Abstract

Hydraulic fracturing is an important method to improve the oil and gas production in low and ultra-low permeability reservoirs. A remarkable progress has been made in the technology and materials. However, the existing conventional hydraulic fracturing technology faces problems, such as reservoir damage, equipment abrasion, low effective propped area, and early screen-out. Therefore, a novel self-propped fracturing fluid (SPFF) was proposed, which remains in the liquid-phase before entering the fracture, and forms solid proppant particles when stimulated by the reservoir temperature after entering the fracture (Chemical proppant, CP).

In this paper, the micro-morphology of CP was studied by SEM, and the temperature of the CP-formed was measured by the CP formation experiments at room temperature and field conditions. Furthermore, the compressive strength, thermal stability, stability in formation fluid, acid and alkali, leak-off, core damage, and fracture conductivity of the developed SPFF were tested.

The test results show that the leak-off volume and core damage level of SPFF were less than that of conventional fracturing fluid, thereby effectively reducing the damage to the reservoir permeability. The CP exhibited good performance in terms of compressive strength, thermal stability, stability in reservoir fluid and treatment fluid. Besides, the conductivity of the propped fracture was high. These advantages determine that CP can meet the field treatment requirements. The CP could enter any narrow fractures, and effectively solved the existing problems in the conventional fracturing technology by significantly improving the fracturing effect, especially the network fracturing effect in tight reservoir systems.

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