Study on the Relationship between the Relative Molecular Mass of a Polymer Clay Stabilizer and the Permeability of a Tight Reservoir

Abstract

Water-sensitivity damage is inevitable during hydraulic fracturing for tight reservoir stimulation. A polymer clay stabilizer is the most effective and commonly used agent for reducing this kind of permeability damage. However, due to the small pore throat radii of tight reservoirs, polymers may be captured and detained, resulting in secondary permeability damage caused by polymer plugging. Therefore, it is necessary to clarify the matching relationship between the relative molecular mass of the clay stabilizer and the permeability of tight cores, which has not been reported yet. In response to this problem, the residual resistance factor and the permeability damage rate of PDMDAAC (poly dimethyl diallyl ammonium chloride, a kind of commonly used polymer clay stabilizer) to tight cores from Xinjiang Oilfield were investigated in cores with permeabilities of 0.10 × 10 –3 μm 2 (0.08–0.17 × 10 –3 μm 2 ), 0.05 × 10 –3 μm 2 (0.035–0.065 × 10 –3 μm 2 ), and 0.01 × 10 –3 μm 2 (0.007–0.020 × 10 –3 μm 2 ) through flow experiments. It was found that the relative molecular masses of PDMDAAC, which did not cause obvious core permeability damage, should be less than 10 000, 5000, and 2000, respectively. In addition, the bridging flocculation principle between the hydrodynamics radius of the clay stabilizer and the radius of the tight core pore throat can be used to explain the matching relationship between the relative molecular mass of the polymer clay stabilizer and the permeability of the tight reservoir. This study points out the direction for the optimization of the polymer clay stabilizer used in tight reservoir hydraulic fracturing and provides some references for the construction of hydraulic fracturing fluid systems for the efficient development of unconventional oil and gas resources.

Novel Environmentally Responsive Polyvinyl Polyamine Hydrogels Capable of Phase Transformation with Temperature for Applications in Reservoir Profile Control

“…Some hydrogels were adsorbed and retained in the relatively large pore throats, which reduced the permeability of the simulation core, resulting in a plugging rate of more than 85%. Excessive temperature might cause the structure of part of the hydrogel to be destroyed [34]. Consequently, the deduction that polyvinyl polyamine hydrogels have a good ability to regulate the 40-60 • C medium temperature reservoir was concluded.…”

“…Gels 2023, 9, x FOR PEER REVIEW 8 of 14 rate of more than 85%. Excessive temperature might cause the structure of part of the hydrogel to be destroyed [34]. Consequently, the deduction that polyvinyl polyamine hydrogels have a good ability to regulate the 40-60 °C medium temperature reservoir was concluded.…”

Probing the Effect of Young’s Modulus on the Reservoir Regulation Abilities of Dispersed Particle Gels

“…The permeability of the simulated core during subsequent water flooding was recorded as k w2 . Plugging rates (R p ) at each measuring point were calculated using the following equations, where F rr was the residual resistance factor [61,62]. The migration performances of the DPG particles could be reflected in R p and F rr .…”