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致密油气已成为勘探热点。吐哈盆地温吉桑地区水西沟群发育多套致密砂岩,但含油气较好的相对优质储层厚度较薄,且横向变化快,加之上覆煤层影响及其本身低孔低渗的特点,导致相对优质储层与围岩的地球物理响应特征差异较小。常规储层预测方法及流体检测结果多解性强、精度低,很难满足该区致密砂岩勘探需要。利用地震、钻井、测井等信息,开展了主要反演井横波估算、弹性参数计算及模型正演、敏感参数分析,结果表明,该区含油气层顶表现为Ⅰ类AVO特征,λρ、Vp/Vs交会可以较好区分含油气砂岩。在此基础上,运用高品质三维地震资料,对温吉桑地区进行了AVO属性分析、叠前同时反演,并综合其他预测结果,对该区有利储层及含油气性进行了预测,在实际致密砂岩勘探中取得了较好应用效果。实践表明,叠前反演技术是目前储层预测、含油气检测的有效方法,极大地减少了常规储层反演的多解性。下一步将以这种技术手段为基础,应用于其他致密油气勘探工区。
Tight oil has become a hot spot for exploration. Several sets of tight sandstone are developed in Shuixigou Group in Wenjisang area of Turpan-Hami basin. However, the relatively high-quality reservoirs with thin oil and gas reservoirs have relatively thin thickness and fast lateral variation. Combined with the influence of overlying coal seam and its own low porosity and low permeability , Resulting in a relatively small difference in geophysical response characteristics between relatively high-quality reservoirs and surrounding rocks. Conventional reservoir prediction methods and fluid detection results are more than sufficient and low precision, so it is difficult to meet the needs of tight sandstone exploration in this area. Based on the information of seismic, drilling and well logging, the main inversion shear wave estimation, elastic parameter calculation, model forward analysis and sensitive parameter analysis are carried out. The results show that the top of the reservoir contains the Class Ⅰ AVO features, λρ, Vp / Vs rendezvous can better distinguish between oil and gas sandstone. On the basis of this, using the high-quality 3D seismic data, AVO attribute analysis and prestack inversion are carried out in Wenjisang area, and other favorable prediction results are combined to predict the favorable reservoirs and hydrocarbon-bearing properties in this area. The actual application of tight sandstone has achieved good results. Practice shows that the prestack inversion technique is an effective method for reservoir prediction and hydrocarbon detection, which greatly reduces the multi-solution of conventional reservoir inversion. The next step will be based on this technical means, used in other tight oil and gas exploration area.