论文部分内容阅读
自７０年代以来，川东石炭系气藏已成为四川盆地天然气勘探开发的主力气藏。为提高钻探成功率，采用地震资料并结合测井与合成地震记录资料，运用模型正演等方法对该区石炭系厚度和储层分布进行了预测。预测方法和步骤为：①用不同频率的子波作合成地震记录，分析能反映石炭系厚度和储渗层的频率范围，确定主频；②以确定出的主频为目标，对地震资料进行叠后高分辨率处理；③建立适合该区石炭系地层组合特点的地质模型并进行正演，将结果与过井地震剖面对照分析，确定地震识别模式；④在高分辨剖面上准确标定层位，进行模式对比，对石炭系厚度及其储渗层的变化进行横向预测。运用该方法，在川东大天池等多个构造（带）发现了１８个构造—地层复合圈闭，圈定了１１７个石炭系储层发育区。经钻探检验，石炭系厚度预测值与实际值误差小于１０ｍ的符合率达７６％。
Since the 1970s, the Carboniferous gas reservoirs in eastern Sichuan have become the main gas reservoirs for natural gas exploration and development in the Sichuan Basin. In order to improve the success rate of drilling, the thickness of the Carboniferous and the distribution of the reservoirs are forecasted by using the seismic data, logging and synthetic seismogram data, and modeling forward modeling. The prediction method and steps are as follows: (1) Synthesizing seismograms with different frequency wavelets, the analysis can reflect the thickness of Carboniferous and the frequency range of reservoirs and determine the dominant frequency; (2) Taking the determined fundamental frequency as the target, the seismic data Post-stack high-resolution processing; ③ establish a geological model suitable for the combination of the Carboniferous strata in the area and forward modeling, the results and over-seismic seismic profile control analysis to determine the seismic identification mode; ④ high-resolution profile accurately calibrated horizon , A pattern comparison is made to make a horizontal prediction of the Carboniferous thickness and the change of its reservoir permeability. Using this method, 18 structural-stratigraphic composite traps were discovered in a number of structures (belts) such as the Tianchi in eastern Sichuan Province, and 117 Carboniferous reservoir development zones were delineated. According to the drilling test, the coincidence rate of predicted value of carboniferous thickness and actual value less than 10m is 76%.