Porosity measurement error and its control method

With the expansion of oil and gas exploration, the lithology and morphology of porosity test samples show diverse development trends. Porosity measurement faces new challenges because the same sample may have different laboratory porosity measurement results, limiting the application of porosity data. Starting from two key parameters of the total volume and skeleton volume of the rock sample, the influence of test error on the porosity measurement results was analyzed. It is found that when the relative error of the test is 0.5%, 1.0% and 1.5%, the absolute error of porosity is 0.5, 0.9 and 1.4, respectively. The test error of the two has similar influence on the accuracy of porosity measurement, and should be effectively controlled. The current situation of error control of rock sample skeleton volume and total volume was analyzed. Volume testing relies on more mature methods and devices, and its test error can be effectively controlled. The development of total volume testing technology lags behind. The acquisition of key parameters in the measurement process is affected by random human factors, resulting in differences between different operators and different laboratory results. The method for effectively controlling porosity measurement error was discussed. A total sample volume measurement system for rock samples based on the fluid density determination principle was introduced, which has no restrictive requirements on the lithology and morphology of the sample, and automates the determination of the total volume of rock sample. The influence of human factors on the test can be reduced. The average relative error of the total volume of rock sample is 0.5%, and the absolute error of porosity measurement can be controlled to about 0.5, which can be used to narrow the difference of measurement results in different laboratories.