PERMEABILITY ANISOTROPY CALCULATION FEATURES OF THE UPPER JURASSIC TERRIGENOUS RESERVOIRS ON THE EXAMPLE OF THE OIL FORMATION

Abstract

The relevance of the research consists in finding the ways to extend the life of the field and increase oil production. The main task is to extract as much hydrocarbons as possible. At present, a technique has been developed that makes it possible to calculate the anisotropy parameters for one of the reservoir layers. Thus, it is possible to take into account in detail the influence of anisotropy in a separate terrigenous reservoir. However, deposits are multi-layer with structural features and formation of the reservoir. Accordingly, there is a need to verify the feasibility of changing the methodology for calculating anisotropic parameters, depending on the change in the environment, under the influence of which a particular reservoir was formed. This field is multilayer, and the difference in sedimentation environments during the formation of reservoir layers is a complicating and at the same time good feature. It is possible, without changing the field, to apply the technique on other layers of the field, in particular on the J11 layer. Calculations will take less time, since all information on the field is loaded and compiled. Additionally, it will be possible to get closer to creating a fully anisotropic model of the entire field and to test the operation of the methodology on a larger scale. The rapid depletion of reserves leads to the fact that it is necessary to increase the oil recovery factor and reduce the amount of residual reserves. In the near future, this problem may become more aggravated, and so far, there is time to develop a methodology for constructing anisotropic models entirely for fields, taking into account all geological and geophysical information and technological development indicators. The aim of this work is to check whether it is possible to apply the technique for determining the parameters of permeability anisotropy in the J11 layer of a previously explored field. J11 layer is composed of terrigenous material and differs from J13 layer in terms of sedimentation and reservoir properties. The study object is a terrigenous layer of a deposit located geographically in Western Siberia. Upper Jurassic deposits with low porosity properties should be investigated for the possibility of extending the approach for calculating the parameters of permeability heterogeneity. Methods. Standard set of geophysical well logging in digital charts is used to dismember the producing formation on the packs. Petrophysical properties are determined using the relation between the core data (porosity, permeability). On the example of one of the wells the permeability distribution in the nearby wells is constructed, and the example of the formation J11 shows the distribution of permeability gradients, on the basis of which the conclusions on patterns of distribution anisotropy considering the geological depositional environments were made. It was determined that for the J11 layer, the algorithms for determining the parameters of the anisotropy of permeability remain the same as for the J13 layer. The developed technique is confidently applied in a reservoir with a different sedimentation environment. The results are reliable and confirm the feasibility of using the methodology without making changes. It was possible to approach the creation of a three-dimensional model for the entire field, taking into account all reservoirs and the filtration of hydrocarbons. This is very important, since modern computer power allows building and calculating more and more complex models with high detail of the reservoir space.

Keywords

• permeability anisotropy
• anisotropy scale
• simulation modeling
• terrigenous reservoir
• petrophysical calculations