A method for simulating micro-fracturing and injection-increasing fracture propagation in offshore oilfields

Abstract

The invention discloses a method for simulating offshore oilfield micro fracturing injection increase crack propagation on the basis of fluid-solid-heat coupling theory. The method comprises the following steps that geological characteristic parameters are obtained on the basis of offshore micro fracturing well geological data; a hydraulic crack propagation model is built, and fluid pressure and filter loss in a crack are obtained; on the basis of a reservoir matrix model, dynamically changing pore pressure in a reservoir is worked out; on the basis of elastic mechanics and permeation fluid mechanics, a pore elastic deformation relation between fluid and rock is built, that is to say, a fluid-solid coupling model is built, and by means of the calculated pore pressure, rock strain caused bythe fluid can be obtained; a heat effect relation between the temperature and the rock is built, a strain, porosity, permeability and temperature fluid-solid-heat coupling model is built, the permeability and porosity after coupling change are obtained, the pore pressure after three-field coupling change is obtained, the changed pore pressure reacts on a Darcy filtration model, and the crack extension dynamic of the next moment is obtained. According to construction and geological parameters, the dynamic extension situation of the hydraulic crack and real-time change situation of the reservoir parameters in the offshore micro fracturing well long-term injection increase process can be predicted according to the construction and geological parameters.

Description

technical field [0001] The invention relates to a method for simulating the expansion of microfracturing injection fractures in offshore oilfields, and belongs to the technical field of oil and gas field development. Background technique [0002] Most offshore oil and gas areas have serious stratum heterogeneity, loose cemented reservoirs, and are prone to sand production. In the later stage of production, due to the poor quality of long-term injection water, the particles and oil pollution contained in it will accumulate near the bottom of the well and block the pores, causing well The actual conditions such as bottom pollution, rapid rise of injection pressure, lack of formation energy, and difficulty in meeting injection volume requirements. In order to solve this series of problems, offshore oilfields generally use micro-fracturing technology to open the formation near the wellbore, penetrate the pollution zone, and then increase the long-term injection with a small disp...

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Problems solved by technology

[0005] So far, there has been no simulation study of fracture propagation for the micro-fracturing stimulation process of offshore high-porosity and high-permeability reservoirs

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