Optimization of Chock Valves for Fracture Clean-up in Tight Gas Condensate Reservoirs

Abstract

Hydraulic fracturing is a vital technique to unlock tight gas condensate reservoirs. The efficiency of clean-up in tight gas condensate reservoirs has a tremendous effect on well delivery. During hydraulic fracturing flowback operations, only part of fracturing fluids flows back to the surface, resulting in discrepancies between the expected fracture length and the effective production fracture length. A reasonable choke size during fracture clean-up can help to maximize the fracture conductivity.In order to get a maximum amount of fracturing fluids flowing back to the surface and a least amount of proppants flowing back, optimization of a chock valve in operations is investigated. Furthermore, effects of a proppant size and well types including vertical and horizontal wells on chock valve adjustments are presented.A chock is adjusted by gradually increasing its diameter as fractures start to close. In addition, the chock size needs to be bigger in a horizontal well than that in a vertical well under the same conditions. If the fracture width close to a proppant size, the chock size will be bigger as the proppant diameter increases; if the fracture width is much larger than the diameter of the proppants, the chock size will be larger with a larger diameter of proppants prior to fracture closure. However, the optimum chock size will be smaller with a larger size of proppants after fracture closure.