Research On Risk Analysis And Control Of Fracturing Process In Horizontal Wells

As the primary means of exploitation of low permeability reservoirs,the horizontal wells have been widely used both domestic and foreign since the emergence of the last century,horizontal well related technologies have also been rapidly developed,especially horizontal well hydraulic fracturing technology.As a result of fracturing the horizontal well production increases greatly,since the 1980 s,a number of fracturing technologies have been developed.At the same time as developing technology,however,it should be recognized that fracturing is a high-risk technique.If the research on the formation of the destination and reservoir before the fracturing is insufficient.Inappropriate choice of material into the well and irrational fracturing design may lead to failure of fracturing construction,or after fracturing can not achieve the desired yield,even the oil and gas can not continue mining.Comprehensive,systematic and in-depth study of the various types of risks that may be encountered during horizontal well fracturing and the methods of controlling the corresponding risks.Guide the whole process of fracturing from the perspective of risk reduction.It is of great significance to improve the success rate of horizontal well fracturing,reduce the risk of fracturing investment and improve the economic benefit of the oilfield.This article is based on the previous studies.This paper comprehensively and systematically summarizes the various risks that may be encountered during the fracturing of horizontal wells and the causes of the risks and the methods of controlling the corresponding risks.The preliminary establishment of horizontal well fracturing risk control system.The influence factors of the pressure loss of the well bore and the effect of artificial cracks on the production dynamics of fracturing process are studied by using the reservoir numerical simulation software.In order to improve the scientific and decision-making efficiency of horizontal well fracturing risk decision-making,the fuzzy comprehensive evaluation method is introduced into the fracturing risk decision-making,and the index system of fracturing risk assessment of horizontal well.Analytic hierarchy process and expert experience are used to determine the weight of each index,and an example is given to illustrate how to use fuzzy comprehensive evaluation method to make decision on fracturing risk.