川西地区宽方位三维地震勘探采集技术研究

3-D seismic exploration acquisition with wide-azimuth

中国石化西南石油局第二物探大队,四川德阳 618000

The Second Geophysical Prospecting Brigade, Sinopec Southwest Exploration and Production Company, Deyang 61800, China

针对川西地区三叠系须家河组储层埋藏深,超致密,且具有很强非均质性和各向异性等特点,通过对以往 束状和砖块状三维地震勘探采集技术的分析和研究,提出了满足P波各向异性分析的宽方位三维采集技术。该 采集技术较之常规束状、砖块状采集技术,在各个方位角上的炮检距和覆盖次数分布更加合理。将宽方位三维 地震勘探采集技术应用于川西某地区,得到了品质较好的地震资料。同时,P波各向异性裂缝预测结果与断裂 展布及构造分析结果相吻合。

Aimed at the characters that Xujiahe formation of Tri-assic in West Sichuan area is of high heterogeneity and ani-sotropies because of a large burial depth, super-compactness, and the basic knowledge from the degree of fracture development. In order to conduct the research for P-wave anisotropy fracture detection technique, 3-D seismic acquisition such as swath geometry and brick wall geometry are applied. The paper proposed a new method for designing 3-D layout aimed at wide-azimuth based on brick wall geometry which can meet the require for analyzing P-wave anisotropy. The method posse more reasonable on the distribution of distance between shot and geophone and on the distribution of fold in every azimuth, and is to detect the distribution of subsurface geological body and the condition of fracture development by using P-wave anisotropy character, as compared with the regular swath geometry and the regular brick wall geometry. By 3-D seismic exploration aimed at wide-azimuth processing and analyzing of the seismic data produced, it is proved that the acquisition techniques presented in favor of the application of P-wave anisotropy fracture detection technique and posses important signification for natural gas exploration in West Sichuan depth reservoir.