Research And Application Of Fracturing Fluid Flowback For Low Permeability Reservoir

Hydraulic fracturing technology is one of the effective technical development of low permeability reservoirs.And the fluid flowback technology after fracturing,can not be ignored in the whole fracturing technology.Fracturing fluid flowback involves some complicated situation,including the change of formation fracture,the characteristics of proppant migration in the fracture and so on.So far,in the field of petroleum exploration and development technology,there is still no mature and system theory of fracturing fluid flowback.In fact,the theoretical basis and application management fracturing fluid flowback,rely on technical's personnel experience basically,or trying blindly.This paper combining with the actual situation of Bonan Yi34 block,conducted a systematic and indepth research on the flowback of fracturing fluid.First of all,It studied the trajectory characteristics of fluid in formation fracture,from the aspects of indoor experiment,theoretical analysis and mechanics.Secondly,it introduced of proppant fluid characteristics,established a proppant motion model in the formation fracture and a proppant motion model before and after the formation fracture closure.Thirdly,it calculate the proppant backflow of critical flow velocity,according to the formation physical property characters of the Bonan Yi34 block.lastly,comparing the proppant backflow threshold and speed the flow of the fluid in the wellbore,it determine the reasonable range of fracturing fluid velocity and proppant backflow threshold,to provide theoretical evidence for the selection of nozzle diameter.In the study of fracturing fluid flowback,I compiled the calculation software of crack closure in the fracturing fluid flowback process.The software can calculate the critical flowback velocity and reasonable nozzle diameter.It helps the scientific and quantitative of the flowback.Selected Yi34-X35 well of Bonan Yi34 block as technology research,fracturing fluid flowback is racking studied.The effect of field application is good.Proppant backflow phenomenon didn't happen in the entire process of blowout.The fracturing fluid flowback rate is more than 75%.The effect of blowout is good.