Evaluation method of hydraulic fracturing effect of oil and gas wells

Abstract

The invention provides a method for evaluating a hydrofracture effect of an oil-gas well. After ending of hydrofracture of an oil-gas well, an instantaneous pumping stopping pressure difference and a virtual instantaneous pumping stopping pressure difference of an oil-gas well reservoir are obtained, wherein the instantaneous pumping stopping pressure difference is a difference between an instantaneous pumping stopping pressure and a reservoir pore pressure and the virtual instantaneous pumping stopping pressure difference is a difference between a virtual instantaneous pumping stopping pressure and a reservoir pore pressure; according to the instantaneous pumping stopping pressure difference and the virtual instantaneous pumping stopping pressure difference, a fracture index is determined; and on the basis of the fracture index, a hydrofracture effect of the oil-gas well is evaluated, wherein when the fracture index is larger than 1, the hydrofracture is effective and the larger the fracture index, the higher of the improvement degree of the filtration capacity of the reservoir of the oil-gas well. Therefore, under the circumstance that no mechanical parameter of the rock is needed, quantitative evaluation of the improvement degree of the filtration capacity of the reservoir of the oil-gas well is carried out after the hydrofracture processing of the well; and the reliability of the evaluation result is high.

Description

technical field [0001] The invention relates to oil and gas exploration and development technology, in particular to an evaluation method for hydraulic fracturing effects of oil and gas wells. Background technique [0002] Hydraulic fracturing is an effective measure to increase the production and ultimate recovery of oil and gas wells. By injecting high-pressure fluid into the formation, fractures are generated in the formation, and the seepage capacity of the reservoir is improved, thereby increasing the production of oil and gas wells. Therefore, in the process of oil and gas development, the evaluation of hydraulic fracturing can provide objective reference value for experience summary and process optimization in fracturing construction, and then provide a basis for the improvement of oil and gas development production. [0003] At present, hydraulic fracturing evaluation methods are mainly divided into fracture diagnosis method and productivity comparison evaluation me...

AI Technical Summary

Problems solved by technology

The research of fracture diagnosis method focuses on the evaluation of fracture parameters after fracturing, such as the length, width, height and conductivity of fractures. These parameters cannot directly quantify the change of reservoir seepage capacity before and after fracturing, and these methods cannot Many parameters are required, especially the rock mechanical parameters required for calculation. At present, the rock mechanical parameters are only obtained through small core tests, which cannot represent the mechanical properties of the entire reservoir, resulting in great uncertainty in the calculation and diagnosis results.

The productivity comparison evaluation method generally adopts effect evaluation, that is, the higher the production rate, the better the fracturing effect. However, the productivity of a fractured well is not only affected by the fracturing process, but also affected by oil and gas saturation, wellbore multiphase flow, and production system. The impact of hydraulic fracturing does not solely reflect the degree of improvement of hydraulic fracturing on seepage capacity.

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