ACCURACY OF POROSITY, WHEN PERFORMING THREE-DIMENSIONAL GEOLOGICAL IMAGES

The relevance of the study is caused by the need to improve the accuracy of forecasting technological indicators of development of hydrocarbon deposits. This will allow us to select the optimal equipment for preparation of raw materials, to shift the timing of commissioning of industrial capacities, to achieve the maximum economic effect from the development of deposits. The aim of the research is to determine the accuracy of calculation of the porosity coefficient of the field, adopted in the calculation of reserves and design development; to estimate the variation of the porosity coefficient in the entire volume of the deposit; to assess the degree of decrease in the accuracy of determining the porosity coefficient during the transition from the stage of core studies to a three-dimensional geological model; to establish the reasons of decrease in accuracy of determination of porosity coefficient at three-dimensional geological modeling. Object: Cenomanian reservoir oil and gas condensate field located in the North of Western Siberia. Methods: variogram analysis, three-dimensional geological modeling, estimation of porosity coefficient determination accuracy. Results. For correct calculation of stocks and preparation of the project document it is required to define porosity coefficient with an error no more than 5 %. The authors have estimated the probability of achieving the required level of accuracy in calculation of porosity when assessing the reserves only according to geophysical researches of wells, the results of geophysical researches of wells data, but given the location of wells in the field area and also taking into account the spatial distribution of porosity. The boundaries of the porosity coefficient change in the entire volume of the deposit were estimated. This can serve as a basis for adaptation of the hydrodynamic model in the future. The ratio of the volume of the studied core to the volume of the studied geophysical researches of wells rock to the total volume of the reservoir rock is calculated, and the accuracy of determining the porosity coefficient during the transition from laboratory studies to the average porosity coefficient in the field volume is estimated.