Intrafracture temporary plugging and diversion fracturing technology suitable for tight reservoirs

As oil and gas exploration and development advances continuously, unconventional tight oil and gas reservoirs have already become the main objects for oilfields to realize reserve and production increase. This type of reservoir is characterized by low permeability (＜0.1×10⁻³ µm²) and large bidirectional stress difference (＞ 10 MPa), so it is difficult to induce fracture network only based on the stimulation of large displacement and liquid rate. To this end, intrafracture temporary plugging and diversion fracturing technology is needed to increase the net pressure further and improve the fracture complexity. The type selection and dosage design of temporary plugging agent is the determinative key to the formation of complex fracture network and consequently influences the stimulation effect of fracturing wells. The water based temperature control dissolution type temporary plugging agent was selected, and the plugging thickness of temporary plugging agent, the height of dynamic fractures and the quantity and thickness of micro fractures were taken into consideration comprehensively to form the method for the dosage design of temporary plugging agent. It has been totally applied in 37 layers of 11 wells, among which, the pressure of 28 layers under the same displacement is increased by 0.5-7.0 MPa after the injection of temporary plugging agent and the efficiency is up to 75.7%. Thus, the goal of intrafracture temporary plugging and diversion fracturing network is reached. The research results provide theoretical basis for the later tight reservoir stimulation, so as to achieve the effective production of tight oil and gas reservoirs.