| Mingyuexia tectonic geological situation is very complex, it is necessary to apply multidisciplinary theories and methods to study the characteristics of drilling geologic environment, and to predict the "three pressures" of the formation-the formation pore pressure), collapse pressure and rupture pressure to establish the formation pressure system of the work area accurately, and to form a set of practical methods and techniques to determine the formation pressure system based on logging and drilling logging data.Based on the elastic mechanics and rock mechanics, five aspects of the study are focused on:? rock mechanics parameter calculation and profile analysis;? the establishment of the rock drillability and grinding profile;? study of PDC bit and roller bit selection in work area. ? Calculation of the formation stress and shtee pressure and establishment of profile;? determination of the safety drilling fluid density window and analysis of the stability of the borehole wall; Through the above work, the following main achievements and understandings have been obtained:(1) The rock mechanics, drilling, geology and logging data are analyzed, and the calculation method of rock mechanics parameters is summarized and the dynamic and static conversion relationship was established;(2) Through the use of logging data, drillability profile of formation rock in the work area was established, the bit selection was carried out based on the gray correlation method, and the results of bit selection in different geological intervals were given;(3) According to the characteristics of reservoir in Mingyuexia area, the calculation model of in-situ stress and formation pressure is optimized, the in-situ stress and three pressure profiles are established, and a reasonable drilling fluid density window is established.(4) Based on the Forward.NET interpretation platform, the program of three-stress calculation of in-situ stress and formation has been improved. The data of several wells have been processed. The rock mechanics parameters, ground stress and three pressure profile have been established.Based on the above research, a set of practical methods and techniques for determining the formation pressure system based on logging, well logging and drilling data are established, which provide scientific basis for drilling optimization design and site construction of new wells in this area, and which can also realize high quality, high efficiency and safety drilling. |
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