Method for measuring reflectivity of solid asphalt based on nuclear magnetic resonance

Abstract

The invention provides a method for measuring the reflectivity of solid asphalt based on nuclear magnetic resonance, which comprises the following steps: (1) collecting a sample, carrying out the measurement of the reflectivity of the solid asphalt by a conventional method, and inputting the actually measured data of the reflectivity of the solid asphalt; (2) identifying the solid asphalt by using a nuclear magnetic resonance transverse relaxation time T2 atlas; (3) extracting two parameters of nuclear magnetic resonance T2 signal amplitude and decay time; (4) respectively establishing unary regression equations of the solid asphalt reflectivity, the signal amplitude and the decay time; (5) establishing a binary regression equation of the solid asphalt reflectivity, the signal amplitude and the decay time; and (6) calculating the reflectivity of the solid asphalt in a large range by using a nuclear magnetic resonance logging technology and a binary regression equation. According to the method, the problem that the maturity of the non-vitrinite of the ancient marine facies stratum is difficult to evaluate is solved; human influence factors of a traditional solid asphalt reflectivity measurement result are reduced; the problem that the traditional determination method has a large demand on the rock core is solved, and the cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of geological exploration, and in particular relates to a method for measuring the reflectivity of solid asphalt based on nuclear magnetic resonance. Background technique [0002] During the exploitation of major oilfields, the thermal evolution process of source rocks and the reconstruction of the evolution history of oil-gas-bearing basins are crucial to the exploration and development of oil and gas. Vitrinite reflectance has been used for the first time since the 1930s to determine the coalification grade, and it has become the most widely used digital quantitative scale for organic matter maturity indicators (Xiao Xianming, Liu Dehan, Fu Jiamo. Bitumen reflectance as a hydrocarbon source Significance of rock maturity index [J]. Sedimentary Journal, 1991 (S1): 138-146.). The vitrinite reflectance refers to the percentage of the reflected light intensity and the incident light intensity of the vitrinite ...

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Problems solved by technology

However, in the process of practical application, the reflectance of vitrinite also has relatively large defects. The main problems are reflected in (Luo Qingyong, Hao Jingyue, Li Kewen, Xu Yaohui, Wang Xiaomei, Wang Huajian, Luan Jinhua, Hu Ke, Li Tian, ​​Zhong Ningning .New parameters for evaluating the maturity of organic matter in the Lower Paleozoic: Re-study on the optical characteristics of graptolite epidermis[J].Acta Geological Sinica,2019,93(09):2362-2371.):

[0003] ① Affected by the depositional environment and surrounding rocks, the types of organic parent materials are quite different, which may lead to the suppression or abnormal increase of vitrinite reflectance, resulting in distortion of Ro data

[0004] ② Vitrinite reflectance is mainly measured by microscope, which is limited by the field of view and operation of the thin section, and the human influence factors are relatively large, resulting in certain deviations in the measured data

[0005] ③The biggest problem is that vitrinite mainly comes from higher plants, that is, only after biological evolution to the appearance of higher plants, can there be vitrinite in the stratum. For ancient strata with a long history, lack of higher plant vitrinite, it is impossible to develop Determination of Vitrinite Reflectance

For a large oil and gas basin, the cost of drilling and coring is high and expensive, and it is impossible to take large-scale coring. Limited by core samples, it is difficult to carry out maturity evaluation work on a large scale

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