Method for optimizing micro abnormal signal of gas logging value

Abstract

The invention belongs to the field of petroleum exploration and development and particularly relates to a method for processing and optimizing a gas logging value of an oil gas well. The method comprises the steps as follows: all depths of a well to be logged are detected to obtain gas logging values, and an original gas logging curve A is formed; when the well depth is i meters, the gas logging value is Ai, a gas logging value set [Ai-l, Ai+l] of the well depths close to the i meters is obtained, the value of l is 2 to 10 meters, and an average value Bi of the gas logging value set [Ai-l, Ai+l] is calculated; a variance sigma i of the gas logging value Ai of the well depth point is obtained according to the average value and the gas logging values; the values of Ai and (Bi+Sigma i) are compared, when Ai is not less than (Bi+Sigma i), the gas logging value of the well depth point i is a high abnormal signal, and the information of the point is output; and all the well depths are optimized in sequence until termination, and all high abnormal signal point information is output. According to the method, the problems of identification and evaluation of the micro abnormal signal of the gas logging value are solved and the subsurface showing is easily discovered and evaluated.

Description

technical field [0001] The invention belongs to the field of petroleum exploration and development, and in particular relates to a method for processing and optimizing gas measurement values ​​of oil and gas wells. Background technique [0002] In the comprehensive mud logging of oil exploration, with the help of comprehensive mud logging equipment, the content of hydrocarbon gas in the drilling fluid can be continuously measured to discover, interpret and evaluate oil and gas shows. Generally speaking, there is no oil and gas show in the well section with relatively stable gas measured value. If there is a peak-the gas measured value is higher than the baseline, it means that there is a oil and gas show, such as figure 1 As shown in the figure, the 1011-1014 m well section in the figure has a peak, so this well section is likely to be an oil and gas layer. Currently, curves are generally analyzed and identified with the naked eye. [0003] However, in the actual mud loggi...

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Problems solved by technology

[0004] ① Carefully distinguish with the naked eye. When using this method, the workload is increased, and the human factor is very large, and oil and gas indications are often missed

[0005] ② Simply multiply all gas measured values ​​by a multiple. This method enlarges or reduces all gas measured values. When a small peak is compared with the upper and lower, there is still no obvious abnormality, and basically no effect

In this paper, the influence of parameters such as drilling time and drilling fluid flow rate on the gas measurement value is analyzed, and the gas measurement value is processed as a whole by the inverse proportional function method, exponential function method and inverse trigonometric function method, but the abnormal value is not processed separately. Does not solve the problem of identifying tiny peaks

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