Superabsorbent Polymers Plugging Technology

Fractured formation losses is an important factor which effects drilling engineering security,efficiency and cost,and effects the discovery and the protection of the oil&gas formation.Porosity,fracture and cavity overlapping exist in the fractured formation at the same time.and sometimes also alone.Particularly severe losses would happen when drill in the large-scale cavity or fracture.The plugging is so difficult that conventional lost circulation materials(LCM) often perform poorly.In order to ensure drilling security and efficiency,reduce constrction cost,and improve the effectiveness of the formation protection,it's very significant to study the LCM which can deal with the fractured formation losses.Combining with the plugging technology all over the world,this paper mainly analyses plugging methods in common use for fractured losses to the fractured formation,and researches on the Super Absorbent Resin(SAR) plugging technology.According to the characteristics of the fractured formation and the distribution of the apertures spaces,this paper analyses flow mechanics in fracture-porous double porosity by penetration mechanics theory.The SAR forms to a viscoelastic gel after water swelling,and easily enters loss channels for plugging.Then we obtains the feasibility of the SAR on plugging the fractured formation.This paper analyses rheological characteristics when the polymer solution flow into the porous medium.and the flow distribution (pressure distribution,velocity distribution and viscosity distribution,etc) is studied by three-dimennsional numerical simulation with the theory of Non-Newtonian hydrodynamics,viscoelastic mechanics and so on. Combining with single-SAR and milti-SAR granule flowing into the porous media,this paper describesplugging mechanism of the SAR. The results show that the SAR solution flows into the porethroat and distorts after compressing.Because of the viscoelasticity,pressure loss whichincrease the resistance,after that,the SAR stagnates and plug the fractures.Base on the water-absorbent theory and performance,and with the systemic of experimental program,we do the experimental researches on the SAR's own performance and plugging properties.With the consideration of a variety of factors,we evaluate and analyse on the plugging effect.The experiments show that the SAR has good plugging effectiveness and raise pressure resistance of the thief zone.The plugging strength is more than 4Mpa.