当前位置: X-MOL 学术Gas Sci. Eng. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Elastic parameters from constrained AVO inversion: Application to a BSR in the Mahanadi offshore, India
Gas Science and Engineering Pub Date : 2018-02-01 , DOI: 10.1016/j.jngse.2017.10.025
K.P. Arun , Kalachand Sain , Jitender Kumar

Abstract We have estimated P-wave velocities (VP) and thicknesses from traveltimes data, and S-wave velocities (VS) and densities (ρ) from amplitudes versus offset (AVO) data by constraining the VP for a set of seismic reflection data including a bottom simulating reflector or BSR (marker for gas hydrates) in the Mahanadi offshore. The elastic parameters (VP, VS and ρ) of the whole-layered model have been derived simultaneously using the genetic algorithm global optimization technique that converges into a global minimum. The result shows a low velocity (1506 m/s) free-gas zone below the BSR that lies at 241 m below the sea floor. The presence of underlying free-gas is further corroborated by the observation of increasing negative reflection coefficients with angles. The VP and VS for gas hydrates bearing sediments above the BSR are estimated to be 1655 and 468 m/s respectively, and match reasonably with the sonic log at site NGHP-01-08A passing through the seismic line. Gas-hydrates and free-gas have been qualitatively estimated as 7.0% and 0.9% using three-phase weighted equation of Lee and Gassmann equation respectively. The combined usage of VP and VS corresponding to a Poisson ratio of 0.4565 provides a better estimation of gas hydrates, which shows comparable result that has been estimated using the Simandoux equation to the resistivity log data at site NGHP-01-08A.

中文翻译:

来自约束 AVO 反演的弹性参数:在印度 Mahanadi 近海 BSR 中的应用

摘要 我们通过约束一组地震反射数据的 VP 来估计来自旅行时数据的 P 波速度 (VP) 和厚度,以及来自振幅与偏移距 (AVO) 数据的 S 波速度 (VS) 和密度 (ρ),包括位于 Mahanadi 近海的底部模拟反射器或 BSR(气体水合物标记)。整个分层模型的弹性参数(VP、VS 和 ρ)已使用收敛到全局最小值的遗传算法全局优化技术同时导出。结果显示 BSR 下方的低速 (1506 m/s) 游离气区位于海底下方 241 m。观察到随角度增加的负反射系数进一步证实了底层游离气体的存在。BSR以上含天然气水合物沉积物的VP和VS估计分别为1655和468m/s,与穿过地震测线的NGHP-01-08A站点的声波测井结果合理匹配。天然气水合物和游离气分别使用 Lee 和 Gassmann 方程的三相加权方程定性估计为 7.0% 和 0.9%。对应于泊松比 0.4565 的 VP 和 VS 的组合使用提供了对天然气水合物的更好估计,这表明使用 Simandoux 方程估计的结果与 NGHP-01-08A 站点的电阻率测井数据具有可比性。9%分别使用Lee和Gassmann方程的三相加权方程。对应于泊松比 0.4565 的 VP 和 VS 的组合使用提供了对天然气水合物的更好估计,这表明使用 Simandoux 方程估计的结果与 NGHP-01-08A 站点的电阻率测井数据具有可比性。9%分别使用Lee和Gassmann方程的三相加权方程。对应于泊松比 0.4565 的 VP 和 VS 的组合使用提供了对天然气水合物的更好估计,这表明使用 Simandoux 方程估计的结果与 NGHP-01-08A 站点的电阻率测井数据具有可比性。
更新日期:2018-02-01
down
wechat
bug