Transverse Hydraulic Fractures From a Horizontal Well

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA non-fractured horizontal well is often not economically attractive in reservoirs where vertical wells are fractured. In many areas the latter are less expensive to complete and, with proper design, they provide at least as good and, usually, better well performance than horizontal wells. A considerable problem with horizontal wells is that they are rarely properly completed and/or stimulated.One way, for a horizontal well to be potentially more attractive than a fractured vertical well, is for itself to be hydraulically fractured.For almost all petroleum engineering applications, at depths where producing formations are found, the stress field leads to a hydraulic fracture that is vertical and normal to the minimum horizontal stress. Therefore the fracture direction and azimuth become important considerations in fracturing horizontal wells and they affect the well orientation. There are two limiting cases: the longitudinal and the transverse. For transverse fractures intersecting a horizontal well it is possible to generate multiple fractures with proper zone isolation.The flow configuration in a transverse fracture intersecting a horizontal well generates an additional pressure drop which can be substantial. We provide a calculation procedure for this and relate the performance of each fracture with wellestablished methodologies, such as the dimensionless productivity index. Obviously, one transverse fracture intersecting a horizontal well cannot deliver the same performance as a fractured vertical well. Multiple transverse fractures are essential to make this configuration attractive. Thus, the question that we answer and quantify is the impact of multiple transverse fractures compared with the base case of a fractured vertical well.What differentiate oil from gas reservoirs are the turbulence effects, often dominating the performance of a gas well but usually negligible in oil wells. This difference leads to a distinguishing performance between oil and gas wells. We present a comparative study of transverse fractures intersecting a horizontal well in oil and then in gas reservoirs, showing their significant differences. c DV DTH s J J + = ) 1 (

The Method of Distributed Volumetric Sources for Calculating the Transient and Pseudosteady-State Productivity of Complex Well-Fracture Configurations

“…The actual values of the convergence skins s 1 and s 2 can be estimated from simple formulas. Following the recommendations in Ref (17), we can estimate the flow convergence skin factor for Fracture 1 from the additional data on fracture conductivity and wellbore radius: However, one should be aware that s 1 and s 2 reflect the complex geometry of the well-fracture interface, often not known accurately. Twisting and turning of the fracture near the wellbore ("tortuosity") can significantly increase the skin values.…”

Solution for a plane strain rough‐walled hydraulic fracture driven by turbulent fluid through impermeable rock

“…10 The subsequent literature has emphasized the importance of considering turbulent flow, 11 especially if the fluid is a gas. [12][13][14] For HF, Nilson 15,16 considered a unidirectional flow for gas-driven HFs in a high-inertia regime for constant-pressure inlet boundary condition. In a similar way, Emerman et al 17 investigated the plane strain problem for gas-driven fractures with constant-inlet-flow boundary condition.…”

“…The subsequent literature has emphasized the importance of considering turbulent flow, especially if the fluid is a gas. ()…”

A numerical investigation on the performance of hydraulic fracturing in naturally fractured gas reservoirs based on stimulated rock volume

“…In low-permeability reservoirs, hydraulic fracture contributes both to well productivity and to the well reserves, because in such reservoirs the well would not produce an economic rate without the hydraulic fracture (Pang et al 2016). In homogenous reservoir with planar fracture geometry, there exists an optimum fracture dimension that would provide maximum reservoir performance for a given amount of proppant (Wei and Economides 2005). So predicting hydraulic fracture dimension by simulating hydraulic fracture propagation is crucial in hydraulic fracturing and completion design (Vinciguerra et al 2004).…”