利用地表岩样进行无井区地震仿真层位标定─—CX盆地的试验研究

Simulated horizon calibration of seismic interface in non-well areas using rock specimens: A test study from the CX Basin

成都理工学院“油气藏地质与开发工程”国家重点实验室,成都 610059

Sate Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu 610059

无井区的地震层位标定是新区地震勘探工作的关键问题和难点之一, 本文基于地表岩样的温压测试资料提出了一种地震反射层位标定的新方法。该方法的基本思路是, ①在新区选取一条露头出露完好的地质露头剖面, 在野外进行详细的岩性、地层产状和厚度描述, 并采集岩石露头标本；②对所取岩样进行常温常压下的密度、孔隙度和超声波测试, 并选部分有代表性的岩样进行模拟地层环境下的温压超声波测试;③分析温压超声波测试结果, 得出该探区速度随埋深变化的经验公式;④利用地质露头剖面的岩性和厚度资料及不同的厚度比例因子和起始深度得到一系列仿真钻井剖面；⑤根据仿真钻井剖面和常温常压下地表岩样的测试资料, 利用得到的经验公式制作出一系列仿真声波测井和仿真声阻抗曲线, 选取与地震剖面频带相一致的子波, 利用仿真声波和仿真声阻抗曲线制作一系列仿真合成地震记录；⑥用仿真合成记录中与地震剖面反射特征最相似的某一仿真合成地震记录来标定地震剖面。我们利用该方法完成了CX盆地的地震反射层位标定, 应用效果良好。初步应用表明, 它不失为无井区地震剖面层位标定的一条新途径。

The horizon calibration of seismic interface in non-well areas is a difficult problem in seismic prospecting woks. This paper presents a new horizon calibration method based on the ultrasonic testdata of rock specimens. The main step of the method is as following: (1) Select a geological sectioll inbare land to conduct detailed lithology, occurrency and depth descriptions, and then collect rock specimens. (2)Measure the density, porosity and ultrasonic velocity of rock specimens under ordinary temperature and pressure, and select some representative specimens for ultrasonic measurement under hightemperature and pressure in simulated stratal environment. (3)Obtain an empihcal hamula of velocityvdriations with depth from the measorements. (4) Make a sdries of simulated-well sections by usinglithology and thickness data along with thickness scale factors and starting depth. (5) Make a series ofsimulated anic and impedance curves with the simulated-well sections and the empirical vdocity-depthformla obtained; then use these simulated curves to make a series of simulated synthetic sesmogramswith the wavelet which consists with the frequency band of seismic sections. (6)Caibrate the Sesmic interface with a simulated synthetic seismogram most similar to surface seismc section in reflection characters. The method is utal to perform the harizon calibration of seismic reflections in the CX basin andgood application results have be obtained.