KD地区飞仙关组鲕滩气、水地震响应特征研究

KD地区飞仙关组鲕滩是良好储层，通常采用亮点技术寻找，但该技术不能判别其内究竟是气还是水。工区内西南面D1、D2、D3、D4井储层厚度大，主产气，地震剖面上为亮点；D6井产水，亮点；东北面D5井岩性发生变化，产水，亮点。这种气水同产、均为亮点的情况，导致亮点技术的不适用性。因此，研究气、水地震响应差异，寻找区分气、水的地震方法极其必要。研究思路是：①利用层序地层学理论寻找有利储层发育的准层序组作为目标层段，去除邻层干扰，挖掘储层地震响应特征；②分析目标层段气、水地震响应差异，根据差异，制作正演模型，找出这种差异的原因，该差异主要是沉积环境变化造成，其次才是地层含水造成；③依据该结论，利用波形分类技术划出较好和较差储层发育相带；④在较好相带内，利用气、水地震响应特征的不同，提取多种地震属性并聚类分析，找到了气层的分布区域，经钻探验证，预测结果准确可靠。

SEISMIC RESPONSE CHARACTERISTICS OF GAS AND WATER LAYERS IN RESERVOIRS OF OOLITIC BEACH FACIES IN FEIXIANGUAN FORMATION IN KD AREA

Bright spot technique is commonly used to identify strata of oolitic beach facies in the Feixianguan Formation in KD area, which are good reservoirs, but it cannot discriminate between gas and water layers. The gas producing D1, D2, D3, and D4 wells encountering thick reservoirs in the southwestern part of the study area, the water producing D6 well, and the water producing D5 well encountering reservoirs of different lithologies in the northeastern part of the study area occur all as bright spots on seismic section, which cannot be distinguished with the bright spot techniques. Therefore, it is critical to study the differences of seismic response of gas and water layers and to develop methods of seismically differentiating gas and water layers. It is considered that study should include as follows: ①the theory of sequence stratigraphy is applied to identify quasi sequence groups with well developed reservoirs, which are to be taken as the target intervals, and the interferences of surrounding layers are eliminated, so as to study the characteristics of seismic responses of the reservoirs; ②a forward model is built based on the differences of seismic responses of the gas and water layers in the target intervals to study the origins of these differences, which is believed that they are caused primarily by the change of depositional environment, and secondarily by water in the strata; ③waveform classification technique is used to delineate the facies zones with good and poor reservoirs; ④in the facies belt with good reservoirs, extraction, and cluster analysis of multiple seismic attributes are performed based on the different characteristics of seismic responses of gas and water layers to identify the distribution areas of gas layers. Drilling results show that the prediction results are accurate and reliable.