Temporary plugging workover fluid and preparation method thereof

Abstract

The invention discloses a temporary plugging workover fluid and a preparation method thereof, and belongs to the field of oilfield chemistry. The temporary plugging workover fluid comprises, based onthe total weight being 100 parts, 0.96-2.7 parts of flour balls, 0.48-1.35 parts of resin balls, 1.92-4.5 parts of an expansion inhibitor, 0.29-0.45 parts of a suspending agent, 0.19-0.27 parts of a fiber synergist, 0.10-0.41 parts of a scale inhibitor, 0.19-0.32 parts of a degradation agent and the balance of water. The flour balls are prepared by mixing wheat flour and floating beads in a mass ratio of 6: 4 to 7: 3, adding water, and performing mixing, extruding, cutting, forming and drying. The density of the flour balls is 0.97-1.02 g/cm<3>, and the particle size of the flour balls is 2-4mm. The resin balls are prepared by mixing petroleum resin and floating beads in a mass ratio of 7: 3 to 8: 3, adding isopropanol and a silane coupling agent, and performing mixing, extruding, cutting,forming and drying. The density of the resin balls is 0.97-1.02 g/cm<3>, and the particle size of the resin balls is 3-5mm. The fiber synergist is polyvinyl alcohol fiber, the diameter of the polyvinyl alcohol fiber is 0.01-0.03mm, and the length of the polyvinyl alcohol fiber is 3-5mm. The temporary plugging workover fluid can form a temporary plugging layer which is compact in structure and excellent in mechanical strength and pressure bearing capacity, and does not damage a reservoir.

Description

technical field [0001] The invention relates to the field of oilfield chemistry, in particular to a temporary plugging workover fluid and a preparation method thereof. Background technique [0002] The leakage of workover fluid into the formation (referred to as lost circulation) not only affects the normal production of the oil well, but also pollutes the reservoir, resulting in the loss of oil and gas production and economic loss to the oil field. The causes of lost circulation include: high reservoir permeability, loose rock cementation, and large pressure difference between the reservoir and the working fluid. In workover operations, the use of temporary plugging and workover fluid can form a temporary plugging layer in the reservoir to prevent lost circulation. [0003] Currently used temporary plugging and workover fluids include superabsorbent resin and water, which can form stagnant gel clusters in the reservoir, accumulate in the reservoir and block the pore throat...

AI Technical Summary

Problems solved by technology

[0004] The water-absorbing resin has a large water-absorbing expansion multiple, and its strength decreases after water-absorbing expansion. The pressure-bearing capacity of the temporary plugging layer is small, the adaptable range is small, and the success rate of temporary plugging is low.

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