Dissoluble polymeric microsphere deep profile modifying and flooding agent and preparation method thereof

Abstract

The invention discloses a dissoluble polymeric microsphere deep profile modifying and flooding agent and a preparation method thereof. The deep profile modifying and flooding agent is copolymerized by an acrylamide monomer, a temperature-resistant and salt-resistant monomer and a dissoluble crosslinking monomer, wherein the preparation method is a reversed phase suspension polymerization method. The dissoluble crosslinking monomer is a polyethylene glycol diacrylate monomer, has temperature dependency and is adaptive to different oil reservoir temperatures by adjusting the dosage and controlling the decomposition temperature and time. The dissoluble polymeric microsphere deep profile modifying and flooding agent has a micrometer size, is matched with the oil reservoir pore throat size, low in initial viscosity, easy to enter into the oil reservoir deep part, initially expanded with water immersion, similar to a deep profile control agent, and is capable of blocking a high permeable layer to promote the fluid diversion. Under the oil reservoir temperature, the deep profile modifying and flooding agent is gradually decomposed into a linear polymer, so that the water phase is tackified and the late polymer deep oil displacement is realized. A system is injected, a double function of the deep profile modifying and the deep oil displacement can be realized and a potential application value is obtained.

Description

technical field [0001] The invention relates to a decomposable polymer microsphere deep control and drive agent suitable for oil reservoir deep control and displacement, belonging to the field of oil field chemistry. Background technique [0002] Due to the heterogeneity of the reservoir itself and long-term water flooding development, at present, most oil fields in my country have entered the stage of high water cut / ultra-high water cut, facing problems such as low water injection development efficiency and difficulty in tapping the remaining oil potential. Therefore, how to improve water flooding efficiency and delay production decline is the main problem facing the current tertiary oil recovery technology. Long-term practice has proved that changing the liquid flow direction and improving the sweep coefficient through profile control and water plugging are effective measures to realize oilfield water control and oil stabilization technology. However, conventional profile...

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Problems solved by technology

It has been reported that colloidal disperse gel (CDG), a single-fluid control and displacement agent, has the potential of deep control and displacement (Guo Zhidong et al., Research on Oil Displacement Characteristics of CDG and Polymer, Oilfield Chemistry, 2009, 26(1): 84- 90); but because of its harsh application conditions and poor temperature and salt resistance, its domestic promotion and use is limited

In recent years, polymer microspheres have been proved to be a new type of material due to their environmental protection, controllable size, high strength, easy elastic deformation, good chemical stability, and the characteristics of "going in, blocking, and moving" to the formation. Excellent deep control and flooding agent (Wang Dailiu et al., Cross-linked polymer microsphere deep control and flooding technology and its application, Oil and Gas Geology and Recovery, 2008,15(2):82-88); Chinese patent "contains core-shell structure Preparation method of gel microsphere emulsion deep control and displacement agent and emulsion deep control and displacement agent (Patent No. CN 102399345 A), but strictly speaking, it can only be a deep profile control agent, which only enters the deep formation Plugging the high permeability layer forces the liquid flow to divert to increase the swept volume, but does not improve the oil washing efficiency

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