Well leakage prediction method with seismic data

A technology of seismic data and prediction method, which is applied in the directions of surveying, earthwork drilling and production, wellbore/well components, etc. It can solve problems such as leakage channels, formation pressure deficit, pressure excitation, etc., achieve accuracy and efficiency improvement, and identification accuracy Effect of improvement, efficiency improvement of recognition

Active Publication Date: 2019-11-12
CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] During operations such as shale gas horizontal well drilling in the Sichuan Basin, lost circulation often occurs, which seriously affects the progress and development effect of shale gas exploration and development projects
[0006] 2. The performance of the drilling fluid is not good or the operation is improper, resulting in artificial leakage channels
[0007] 3. The pressure of the drilled formation is insufficient, or the density of the drilling fluid is too high, resulting in a large pressure difference
[0008] 4. The viscosity of the drilling fluid is too high and the shear force is too high, resulting in too high pressure to start the pump, resulting in pressure excitement and formation leakage
[0009] 5. The sand-carrying performance of the drilling fluid is not good, the well wall is not clean, or the water loss is too large, the filter cake is thick, and the operation of drilling in and out and pumping is improper, resulting in pressure surge
At the same time, since the recognition of micro-structures in the above-mentioned prior art is only obtained by calculating the curvature, or only by improving the seismic resolution to identify micro-structures
In the actual application process, even if the above-mentioned existing technologies are used to predict the leakage points of fractured wells in horizontal wells, the identification effect of the micro-structure is relatively simple, so the identification effect is not ideal, which leads to the accuracy and efficiency of the prediction of leakage points. not ideal

Method used

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  • Well leakage prediction method with seismic data
  • Well leakage prediction method with seismic data
  • Well leakage prediction method with seismic data

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] As a preferred embodiment of the present invention, it discloses a lost circulation prediction method based on seismic data, the steps of which are as follows:

[0044]a. High resolution processing: processing conventional lower resolution seismic data into high resolution data;

[0045] b. Fine horizon correlation: Accurately pick up seismic horizons according to the usual seismic horizon correlation technology;

[0046] c. Automatic identification of folds: calculate the curvature of the formation along the seismic horizon, find folds, and judge the positive or negative of the curvature at the same time;

[0047] d. Judging the nature of folds: judging whether it is an anticline or a syncline according to the positive and negative changes of the curvature;

[0048] e. Extract the amplitude difference: calculate the amplitude difference in each direction within the scope of the target layer with the center of the slight fold;

[0049] f. Calculation of slight wrinkle...

Embodiment 2

[0057] refer to figure 1 , as the best implementation mode of the present invention, its steps are:

[0058] a. High-resolution processing: process conventional lower-resolution seismic data into high-resolution data; if the resolution of seismic data is already high, this step can be ignored. The high-resolution processing method is arbitrary, but the resolution There should be a significant improvement.

[0059] b. Fine horizon correlation: Accurately pick seismic horizons according to the usual seismic horizon correlation technology; the picked seismic horizons should be on the same reflection feature point or geological interface, and the reflection feature points are peaks or troughs.

[0060] c. Automatic identification of folds: calculate the curvature of the formation along the seismic horizon, find folds, and judge the positive or negative of the curvature at the same time;

[0061] d. Judgment of the nature of folds: Judging whether it is an anticline or a syncline...

Embodiment 3

[0070] Specific application examples: Refer to 2 and 3 to clarify the principle of the specific calculation method.

[0071] figure 2 Contains an anticline and a syncline, just take the anticline as an example. The stratum center is determined, and the stratum thickness (time window length when the seismic section is in the time domain) is the range between the top and bottom boundaries of the stratum. According to the horizon data picked up by the formation center, the curvature can be calculated, folds can be found, and the positive and negative of the curvature (dorsal and syncline properties) can be obtained to determine the core of the fold and the seismic trace where the fold center is located—the central trace, and then from the upper Calculate the amplitude difference on both sides of the center track point by point. In actual calculation, also according to image 3 Calculate the amplitude difference between multiple traces in each direction of the central trace, a...

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Abstract

The invention discloses a well leakage prediction method with seismic data, and relates to the technical field of seismic data application of oil and gas field exploration and development. The well leakage prediction method includes the steps that a, high resolution processing is conducted; b, fine horizon correlation is conducted; c, a fold is automatically identified, specifically, formation curvature is obtained along the seismic horizon; d, the fold property is judged, specifically, anticline or syncline are judged according to positive and negative change of the curvature; e, amplitude difference is extracted, specifically, the amplitude difference of each direction in the range of a target layer is calculated with the center of a micro-amplitude fold; f, the micro-amplitude fold amount is calculated, specifically, according to three parameters of positive and negative sign symbols of the curvature, the curvature and an amplitude difference value, the micro-amplitude fold amount is calculated comprehensively; g, the micro-amplitude fold is classified, specifically, according to the calculated micro-amplitude fold amount, the micro-amplitude fold is classified; and h, a well leakage point is predicted, specifically, according to well trajectory coordinates, possible well leakage point positions are picked up from distribution data of the micro-amplitude fold. According to the well leakage prediction method, the accuracy and the efficiency for predicting the fractured leakage point of a horizontal well according to the micro-amplitude fold are significantly improved.

Description

technical field [0001] The invention relates to the technical field of application of seismic data in exploration and development of oil and gas fields, in particular to a method for predicting lost circulation of seismic data. Background technique [0002] During the drilling of shale gas horizontal wells in the Sichuan Basin, lost circulation often occurs, which seriously affects the progress and development effect of shale gas exploration and development projects. [0003] Lost circulation refers to a kind of downhole fluid that directly enters the formation under the action of pressure difference when various working fluids, including drilling fluid, cement slurry, completion fluid and other fluids, etc. Complications. The present invention mainly refers to the lost circulation in the drilling process. Most drilling processes have varying degrees of lost circulation. Severe lost circulation will lead to a drop in pressure in the well, affecting normal drilling, causin...

Claims

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Application Information

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IPC IPC(8): E21B47/00E21B47/10G06Q50/02
CPCE21B47/00E21B47/10G06Q50/02
Inventor 吴大奎吴宗蔚胡天文欧阳明华
Owner CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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