Method applying seismic layer velocity to identify shale gas sweet point

Abstract

A method applying seismic layer velocity to identify a shale gas sweet point comprises the steps that a shale bed section is optimized from a seismic cross section according to the remarkable difference existing between a shale formation interface having strong reflection characteristics and overlying and underlying formations by combining with an exploratory well; according to the characteristic that gas contained in shales causes lower seismic wave propagation velocity, the gas-bearing properties of the shales can be identified according to the anomalies of the seismic layer velocity; on the seismic cross section, the zones having better gas-bearing properties of the shales can be optimized through seismic layer velocity analysis. On a plane, the zones lower in seismic layer velocity anomaly, namely the zones higher in shale gas content, are selected out by analyzing the distribution characteristics of the layer velocity of the shale bed section; fracture distribution density can be researched by arranging ant bodies and observing shale formation earthquake isochronal slices, and further shale gas sweet point zones are identified through fusion with a layer velocity plane graph. By utilizing the method, the problems including prediction limits, distribution prediction and the like of the shale gas sweet point can be effectively solved, the shale gas sweet point zones can be accurately identified, and important geological information and basis can be provided for shale gas exploration and development.

Description

technical field [0001] The invention belongs to oil and gas exploration and development technology, in particular to a method for identifying shale gas sweet spots by using seismic layer velocity. Background technique [0002] In recent years, the exploration and development of shale gas in my country has developed vigorously, and shale gas in the Sichuan Basin has been commercially developed. Shale gas can effectively reduce environmental pollution and make up for the shortage of oil and gas energy. As an unconventional oil and gas resource, shale gas has the characteristics of tight reservoirs, low oil and gas abundance, and wide distribution area. It usually requires horizontal drilling and fracturing to increase production. my country's shale gas drilling, fracturing and other development technologies have made great progress through independent research and development on the basis of learning from foreign advanced technology practices, and the drilling and fracturing ...

AI Technical Summary

Problems solved by technology

In addition, organic-rich shale is rich in kerogen, and the density of kerogen is low, ranging from 0.95-1.05g / cm 3 , also greatly reduces the volume density of the reservoir, resulting in the slowing down of the seismic wave propagation process

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