Application of geostatistical inversion in prediction of conglomerate interlayer in heavy oil reservoir

With the intensification of development, CNOOC continues to break through the lower limit of production, and is increasingly moving towards deep, low permeability, deep water and heavy oil. More than 60 % of the proven crude oil geological reserves in the Bohai Sea are heavy oil, which is difficult to develop. The key geological factors affecting the thermal recovery development of heavy oil reservoirs include reservoir type, oil saturation, interlayer and small faults, among which interlayer has the greatest impact. D Oilfield is a thick block super heavy oil reservoir with braided river deposition and strong reservoir heterogeneity. Aiming at the characteristics of thin conglomerate interlayer and low seismic prediction accuracy in D Oilfield, high-resolution geostatistical inversion technology was used to study the standardization of logging curves, probability density parameters and variogram functions. The quantitative characterization results of lithology and thickness were obtained. The conglomerate interlayer with a thickness of less than 5 meters was identified. The plane distribution conforms to the geological characteristics of the study area, which provides a basis for the construction of a three-dimensional geological model of the interlayer inside the heart beach.