A real-time risk assessment method and device for downhole sand plugging accidents in shale gas fracturing

Abstract

The embodiment of the invention provides a shale gas fracturing underground sand blocking accident real-time risk assessment method and a shale gas fracturing underground sand blocking accident real-time risk assessment device. The method comprises the following steps: selecting different underground related events from a plurality of underground related events as a target node and a root node respectively, and selecting risk characterization parameters as leaf nodes; constructing a Bayesian network according to the target node, the root node and the leaf node; wherein the target node, the root node and the leaf node in the Bayesian network have a plurality of states respectively; Respectively determining the probabilities of the target node, the root node and the leaf node in each state to obtain a risk prediction model; and inputting the risk characterization parameter value monitored in real time into the risk prediction model, and calculating to obtain the risk probability of the sand blocking accident. By utilizing the method, the risk assessment of the sand blocking accident can be more accurately realized under the condition that the monitoring parameters are considered.

Description

technical field [0001] The embodiments of this specification relate to the technical field of risk assessment, and in particular, to a real-time risk assessment method and device for a sand plugging accident in a shale gas fracturing well. Background technique [0002] Hydraulic fracturing technology uses a high-pressure pump set on the ground to inject large-displacement, high-viscosity liquid into the formation through the wellbore, and hold high pressure at the bottom of the well. When the high pressure exceeds the bearing capacity of the formation, fractures will be formed in the formation near the bottom of the well. Continue to pump in the liquid carrying the proppant, and the fractures gradually extend forward, and the proppant plays the role of propping the fractures, forming sand-filled fractures with a certain size and high conductivity to achieve the effect of increasing production. However, during the fracturing process of shale gas wells, due to unfavorable fact...

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Problems solved by technology

[0004] The purpose of the embodiments of this specification is to provide a real-time risk assessment method and device for downhole sand plugging accidents in shale gas fracturing, so as to solve the problems of large uncertainty and non-real-time performance in existing risk assessments

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