Horizontal well crack recognition method

A technology for fracture identification and horizontal wells, which is applied in earth-moving drilling, wellbore/well components, etc., and can solve the problems of difficulty in identifying fractures and weak response from logging data.

Active Publication Date: 2016-02-10
CHINA UNIV OF PETROLEUM (BEIJING)
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Problems solved by technology

[0010] In the actual fracture identification, due to the common influence of conventional logging data on lithology, petrophysical properties, fluids, fractures and other factors, the logging curve has a certain response to fractures, but the response is weak; at the same time, the response characteristics of conventional curves, There are multiple solutions, and fractures are not the only factor causing the response of conventional curves, so it is difficult to identify fractures directly using logging data

Method used

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Embodiment 1

[0059] Adopt the method of the present invention to identify the cracks of the horizontal well A of the tight sandstone reservoir in the southwestern margin of the Ordos Basin; the average porosity of the reservoir at the position of the horizontal well A is 8.6%, and the average air permeability is 0.2mD, which is a typical tight sandstone reservoir. In sandstone oil reservoirs, fractures are widely developed, mainly high-angle fractures; the initial production of horizontal well A is 14.18t / d.

[0060] The specific steps are:

[0061] (1) Detect the horizontal section of the horizontal well, take the depth in the horizontal direction as the abscissa, and the logging value as the ordinate, and obtain the logging curve sensitive to fractures and the rock density curve; wherein, the logging curve sensitive to fractures is : Deep induction resistivity ILD curve, medium induction resistivity ILM curve, eight lateral resistivity LL8 curve, borehole CAL curve and acoustic time diff...

Embodiment 2

[0084] The method of the present invention is used to identify the fractures of the horizontal well B in the tight sandstone reservoir in the southwestern margin of the Ordos Basin; the block where the horizontal well B is located is the same as that of the horizontal well A; the initial production of the horizontal well B is 0.42t / d.

[0085] Each step is the same as embodiment 1; each reconstruction curve and crack identification result are as follows Figure 4 shown.

[0086] from image 3 and Figure 4 It can be seen that the level of the fracture index reflects the degree of fracture development. Horizontal wells with a high degree of fracture development have high production (such as image 3 shown); horizontal wells with low degree of fracture development have low production (such as Figure 4 shown). Therefore, comparing the development degree of the fracture identified in the horizontal well with its initial production well shows that the development degree of the ...

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Abstract

The invention relates to a horizontal well crack recognition method. The horizontal well crack recognition method comprises the following steps: detecting a horizontal section of a horizontal well to obtain a well logging curve which is sensitive to a crack and a rock density curve, and further reconstructing to obtain a crack fractal index curve, a crack feature index curve and a stratum brittleness index curve; obtaining a crack index curve according to the various curves obtained by reconstruction; and recognizing development degree of the crack of the horizontal well in the horizontal direction according to the crack index curve, wherein the development degree of the crack is increased along with increasing of crack indexes. According to the method provided by the invention, response strength of the crack is amplified by well logging data, non-crack influences are eliminated, crack information is extracted comprehensively from the well logging data, and cracks of the stratum surrounding the horizontal well are recognized accurately.

Description

technical field [0001] The invention relates to the field of reservoir geophysical well logging, in particular to a method for identifying fractures in horizontal wells. Background technique [0002] With the development of technology, in recent years, the application of horizontal well technology has brought about a new revolution in oil and gas exploration and development. Especially for the development of unconventional oil and gas resources such as tight gas, tight oil, and shale gas, horizontal well technology is widely used to increase productivity. Unconventional oil and gas reservoirs have poor physical properties, strong heterogeneity, and developed natural fractures. The existence of natural fractures plays an important role in the distribution and efficient development of unconventional oil and gas. Therefore, how to identify fractures in horizontal wells is of great significance for guiding unconventional oil and gas exploration and development. [0003] Core a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B49/00
Inventor 曾联波吕文雅刘国平
Owner CHINA UNIV OF PETROLEUM (BEIJING)
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