非均质致密砂岩储层结构高精度谱成像方法研究

With the increasing difficulty of oil and gas exploration in China, the exploration and development objectives have gradually turned to unconventional oil and gas reservoirs, such as tight oil and gas reservoirs. The typical characteristics of tight reservoirs are with low porosity and permeability, and heterogeneous. The resolution of spectrum imaging results obtained by widely used time-frequency transform is not sufficient to accurately describe the spatial structure of the heterogeneous tight sandstone reservoir. The synchrosqueezing transform can obtain more accurate spectrum imaging results by relocating the time-frequency coefficients. Therefore, this project intends to develop a spectrum imaging method with high precision to target tight sandstone reservoirs in the heterogeneous media by using the synchrosqueezing transform, which would take advantage of the latest developments in modern mathematics and signal science. For the accuracy spectrum imaging, the following researches are carried out: (1) Constructing a multi-parameter synchrosqueezing transform suitable for seismic signal analysis in the heterogeneous tight sandstone reservoir, giving a fast algorithm for the forward and backward transform; (2) Using wave field forward modeling, studying the relationship between the property of the basic atom family (transformed atom) and the parameters contained in the basic function (nuclear function), and giving its parameter selection strategy; (3) Within the framework of the transform domain with multi-parameters, a high-precision spectrum imaging method for heterogeneous tight sandstone reservoirs is proposed and used to describe the spatial structure and distribution of heterogeneous tight sandstone reservoirs.

随着我国油气勘探开发难度的增大，勘探开发目标逐渐转向致密油气藏等非常规油气藏，其典型特点是低孔隙度、低渗透率、强非均质性，将常规时频变换用于地震资料得到的谱成像结果分辨率不足以精确描述非均质致密砂岩储层的空间结构特性。同步挤压变换对变换域系数进行能量重排，可以得到较为精确的谱成像结果，因此，本项目拟结合同步挤压变换，利用现代数学和信号科学的最新进展，针对非均质致密砂岩储层结构高精度谱成像问题，开展以下研究：（1）构造适用于非均质致密砂岩储层中地震信号分析的多参数同步挤压变换，给出其正反变换的快速算法；（2）利用波场正演模型等已知信息，研究多参数同步挤压变换的基本原子族（变换原子）性质与基本函数（核函数）所含参数的关系，给出其参数选取策略；（3）在多参数局域化变换域框架内，提出非均质致密砂岩储层结构高精度谱成像方法，并用于描述非均质致密砂岩储层的空间结构和空间展布等特性。

随着我国油气勘探开发难度的增大，勘探开发目标逐渐转向致密油气藏等非常规油气藏，其典型特点是低孔隙度、低渗透率、强非均质性，将常规时频变换用于地震资料得到的谱成像结果分辨率不足以精确描述非均质致密砂岩储层的空间结构特性。为解决这一难题，本项目开展了系列研究，主要包括：首先开展了地震数据多尺度信噪分离方法研究，为后续相关解释工作提供技术支撑和数据基础；开展了薄互层型油气储层同步挤压变换域分析方法研究，证明了同步挤压变换对复杂储层的精细表征能力；提出了致密砂体结构同步挤压域预测方法，实际应用算例表明，其对非均质致密砂体储层表征能力远远优于工业界常用的谱成像方法；为刻画多尺度地质结构，提出了一种多尺度相干属性分析方法，结合所提出相干体算法和高阶同步挤压方法，进一步给出了一种高阶谱相干属性，其对复杂多尺度地质结构空间特性的表征远远优于商业软件常用的相干体技术。将本研究系列方法应用于多个工区实际地震数据，并与商业软件常用方法结果进行了详细对比和分析，验证了本项目所提出方法的有效性和优越性，为致密砂岩储层等非常规油气储层勘探开发提供了重要技术支撑。