Abstract:
Objective In view of the lack of effective breakthrough in the early stage for conventional reconstruction of Chang 6 tight sandstone reservoir in the southern area of Ordos Basin, the production of a single well was not significantly improved, then the complex fracture network volume fracturing technology was explored to improve the effect of tight reservoir reconstruction in the block.
Methods Based on the geological characteristics of the reservoir and the rock mechanics parameters, the brittle index and volumetric fracturing feasibility of Chang 6 reservoir were evaluated. The onset pressure and orientation of near-well fracture were analyzed. The expansion law for the two factors of proximity angle and horizontal stress difference on far-well fracture that encounter natural fracture was defined. The impacts of fracturing design parameters on fracture morphology and volume were simulated and optimized.
Results The key parameters of the optimized fracturing design are as follows: the fracture scale is 1 000 m3, the designed discharge rate is 8.0-10.0 m3/min, the proportion of slick water pre-fluid is 30%, and the sanding strength is 13%-15%. It is easier to obtain the optimal reservoir reconstruction volume and higher conductivity under the conditions.
Conclusions Adaptive method is proposed for evaluating and optimizing volumetric fracturing design parameters for complex fracture network in Chang 6 tight sandstone reservoir, which provides theoretical basis and on-the-ground guidance for the application of complex fracture network volumetric fracturing techniques.