When dealing with unconventional reservoirs, a correct early Drawdown Management is critical to maximize the ultimate recovery of the well. If an aggressive drawdown is generated in the stimulated rock volume during the early production time, the hydraulic fracture that has been created takes the risk of being damaged and lose conductivity. Increasing the choke size to speed up production, although economically tempting, can generate serious damage in the hydraulic fracture network that has been created during the well's completion.
The Linear Flow plot exhibits a straight-line during the linear flow regime period, and it serves as a very accurate diagnostic tool to assess the potential of a multi-fractured horizontal well. If the choke size of the well is increased in a way that generates a highly aggressive drawdown in the reservoir (and therefore damaging the hydraulic fracture conductivity) the slope of this straight-line increases indicating that the well's productivity index has been reduced. Moreover, the slope "m" of this straight-line is inversely proportional to the triple product of the variables xf (hydraulic fracture half length), Hf (hydraulic fracture height) and the square root of k (effective permeability). This product: xf.Hf.√k is called the Liner Flow Parameter and is a very good indicator of the well's productivity. Therefore, if by an incorrect Drawdown Management, the choke size of the well is increased and the slope "m" of the straight-line in the Linear Flow plot increases, then, the Linear Flow Parameter should decrease in the same way. The goal of this work is to quantify the well's EUR loss that is directly associated to a negative variation of the triple product xf.Hf.√k. In other words, a general equation should be found to relate the change of the slope "m" to the loss of the well's productivity.
Drawdown Management Strategies play a key role during the early production time of an unconventional well. The Choke Management should be carefully planned in order to avoid reservoir damage. An early-time aggressive drawdown created in the reservoir can seriously reduce the size of the SRV and damage the hydraulic fracture conductivity. A correct Drawdown Management Strategy should be one that can ensure the economical production of a well, and at the same time, maximize the future performance and the estimated ultimate recovery.