**5. Prospect for future application**

Although the proposed non-contact drilling and coring characteristics monitoring method, SVM pattern recognition method, and drillability recognition based drilling strategy in this chapter are more specific to the interplanetary drilling actives, it should point out that these technologies may also be applied to terrestrial oil and gas well drilling operations. Specially speaking, even although by detecting devices applied into terrestrial oil and gas well drilling operations, the in-situ geological information can be acquired before, due to the unpredicted and variable online drilling conditions, there still exists great challenges in drill bits' selection, fluid system monitoring and parameters' optimization, adjustment of drilling parameters, well drilling faults' diagnosis, etc., [50, 51].

To solve the above problems, intelligent drilling technologies have been gradually widely employed in oil and gas well drilling activities. However, so far more attention was paid into the drill bit's wearing recognition, drilling faults' identification, formations' lithology evolution, etc. [52–54], few works were conducted to focus on the coring characteristics monitoring and adjustment. Since the ultimate goal of commercial drilling is to extract oil as much as possible, it perhaps is better to apply some facilities to monitor the online coring results into the inner tube. Herein, the proposed non-contact drilling and coring characteristics monitoring method is developed to conduct experimental validations, but once its specific structure parameters and installation conditions can be optimized further it may be employed into practice to enhance the online coring monitoring performance.

Given suitable drilling parameters in oil and gas well drilling are more dependent on the empirical formula concluded by experts [55], it is also urgently necessary and important to conduct rigorously theoretical calculation and experimental validation works on the soil-machine interaction, wherein the soil or rock's flow monograph can be comprehended more basically and the minimum power of the actuator under specific formation could then be referenced for future application. Therefore, the proposed drilling and coring characteristics monitoring method may be applied to further experiments. Moreover, considering the increasing costs of human resources in the future, the unmanned oil and gas drilling is being more popular than before. The proposed drillability recognition based online drilling strategy is exactly developed for this issue. By only required some basic force sensor resources, it can be simply applied to recognize different drillability levels of uncertain drilling formations in practice. However, it should be noted that for future application, more considerations should be taken into optimizing the fluid system's disturbance on the recognition and the longer depth's coupling influence on the mechanical system.
