DOWNHOLE MEASUREMENT WHILE DRILLING TOOL WITH A SPECTROMETER AND METHOD OF OPERATING SAME

摘要

A pulser assembly for a downhole measurement-while-drilling tool comprises a motor subassembly and an electronics subassembly electrically coupled to the motor subassembly. The motor subassembly comprises a motor, a motor subassembly housing that houses the motor, a spectrometer inside the motor subassembly housing and a driveshaft extending from the motor out of the motor subassembly housing for coupling with a rotor of a fluid pressure pulse generator. The spectrometer includes an optical sensor for optical communication with a lubrication liquid when the lubrication liquid is sealed inside the motor subassembly housing. The electronics subassembly comprises electronics equipment and an electronics subassembly housing that houses the electronics equipment. Optical measurements from the spectrometer may be used to determine a molecular composition of the lubrication liquid in the downhole tool.