Derrick Structure Research Articles

The Old Derrick Steel Truss Structure in Linear Buckling Analysis (Eigenvalue)

The old derrick steel truss structure had been found in imperfect structure such in some member loses and unsual bolt holes. The derrick structures were located in critical path room publics for instance the public transportation path and the electricity transmission networks. This research had a numerical model the single element linear buckling (eigenvalue) that were based on the finite element method. The derrick prototypes had been modeled in single element that had the largest axial compression load that was defined in the perfect model. The artificial circle holes were attached on the member then was defined in the imperfect model. The artificial circle hole as representative the unused bolt holes. The linear buckling analysis had been performed by utilizing the 3D frame and 3D solid idealization with the 6 buckling modes had been required. This research had also compared the single element buckling and the overall derrick structure buckling analysis. The results showed that the buckling capacity reduced due to the number of holes. The greates number had the lowest critical loads (Pcr) then had buckle early. The numerical buckling pattern had similarly with in the elastic buckling theory (Euler buckling) at every mode. The critical buckling stress was lower than the yielding stress for every models. The results also showed that the critical load of the single element was lower than the overall structure. However, considering the environmental load such in the seismic load then the overall derrick structure buckling failure had higher vulnerability than the single element buckling failure.

Fractures on a drillship derrick, evaluation and improvement

During the service life, the drillship derrick structure is exposed to wave and wind actions and drilling operations. Due to these actions, the derrick structural members are subjected to the variable amplitude stresses and very high number of load cycles that may generate the fatigue cracks, leading to the total structural fracture eventually. The fractures found on the footing of a drillship derrick are analysed, and based on the structural durability, the improvements are determined for the specific case. To perform the structural durability evaluation and to propose the necessary improvements, at the beginning of the analysis, it is important to define the loadings (corresponding loads due to waves, wind and drilling acting on the derrick structure) taking into account the drillship service. After that, in order to validate the fatigue life of the structure, the stresses caused by these loads must be determined, their representative spectra (cumulative frequency distributions) have to be derived and the data regarding corresponding allowable stresses should be defined. Using the methods defined in the classification societies' rules and the finite element analysis, the procedure for determination of the operational stress spectra and evaluation of the fatigue life utilising the hot-spot stress approach for highly stressed areas of a drillship derrick, cracked at usage, is presented.

Time-Dependent Reliability Analysis of Oil Derrick Structures in Mechanism Failure Mode

Most research studies on the reliability of oil derrick structures have focused on static reliability analysis. Strength degradation with time of oil derrick structures and mechanism failure should also be considered in reliability analysis. In order to address this issue, we propose a new time-dependent reliability analysis method for oil derrick structures in mechanism failure mode and apply it to a tower derrick structure. We used the Monte Carlo finite element method to compute the static failure probability of each derrick component, and steps were employed to determine the main failure mechanisms. The time-dependent failure probabilities of each derrick component in the main failure mechanisms were calculated by the total probability theorem. The time-dependent reliability of a derrick structure system was obtained by considering the system as a series of parallel subsystems. A tower derrick example was used to demonstrate the accuracy and applicability of the proposed method. The results revealed that the proposed method is accurate and reliable.

Deflection Mechanism and Treatment Technology of Permanent Derrick of Freeze Sinking on Deep Alluvium

