The Basic Study For NMR Logging Interpretation In Outer Daqing Oilfield

Nuclear Magnetic Resonance (NMR) logging technology was established based on completely new reservoir response parameters, which is of apparent technology characteristics. It provides new ideas and methods for the problems that many conventional loggings can't solve in practical applications. However, this technology hasn't been far from perfect. And there still exist many problems during applications in outer Daqing oilfield. The study aims at the geological conditions of Daqing oilfield, whose emphasis is on basic experiments for NMR in shaley sandstone. We studied the influence of clay in core, para-magnetic material and oil with different properties on the relaxation signature of NMR in rock. And the relation between porosity difference of different echo time and clay content were built. The evaluation method for porosity was established on the basis of experiments. Permeability interpretation model (SDR-reg) for shaley sandstone was determined by comparative analysis for three kinds of permeability interpretation models. We further analyzed several kinds of spectrum unfolding processing methods for representative raw data and made the choice according to the purpose of study. The determination method for irreducible water and movable fluid volume and identification methods for hydrocarbon zone were discussed on the respect of processing and interpretation for NMR logging data. Finally example analysis of application was given. The obtained results as follows: 1. We find from the experiments that there exists a good corresponding relation between nuclear magnetic spectrum T2 of core and intrusive mercury aperture. Using conversion model, aperture distribution curve can be built through nuclear magnetic spectrum T2 and can evaluate pore structure of rock. 2. We studied the influence of different shale content on Nuclear magnetic measurement result, and know that NMR can basically reflect irreducible water porosity of clay when echo time is 0.3ms. The relation between porosity difference of different echo time interval and clay content was established. The signal of echo time interval of 0.45ms and 0.6ms can be corrected by means of this relation, thus making average porosity error less than 1pu. It shows that the correction model is effective. Though the correction was made for the measurement results of 1.2ms echo time interval, there existed a very large error.