Method for fracturing high-angle naturally-fractured oil reservoir by using permanent plugging agent

Abstract

The invention discloses a method for fracturing a high-angle naturally-fractured oil reservoir by using a permanent plugging agent; the method comprises: drifting a well with a drift size gauge tool, and washing mechanical impurities in a shaft; running pressure test; perforating a segment to be fractured in the shaft; tripping in a fracturing string to carry out fracturing; pumping a prepad fluid; squeezing large-particle-size temporary plugging agents of different ratios in multiple rounds to a prepad fluid phase in a slug manner so that high-angle natural fractures are plugged primarily; pumping a sand-carrying fluid; filling the high-angle natural micro fractures by using a small-particle plugging agent in spiral slug sand-adding manner so that effective propagation of the fractures is ensured; finally, opening the well for gushing, acquiring production, and completing the well. The method provided herein has the advantages that upper and lower high-angle natural factures of a reservoir are effectively plugged, fracture breakthrough during fracturing is prevented, fracture height is controlled, long-fracture modification is achieved, full modification of the reservoir is guaranteed, a fracturing technical mode suitable for high-angle naturally-fractured reservoirs is formed, and initial yield is increased by 20% and above.

Description

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AI Technical Summary

Benefits of technology

This patented technique helps create new ways to improve hydraulic conductivity (hydrofracturability) within rocks that are difficult to drill due to their size. It involves injecting special agents into the rock before it becomes too much water, which increases its permeable area while reducing resistance against flow. By doing this, hydrostatic presses can help crack open these areas without damaging them. Additionally, there're also methods used to prevent blockage faults caused by excessive fluid movement inside the porous media after injection. Overall, this approach enhances the efficiency and quality of producing crude oil outcomes.

Problems solved by technology

Technological Problem: High Angle Fracturism Different techniques can help create stable long horizontal cracks called tungsten depletion zones within deep shale basins near China's North East Copper Development Zone. These areas may contain significant amounts of unexplored rocks containing mineral resources like iron oxide hydroxides. Current methods involve injecting temporary plugs made from materials like bentonite clay, cement slurrings, etc., but they often result in incomplete closure of certain fissile structures leading to leakages during drilling operations. Therefore there needs an efficient way to temporarily plugged off highly stressed fractuous sections without causing damage to existing fractars.

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