深层钾盐矿高分辨率地震处理关键技术应用:以罗布泊为例

罗布泊是我国重要的钾盐勘探区,因地表松散,造成地震激发和接收效果差,噪声干扰严重,资料信噪比低。利用过井LDK01的两条交叉石油地震勘探测线,针对目标层信噪比低、干扰波类型多等问题,首先采用了分频分时去噪技术有效压制野值低频噪音,其次利用锥形FK滤波压制强面波干扰,然后利用空变时变地表一致性反褶积改善近地表激发接收条件能量差异性,最后利用俞氏子波反褶积提高纵向分辨率,通过对不同高分辨率去噪技术的组合应用,处理过程中相对保持振幅、频率、相位和波形等动力学特征,提高剖面成像质量。借鉴罗西1井揭示的地质资料,清楚识别了侏罗系底界、白垩系底界、古近系底界、古近系上段底界、新近系底界、新近系上段底界6套界面,为进一步完善罗布泊钾盐深层成藏理论提供依据。

Key technology application in high resolution seismic data processing for deep potash deposits:An example from Lop Nur

Lop Nur is an important potash exploration area in China. However, the loose ground surface in the area causes low seismic excitation/reception and strong noise interference, resulting in poor-quality seismic data with low signal-to-noise ratio. To solve this problem we used two crossed seismic lines passing through well LDK01. Noise reduction technology using frequency and time dividers was adopted first to effectively suppress outlier low-frequency noise, then the cone-shaped FK filter was used to suppress the strong surface wave interference. Next, space variant surface-consistent deconvolution using varying time intervals was performed to narrow the energy difference in the received near surface excitation signals. Finally, wavelet deconvolution developed by Yu et al. was used to improve the vertical resolution. By using a combination of different high-resolution noise reduction technologies, the dynamic characteristics such as amplitude, frequency, phase and waveform were relatively maintained during data processing, and the quality of profile imaging was improved. Referencing to the geological data from well LUOXI 1, six sets of interfaces—Jurassic, Cretaceous, Paleogene, upper Paleogene, Neogene and upper Neogene bottom boundaries—have been clearly identified, which provides a basis for further improving the Lop Nur deep reservoir formation theory.