四川盆地龙岗西地区生物礁储层叠前描述技术

Prestack Descriptive Technique for Reef Reservoir in West of Longgang Area, Sichuan Basin

生物礁储层在碳酸盐岩高产油气田中占有重要的地位,具有极大的开采效益和经济价值。但是生物礁油气藏研究还有很多不确定因素,首先山区地震资料处理是个难题,主要表现在静校正、叠前去噪、偏移成像等方面,其次是生物礁储层的识别与解释及有利储层研究具有较大的困难。针对这种情况,就四川盆地龙岗西部地区长兴组生物礁储层展开攻关研究,分别选用等效近地表模型层析静校正技术和全局寻优剩余静校正技术解决长波长静校正和短波长静校正问题;选用分频去异常噪声、十字排列域锥体滤波等技术提高资料信噪比,解决叠前去噪问题;选用高分辨率宽带子波约束反褶积、地表一致性反褶积和单道预测反褶积串联的方法提高资料垂向分辨率;选用各向异性弯曲射线叠前时间偏移技术提高成像精度。试验了生物礁储层地震预测与流体检测的多种技术方法,并优选了适合该区的技术与方法,取得了较好的效果。总结提炼了适合该区生物礁储层研究及流体检测的一系列方法技术,对类似地区生物礁储层研究及油气检测具有一定的指导和借鉴意义。

Reef reservoir is important for high-yield carbonate oil and gas field, and it has large development efficiency and economic value, but there are many uncertain factors influencing reef reservoir study. Firstly, it's difficult to process seismic data of mountain area, and the problems include static correction, prestack noise removing, and migration imaging, etc. Secondly, it is difficult to identify and interpret potential reef reservoir. In the light of these problems, this paper studies reef reservoir of Changxing Formation in the west of Longgang area, Sichuan Basin. Equivalent near-surface model tomographic static correction and global optimization of residual static correction are respectively employed to resolve the long-wavelength and short-wavelength static correction problems. Then frequency-dependent noise attenuation method and conical shaped filter method in the F-Kx-Ky domain are selected to be used to improve the S/N ratio and solve the problem of prestack noise removing. High-resolution wide-band constrained deconvolution, surface consistent deconvolution and single-channel predictive deconvolution techniques are used to improve vertical resolution. Finally, anisotropic ray-bending prestack time migration is used to improve the imaging accuracy. Besides, many techniques for reef reservoir prediction and fluid detection are tested, and techniques suitable for this area are selected, achieving better results. The techniques suitable for reef reservoir prediction and fluid detection of the area are summarized and refined, and they could be taken as guidance for reef reservoir study and oil/gas detection in similar area.