The Water Plugging Experimental Study On Low Permeable And Fissured Reservoir Of Qiang 1 Block

This article is about the water plugging experiment research in Qiang 1 block low permeability fractured reservoir of injected water along the direction of fracture water channeling is serious, oil well flooding in main crack direction, block production decreasing rapidly, production decline faster. By measuring the initial viscosity, gel time and gel strength of different formulation system, the performance of water plugging system was optimized. The experimental results show that when the polymer is 2500 × 104, the polymer concentration is 3000mg/L, the concentration of the crosslinking agent A is 0.2%, the gel strength can be the biggest. Change the initiator concentration range from 0.4% to 0.6%, stabilizer concentration from 0.03% to 0.1%, and gel strength can be controlled in 20000 to 40000mPa?s, the gelling time can be controlled in the 24 to 50 hours. The effective time of addition of the water plugging agent is more than twice as long as the effective time of the water shutoff system without stabilizers. The static performance of the system is evaluated, and the blocking agent has good thermal stability, salt resistance and shearing resistance.Experimental study on the water plugging of low permeability fractured core was carried out by means of the experiment of fracture core injection. The experimental results show that the plugging rate of the fracture cores reaches 96.55% when the plugging agent injection amount is 0.3PV. The displacement amount of water poured into the above 20 PV, the blocking agent injection amount is 0.2 to 0.3PV, the core fracture plugging rate is still above 94%. The result shows that the plugging agent is strong in erosion resistance and stable plugging effect, which can meet the need of water plugging in fractured reservoirs.The experiment carried out by two parallel cores injection in low permeability fractured core water plugging and oil displacement experiment.The experimental results show that when the water plugging agent is injected into 0.3 to 0.6PV, the plugging rate of the high permeability core is more than 99%, and the distribution of the low permeability core is 80% of the total displacement. It shows that the plugging agent system can effectively block the high permeability cores in heterogeneous reservoirs, and can effectively improve the shunt capacity of the low permeability reservoir. Repeatedly blocked is favorable for water plugging, plugging agent injection volume were 0.5PV and 0.3PV, a water blocking and improve the recovery rate of 20.9%, two times water plugging and enhance oil recovery of 5.4%.