Comprehensive judgment method of low production causes in tight gas reservoirs——Taking the LX gas reservoir in Ordos Basin as an example

The low productivity of tight gas reservoirs arises from complex and multifaceted causes, and elucidating these factors is crucial for guiding the formulation of effective stimulation strategies. Conventional analytical methods have predominantly emphasized the role of individual factors, thereby lacking the necessary systematic and integrative perspective to comprehensively reveal the underlying mechanisms of poor well performance. To overcome these limitations, a comprehensive diagnostic approach is proposed to identify the controlling factors of low productivity in multilayer tight gas reservoirs. Taking three typical cluster well groups of LX tight gas reservoirs in the Ordos Basin as examples, the causes for the low production of the gas wells were analyzed from different aspects by using geological, engineering, and developmental data after excluding the special reasons such as defects in drilling and completion process, reservoir water lock, and water flooding. The results show that the main reasons for the low production of gas wells in LX reservoirs include fewer exploited gas layers, poor physical properties, poor fracturing and crevasse making effects, and insufficient formation energy. In addition, corresponding treatment measures such as reperforation and refracturing were proposed. Finally, the effects of the measures in the two low-yield wells where the reperforation was implemented were analyzed: the production and Tubing-head pressure increased significantly, and the low-yield wells were transformed into non-low-yield wells with good results. The results of the measures demonstrate the feasibility of the new method.