Method for logging well by saturation of carbon hydrogen ratio to stratum fluid

Abstract

The invention discloses a method for logging well by saturation of a carbon hydrogen ratio to a stratum fluid. The method comprises the following steps of (1) recording on-site data; (2) and analyzing the data, including (a) correcting the depth and dividing a lithologic profile, (b) establishing a "carbon hydrogen ratio interpretation model" having an oil layer water logging degree standard interpretation chart and selecting carbon hydrogen ratio interpretation parameters CHRw and the maximum value CHRmax, (c) establishing a carbon hydrogen ratio interpretation parameter card, (d) solving water saturation, oil saturation, water content and oil displacement efficiency, (e) evaluating oil or remaining oil saturation, movable oil saturation and oil layer water logging degree of a reservoir stratum, and (f) making out a result map and interpreting an analysis report. According to the method, abundance of carbon and hydrogen elements in the stratum fluid is detected, double unification connection is carried out based on the ratio of the carbon element to the hydrogen element, and the oil saturation, the oil layer water logging degree and the water content of the reservoir stratum are subjected to full quantitative evaluation, so that accuracy of the data is improved, the application effect is improved remarkably, and the application range is expanded.

Description

technical field [0001] The invention relates to the field of geophysical nuclear logging, in particular to a method of directly detecting the abundance of carbon and hydrogen elements in formation fluids, and based on the ratio of the two, CHR, to fully quantitatively evaluate the oil content or remaining oil saturation of reservoirs and Water flooded degree of oil layer, logging method for judging oil, water, dry layer and water flooded degree of oil layer. technical background [0002] In the process of oilfield exploration and development, it is urgent to evaluate the oil-bearing or remaining oil saturation, the water flooding degree of the oil layer and the distribution of remaining oil, so as to provide data basis for the design and adjustment of the oilfield development plan. The logging methods currently used for the above purpose are as follows Several: [0003] 1) "Carbon-oxygen ratio energy spectrum logging" (referred to as C / O logging), which detects the abundanc...

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Problems solved by technology

In the 1970s, "carbon-oxygen ratio logging" was introduced into China. Since most oilfields in my country are low-porosity and low-permeability reservoirs, the effect is not good due to the influence of porosity.

[0004] 2) "Compensated carbon-oxygen ratio energy spectrum" logging through tubing (referred to as "RST" logging), which is a so-called reservoir saturation logging developed from carbon-oxygen ratio. Due to the small diameter of downhole tools, It can be used to log in the production well through the tubing to quantitatively evaluate the remaining oil saturation and water flooding degree of the oil layer. It is suitable for the formation with a porosity greater than 20%, but due to the limitation of low porosity and the influence of many factors, the effect is also not good

[0008] The applicant once applied for a patent in 2002, and the patent application number 02004486.9 discloses a logging method for formation fluid saturation of carbon-hydrogen ratio, but wherein: 1) "carbon-hydrogen atomic number ratio response equation" only expresses pure The ratio of carbon and hydrogen atoms in sandstone reservoirs does not express the contribution of carbon atoms in calcium carbonate cement, and does not accurately and objectively reflect the ratio of carbon and hydrogen atoms in real formations, which lacks accuracy; 2) "Oil-bearing The “saturation model” only considers the contribution of crude oil, water and high-energy gamma ray degradation reactions to the hydrocarbon energy window, and does not objectively express the contribution of carbon in calcium carbonate cement in the actual reservoir and the measurement environment (casing paraffin and bitumen remaining on the wall) to the contribution of hydrocarbons, and the contribution of the degradation reaction to the energy window of hydrocarbons is relatively small; 3) the "data interpretation method" only relies on the interpretation chart to select waterline parameters, which is impossible It is lacking, but lacks completeness and accuracy, and does not objectively express the main characteristics of the oil reservoir and the state after development; 4) The carbon and hydrogen elements in the "carbon-hydrogen ratio" are in two different nuclear reaction stages, and should be organically The normalized connection is the key technology to realize the carbon-hydrogen ratio logging method, but it does not express how to normalize the connection; 5) The application range is limited to sandstone with a single lithology or relatively few calcium carbonate cements Sandstone, but not for metamorphic rocks, carbonate reservoirs

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