Aiming at the problems of deflection and operation safety of permanent derrick of freeze sinking shafts, the mechanism analysis of uneven settling of the derrick foundations in frost‐thawed soil was conducted. In addition, research on ground stabilization and derrick deviation rectification technologies was also studied in this paper based on the engineering practice of derrick of auxiliary shaft in the Dingji Coal Mine. Firstly, since the soil texture and artificial freeze temperature field are uneven, the bearing capacity and compression modulus of soil mass decrease after freeze thawing, resulting in uneven settlement of the foundation soil of the derrick footing and causing the deflection of the derrick. The finite element numerical analysis indicates that, in the event of uneven settling, the greatest tensile stress in the derrick structure of Dingji auxiliary shaft increased by 39.83% and the largest pressure stress increased by 33.33%. Secondly, this study used sleeve valve pipe single‐fluid static pressure grouting technology to reinforce the foundation of the derrick footing. The reinforced depth of grouting is 32 m, and every derrick foundation has adopted three circles of grouting holes for grouting reinforcement. Meanwhile, the hydraulic synchronous jacking system was used to rectify the deviation of the derrick, restoring the centre line of derrick ascension to the original design state. Finally, the practice of grouting, foundation consolidation, and derrick deviation rectification projects of the Dingji auxiliary shaft suggest that, after grouting reinforcement, the rate of foundation settlement is gradually decreased and tends to be stable. This has resulted in uniform settlement, and through four basic jacking, the deflection of the derrick has been corrected to its initial design state.

A study on multi-objective optimal design of derrick structure: Case study

Engineering system problems consist of multi-objective optimisation and the performance analysis is generally time consuming. To optimise the system concerning its performance, many researchers perform the optimisation using an approximation model. The Response Surface Method (RSM) is usually used to predict the system performance in many research fields, but it shows prediction errors for highly nonlinear problems. To create an appropriate metamodel for marine systems, Lee (2015) compares the prediction accuracy of the approximation model, and multi-objective optimal design framework is proposed based on a confirmed approximation model. The proposed framework is composed of three parts: definition of geometry, generation of approximation model, and optimisation.The major objective of this paper is to confirm the applicability/usability of the proposed optimal design framework and evaluate the prediction accuracy based on sensitivity analysis. We have evaluated the proposed framework applicability in derrick structure optimisation considering its structural performance.

Neural Network Control for Column Processing System of the Four-Single Pipe Rig

With the oil and gas exploration, the drilling is developed toward the deeper and more complex stratigraphic, the number of super deep well has been continued growth. In order to improve the tripping efficiency of deep wells and complex wells, equipment manufacturers develop four-single pipe rig to reduce the times of make-and-break during tripping, tripping operations efficiency is greatly improved. The four-single pipe rig is 10 meter higher than three single pipe conventional rig, pipe rack size of four-single pipe rig is smaller which be decision by K type derrick structure, so it is asked the control precision of the pipe string processing system is more higher, the conventional PID control precision cannot meet the requirements of the pipe string movement system. Combined with PID control in real-time data, pipe string position data and pipe string moving model, embedded in the physical model of artificial neural network adaptive control algorithm is established, and the model error sensitivity of propagation equation is derived. Simulation results show that the model has higher accuracy, robust adaptable, can meet the pipe moving automatic control system requirements of the four-single pipe rig.

Damage Identification of a Derrick Steel Structure Based on the HHT Marginal Spectrum Amplitude Curvature Difference

For the damage identification of derrick steel structures, traditional methods often require high-order vibration information of structures to identify damage accurately. However, the high-order vibration information of structures is difficult to acquire. Based on the technology of signal feature extraction, only using the low-order vibration information, taking the right front leg as an example, we analyzed the selection of HHT marginal spectrum amplitude and the calculation process of its curvature in practical application, designed the damage conditions of a derrick steel structure, used the index and intrinsic mode function (IMF) instantaneous energy curvature method to perform the damage simulation calculation and comparison, and verified the effect of identifying the damage location in a noisy environment. The results show that the index can accurately determine the location of the damage element and weak damage element and can be used to qualitatively analyze the damage degree of the element; under the impact load, the noise hardly affects the identification of the damage location. Finally, this method was applied to the ZJ70 derrick steel structure laboratory model and compared with the IMF instantaneous energy curvature method. We verified the feasibility of this method in the damage location simulation experiment.

