Evaluation Of Acid Pressure Effect Of Fracture-cavity Carbonate Reservoirs In M ​​oilfield

The target reservoir is the Ordovician carbonate reservoir, which characterized by complex geological conditions, strong heterogeneity and special reservoir types. The target reservoir depth is 6000-8000m, and the types of reservoir space are various, that is mainly composed of ancient karst cave system, natural fractures and dissolution cavities system. Different types of reservoir space are intertwined in different combinations to form a fracture-cavity reservoir. To make reservoir space connect with the wellbore, acid fracturing stimulation is the main means of production in the target reservoir, but the success rate of acid fracturing stimulation is only 60%-70%, so it is the most important to evaluate the effect of acid fracturing and scientifically explain the types of the connection which belong to fracture and reservoir space. What are the reasons affecting the extension of the fracture? Which type is the facture connected?In order to study a method, that is used to evaluate the effect of acid fracturing stimulation in fracture-cavity carbonate reservoirs, in this paper, specific contents are as follows:(1) Through the analysis of the geological characteristics, reservoir characteristics and reservoir space system, clear the problems and difficulties of the acid fracturing stimulation in this reservoir.(2) Through the analysis of acid systems and fracturing fluid systems, clear the applicability of the acid fracturing.(3) From two aspects of geological factors and construction factors, analyzing the influencing factors of acid fracture, and the PLS-BP was used to research the main factors influencing the acid fracturing effects.(4) Through detailed analysis of the acid fracturing curve, the net pressure curve, the pump pressure curve, establishing a method that is used to judge the types of the fracture connected fracture-cavity.In this paper, the main factors influencing the acid fracturing effects are cleared, a method that is used to judge the types of the fracture connected fracture-cavity is formed. The research results have some guiding significance of evaluation the effect of acid fracturing which applied in fracture-cavity carbonate reservoir.