Analysis and optimization of multiple factors influencing fracturing induced stress field

Abstract

The induced stress field caused by hydraulic fracturing plays a key role in controlling the formation characteristics of fractures and is the essential prerequisite for optimal design of fracturing parameters. In order to determine the disturbance range of induced stress field on fracture morphology, the multiple factors analysis and optimization are an important inspect. Setting the induced stress control range (ISCR) as the evaluation objective, it can be defined as the combined response of the peak value of induced stress difference and stress steering distance, taking them as double evaluation indexes. Six uncertain fracture parameters with a reasonable range are used to fit the response of evaluation indexes. Through the finite element numerical simulation method, the induced stress field around the fractures can be calculated and the evaluation indexes are described quantitatively. Applying the multi-factor orthogonal test method, combined the matrix analysis model with the fuzzy comprehensive evaluation model, these fracture parameters are evaluated and optimized. The results show that the influence factors on the ISCR in the descending order are determined as follows: fracture height, fracture net pressure, Poisson's ratio, maximum and minimum horizontal stress ratio, fracture spacing and its number. According to the multi-factors sensitivity analysis results, the selected levels of different factors are optimized and the combination of parameters optimization is screened out. It provides a theoretical basis to control the reservoir stress field for the optimization of the field fracturing treatment.

Analysis of the Induced Stress Fields Around Hydraulic Fractures Considering the Influence of Natural Fractures and Bedding Planes

“…The SRI around HF is jointly affected by geological factors (in situ principal stress difference and rock Poisson’s ratio), engineering factors (fracture net pressure), and fracture geometric parameters (fracture height and fracture spacing). 21 …”

“…Morrill and Miskimins 20 simulated the distribution pattern of stress field around HFs in horizontal wells and suggested weakening the SSE by optimizing perforation spacing. Guan et al 21 used the finite element method to explore the distribution law of ISF and quantitatively characterized the control range of ISF within the process of hydraulic fracturing.…”

Quantitative study on natural gas production risk of Carboniferous gas reservoir in eastern Sichuan

“…It converts a qualitative evaluation into a quantitative one according to the membership theory of fuzzy mathematics, in order to perform a comprehensive evaluation of things or objects restrained by multiple factors. Since it can comprehensively analyze multiple risk factors, it is applicable for the synthetic analysis of the sensitivity and other fuzzy information of risk factors (Zhang and Feng 2018;Guan et al 2019). The principle of FCE is described as follows:…”