莺歌海盆地“暗点”型油气藏指示因子构建及应用

A dim-spot reservoir indicative factor in the Yinggehai Basin

莺歌海盆地中深层高温、超高压领域"暗点"型目标油气勘探潜力巨大,传统储层预测和流体识别方法虽对中浅层"亮点"型目标效果显著,但对中深层"暗点"型油气藏识别困难。为此,从Zoeppritz方程Fatti近似公式出发,利用"暗点"型储层AVO截距相对较小的特点,构建了只与纵、横波阻抗有关的"暗点"型油气藏指示因子,该因子可以放大Ⅱ类AVO异常的差异。数值模拟实验表明,该因子可有效识别"暗点"型目标的Ⅱ类AVO异常。实际应用证实了该指示因子的有效性与可靠性,为莺歌海盆地乐东区中深层"暗点"型油气藏的预测提供了技术支撑。

Dim-spot targets in mid-deep layers with high temperature and high pressure in Yinggehai Basin have great exploration potential.Conventional reservoir prediction and fluid identification methods are rather effective for the mid-shallow bright-spot reservoir identification in the area,but can hardly identify dim-spot reservoirs.Based on the Fatti equation,a dim-spot reservoir indicative factor related only to longitudinal and transverse wave impedance is constructed with the relation of relatively small intercept for dim-spot,which can highlight differences of the ClassⅡAVO abnormality.Numerical simulations show that this factor can be used to well identify the ClassⅡAVO abnormality.Seismic data applications verify the validity and reliability of the proposed factor.