鄂尔多斯盆地苏里格气田河道砂体识别研究

【作者】 邹新宁；

【导师】 孙卫；

【作者基本信息】 西北大学 ， 矿产普查与勘探， 2006， 博士

【摘要】 本文针对鄂尔多斯盆地苏里格气田上古生界盒8低渗河道砂岩储层有效厚度薄、横向变化大、地球物理特征复杂的特点,运用地震相分析、叠置河道识别和储层含气性预测相结合的方法,划分出储层有利地震相分布区,识别出叠置高能河道,预测出储层含气有利区,筛选出开发目标区块,为气田开发部署、方案编制提供了重要依据。研究成果及创新在于: 通过地震地质层位的精细标定和储层波形特征分类,首次将苏里格气田盒8储层地震反射模式划分为两大类十亚类,其中的两个亚类属最有利模式。利用地震相自动分析技术将盒8地层地震相划分为三类,地震相与砂岩厚度有较好的对应关系,由地震相转换的砂岩厚度较来自波阴抗反演的结果可靠。首次提出弧长、有效带宽和能量半衰时为盒8地层较为敏感的叠后属性,其分别反映出砂体的平面分布、地层岩性的纵横向变化以及储层的平面宏观非均质特征。 采用层拉平地震古地貌恢复和广义S变换高分辨率地震层序分析方法在苏里格气田识别出四条盒8期叠置主河道。河道在平面上呈近似南北向展布,表现出频繁分流、交会、复合的特征,并有七个交会区。叠置河道的分布区和交会区是储层含气的有利区。识别结果反映出河道沉积及其变化规律,刻画出辫状河道平面宏观展布特征,河道形态及其分布比较符合目前的地质认识。河道识别结果对气田开发方案布井具有指导作用。 首次联合应用AVO技术、地震子波能量吸收分析以及叠前弹性参数反演方法对盒8储层的含气性进行了预测,划分出十二个Ⅰ+Ⅱ类含气有利区。平面上Ⅰ、Ⅱ、Ⅲ类含气区相间分布,呈现出高度零散分布特征,表现出强烈的非均质性。储层含气性的综合预测在一定程度上降低了预测结果的多解性。预测结果为开发目标区块筛选提供了重要依据。 通过对苏里格气田盒8储层地震相分析结果、盒8期叠置河道识别结果以及储层含气性预测结果的综合分析,评价出五个最有利的含气区块和五个较有利的含气区块。确定苏10、苏25、苏5、苏13以及苏6井区五个最有利的含气区块为下一步开发建产的首选区块,为气田开发部署指明了方向。 目前,苏6井区已成为开发建产区块,其它四个区块被选为重点开发评价区块。更多还原

【Abstract】 Aiming at He-8 low-permeable sandstone reservoir characteristics of thinner effective thickness, faster lateral change and more complicated geophysical character of Sulige gas field in Permian system of Ordos Basin, this paper plotted out the favorable zones of seismic facies, recognized the high energy fold-channels, forecasted the favorable gas-bearing areas and selected the development object blocks by combining seismic facies analysis, channel identification and gas-bearing reservoir predicting methods. The research results have provided important proofs for exploitation arrangement and plan programming of the gas field. The main productions and innovations in the paper are as follows:According to the refined demarcation of seismic and geological layers, and waveform characteristics classification, it is the first time to divide the seismic reflection patterns of He-8 reservoir into two main categories and ten sub-categories, and two sub-categories of them are the most favorable reflection patterns. Using the seismic facies analysis technique divided He-8 reservoir seismic facies into three categories. The seismic facies have better corresponding relation with the sandstone thickness, and sandstone thickness from the seismic facies conversion is more reliable than that from the impedance inversion. It is the first time to bring forward that arc length, effective band width and energy half-time are the most hypersensitive post-stack attributes to He-8 stratum. Their planar results reflect the distributing characters of sand bodies, the lithology changes in horizontal and vertical direction, and macroscopic heterogeneity of the reservoir, respectively.Integrating the results of seismic ancient landform restoration from layer flattening and high resolution seismic sequence analysis from Generalized S Transform, four main folded channels have been identified. Their distribution on the plane is near north-south direction, putting up frequent distributing, intercrossing and complex characteristics, and including seven intercrossing districts. The distributing and intercrossing zones of the channels are gas-bearing favorable areas. The identifying results reflect sediment and transformation characters of the channels, and delineate the macroscopically distributing patterns of the braided rivers. And the channels’ configuration and distribution accord with the current geological understanding. That has some guiding roles to optimize the development project and dispose the exploitation wells.It is the first time in Sulige gas field to predict He-8 gas-bearing reservoir by combining AVO technology, seismic wavelet energy absorption analysis and pre-stack elastic parameters inversion methods. From the forecasting results, dozen gas-bearing favorable zones have been marked off. On the plane, type I, II and III gas-bearing zones distribute alternately, showing a highly fragmented distributing characteristics, and presenting strong non-homogeneous characters. Integrated forecasting results could reduce the uncertainties some extent. The results provide important proofs for the selection of the development object blocks.From the comprehensive appraisal results of seismic facies analysis, channel identification and gas-bearing reservoir prediction, five most favorable gas-bearing blocks and five more favorable gas-bearing blocks have been offered. And the five most favorable gas-bearing blocks (SulO, Su25, Su5. Sul3 and Su6) have been confirmed as the first selected blocks of development production. That shows clearly the way for development arrangement of the gas field.At present, Su6 block has become a production block, and the other four blocks have been elected as the important evaluation blocks.更多还原