Adaptability Research On Self-Assembled Particles Profile Control In Bohai Oilfield

In middle and late development stages of Bohai Oilfield,severely channeling-path was formed due to long-term water flooding.Finally,it result low water displacement efficiency,high water content and low exploitation degree.In recent years,chemical displacement method was used to block high permeability channel path and improve water displacement efficiency,and particle profile control technology was widely used as it can plug channeling-path and improve displacement efficiency.In order to improve traditional particle plugging agent deficiency,a new type self-assembled particles was studied through laboratory experiments.Firstly,self-assembled particles size,suspension performance,fire-resistance and salt-resistance were evaluated by static experiments.Secondly,sand-filled pipes with different permeability and heterogeneous were used to evaluate its applicability,and optimize its parameters.Finally,microscopic visualization models were used to study the plugging mechanism.Static experiments showed that self-assembled particles consist of rigid kernel and softening film,and its average diameter was 106.19¹83.59?m.It was effective below100?and 35000 mg/L,which showed good fire-resistance and salt-resistance,and suitable for Bohai Oilfield reservoir conditions.Plugging experiment showed that,for homogeneous sand-filled pipes,which permeability was about 10000×10^-3?m²,with bridging particles profile control system,and injection rate was 1.0mL/min,slug size was0.05 PV,particles concentration was 5.0%,suspending agent concentration was 0.2%,permeability descended to 240×10^-3?m²,and effective plugging rate was above 97%.Oil displacement experiments showed that,for parallel sand-filled pipes,which permeability ratio was within 20(20000/1000×10^-3?m²),with self-assembled particles profile control system,11.58%⁴8.80%of OOIP can be recovered in low permeability pipes and 32.44%⁴7.57%of OOIP can be recovered in high permeability pipes.Finally,29.33%⁴3.00%of OOIP can be recovered in parallel sand-filled pipes.Microscopic visual model research revealed that self-assembled particles displacement system had plugging function with filling,bridging and adhesion.The research can provide basis data and theoretical for self-assembled particles profile control technology.