大牛地气田井间二次约束的储层建模方法

大牛地气田属于岩性气藏，搞清岩性和孔、渗、饱属性的空间展布是三维地质建模的重点，对于有利区评价具有重要意义。但由于大牛地气田在开发初期井距较大，采用常规的随机模拟方法难以减小井间预测的多解性，故采用井间约束的建模方法是储层建模发展的方向。当前研究的热点仍是相控建模，以及应用地震资料约束建模，但很少讨论根据工区的资料特点设计建模方案并分析约束条件的适用性。为此，根据大牛地气田的实际情况和资料特点，提出了“井间二次约束的储层建模方法”。即在地震属性与岩性相关性较好的前提下，利用地震属性的趋势控制井间砂体展布，建立岩相模型；在此基础上，分析各微相属性的地质统计学特征，按分布规律输出结果，进行相控下的属性随机建模。预测结果经过新井验证，精度在85％左右。该方法重视约束适用性的讨论，强调了要根据不同地区资料特点设计建模方法的重要性，对于其他地区的建模具有一定的借鉴价值。

RESERVOIR MODELING METHOD OF SECOND-ORDER INTERWELL CONSTRAINT IN DANIUDI GAS FIELD

As Daniudi gas field belongs to lithologic gas reservoir, it is the key for 3D geologic modeling to determine the spatial distribution of lithology, porosity, permeability and saturation, which is of great significance for evaluating the favorable zones. The uncertainty of interwell prediction can't be eliminated by using the conventional stochastic modeling method because the wells are sparse in the earlier development phase of Daniudi gas field, and geologic modeling method with interwell constraint is the development direction for the reservoir modeling. The present research hotspots are facies controlled reservoir modeling and seismic constraint modeling, but it is not common to design modeling scheme and analyze the application of the constraint conditions based on the properties of the seismic data at the working area. Therefore, on the basis of the actual situations and the properties of the seismic data in Daniudi gas field, the paper put forward the reservoir modeling method of interwell second order constraint, that is, on the premise of good correlation between the seismic attribute and lithology, we can control the interwell sandstone distribution with the trends of the seismic attribute, and build the lithofacies model; then, we can analyze the geologic statistic characteristic of each microfacies, and output the results based on the distribution rule, and perform seismic attribute stochastic modeling with facies constraint. The data from newly drilled wells indicated that the precision degree of the prediction results reaches up to 85%. This method emphasized on the discussion about the application of the constraint conditions, and stressed the significance of designing modeling method according to the properties of the seismic data at different areas, and should have some references valuable for the reservoir modeling at some other areas.