Aiming at the difficulties that some high-porosity water-bearing sandstones and oil-bearing sandstones in deep-water clastic reservoirs in West Africa have similar amplitude bright spots and show Class III AVO anomalies with remote-trace amplitude enhancement,this paper proposes to use flat spots to detect the hydrocarbons in the reservoirs.As revealed by the data on the geometric shapes,amplitude,and phase of seismic reflection,four types of flat spots are have developed in the study area,namely individual flat spots,short-axis double flat spots,short-axis composite individual flat spots,and long-axis composite individual flat spots.The target layer W is dominated by short-axis double flat spots.Based on the forward modeling with reflection coefficients and stratigraphic dip as core parameters,a quantitative discrimination template of seismic reflection of flat spots was established in this study.The flat spot distribution was determined using the flat spot strengthening technology and the common isoline trace gathering stacking technology.It was inferred from the discrimination criteria of hydrocarbon flat spots that the upper flat spot strips represent gas-oil interfaces and the lower flat spot strips represent oil-water interfaces.Based on this and the analysis of sensitive attributes in hydrocarbon detection,the area of oil- and gas-bearing zones was effectively predicted.Therefore,the application of flat spots can reduce the multiplicity of solution in the hydrocarbon detection and improve the prediction accuracy of reservoirs.
冯鑫. 平点技术在西非深水碎屑岩储层烃检中的应用[J]. 物探与化探, 2022, 46(2): 433-443.
FENG Xin. Application of flat spots in detection of hydrocarbons in deep-water clastic reservoirs in West Africa. Geophysical and Geochemical Exploration, 2022, 46(2): 433-443.
Zhao Z G, Yang R Z, Ma Y L, et al. Method for pinpointing the contacts of oil, gas and water by common contour binning stacking and its application[J]. Natural Gas Geoscience, 2013, 24(4):808-814.
Rob S, Mike B. 地震振幅解释与应用[M]. 北京: 石油工业出版社, 2014:73-92.
[4]
Rob S, Mike B. Seismic amplitude:An interpreter's handbook[M]. Beijing: Petroleum Industry Press, 2014:73-92.
[5]
Alistair R Brown. 三维地震数据解释[M]. 北京: 石油工业出版社, 2015:115-138.
[5]
Alistair R B. Interpretation of three-dimensional seismic data[M]. Beijing: Petroleum Industry Press, 2015:115-138.
[6]
Clark V A. The effect of oil under in-situ conditions on the seismic properties of rocks[J]. Geophysics, 1992, 57(7):894-901.
doi: 10.1190/1.1443302
[7]
Cliff D C B, Tye S C, Taylor R. The Thylacine and Ceographe gas discoveries,offshore Eastern Otway Basin[J]. Appea Journal, 2004, 44(1):441-462.
doi: 10.1071/AJ03017
[8]
Francis A, Millwood H M, Mulholland P, et al. Real and relict hydrocarbon indicators in the East Irish Sea Basin[J]. Geological Society London Special Publications, 1997, 124(1):185-194.
doi: 10.1144/GSL.SP.1997.124.01.11
[9]
Greenlee S M, Gaskins G M, Johnson M G. 3-D seismic benefits from exploration through development:An Exxon perspective[J]. The Leading Edge, 1994, 13(7):730-734.
doi: 10.1190/1.1437031
[10]
Luchford J. A view of amplitude fit to structure as a hydrocarbon-indicating attribute[J]. First Break, 2001, 19(7):411-417.
doi: 10.1046/j.1365-2397.2001.00190.x
Pan G C, Pei J X, Zhou J X, et al. An analysis of flat spot features on a gas-water interface in the middle-deep overpressure zone,Yinggehai basin[J]. China Offshore Oil and Gas, 2014, 26(5):42-46.
Deng Y, Pan G G, Li M, et al. Prestack AVO characteristics and identification of flat spot in Yinggehai Basin[J]. Oil Geophysical Prospecting, 2019, 54(5):1123-1130.
Gong M P, Zhang J H, Wang Y G, et al. Current situations and recent progress in different azimuths seismic exploration[J]. Oil Geophysical Prospecting, 2018, 53(3):642-658.
Feng X, Han W M, Fan H Y. High density 3D seismic exploration of deep water targets in West Africa[J]. Geophysical Prospecting for Petroleum, 2020, 59(1):150-157.
Xu L, Wang S Y, Zhang J Q, et al. Forward simulation of approximate vertical reflection method and its application to underground engineering[J]. Geophysical and Geochemical Exploration, 2020, 44(3):635-642.
Tan L, Liu H, Tang Y Z, et al. Reservoir characteristics and seismic response of Longwangmiao Formation of Longnvsi structure in Sichuan Basin[J]. Natural Gas Geoscience, 2020, 31(12):1802-1813.