| This paper presents the study of the full scale drilling simulating test device under the condition of bottom hole pressures. This device is the first one in China hich can simulate the bottom hole pressures in 6000m deep well. We set up this device to overcome the shortcomings that the drilling wellsite test can only obtain the synthetical effect of different technical parameters, and the stratigraphic parameters can be not determined and controlled while drilling. So the successful study of this device will supply the means of the simulating test for the petroleum drilling of our country, especially in the further study of basic theory and applying technology in deep wells. On the basis of analyzing the rock mechanics, the bit working circumstance and property in the bottom hole of 6000m deep well, and making use of the former equipment such as a derrick, platforms etc, the paper demonstrates that the research and design of the mechanical device have been established including the high pressure simulating well bore, the high pressure connector between the static well bore and the rotating drill pipe, the high pressure simulating system of circulating fluid and the high pressure desander etc. The produce, control and dynamic analysis of the bottom hole four-dimensional pressure (over burden, confined, pore and column pressure ) have been studied. As a result the simulating in the circumstance of the four-dimensional bottom pressure has been achieved. In addition, the paper describes the process and result of the debugging and the performance test.Several conclusions, curves and formulas in this paper not only have some academic value, but also have some guidance on field engineering construction.In chapter one, the basic composition, function and simulating press of the full scale drilling simulating test device have been generalized. Furthermore, the current research results in domestic and international of the similar problem and its practical significance have been illustrated.In chapter two, the rock mechanics and the bit working circumstance in the bottom hole of 6000m deep well have been discussed. On the basis of which the high pressure simulating well bore and the high pressure connector between the static well bore and rotating drill pipe have been designed.In chapter three, in order to simulate the actual drilling fluid column pressure and to supply the extreme high pressure drilling circulating fluid for the device, the high pressure circulating fluid simulating system has been designed based on the experience of drilling fluid circulating system in the wellside. To purify the drilling fluid, the high pressure desander has been designed.Chapter four analyzes the static working state of the servo-overflow valve that is the key spare part of setting up four-dimensional pressure. By studying the control law, joint control has been realized between PLC and computer.In chapter five, on the basis of setting up a set of math models of four-dimensional pressure control system, and making use of copying tool-Simulink supplied by Matlab, the frequency and time field specific property has been analyzed, and several curves of frequency and time field specific property in the systemhas been obtained. As a result, some modelled conclusions have been acquired.In chapter six, based on the preceding chapters' research, the practicalityof the full scale dr i 11 ing simulating test device has been tested by the debugging and the performance test. Under simulating drilling conditions, the rockmechanical properties and the bits' dynamical tests are analyzed and set forthspecifically. At the same time the effect of bottom pressure difference on the oil field exploration and development has been discussed. Some valuable parameters have been supplied for SongshenlOl well during the actual operations. The paper includes the theories and technologies that related with drilling, machinery, fluid mechanics and automatization, etc. The solutions for these problems not only provide beneficial e... |
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