PROCEDURE AND DEVICE TO MEASURE FULL POROSITY BY METHOD OF NUCLEAR MAGNETIC RESONANCE

摘要

measurement technology. SUBSTANCE: procedure and device can be employed to measure full porosity of each stratum passed by borehole, sensitive to short-time relaxation that can be caused by water bound in clay. Sequence of oscillating magnetic fields of alternating phase of the type of CPMG or similar sequence of pulses to excite signals in volume of stratum measured by instrument of nuclear magnetic resonance logging is generated in borehole. Extraction of components of signal with short time T2 is obtained thanks to shortened interval between echo signals and improved signal-to-noise ratio. Signals of spin echo are received and value of each signal is measured. Values of signal are divided into first and second multitudes, first multitude containing early echo signals and second multitude containing the rest of echo signals. Second multitude is subdivided into system of groups. Value of aperture sum is formed per each group of second multitude which gives system of aperture sums. Characteristic of stratum is determined on basis of aggregation of aperture sums and value of each signal of first multitude. EFFECT: potential for determination of porosity stipulated by water bound in clay and microporosity in addition to porosity corresponding to free fluid and capillary porosity. 17 cl, 9 dwg