Calculation method of charging dynamics in tight gas reservoirs

Abstract

The calculation method of tight gas reservoir charging power includes the following steps: 1) Read the mudstone compaction degree data of a single well on the well logging curve; 2) Fit the depth-AC relationship of the non-hydrocarbon-generating-normal compaction section to get The expression of the trend line of the normal compaction section; 3) Filter the data of the hydrocarbon generation-under-compaction section. First, draw the depth and corresponding mud content in the logging curve into a depth-lithology longitudinal profile; then in the profile Select the calculation data of the under-compacted section; 4) Calculate the excess fluid pressure, that is, the charging power, and mark the calculation results on the data screening section of the profile; 5) The charging power provided by the source rock and the charging power obtained by the reservoir Pay attention to dynamic characterization. By adding mudstone section screening and standardizing the mudstone section screening, the present invention can compare data between well points, and then through fitting of compaction trends and calculation of charging power, the size of the charging power is finally obtained. The calculation process More concise, more precise and more comparable.

Description

technical field [0001] The invention belongs to the technical field of oil and gas reservoir exploration, and in particular relates to a calculation method for charging dynamics of tight gas reservoirs. Background technique [0002] The reason why oil and gas can migrate and charge is mainly due to certain differences between source rocks and reservoirs, such as fluid potential difference, density difference, concentration difference, etc. During the evolution of oil and gas-bearing formations in geological history, It is necessary to reduce and reconcile these differences, resulting in the accumulation and accumulation of generated oil and gas under different dynamic mechanisms. In terms of mechanism, the fluid potential difference can form directional flow to make oil and gas migrate and accumulate, while the density difference shows that oil and gas accumulate and accumulate due to the vertical differentiation of fluids due to different densities, and the concentration di...

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Problems solved by technology

[0014] To sum up, among the current methods for studying gas reservoir charging dynamics, the effective inclusion method and immature source rock hydrocarbon generation simulation method both have the above-mentioned problems. The data is easy to obtain, the method is simple and easy to implement, but the accuracy is not high, and the minimum error is also ±2MPa

In "Calculation Method of Upper Paleozoic Charging Dynamics in Sulige Gas Field" (Chen Zhanjun et al., 2016), although new measures are used to improve the calculation accuracy, some steps are subjective, such as selecting layers with high shale content, shale How high is the content? How thick should the layer with high mud content be? How to draw up the trend line of normal compaction section? Is there a unified expression formula? The charging power in the reservoir can be characterized by the intermediate value of the overlying and underlying mudstone. How should the intermediate value be chosen? How to distinguish the normal compacted section from the under-compacted section has no specific operability content, so the corresponding calculation method is transformed into an executable, quantifiable, and unified calculation technology to achieve large-scale application. It is necessary to abandon the subjectivity, arbitrariness and flexibility of calculating a small number of wells

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