Study on fracture conductivity under dynamic sand laying mode

Abstract

The existing API static sand laying fracture conductivity evaluation experiment ideally believes that the proppant is evenly and statically laid in the fracture, without considering the actual fracturing conditions, the proppant migrates along the fracture and leaks into the formation. In order to more truly simulate the actual fracturing conditions, the experimental study of fracture conductivity is carried out by using the dynamic conductivity testing device, which is closer to the field reality than static sand laying. The parameters of the indoor dynamic sand laying diversion experiment are determined by the similarity criterion and the indoor fracturing fluid rheology experiment. The orthogonal experiment and the shear support fracture dynamic diversion experiment are designed to study the effects of pumping displacement, fracturing fluid viscosity and construction sand ratio on the dynamic sand laying diversion ability, and optimize the on-site construction parameters. The experimental results show that increasing the construction displacement, sand ratio and selecting the appropriate fracturing fluid viscosity have a positive impact on the fracture conductivity of dynamic sand laying support, among which the sand ratio has the greatest impact. Under the condition of effective closure stress of the reservoir, the natural non sanding shear fracture and the dynamic paving shear fracture with 12% sand ratio have no conductivity, which is difficult to meet the requirements of field production. When the 1-3 mm shear joint is dynamically paved with 18% sand ratio and the closing pressure is 30-70 MPa, the conductivity is positively correlated with the sand concentration, but it is nonlinear with the shear dislocation. The shear joint pump injects 18% proppant with sand ratio, which can support the fracture under high closing pressure and provide conductivity. It is necessary to appropriately increase the pump injection ratio of more than 18% sand ratio according to the proportion of on-site shear cracks to effectively support shear cracks.