UDK 622.276.5

Y. S. Oryngozhin, Dr. of Tech. Sci., Professor

A. A. Shukmanova, doctoral PhD

K. I. Satpayev Kazakh National Technical University

THE TRANSFORMATION PARAMETERS OF THE GEOLOGICAL MODEL PARAMETERS TO FILTER GRID MODEL

For a correct simulation of the formation region of interest is paramount consideration the variability of filtration and reservoir properties of the rocks , as well as the inclusion of spatial geometry of the structure of the productive formations and their discontinuity .

In a non-uniform thickness , permeability, and other physical properties of the formation, but on the area exposed for the process of oil displacement occurs in all areas, but at different rates depending on the changes in physical properties. Another character in the process acquires a mercurial formation characterized by discontinuities in one form or another . Real formations may have lenticular structure , flaking collectors on individual streaks , their thinning , etc. This ultimately leads to losses in the extraction of oil .

The discontinuity of the formation may occur as a result of disjunctive dislocations. In many cases, the discontinuity of the formation is the result of combined effects of various factors on the process of sedimentation.

Even the detailed geological model consisting of millions of cells that can not display the actual structure of the layers in the space between the holes . Created probabilistic models are in most cases non-uniform , but continuous between wells. These models do not reflect discontinuous reservoirs , thereby deducing the CIN weakly dependent on well spacing . In the transition from a three-dimensional geological model , which can consist of tens of millions of cells to the hydrodynamic model consisting of tens or hundreds of thousands of cells , there is desensitization variability of reservoir properties .

In general, the inhomogeneity during the transition from the formation geological model to hydrodynamic produced, at least two methods:

1 ) construct a modified phase curves , taking into account the heterogeneity of sand members of permeability ;

2) by calculating the sweep efficiency of the selected pattern of wells , taking into account the discontinuous layers .

Currently , when averaged geological models , the established practice of their preparation for reservoir simulation development process is to divide the model to approximately equal intervals , the amount of which is determined by the capabilities of the software and hardware , and averaging the characteristics of reservoir within these intervals. With this averaging often blurs and fades discontinuous layers .

To improve the quality produced by geological and engineering models should be significantly strengthened the role of geological experts to conduct detailed correlation of simulated objects , making structural and lithologic patterns. Detailed correlation of well sections is the main method for studying the internal structure of the subsoil , built on the principle of comparing the well sections to highlight in cuts and tracking in area reservoirs and impermeable layers between them.

One way to study the detailed geological structure of the reservoir is to compare the well sections of the zonal method of correlation. Zonal correlation is to compare a section of the reservoir and the allocation within individual zones , which are characterized by common lithologic and physical properties spread out over the square, and known differences vertically. Detail or zonal correlation is carried out in relation to one or more selected Tetrad horizons. The more the horizons of reference can be used in the correlation , the more accurate the results. In wells and reservoirs collectors tight partitions between them isolated using conditionally limits collectors .

In separate wells of a partial fusion occurs designated zones , and sometimes all of the intervals , are connected together to form one monolithic permeable formation . The provision of such zones within the reservoir provides a more detailed understanding of the geological structure of it and build the zonal maps, which are the basis for the design and adjustment of the accepted system design, as well as measures used to influence the formation.

For the design of field development , as well as for calculating the reserves should be during the detailed correlation allocate zonal intervals thin , and not limited to the dismemberment of the cut deposits only a few large packs . Practice shows that the minimum thickness of the layers available for that purpose, is approximately 0.5-1.0 m. These values can be considered decisive for the selection of individual zonal intervals .

In any case, the choice of the number of intervals productive zone of the geological formations in the filter and the corresponding models can not be carried out such consolidation , in which some sections of clay with thickness of 0.5-1.0 m, and more neighboring would be absorbed zonal intervals.

To characterize the discontinuity layer is necessary to determine the spread over the area of each selected interval zone or layer. Under existing rules mining geometry , the border of the zone interval on the map is held at half the distance between two adjacent wells , one in the context of which this zone interval is present , and the other is wedged out . As already mentioned, some individual wells zonal intervals merge together to form an area of their distribution zones merge. The boundaries of these zones on the card are set in the same manner as during the boundaries of zone intervals .

Areas dedicated zone intervals are filled to their respective grid cells of the geological model with preservation of all allocated impermeable boundaries .

Grid geological model usually is using in modern software , has a large dimension of the order of millions of grid blocks. The direct use of such a network, a digitized appropriate filtration-capacity parameters in the filter model almost makes it impossible to perform multiple calculations forecasting technological parameters . Hence the dimension of the grid geological model is reduced by 1-2 orders of magnitude with the appropriate procedures of averaging .

At coincidence grid geological and model input data is done directly from the geological and mathematical models . If the geological data grid is not built, its construction and filling is made using cards of relevant parameters by various means (graphic, software , manual, including funds that are part of the filter model).

A common method of averaging parameters detailed geological grid on the cell enlarged geologic grid technology is a rescaling - Upscaling. In this case, the average porosity values are calculated by arithmetic averaging , averaging is performed by weighting the saturation parameter pore volume. To obtain the values of permeability units in the technology used Upscaling method diagonal permeability tensor , built on the numerical solution of incompressible fluid -phase filtration for each block filtration model . For each block of the dynamic grid solves the problem of filtering a single-phase incompressible flow in three directions. This method allows the anisotropic permeability field that reflects the presence of a cross-sectional thin streaks - non-reservoir and collectors with different properties.

It will be appreciated that averaging methods can be used only within the areas of permeable reservoir rocks and should be averaged properties packs comprising impermeable sections with thicknesses over 0.5-1.0 m.

At present the problem of averaging given much attention , it is devoted a lot of publications. However, the correct solution to the problem of averaging the equations of multiphase flow is absent. Therefore averaging algorithms used in modern software packages , in varying degrees, are approximate , and the procedure for converting the grid geological model of the grid filter models require in each case an individual approach and conduct special test calculations . As a first test calculation is checked coincidence of geological reserves of geological and models.

The recent emergence of modern simulation software , high-performance computer with a clock speed of over three gigahertz and parallel cluster computing systems to create and effectively calculate filtration models , numbering several million cells , thereby minimizing the averaging procedure for converting the parameters of a geological model parameters filtration grid model .