The Development Of Simulation Test Device About The Stability Of Hole Wall

With the continuous development of drilling, drilling technology is evolving and has gotten a new breakthrough. But in the drilling project, the problems of hole wall stability are historical and not completely solved. Such as the hole wall collapse of broken formation, hole shrinkage of plastic flow rock formation, borehole collapse of high ground stress zone, formation gushing, boulders, mud loss, etc. These complications may also occur simultaneously, which increase the difficulty of drilling and seriously affect the stability of the hole wall. At present, the researches of the impact of drilling fluid on hole wall stability are mostly theoretical as follows: laboratory test analysis, research and development of new drilling fluid and the improvement of drilling fluid performance. Because of the complexity and concealment of drilling project, field studies need to spend a lot of manpower and resources, and the various factors can not be measured and adjusted intuitively and effectively, but the final results can be seen. In order to study the consolidated results of the interaction of hole wall and drilling fluid in complex situations intuitively and economically, the simulation test device is required, which studies the changes of the particular test values under the simulation status though computer techniques and simulating each test value under the simulation status as close as possible.By studying the drilling simulation test device at home and abroad, the structure and working principle of the simulation test device is analyzed. Combined with the mechanical characteristics of hole wall, a comprehensive evaluation testing device of drilling fluid is designed, which can simulate the overburden pressure of 500 m vertical depth, the rotary motion state of drill pipe, the circulatory state of drilling fluid at different annular clearance, drilling fluid pressure and the stratum situation of different components. In the state of drilling fluid circulation, completion the research of the development of the results of the cell wall by multiple factors influence.This paper shows the research status of the unstable hole wall, and introduces the researches of simulation test device at home and abroad latter. The integrated design of the simulation test device is completed though the researches of the real situation of bore. then the design of each system and component is described, and finally the device is manufactured and its hardware and software are debugged. Details are as follows:The first chapter shows the harm caused by the unstable hole wall and the research status of the unstable hole wall, summarizes the research status and development trend of other simulation devices, and elaborates the research content and the main design mind map of the device and the main outcome.The second chapter analyzes the influence factor of the hole wall stability, and introduces some laboratory evaluation method of hole wall stability. The result, which is that the simulation test need to be conducted relying on simulation device, by analyzing the deficiencies of some kinds of experiment methods.On the basis of the researches of simulation devices at home and abroad, the third chapter presents the design goal of the mud comprehensive evaluation test device and the overall design principles that should be followed. The design idea is proposed and the body diagram of simulation test device is drawn.The fourth chapter firstly introduces the design of each system of this device. The comprehensive simulation system, integrating multiple simulation factors, completes the simulation of hole bore and formation with special component, the visualization of the flow field in the bottom of the bore, the visualization of the flow field of annular clearance and the simulation of drill pipe rotation. This system is the core of the whole device, though which the simulation status and the effect are expressed on the simulated hole wall. Secondly, this chapter introduces the working principle of overburden pressure simulation system, elaborates the design of master cylinder including the shape design, material selection, and checking. And then this chapter introduces the control process of fluid column pressure, the upgrading of the entire system back pressure valve and the calculation of flow, and the rotating connector of drill pipe, lastly describes the working principle of computer data acquisition system, shows the comparison and selection of three kinds of signal measurement and analysis systems for data collection.The seventh chapter of shows the hardware and software debugging of mud comprehensive evaluation test device that has been developed. Hardware debugging introduce the alone and joint debugging of each system and component. The places with problem have been improved. Software debugging completed the connectivity of the entire test device, and completed the calibration work of soil pressure sensor.This paper completes the design, equipment manufacture and assembly of the simulation test device of hole wall stability, on the basis of analyzing the deficiencies of laboratory evaluation method of hole wall stability and studying the drilling simulation test device at home and abroad. The alone and joint debugging of each system and component and software debugging shows that the test device can work normally, and provide simulation parameters. For the specific component formation, under the situation of drilling fluid circulation and the influences of a variety of factors, the development law of hole wall stress and strain and the appropriate countermeasures in accordance with the law still need further experimental researches.