Optimal design of method for shortening echo spacing by nuclear magnetic resonance while drilling
Nuclear magnetic resonance(NMR)logging is a geophysical method to directly detect the fluid properties of reservoir pores.NMR while drilling technology is a technical method for obtaining real-time evaluation parameters of oil and gas reservoirs during the drilling process.Facing the problem of NMR measurement while drilling in complex oil and gas reservoirs,the instrument measurement time can be reduced by shortening the echo spacing of the pulse sequence,and the short relaxation component with rapid decay can be obtained,thus realizing the fine characterization of the reservoir pore structure.In this paper,a multi-level energy release method is proposed,which can gradually reduce the antenna quality factor and shorten the dead-time.Without changing the signal-to-noise ratio of echo acquisition,the design of a short echo spacing acquisition system for pulse sequence is tested and verified on the experimental prototype of NMR logging while drilling instrument.The results show that the signal-to-noise ratio of the echo signal is good,the ringing noise is clearly distinguished from the echo signal.The test results are consistent with the simulation results,and the short echo spacing data acquisition can be realized,which verifies the effectiveness and practicality of the method.
NMR instrumentsNMR while drillingEcho spacingRelaxation components
NETL
NSTL
万方数据
维普
