Acid fracturing, as a conventional and effective stimulation method, has been widely used in carbonate formation. But because of serious acid leak-off and rapid acid/rock reaction speed, the length of effective acid etched fracture is always restricted, even the high viscosity acid and emulsified acid were applied; besides the effective duration of etched fracture was short, especially in deep well, because of the high closure stress acted on the fracture wall where the rock were softened significantly after contact with acid. In contrast, propped fracturing can create longer conductive fracture, and its effective duration is longer because the existence of proppant.

The carbonate reservoir are deeply buried (>4500m) with high temperature (>130°C), ultra-low porosity/permeability, high young's modulus and tensile strength, and the natural fractures often densely distributed in it, all of which makes the propped fracturing difficult. A new temperature-stability and shearing resistance delayed cross-linked guar fracturing fluid with low damage was developed to qualify for the fracturing treatment. Small size high strength ceramic proppant was selected to fulfill the narrow width of fracture, and proppant slugs was utilized to erode the tortuousness of near-wellbore fracture path and plug near-wellbore multiple hydraulic and natural fractures. The technology countermeasure ensured the success of propped fracturing treatment.

The net pressure and production history matching both indicated that the propped fracturing created longer conductive fracture and realized deep penetration. The well production increased dramatically after the stimulation. Besides, the comparison of production after gelled acid fracturing, surface cross-linked acid fracturing and propped fracturing in the same layer same well suggested that propped fracturing was more effective than the acid fracturing. The production test further showed propped fracturing could provide longer effective duration, and the well rate-maintenance capability was very excellent.

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