Research on the integration of geology and engineering

Research tasks

This research plan is to implement the spatial spread of high-quality reservoirs and reservoir parameters in the target layer section through pre-stack inversion reservoir characterization. On the basis of three-dimensional elastic parameters, research on geomechanical parameters and geostress prediction have been carried out. A fine three-dimensional geological engineering integration model has been established. The drilling rate of horizontal well oil reservoir through the optimization design of horizontal well trajectory is improved. The engineering “sweet spot” quality evaluation parameters for excellent and fast drilling and fracturing design have been provided.

Research ideas

eas First of all, the main features of this project are clarified that the project is a "geological engineering integration" project. The core and key of the project is a fine three-dimensional geological engineering integration model. In order to achieve this goal, how to obtain accurate three-dimensional elastic parameters through prestack seismic inversion, so as to predict the spread of high-quality reservoirs and carry out geostress prediction, which has become the top priority of this study, and the technical difficulties include pre-stack geostatistical inversion, reservoir parameter petrophysical inversion and formation pressure and ground stress prediction. In view of these technical difficulties, first of all, on the basis of the environmental correction and normalization of logging data, logging processing and petrophysical modeling are carried out. The high-quality reservoir identification based on “two parameter” model and reservoir quantitative interpretation of petrophysical templates are established. Prestack geostatistics inversion is carried out to obtain data bodies such as impedance, Poisson's ratio, lithology and reservoir probabilistic bodies. By petrophysical reservoir parameter inversion, quantitative prediction of reservoir parameters such as clay content and porosity which are the basis for high-quality reservoir geological modeling.

Secondly, the rock brittleness calculation and analysis are carried out on the basis of the prediction of prestack elastic parameters. The formation pressure prediction model is optimized by the pressure measurement data at the key well point and then the 3D formation pressure prediction is carried out by the high-precision inverted velocity. The relative size of the stress environment and stress components are determined. The stress engineering data and Kaiser data are combined with the stress calculation model parameters to scale the 3D geostress prediction. The fracture prediction is carried out by curvature, ant body and other methods. The quality control and scale are carried out in combination with imaging logging, to obtain a crack density body. Finally, based on pre-stack seismic inversion, stress and rock mechanics, a fine three-dimensional geological model was established. The drilling trajectory of the horizontal well was adjusted and the drilling rate of high-quality oil reservoir was improved. The average oil reservoir drilling rate reached 96%.

Research Results

The main target layers of the project are highly heterogeneous. The characteristics of high-quality reservoir spread are not ensured. The spatial spread of rock mechanical parameters is not clear. The horizontal well trajectory design and site optimization are difficult. Through innovative petrophysical inversion, a fine geological model was completed for tight sand and shale reservoirs. The final project result was highly recognized by the customer.