Feasibility Evaluation Of Fracturing Sand Control In Unconsolidated Sandstone

For unconsolidated sandstone reservoir,conventional sand control technology often reduces the oil production rate,so that there is an irreconcilable contradiction between increasing oil production and controlling sand production.Fracturing sand control technology is the most commonly used method to solve this problem.But a single method may not apply to all loose sandstone reservoir conditions,this article choose the initiation condition and shape of crack as the main reference factors,and make a series of studies for the applicability of fracturing sand control in unconsolidated sandstone.Direct at the fracture initiation process of fracturing sand control technology and refer to the actual physical property of unconsolidated sandstone,this paper use artificial sample to simulate the formation and study its mechanics and seepage characteristics.The influence of rock properties,construction parameters and stress conditions on the fracturing pressure and fracture initiation of unconsolidated sandstone was studied by the real three axis fracturing simulation experiment.The results show that with the increase degree of looseness,the fracture pressure decreases,while the injection rate is increased.For the rock samples with same property,the fracture pressure increases with the increase of fluid rate.And with the decrease of the fluid rate and the stress difference,the fracture morphology changes form main crack to crushed zone and infiltration area.The numerical simulation analysis of crack initiation in unconsolidated sandstone is carried out at the same time.The fluid structure coupling model of physical and dynamic evolution is established,and the crack initiation law under parameter separation condition is studied.The results show that the length and width of cracks decrease with the increase of permeability under the same formation strength.When the permeability increases to a certain critical value,the stratum will not crack,and that critical value will reduce with the decrease of the layer strength.Under the same permeability,the decrease of the strength parameter will lead to the decrease of the crack width,but the effect on the crack length is samll.When the formation strength is extremely low,the crack cannot form wide seam even when it is cracked,and it is not suitable for fracturing sand control process.Combined the experimental law of fracturing with the existing theory of fracture pressure,a formula for calculating the initiation of porous formation is presented.At the same time calculation formula of dynamic distribution of bottom hole injection pressure is deduced,Combine two formulas simultaneously and simplified it,a feasible evaluation model judging unconsolidated sandstone formation fracturing was given out,and the experimental parameters was used to verify the accuracy of the model.