DOWNHOLE OPTICAL FLUID ANALYZER HAVING INTERMITTENTLY DRIVEN FILTER WHEEL

摘要

A downhole optical fluid analyzer having an intermittently driven filter wheel. In at least some embodiments, the tool operates by passing light along an optical path through a downhole sample cell to a detector. At least one filter wheel having multiple filter elements intersects the optical path to operate on the light. The filter wheel is preferably driven in a variable speed manner to prolong each filter element's residence time on the optical path. Such driving may be accomplished by converting the continuous rotation of an electrical motor to an intermittent motion of the filter wheel. Possible mechanisms for this convertion include a peg-and-slot mechanism in which a circulating peg engages successive slots in a slotted wheel to impart intermittent motion. Other suitable mechanisms are also described.