A Lost Loss Prediction Method Based on Seismic Data

Abstract

The invention discloses a lost circulation prediction method of seismic data, which relates to the technical field of seismic data application in exploration and development of oil and gas fields, a. high-resolution processing; b. fine horizon comparison; Stratum curvature; d. Judging the nature of folds: judging whether it is an anticline or a syncline according to the positive and negative changes in the curvature; e. Extracting the amplitude difference: calculating the amplitude difference in each direction within the range of the target layer with the center of the slight fold; f. Calculating the amount of the slight fold : According to the three parameters of curvature sign, curvature size and amplitude difference, comprehensively calculate the amount of micro-folds; g, classification of micro-folds: classify micro-folds according to the calculated amount of micro-folds; h, lost circulation Point prediction: According to the coordinates of the well trajectory, the position of the possible lost circulation point is picked from the micro-fold distribution data. The accuracy and efficiency of the method for predicting fractured lost circulation points of horizontal wells based on slight folds 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...

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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

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