Jurassic-Cretaceous formations of Gydan and Yenisei-Khatanga petroleum areas: accuracy of innovative reservoir properties prediction using seismic and drilling data

The paper is devoted to new data on reservoir properties behaviour in the Jurassic-Cretaceous formations of the western part of the Yenisei-Khatanga regional trough and the neighbouring territory of the West Siberian Plate’s north-east. To obtain the results, innovative technology of integrated spectral and velocity prediction was applied with the use of seismic and drilling data. The behaviour of reservoir properties of the formations is presented in the form of predicted weighted parameters (average net thickness and specific reservoir storage capacity) for six Jurassic-Cretaceous oil and gas bearing reservoirs. The data obtained allowed revealing the high-capacity zones within each of the studied reservoir, unravelling common factors of occurrence of higher reservoir property values for the neighbouring reservoirs, and also identifying the fundamental difference between Cretaceous and Jurassic regional reservoir properties. Reliability of the obtained results and accuracy of mapping are evaluated by means of direct matching the predicted values of reservoir properties and new well data unused in building these maps. The mean errors of mapping was 6.65 and 5.19 % for net thickness and specific storage capacity, respectively, these results are acceptable and satisfactory in regional predictions. Confidence level of prediction of net thickness and specific storage capacity of the Jurassic-Cretaceous reservoirs that is based on drilling data is 0.86; it is quite sufficient to use the obtained new information in planning further exploration and prospecting activities