基于模态分析的海洋钻机井架结构动力修改

基于模态分析的海洋钻机井架结构动力修改

A Study on a Multi-Objective Optimization Method Based on Neuro-Response Surface Method (NRSM)

The geometry of systems including the marine engineering problems needs to be optimized in the initial design stage. However, the performance analysis using commercial code is generally time-consuming. To solve this problem, many engineers perform the optimization process using the response surface method (RSM) to predict the system performance, but RSM presents some prediction errors for nonlinear systems. The major objective of this research is to establish an optimal design framework. The framework is composed of three parts: definition of geometry, generation of response surface, and optimization process. To reduce the time for performance analysis and minimize the prediction errors, the response surface is generated using the artificial neural network (ANN) which is considered as NRSM. The optimization process is done for the generated response surface by non-dominated sorting genetic algorithm-II (NSGA-II). Through case study of a derrick structure, we have confirmed the proposed framework applicability. In the future, we will try to apply the constructed framework to multi-objective optimization problems.

Reliability Analysis of Double Derrick Based on Stress Analysis

The double derrick as an important part of the drilling rig hoisting system in deep sea oil and gas development, its working environment is much more complex than land rigs working environment. Therefore, in order to ensure the quality of drilling, it is very important to analyze the reliability of the deep double derrick structure and its dynamic load characteristic. Based on the ANSYS software to establish finite element model of double derrick, through the static analyzing to the derrick, get the stress distribution of the derrick structure in static action and the derrick stress deformation trend, provided a reference for evaluation of derrick. Selected the calculation method of double derrick overall reliability index, and according to the results of the finite element calculation of static strength calculated the double derrick overall reliability index, compared with the general standard, know that double derrick with high reliability.

The Design of Self-Erection Derrick of Simple Offshore Workover Rig

Though the use of modular technology, a sub-vertical lifting offshore workover rig derrick for the marine small platform is designed, which can be installed and moved quickly. The overall derrick structure and most of the part design and selection are completed by Solidworks and Auto CAD. The static calculation for the derrick is done with the help of finite element analysis software ANSYS, and analyzed the results to ensure that the derrick designed could meet the strength requirements.

Mechanical Characteristics Analysis and Design Optimization of the Derrick

In this paper, numerical simulation technology was applied to comprehensively analyze and study the mechanical properties of the derrick. The three-dimensional finite elements analysis model of the derrick structure was established, which provided the physical model of the numerical simulation and the optimization of the three-dimensional derrick. The finite element simulation method was applied to analyze and optimize the mechanical and deformation of the three-dimensional derrick structure, so that the theoretical method to study and design the three-dimensional derrick using finite element method was established.

Dynamics Simulation Analysis on Hydraulic Excavator Working Mechanism Based on Rigid-Flexible Coupled Modeling

Taking a type excavator as an example, three-dimensional model was established using CATIA software, using the ADAMS software to the dynamic simulation analysis; get the movable arm hinged point load curve. The maximum load into ANSYS finite element analysis was carried out on the derrick structure, derived from ANSYS MNF file imports ADAMS to get the coupled model and dynamics analysis, get the time-varying curve working device. Results show that the coupled model is more in line with the actual, work can be more fairly reflect device performance, can provide the basis for further optimization of the structure of excavator.

A Steel Headframe Structure before and after the Comparison and Analysis of the Performance of Process Modification

Because the coal mine derrick technology needs, to be in from the original winch system of backward 10m based on a new set of new ground winch system, resulting in the original derrick structure stress state change. By using SAP2000 finite element software, the establishment of three-dimensional finite element model, the dynamic characteristics and technological transformation and bar stress were analyzed, for the coal mine derrick technological transformation to provide certain reference.

