Research On Guiding Force Distribution Of Rotary Steering Drilling Tool

Nowadays, the development trend of drilling industry is to be intelligentized and informationalized in drilling technology and the rotary steering drilling tool is a revolutionary product in this development environment. Compared with the traditional slide steering drilling tool, rotation direction is more advantageous. However, the core technology has always been grasped in the hands of foreign giant oilfield service cooperation since it was launched. These cooperation implement technical blockade to this new tool, monopolizing the drilling market. They even rent it to domestic construction teams with high price. While, domestic research of this technology is still in primary stage and no rotary steering drilling tool has been really developed to be commercially marketed. Therefore, we should put more emphasize on the research of this technology in order to invent rotary steering drilling tool with intellectual property right of our own country as soon as possible.This paper is based on the static push-by rotation-oriented model manufactured by Daqing Drilling Research Institute. Three dimensional small deflection method is used to establish the dynamic equations of the bottom drilling tool with rotary steering tool. The relationship between the offset lateral force and the guiding force of the drill bit is obtained by the weighted residual method. According to the guiding force of the drill bit needed by guide tool, the algorithm of the ground control command is obtained. At the same time, the mathematical and mechanical models of the offset mechanism of the guide tool are established as well. Divide the control surface into 120 and 60 zones and calculate guiding force distribution plan of two cases. Considering the actual situation, the guiding control scheme of 60 zones is preferred. At last, the work block diagram of three working modes of rotary steering tool is given to designers for reference.Field practical application results show that the drilling in parts of inclined section and horizontal section in directional well are successfully realized after incorporating the research control scheme algorithm into CPU under the well. The orientation process also proves that the ground control command is accurate and the distribution of guiding force under the well is steady and viable.