A Method for Evaluating Caprock Effectiveness

An effective and caprock technology, applied in the field of oil and gas exploration, can solve problems such as the inability to achieve effective evaluation of caprocks

CN110764159BActive Publication Date: 2022-05-03CHINA PETROLEUM & CHEM CORP +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2022-05-03

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Abstract

The invention relates to a method for evaluating the effectiveness of cap rocks, which comprises the following steps: using macro indicators to dynamically evaluate the effectiveness of cap rocks; using micro indicators to evaluate the effectiveness of cap rocks; using formation water chemistry and organic geochemical indicators in formation water Evaluate the effectiveness of the caprock. The method of the present invention first qualitatively studies the effectiveness of the caprock according to the macroscopic factors such as lithology, burial depth, thickness and distribution of different structural parts, and then combines the microscopic research to quantitatively evaluate the sealing performance of the caprock with the breakthrough pressure and the content of ultramicropores <2.5nm , and finally combined with the chemical characteristics of the formation water, the separation effect of the cap rock on the formation water is analyzed, and finally the macro-micro-hydrochemical trinity comprehensive evaluation of the effectiveness of the cap rock is realized.
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Description

technical field

[0001] The invention belongs to the technical field of oil and gas exploration, and in particular relates to a method for evaluating the effectiveness of cap rocks. Background technique

[0002] Chen Jianliang (Chen Jianliang, Shi Hesheng, Shu Yu et al. Application of logging caprock evaluation method in Zhuyi sag[J]. China Offshore Oil and Gas. 2007,19(3):157-160) Calculation of porosity using logging data processing Breakthrough pressure, and core analysis data as a calibration, combined with other research results, the quality of the caprock and the distribution of oil and gas were studied.

[0003] Amirsaman Rezaeyan et al. (Amirsaman Rezaeyan,Seyyed Alireza Tabatabaei-Nejad,Elnaz Khodapanah,et al.A laboratory study on capillary sealingefficiency of Iranian shale and anhydrate caprocks[J].Marine and Petroleum Geology,2015,66(4):817-828 ) under the confining pressure of 24.13-37.92 MPa, the sealing performance of the caprock was evaluated by using the dif...

Examples

Embodiment 1

[0048] Example 1: Taking the Shizhu syncline in Western Hubei-Eastern Chongqing as an example

[0049] (1) Determine the structural characteristics of the study area and the thickness distribution of the main cap rocks (see figure 1 ). According to the statistics of oil and gas wells and failed wells, the formation thickness in the effective caprock development area is at least 300m. In most areas of the Shizhu syncline in the Western Hubei-Eastern Yu region, the thickness of the shale formation is greater than 300m, and the macroscopic conditions of the caprock are good.

[0050] (2) According to the water chemical zoning, the minimum buried depth is determined to be 500m (see figure 2 ). Excluding the impact of structural surface water and groundwater in the fault zone, statistics show that the water chemical alternation block zone is below 500m, indicating that the preservation conditions are good.

[0051] (3) According to the breakthrough pressure and ultramicropore...