Vibration test and assessment for an ocean drilling rig derrick: Taking the ZJ50/3150DB drilling rig as an example

Abstract The rig derrick of a ZJ50/3150DB drilling rig in an offshore jacket platform located in the Bohai bay vibrates obviously when drilling. In order to assess the safety of the derrick when drilling, vibration test for the derrick was carried out and a finite element model of the derrick was built to analyze the impact of vibration on the derrick's structure safety, in combination of the field test data with the calculation results got using the model. Natural frequency, amplitude-frequency response when drilling, vibration amplitude and vibration acceleration of the derrick were tested. Based on the derrick drawing and field situation, the finite element model of the derrick structure was built using ANSYS software. The first-order natural frequency of the derrick calculated using the model was 0.555 8 Hz, which coincided with the filed test data and proved the validity of the model. The analysis of the field test data and the calculation results, show, the derrick is resonance-prone when the rotation speed of the top drive is 36 r/min, the derrick C-style opening has low torsional strength, the two front brace rods of the derrick substructure are crucial components that concern the derrick safety, and derrick vibrations under different working conditions and shock vibration happening when the top drive passing by the monkey board meet safety requirements.

Finite Element Analysis and Optimal Design for the Derrick of Workover Rig

It proposed the finite element analysis to the derrick of workover rig in the paper. The stress distributing rule of derrick has been found, based on the finite element analysis of established derrick model. It analyzed the reasons for the effects of derrick thigh stress due to the derrick sustentation disposal format, the function of doorframe structure and the producing of dangerous section. The optimal derrick structure has been made up after calculating the derrick working stress, stress state and displacement measure.

The Stress Analysis of Drilling Derrick Structure Based on Finite Element Method

Oil-drilling derrick is the most important integrant of the equipments in oil industry and is also a giant load bearing structure. In this paper, the 3D geometric model of the derrick is created by commercial finite element analysis (FEA) software ANSYS, and the static stresses under several working conditions are analyzed. The displacement and stress distribution of the derrick acquired can lay the theoretical basis for the optimization design of structural and material choices of the derrick further.

Derrick Stress Monitoring System Based on Fiber Bragg Grating Sensor Technology

The importance and urgency for security condition monitoring of the in-service derrick is more and more people paying attention. Based on the FBG sensing technology developed a derrick stress monitoring system. The derrick stress monitoring system, composed by the derrick, a certain number of series of FBG sensors, sensor cables, signal demodulation devices, a portable computer that including a central processing and control platform. Carrying out study in the the ZJ70 model derrick. The experimental results show that the set of strain measurement system has good linear characteristics, repeatability and high sensitivity. Can satisfy the derrick stress monitoring requirement, can realize derrick stress real-time, online, continuous monitoring, expanding the development and application of optical fiber sensing technology in the field of the derrick structure monitoring.

Stress Real-Time Monitoring of Marine Derrick Based on Environmental Loads

Aiming at the design feature and the operating of K-type derrick, an effective method used to stress real-time monitoring consider environmental loading is proposed. The challenge to the South China Sea offshore drilling derrick is a illustration. The derrick corrosion and wall thinning conditions is be considered, then using finite element software analyze derrick structure of static analysis, get the higher force about main member of derrick. Based on finite element analysis, select the key parts layout of measuring points, then monitor derrick stress under nine storms environmental loading and extreme work condition. The measured data results show that: the nine storms environmental load affect capacity of drilling significantly, the different parts of the main member stress have the different degrees of influence by environmental load, the maximum can reach 50.8%. This real-time monitoring method of stress, can protect the safety of marine operations, has a certain value of engineering application.

Strength Analysis and Calculation of JJ225/42-KC Type Oil Rig Derrick

Abstract. Oil rig derrick is a large and complex metal frame with lots of bars and complex force. Moreover, the use of working condition is complex and harsh, so it is quite necessary to analyze strength and calculate oil rig derrick. In this paper, with the basic structure and force characteristic of JJ225/42-KC type oil derrick, the ANSYS finite element software is used to establish JJ225/42-KC type oil derrick structure finite element model. The strength and stability analysis of the maximum hook load working condition, the working wind load working condition and the maximum wind load working condition of three combined working conditions indicates that the overall structural design of JJ225/42-KC type oil derrick is reasonable with good both dynamic and static characteristics and the derrick meets the requirements of the strength. What is more, the derrick has a excellent overall stability. In the end, the strength of the lifting devices and the derrick leg pin of JJ225/42-KC type oil derrick are calculated and checked, showing that all meet the requirements of the strength.