3D model of the jack-up that uses non-linear analysis methods by including large deformations and rotations was highlighted. In this paper it was also emphasized that the meaning of RPD has to be understood properly in relationship with moment or shear carrying capacity at the spudcan for a given jack-up. The present paper includes material plasticity effects in addition to the other nonlinearities in the 3D analysis to investigate the failure mechanism of a critical brace. Both applied moments due to the vertical load eccentricity at the spudcan and lateral displacement effects of it are considered. The behavior of a trussed leg jack-up depends heavily on the bracing pattern, chord and bay spacing as well as the size of the braces. For a well-designed jack-up the reserve strength beyond the initial exceedance of the allowable limits of member stress following the codes to the actual physical failure is considered to be important. This reserve strength could prevent actual damages to the rig. This paper discusses these aspects using one particular jack-up as example. The particular jack-up has shown very high RPD and reserve strength when a brace fails due to a large spudcan moment being applied or base deflection. The failure of the brace, however, does not indicate that the ultimate strength of the rig has been reached which is expected to be much higher. Although the analysis is for one particular jack-up, it discusses the parameters that in general could make the reserve strength large indicative of good design. These observations and the overall methodology of analysis used here could be beneficial to other rigs.

The Research on Bulk System Transfer Ability of CPOE-16 Jack-Up

2013 ◽  
Author(s):  
Ji Zeng ◽  
Gang Chen ◽  
Kuichen Zhu ◽  
Jian Mo ◽  
Chenfeng Li
Keyword(s):  
Fluid Flow ◽  
Continuity Equation ◽  
Bulk Material ◽  
Phase Flow ◽  
Bernoulli Equation ◽  
Offshore Drilling ◽  
Two Phase ◽  
Bulk System ◽  
Drilling Rigs ◽  
Jack Up

Bulk transfer systems are part of very important bulk material transferring systems used on drilling rigs, and mainly provide and transfer pulverous material for offshore drilling rigs. The authors use the continuity equation of fluid flow, Bernoulli equation, Theory of energy loss, and gas-solid two phase flow theory to evaluate the bulk transfer ability of the bulk system for the CPOE-16 Jack-up, and to optimize the bulk piping layout, elbow radius and elbow quantity. These research results have been applied to the CPOE-16 Jack-up and have proven that implementation of these results can be effective.

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