Determination of Performance of Multiple-Fracture Horizontal Well by Incorporating Fracture-Fluid Leakoff

Abstract

Summary Multiple-fracture-horizontal-well (MFHW) technology plays a crucial role in production from less economically attractive reservoirs, through enhancing the well productivity. The formation around the fracture might be damaged considerably during fracturing processes because of the fracture-fluid leakoff into the reservoir. Different attempts have been made to achieve an optimal design for MFHWs; however, the effect of fracture-fluid leakoff has been neglected in most of these research investigations, leading to unrealistic and inaccurate results. This study aims to fill this knowledge gap. A new mathematical approach is introduced to evaluate the effect of the fracture-fluid-leakoff phenomenon on the fracture characteristics during hydraulic fracturing. The unified-fracture-design (UFD) concept is used in this research work to optimize the productivity of MFHWs where the direct boundary-element method (DBEM) is applied. The distributed-volumetric-sources (DVS) method, which offers a semianalytical response of a reservoir to closed outer boundaries with respect to a source, is also extended, and the results obtained from these two different techniques are compared. Then, the proposed methodology is applied to a synthetic case study to evaluate the influence of fracture-fluid leakoff on the productivity index (PI) and to obtain the fracture dimensions that result in the optimal productivity. It is concluded that leakoff leads to influx-pattern variation. Also, it is found that the optimal fracture for the leakoff case is shorter and wider at a constant proppant number, in contrast to the case without a leakoff event. This study proposes an accurate and reliable approach for productivity determination of MFHWs that can assist the petroleum industry to optimize hydraulic-fracturing operations.

Productivity analysis for a horizontal well with multiple reorientation fractures in an anisotropic reservoir

“…Wang et al [21] applied the UFD method to calculate the productivity index of a horizontal well with fracture networks in a closed rectangular reservoir and stated that the productivity index reaches the peak when fracture networks penetrate throughout the seepage area under infinite conductivity. Asadi et al [22] combined the UFD method with Direct Boundary-Element Method (DBEM) to evaluate the influence of fracture-fluidleak off on the productivity index of multiple-fracture horizontal wells and found that the optimal fracture with leak off should be shorter and wider for a fixed proppant number than the case without leak off. Guk et al [23] employed the UFD method to develop a rigorous and unified optimization technique with type curves and calculated the optimal fracture number for a given proppant number by using type curves.…”

“…The previous models were established on the assumption of the ideal planar fractures [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. In fact, many complex fractures can be formed in tight reservoirs, such as multi-wing fractures, non-planar fractures and reorientation fractures [25][26][27][28].…”