The Surface Commands Control System Research For Rotary Steering Drilling Downward Communication

There are three parts of the rotary steering drilling downlink signal transmissioncommunication system from the ground to the downhole, ground control system，downholesteering tool and drilling fluid transport channel. Based on downhole data, the ground controlsystem sends out control commands to the steering tool by the downlink communicationchannel, guid drilling downhole tools with design of the trajectory, implement operationrequriements of different functions. Hence，both the actual needs in drilling operation and thefunction components of drilling a closed-loop system can deciding the necessity of whichSend the control command by ground control system and complete the downwardcommunication.This paper focuses on the research of the ground commands transmission control systemresearch in rotary steering drilling downward communication. On the basis of the fullunderstanding of rotary steering drilling downward communication system，drilling fluid as aninformation channel, in combination with drilling fluid the variable displacement solution andthree drop three rise instruction code，build the ground visualization monitoring interface.Design of the information playback interface and instruction download interface，completedthe data and curve drawing. With the need of drilling engineering, complete the options andsend of the corresponding control instruction encoding, design of the hardware interface andsoftware program in encoding pulse command control system. Implements communication ofthe ground monitoring and control system with DSP sends instructions system. Complete thecontrol of the frequency of mud pump with frequency conversion and pulse width encoding,achieve the goal of control instruction downlink.Experimental tests show that the ground monitoring and control system can be effectivecommunication with DSP instructions sent system, and can completely sent the drillinginstructions, meet the practical requriement of steering drilling downward communication.Through the augmented conversion for state-space model and combined with the recedinghorizon control principle, an augmented minimal state-space model predictive controller isdesigned. An algorithm of state feedback gain matrix with Laguerre function is proposed, andsimulation study is realized with MATLAB for steering drilling stabilized platform control system. The simulation results show that stabilized platform predictive control system can wellsatisfy the requriements of the drilling engineering for control precision and dynamiccharacteristics, and the system has strong robustness to the model perturbation and the discvalve friction disturbing torque with time variation.