Approximate Modeling of Fractured Horizontal Wells
Abstract/Contents
- Abstract
- Non-conventional wells encompass a wide range of non-vertical wells; e.g., multilaterals. By providing maximum areal contact with the reservoir, these wells increase the well productivity compared to conventional wells. Such wells are feasible because of the recent developments in directional drilling technology. NCWs are being used to intersect single or multiple fractures, which could be natural or hydraulically induced. Due to the novelty of such wells, new methods are required to evaluate their productivity performance. These methods need to account for reservoir heterogeneity in order for them to give reliable results. Traditionally finite difference (FD) simulation has been used for the modeling of wells. However, in the case of fractured wells, FD modeling may be time-consuming or suffer from numerical/convergence issues.Semi-analytical methods have been used successfully to model single-phase flow problems. A variety of software has been developed by the Stanford University Petroleum Research Institute for Horizontal Wells (SUPRI-HW) using the semi-analytical approach. The fracture program models fractures (longitudinal or transverse) traversing a horizontal well. The latch program models NCWs in heterogeneous reservoirs, but does not model fractures. This project involves combining the fracture modeling capability of the fracture program together with the NCW and approximate heterogeneity modeling capabilities of the latch program, thereby allowing the approximate modeling of fractured NCWs in heterogeneous reservoirs. The skin concept is used in our method to combine the fracture and latch programs. A reference inflow and pressure profile is generated using the fracture program. An effective skin factor, sfrac is then determined for each fracture-containing well segment. The fracture skin factor, sfrac can then be used in latch to model fractured NCWs. A number of cases involving a horizontal well intersecting longitudinal and transverse fractures (2D and 3D fractures) in homogeneous reservoirs are presented. The impact of various reservoir parameters such as total flow rate, porosity and anisotropy on the effective skins is examined. The results indicate that the skins computed using our procedure are not sensitive to many reservoir parameters, with the exception of permeability anisotropy. These findings are consistent with expectations. The method was then applied to heterogeneous reservoirs. The latch program is used to determine a heterogeneity skin factor, shetero, which approximately captures the effects of near wellbore heterogeneity. A total skin factor, stotal is computed by summing shetero and sfrac. Running latch with stotal gives the inflow and pressure profile of fractured horizontal wells in heterogeneous reservoirs. An example demonstrating the method for heterogeneous reservoirs is presented, though difficulties were encountered in validating this solution against finite difference results.
Description
| Type of resource | text |
|---|---|
| Date created | July 2001 |
Creators/Contributors
| Author | Hayat, Asim |
|---|---|
| Primary advisor | Durlofsky, Louis J. |
| Degree granting institution | Stanford University, Department of Petroleum Engineering |
Subjects
| Subject | School of Earth Energy & Environmental Sciences |
|---|---|
| Genre | Thesis |
Bibliographic information
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Preferred citation
- Preferred Citation
- Hayat, Asim. (2001). Approximate Modeling of Fractured Horizontal Wells. Stanford Digital Repository. Available at: https://purl.stanford.edu/sm925hd2158
Collection
Master's Theses, Doerr School of Sustainability
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