Strength sensitivity evaluation method for shale reservoir

Abstract

The invention relates to a strength sensitivity evaluation method for a shale reservoir. The intensity sensitivity evaluation method comprises the following steps: measuring the compressive strength of the core after executing a standard process so as to obtain a first compressive strength; measuring the compressive strength of the core after executing a specified process so as to obtain second compressive strength; and obtaining a strength sensitivity index of the core by virtue of the first compressive strength and the second compressive strength, and evaluating the sensitivity of the shalereservoir by utilizing the strength sensitivity index. According to the sensitivity evaluation method disclosed by the invention, the limitation of the existing sensitivity evaluation is overcome, thesensitivity performances of the shale reservoir, such as water sensitivity, acid sensitivity, alkali sensitivity, stress sensitivity, temperature sensitivity and the like can be evaluated from the mechanical property, formation damage and collapse caused by operations such as hydraulic fracturing, acid squeezing, squeeze water throughput, waterflooding displacement and the like can be avoided, and a basis can be provided for optimizing the construction process parameters.

Description

technical field [0001] The invention relates to the field of oil and gas exploitation, in particular to a sensitivity evaluation method for shale reservoirs. Background technique [0002] With the continuous growth of energy demand in countries all over the world, the situation of conventional energy supply is becoming increasingly severe. After entering the 21st century, with the successful development of shale oil and gas in the United States, especially after 2005, the production of shale oil and gas in the United States has increased significantly, and people have shifted more attention to unconventional oil and gas resources. Unconventional oil and gas resources will become the post-oil era. Strategic supplementary sources of energy for conventional oil and gas resources. [0003] Oil shale, also known as kerogen shale, is a solid combustible organic mineral with high ash content (>40%). As one of the unconventional energy sources, oil shale resources are very rich ...

AI Technical Summary

Problems solved by technology

The advantage of this process is that the technology is mature and the heating cycle is short, but there are great limitations: 1) Ecological and water quality damage is serious

2) Serious ash pollution

The oil shale obtained through excavation and mining is used to extract shale oil or directly burn, producing a large amount of ash. If it is not recycled, it will not only cause air pollution, but also the waste ash occupies a large area, and metal elements and trace elements infiltrate into it. Underground water, endangering people's production and life

3) Direct mining takes up a lot of land, and once it is reclaimed, it cannot be completely repaired

4) The slag discharge after dry distillation needs to be cooled with a large amount of water, which consumes a large amount of water resources and produces a large amount of waste water to pollute the environment, and the thermal energy of the thermal residue is not utilized, resulting in a waste of thermal energy

5) The development of medium and deep oil shale has no economic benefits due to the increase in mining costs

[0007] In addition, shale oil and gas reservoirs have high clay content, mixed with minerals such as quartz, feldspar, mica, calcite, dolomite, pyrite, apatite, etc. Some reservoirs contain salt interlayers to varying degrees, matrix porosity, Very low permeability (the range of porosity is generally 1-5%, and the permeability is generally less than 0.001×10 -3 μm 2 ), measures such as large-scale hydraulic fracturing, squeezing acid to dissolve some minerals, and squeezing water to dissolve salt need to be taken during the mining process, which will have a great impact on the mechanical properties of the reservoir rock. If the measures are not taken properly, it will cause damage to the reservoir and even cause the collapse of the reservoir

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