Thin reservoir prediction technology with sensitive parameters of tight gas in southwest Ordos Basin

Abstract

In the southwest of Ordos Basin, the loess layer is very thick, the surface elevation changes rapidly, and the near-surface low-velocity zone velocity changes greatly in vertical and horizontal directions, resulting in prominent static correction problems. Affected by the strong absorption of the loess layer, the effective frequency band of the original data is narrow, the apparent main frequency is low, and the "double high" processing is difficult. The reservoirs of He-8 and Shan-1 are deep-buried, thin and dense, and their lateral changes are fast. In this paper, the sensitive data of "two widths and one height" 3D seismic is optimized to obtain high-quality sensitive data. The sensitive orientation is optimized by combining drilling data, and the sensitive parameter based on pre-stack inversion technology is adopted to improve the prediction accuracy of thin reservoirs. The new Chengtan-3-Long19 He-8 sand belt was discovered, the well location deployment plan was optimized, the efficient drilling of horizontal Wells was supported and the fracturing plan was optimized. 26 well locations were deployed using 3D seismic, 11 were completed drilling, and 9 were class I + II, an increase of 30% compared with 2D seismic.