The Research And Design Of Downhole While Drilling Communication System

With the growing demand for oil, the oil exploration technology will also be continuously updated and improved. For now drilling oil exploration, the MWD systems account for a very important position, where the wireless communication system for MWD systems is very critical part. And the wireless communication system has been the hop topic since researched. With the growth in oil demand, growing safety awareness, the MWD communication system is expected to perform better. Electromagnetic MWD technology began to rapidly rise in recent years, it is a important turning point for the MWD technology. But the communication system is not perfect, inadequate technology has led to some limitations in its application. So the study MWD communication system has a very important significance for MWD technology development and improvement.In this paper, the main part of the measure electromagnetic MWD communication system has been studied and analyzed, including the basic theory of electromagnetic field analysis, research and analysis channel, research and analysis of electromagnetic field characteristics in a moving medium, etc. Based on these studies, the current distribution channels in the drilling environment, the establishment of a theoretical model of the channel and the electromagnetic field in a moving medium of reflection, refraction model are obtained. On the basis of a series of theoretical analysis and research, we designed a set of electromagnetic MWD wireless communication system, which analyzes the actual situation in the future using AT89S51 microcontroller as the main chip designed as the core of a AD9850 DDS signal generator device. It has the advantage of adjustable frequency and waveform, it can produce different frequencies, different waveforms to meet different needs, facilitate the transformation uses in different communication environments. In this paper, 2MHZ sine wave carrier frequency and 1KHZ square wave baseband signal are used to design and achive each module in communication systems, including DDS signal generator module, a modulation module, transmitting and receiving antennas module, demodulation, and filtering module. Test results obtained under laboratory conditions show that each module can basically achieve the corresponding functions, meet the design requirements.In this paper, the communication system is designed flexible and simple, but the noise immunity and stability of the system needs to be further improved. Thus, the system applies only to tests under laboratory conditions.