The whole well drill string dynamics analysis software includes pre-processing, calculation and analysis module and post-processing display part. The pre-processing part includes the input of drilling parameters and drill string parameters, the establishment of geometric model, the application of boundary conditions, mesh generation and data output and storage; The calculation and analysis module includes static analysis and frequency domain analysis; The post-processing part of dynamic characteristic calculation is mainly to further solve the strain and stress at each position of the drill string according to the data obtained from the core part of the calculation, form dynamic stress diagram and curve diagram, and make animation to observe the motion of the drill string conveniently and intuitively.
1 Software overview
This software operation manual describes in detail the overall structure, performance indicators, system functions and operation methods of each functional module of the bit drill string system dynamics analysis software, which can be used as a reference for all users.
1.1 purpose of software
The whole well drill string dynamics analysis software includes pre-processing, calculation and analysis module and post-processing display part (see Fig. 1). The pre-processing part includes drilling parameter and drill string parameter input (see Fig. 2), geometric model establishment, boundary condition application, mesh generation and data output and storage (see Fig. 3); The calculation and analysis module includes static analysis and frequency domain analysis; The post-processing part of dynamic characteristic calculation is mainly to further solve the strain and stress at each position of the drill string according to the data obtained from the core part of the calculation, form dynamic stress diagram and curve diagram, and make animation to observe the movement of the drill string conveniently and intuitively (see Fig. 4).
Figure 1 software system structure < br / >
Figure 2 pre processing parameter input < br / >
Figure 3 pretreatment structure < br / >
Figure 4 post processing structure
1.2 software performance index
1. Pretreatment module
The pre-processing module can meet the requirements of fast modeling, mesh generation, boundary condition application and data management of whole well dynamics analysis, meet the needs of frequency domain analysis of whole well dynamics, and reduce the complexity of modeling< br />
Technical indicators:
Model establishment: quickly generate the whole well drill string model according to the input drill string and downhole tool size parameters.
Mesh generation: key areas can be meshed according to the object of interest.
Application of boundary conditions: the boundary conditions are freely applied according to different analysis contents (statics / dynamics).
2. Calculation and analysis module
The calculation and analysis module can carry out static analysis and frequency domain analysis through the data generated by pre-processing modeling. This module obtains the contact position, contact reaction force calculation and friction resistance calculation through the static analysis module, the resonance frequency and vibration mode can also be obtained through the free vibration analysis, and the vibration condition (amplitude and stress) of a node within the specified speed range at the critical speed, the vibration condition and vibration form of the whole well drill string can also be obtained through the forced vibration analysis. Through analysis and calculation, it can quickly and effectively control the well trajectory, check the drill string strength, optimize the drill string combination and working parameters, optimize the wellbore structure, diagnose, find and solve various downhole problems in time< br />
Technical indicators:
Static analysis: contact reaction force calculation and friction resistance calculation.
Frequency domain analysis: free vibration analysis, resonance rate calculation, forced vibration analysis, critical speed calculation.
3. Post processing module
The post-processing part of dynamic characteristic calculation is mainly to further solve the strain and stress at each position of the drill string according to the data obtained from the core part of the calculation, form dynamic stress diagram and curve diagram, and make animation to observe the motion of the drill string conveniently and intuitively< br />
Technical indicators:
Curve: time history curve of strain, stress and resonance rate at each position of drill string, and time history curve of contact reaction force and friction resistance between wellbore and drill string.
Cloud chart: display of deformation, stress and mode under various factors.
Animation: each time history state of drill string dynamic process.
1.3 software operation environment
Operating system: & nbsp; Windows 7 (64 bit) and above
2 software operation and use
2.1 interface introduction
(1) Software startup: Click drilling.exe to start the software, create a new project, and set the project name, project path and calculation problem type. As shown in Figure 5.
Figure 5 & nbsp; New project
(2) Overall interface introduction: the whole interface is mainly divided into menu bar, operation control area, display control area, display control area toolbar, status bar and information output. As shown in Figure 6.
Figure 6 Introduction to the overall interface
(3) Introduction to display control area toolbar: the whole toolbar is mainly divided into display mesh surface, translation, rotation, scaling, screen scaling, shadow, shadow and line, axis finite element, pick, clear, import geometric model, import mesh model, plan view and stereo view. As shown in Figure 7.
Figure 7 introduction to toolbar
2.2 model establishment
2.2.1 preprocessing parameter input window & nbsp;
(1) First, click the well trajectory input window to input the well number, well depth and well coordinates, or import the well size data, and then click OK to store the well model data. As shown in Figure 8. Then click the wellbore structure input window to input the wellbore type, depth, length, inner diameter and friction coefficient parameters of the wellbore structure corresponding to the wellbore trajectory, and click OK to store the wellbore structure data corresponding to the wellbore model. As shown in Figure 9. Secondly, click the BHA input window to input the parameters such as BHA type, well depth, length, inner diameter, outer diameter and line weight. Click OK to store the BHA data corresponding to the wellbore model and display the finally established drill string well model. As shown in Figure 10 and Figure 11< br />
Pay attention to the input model data, in which the inner diameter of the wellbore structure is greater than the outer diameter in the BHA.
Fig. 8 borehole trajectory input
Fig. 9 wellbore structure input
Figure 10 BHA input
Figure 11 model establishment
two point two3.2 grid division
(1) Click automatic mesh generation to set the mesh division unit size of the calculation area and display it. As shown in Figure 12.
Figure 12 & nbsp; grid settings
(2) If you need to encrypt an area, you can customize the subdivision. As shown in Figure 13.
Figure 13 & nbsp; Make custom sectioning settings
2.2.3 boundary condition application & nbsp;
( 1) Click the boundary condition setting to calculate the regional constraint and load application. The input mode can be model pick and manual input. Select 1 as the node of free stress and - 1 as the node of displacement constraint. TX, ty, TZ, Rx, ry and RZ are three positive direction values and three tangential direction values respectively. The application node input in the node box displays and the input window. Click Save to complete the application. Click Reset before each reapplication, as shown in Figure 14.
Figure 14 & nbsp; Boundary condition setting
2.2.4 contact static analysis < br / >
The beam under uniformly distributed load is fixed at both ends, and the beam length is set as l = 10m, and the spacing between the beam and the rigid surface is & Delta= 0.05m, bending stiffness of beam EI = 6.1350 & times; 104n ∙ m2, load Q takes three different values: (1) q = 353.376n/m( 2)q=400N/m;( 3)q=1500N/m。 It is divided into 100 units, and the length of each unit is 0.1M. Under different load conditions, the cloud diagram of the contact deformation between the beam and the rigid plane is shown in Figure 15, and the cloud diagram of the contact position is shown in Figure 16.
As shown in Figure 15 & nbsp; Nephogram of contact deformation between beam and rigid plane under different loading conditions < br / >
As shown in Figure 16 & nbsp; Contact displacement nephogram display
2.2.5 frequency domain analysis < br / >
The beam fixed at both ends with a length of 10m is still studied. The elastic modulus of the beam is 100GPa, the Poisson's ratio is 0.3, the inner diameter of the drill string is 0.2m, the outer diameter is 0.3m, and the density is 7800 kg / m3. The first five natural circular frequencies of the beam are calculated as follows: 33.23156.14344.94595.89695.33。 The first five modes are shown in Figure 17, where the fifth frequency corresponds to axial rotation.
Fig. 17 the first five order arrays of beams, in which the fifth order vibration mode is axial torsional vibration