Yield prediction method for volume fracturing horizontal well of low-permeability heterogeneous stress-sensitive reservoir stratum

Abstract

The invention discloses a yield prediction method for a volume fracturing horizontal well of a low-permeability heterogeneous stress-sensitive reservoir stratum. The yield prediction method mainly comprises the following steps that basic parameters of the reservoir stratum, fluid and a horizontal shaft are collected; a heterogeneous gas reservoir is partitioned into at least two vadose zones in the length direction of the horizontal shaft, and the vadose zones include artificial fractures; a vadose unit simulation model of each vadose zone is established; vadose simulation models of at least two vadose units are established; the vadose simulation models of all the vadose units are coupled; time discretization is carried out, the previous five steps are repeated, and the unstable-state yield of the volume fracturing horizontal well of the ultra-low-permeability heterogeneous stress-sensitive reservoir stratum is predicted. According to the technical scheme, the unstable-state yield of the volume fracturing horizontal well of the ultra-low-permeability heterogeneous stress-sensitive reservoir stratum can be predicted, the defects that in the prior art, only homogeneity gas reservoirs can be predicted without consideration of the starting pressure and stress sensitive effects are overcome, and thus the effectiveness and the effect of fracturing transformation of the tight gas reservoir horizontal well are improved.

Description

technical field [0001] The application belongs to the field of oil and gas field development, and in particular relates to a method for predicting the output of a volume-fractured horizontal well in a low-permeability heterogeneous stress-sensitive reservoir. Background technique [0002] With the rapid development of the global energy industry and the increasing demand for energy, more and more low-permeability oil and gas reservoirs have been put into development and utilization. Ultra-low permeability gas reservoirs are characterized by extremely low reservoir permeability, plane heterogeneity, starting pressure gradient, and stress-sensitivity effects. Fracturing horizontal well technology is one of the key technologies for increasing reserves and production of ultra-low permeability gas reservoirs and economically and effectively developing them. However, the stimulation mode of conventional fracturing to form a single fracture cannot effectively communicate with the re...

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Problems solved by technology

[0003] At present, the production prediction models for volumetric fracturing of horizontal wells mainly include dual-linear flow, tri-linear flow, and five-linear flow and other seepage models. None of the above models considers the heterogeneity of ultra-low permeability gas reservoirs and ultra-low permeability gas reservoirs at the same time. Combined effects of threshold pressure gradients in the presence of fluid flow and reservoir stress-sensitivity effects in pressure drops

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