薄层砂岩含气性多维信息加权约束地震反演判识方法及应用——以鄂尔多斯盆地庆北地区山西组一段为例

针对中国陆相含油气盆地深层勘探程度低、沉积相纵横向变化快、薄储层非均质性强、含油气性分布不稳定等造成的薄储层识别和含气性预测难题;通过地质、地震、测井和钻井资料综合分析,基于地震正演技术,挖掘储层参数潜在的地震响应特征,提出了一种以多种地震属性加权为反演约束条件的薄储层及烃类高精度预测方法.通过由简入繁设置理论模型进行反演测试,在增加条件复杂性如薄互层模型以及加20％噪声的情况下,该方法的反演结果能够保持良好的稳定性.该方法在鄂尔多斯盆地庆北地区山西组一段进行了应用,结果显示对陆相薄层砂体有很好的适用性;经对比,含气性预测结果与实际钻井结果吻合度高,符合研究区地质认识,表明该方法能够有效判识薄层砂岩含气性及其饱和程度.通过含气性分析和识别,精细刻画了研究区山一段的天然气空间分布,指出该区天然气呈离散型富集,并划分出3类区域,其中西南部环A井和B—C井一线的砂带、含气性良好,具有良好的勘探前景.该方法具备不依赖于钻井数量和勘探程度、应用条件要求低、适应性广、流体识别精度高等优势,有望对陆相薄储层钻探目标选择提供更为可靠的参数依据,并为复杂地质条件下的含气性识别提供了新的技术思路和方法.

Identification method of gas bearing property of thin tight sandstone based on comprehensive analysis of geology and geophysics: a case study on the 1st Member of Shanxi Formation in North Qingcheng area of Ordos basin

To address the problems of low degree of deep exploration, rapid vertical and horizontal changes of sedimentary facies, strong heterogeneity of thin reservoirs and unstable distribution of oil and gas in continental petroliferous basins in China, geophysical inversion is carried out under the multi- dimensional information constraints of geology, well logging, drilling, oil testing and other data through comprehensive analysis of geology and geophysics. After many iterations, a new set of geophysical inversion is explored, the hydrocarbon detection technology of natural gas can be comprehensively identified by geological and geophysical methods. The method has been applied to the 1st Member of Shanxi Formation in the north of Qingcheng, Longdong, Ordos basin. The results show that it is very suitable for the continental thin sand body. A comparison shows that the prediction results of gas bearing property are highly consistent with the actual drilling results, which is in line with the geological analysis of the study area. Through gas bearing analysis and identification, it is demonstrated that the natural gas is distributed in discrete local branches, the spatial distribution of natural gas in the first member of the mountain in this area is described in detail, and three types of areas are divided. Among them, the sand belt and gas bearing property in the southwest of well A and well B- C are good, with good exploration prospects, and is expected to provide parameter basis for drilling target selection. This method has the advantages of not depending on the number of wells and the degree of exploration, low requirements of application conditions, wide adaptability, high accuracy of fluid identification, and provides a new technical idea and method for oil and gas detection and identification under complex geological conditions.