Patent ID: 11912932
Assignee: CHINA UNIVERSITY OF PETROLEUM (EAST CHINA)
Field: Basic materials chemistry (Chemistry)
Classification: CPC C  Y | IPC C  E

Claim 0:
1. An encapsulated polymer flooding method for enhancing oil recovery, comprising:
(i) determination of reservoir parameters, a well deployment, and a development dynamic state of a target oil reservoir:
determining reservoir permeability, porosity, heterogeneity, temperature, salinity, positions of and a relative distance between a water injection well and a producing well, and a remaining oil distribution;
(ii) determination of a near-wellbore targeted profile control area and a far-wellbore targeted viscosification area:
determining an area with the maximum intra-reservoir longitudinal permeability ratio or a longitudinal permeability variation coefficient greater than 0.6 in a seepage direction as a near-wellbore targeted profile control area of the oil reservoir, defining the maximum horizontal distance between the near-wellbore targeted profile control area of the oil reservoir and the water injection well as a targeted distance x1, determining an area with the intra-reservoir longitudinal average remaining oil saturation greater than 0.6 as a far-wellbore targeted viscosification area, and defining the minimum horizontal distance between the far-wellbore targeted viscosification area and the water injection well as a targeted distance x2;
(iii) design and synthesis of an encapsulated polymer according to conditions of the target oil reservoir:
an encapsulated polymer referring to a microencapsulated polymer formed by wrapping a polymer with a shell layer by a chemical encapsulation method,
customizing a particle size and an elastic modulus of the encapsulated polymer according to near-wellbore permeability conditions; and
customizing a trigger mechanism of the encapsulated polymer according to the targeted distances and the conditions of the reservoir, the trigger mechanism of the encapsulated polymer comprising an electrostatic shielding mechanism of salinity, a water percolation and swelling mechanism, and a temperature dissolution mechanism;
(iv) evaluating and determining whether the anti-shearing performance, the sustained release and viscosification performance, the injection performance, and the profile control performance of the encapsulated polymer meet expected performance requirements based on laboratory tests; and performing step (iii) to redesign an encapsulated polymer if no;
(v) formulating an injection scheme for an encapsulated polymer flooding field; and
(vi) monitoring the development dynamic state of the oil reservoir, and iteratively regularly optimizing the properties of the encapsulated polymer and the injection scheme for the flooding field according to steps (i) to (v).