either batchwise accompanied by agitation or continuously as when the oil is being injected down a well the amount of tracer material to be used depends primarily on the subsequent use of the trace containing oil if the oil is to be used in monitoring a downhole hydraulic pumping system during production of reservoir oil about 50 to 250 weight parts per million of the tracer material should be used in the oil power fluid when the oil is to be injected into a subterranean reservoir as in an enhanced oil recovery process or an investigation of the dynamic conditions of fluid flow in the reservoir there is a possibility the oil will be highly diluted with reservoir fluids before eventually being recovered from the reservoir thus about 250 to 10 000 weight parts per million of the tracer material should be added to oil to be injected into a reservoir further the particular tracer materials can vary in their sensitivity to detection in the election capture detector and the amount of each which should be used will vary depending on this sensitivity since the amount of tracer material employed is small compared with the amount of oil to which it is added in some instances it may be desirable to prepare a concentrated solution of the tracer material in an oil solvent generally about 1 000 to 100 000 weight parts per million tracer material in an oil solvent can be used the.