A method for measuring gas-bearing porosity of shale

Abstract

The invention discloses a method for measuring the gas-containing porosity of shale, which comprises the following steps: 1) sample preparation; timely take shale without water soaking from the middle of the full-diameter rock core, cut it into rectangles, and clarify the bedding direction and quality less than 40g, and carry out sample numbering; prepare stratum salinity brine, or standard brine of 50,000 salinity for standby; 2) weigh the sample quality with the cut rectangular core; vacuumize the rectangular core sample and fluid, and Absorb and saturate the fluid in the bedding direction, then completely soak in the liquid, and further absorb the liquid until the mass does not change; weigh the mass of the sample in the fluid, take out the completely saturated fluid core and suck the fluid on the rock surface, and then weigh it in the air Medium mass; calculate the air-containing pore volume and apparent volume; 3) measure the pore volume after dry distillation; 4) parameter calculation; calculate the air-containing porosity and total porosity. The invention can directly measure the gas-containing porosity, and the measurement result is accurate.

Description

technical field [0001] The invention relates to a shale gas reserve prediction technology, in particular to a method for measuring shale gas-containing porosity. Background technique [0002] The existing indirect methods for measuring air-containing porosity have the following disadvantages. First, the existing methods are complicated and cannot directly measure air-containing porosity. It is necessary to first measure porosity and water saturation, and then calculate the air-containing porosity. Second, there are large errors caused by multiple measurements and numerical transfers; the heating distillation temperature and heating distillation time affect the water content test, and there are differences in the selection of porosity test methods. These experimental links have large systematic errors and accidental errors. The third is that shale has low porosity and small pore volume, and the appropriate test methods and test conditions for shale porosity have not been opti...

AI Technical Summary

Problems solved by technology

[0002] The existing methods for indirectly measuring air-containing porosity have the following disadvantages. First, the existing methods are complicated and cannot directly measure air-containing porosity. It is necessary to measure porosity and water saturation first, and then calculate the air-containing porosity

Second, there are large errors in multiple measurements and numerical transfers; the heating distillation temperature and heating distillation time affect the water content test, and there are differences in the selection of porosity test methods. These experimental links have large systematic errors and accidental errors.

Third, shale has low porosity and small pore volume, and the appropriate test method and test conditions for shale porosity have not been optimized

Conventional porosity, water saturation measurement methods and test conditions are no longer suitable for shale gas reservoirs

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