An accurate NMR porosity test method for oil-bearing shale

Abstract

The present invention provides an accurate test method for nuclear magnetic resonance porosity of oil-bearing shale, by testing different waiting time, echo interval saturated kerosene shale nuclear magnetic resonance T2 spectrum distribution and porosity, and comparing with helium porosity to calibrate the waiting time and echo interval, NMR T2 spectrum distribution at the optimal waiting time and echo interval can accurately characterize the physical characteristics of oil-bearing shale reservoirs. The present invention attributes the factors affecting the accuracy of NMR porosity testing of oil-bearing shale to the type of sample saturated fluid and test parameters (waiting time and echo interval), and eliminates the influence of shale sample hydration by saturated kerosene; by analyzing the T2 spectrum The optimal waiting time and echo interval are calibrated by the distribution change and helium porosity; using the method, by testing the NMR T2 spectrum distribution and porosity of saturated kerosene shale with different waiting times and echo intervals, an accurate characterization can be obtained. The best test parameters for the porosity of oil-bearing shale, the experimental operation is simple and easy, and the operability is strong.

Description

technical field [0001] The invention relates to an accurate test method for nuclear magnetic resonance porosity of oil-bearing shale, and belongs to the technical field of nuclear magnetic resonance test of shale reservoir physical properties laboratory. Background technique [0002] The successful exploration and development of shale oil and gas in North America has greatly promoted the process of global shale oil and gas exploration and development. The exploitation and utilization of shale oil and gas are of great significance to alleviating the energy crisis, prolonging the life of the petroleum industry and adjusting the national energy structure. [0003] Shale oil and gas refers to the accumulation of hydrocarbons in shale formations, including oil and gas in thin interlayers of sandstone and carbonate rocks in shale formations. Different from conventional reservoirs, shale reservoirs have complex mineral composition, ultra-low porosity, ultra-low permeability, and r...

AI Technical Summary

Problems solved by technology

[0004] At present, domestic and foreign scholars have carried out a large number of shale NMR tests based on conventional reservoir NMR test methods, and obtained NMR T values ​​of shale saturated fluids with different morphological characteristics. 2 These test methods generally have the following defects: the sample pretreatment is not carried out before the test, and the pore fluid of the sample is removed, making it difficult to meet the requirement of a single saturated fluid during the sample test; the sample is saturated with water or brine, ignoring the influence of clay mineral hydration ; The test parameters of waiting time and echo interval mostly use conventional reservoir test parameters or unspecified test parameters, ignoring the influence of test parameters on NMR test results

Images