A Review of Fundamental Research on Hydraulic Fracturing of Glutenite Reservoirs in China

There are abundant tight oil and gas resources in glutenite reservoirs in China, and hydraulic fracturing is essential for developing this kind of resources. At present, the basic scientific problems involved in hydraulic fracturing of glutenite reservoirs, including simulation of fracture propagation, proppant transport and fracture conductivity, are not systematically clarified yet. The deficiencies of existing research ideas and methods are summarized, then suggested solutions and development prospects are proposed. The analysis shows that for the fracture propagation experiment, the establishment of a scalable glutenite sample preparation method and the experimental parameter conversion method is an urgent problem to be solved. The particle flow code (PFC) method has advantages in simulating the fracture propagation in microscopic scale. However, the simulation of fracture propagation in oilfield scale faces the problem of cross-scale calculation, so establishing a fast and effective cross-scale simulation method is very important. For the proppant transport experiment, the key is to develop plates with unidirectional filtration and different roughness to simulate the hydraulic fracture surface of glutenite reservoirs. The CFD-DEM coupling method to simulate the proppant transport has a good prospect, but it is necessary to consider the special properties of the glutenite reservoirs, and improve the mathematical model and explore corresponding solution method. The key to the experimental research of the fracture conductivity is to make samples that meet the size and shape requirements. Downhole drilled core, man-made rock and 3D printing technique can be adopted for sample procession. For computer simulation of conductivity prediction, combining PFC with CFD method to predict the conductivity of glutenite is an important exploration direction in the future.