### Abstract

Using a combination of analytical calculations and 3D finite element simulation, we have developed a comprehensive skin factor model for perforated horizontal wells. In this paper, we present the mathematical model development, and validation of the model by comparison with finite element simulation results. With the new perforation skin model, we then show how to optimize horizontal well perforating to maximize well productivity. A cased, perforated well may have lower productivity (as characterized by a positive skin factor) relative to the equivalent openhole completion because of two factors - the convergence of the flow to the perforations and the blockage of the flow by the wellbore itself. Because of the orientation of a horizontal well relative to the anisotropic permeability field, perforation skin models for vertical wells that consider these effects, notably the Karakas and Tariq model, are not directly applicable to perforated horizontal completions. Using appropriate variable transformations, we derived a skin factor model for a horizontal perforated completion that is analogous to the Karakas and Tariq vertical well model. The empirical parameters in the model were determined from an extensive 3D finite element simulation study. The results of the new model show that the azimuth of a perforation (the angle between the perforation tunnel and the maximum permeability direction, usually thought to be the horizontal direction) affects the performance of perforated completions in anisotropic reservoirs. When perforations are normal to the maximum permeability direction, perforations will enhance horizontal well flow compared with an openhole completion (a negative skin factor). But if perforations are in the same direction as the maximum permeability, significant positive skin will result. The new skin factor model provides a clear guide to the shot density, perforation orientation, and level of perforation damage that is tolerable to create high productivity perforated completions in horizontal wells.

Original language | English |
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Title of host publication | Proceedings - SPE Annual Technical Conference and Exhibition |

Pages | 303-316 |

Number of pages | 14 |

Publication status | Published - 2002 |

Externally published | Yes |

Event | Proceedings of the 2002 SPE Annual Technical Conference and Exhibition - San Antonio, TX, United States Duration: 2002 Sep 29 → 2002 Oct 2 |

### Other

Other | Proceedings of the 2002 SPE Annual Technical Conference and Exhibition |
---|---|

Country | United States |

City | San Antonio, TX |

Period | 02/9/29 → 02/10/2 |

### Fingerprint

### ASJC Scopus subject areas

- Geotechnical Engineering and Engineering Geology
- Geology

### Cite this

*Proceedings - SPE Annual Technical Conference and Exhibition*(pp. 303-316)

**A New Skin Factor Model for Perforated Horizontal Wells.** / Furui, Kenji; Zhu, D.; Hill, A. D.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Proceedings - SPE Annual Technical Conference and Exhibition.*pp. 303-316, Proceedings of the 2002 SPE Annual Technical Conference and Exhibition, San Antonio, TX, United States, 02/9/29.

}

TY - GEN

T1 - A New Skin Factor Model for Perforated Horizontal Wells

AU - Furui, Kenji

AU - Zhu, D.

AU - Hill, A. D.

PY - 2002

Y1 - 2002

N2 - Using a combination of analytical calculations and 3D finite element simulation, we have developed a comprehensive skin factor model for perforated horizontal wells. In this paper, we present the mathematical model development, and validation of the model by comparison with finite element simulation results. With the new perforation skin model, we then show how to optimize horizontal well perforating to maximize well productivity. A cased, perforated well may have lower productivity (as characterized by a positive skin factor) relative to the equivalent openhole completion because of two factors - the convergence of the flow to the perforations and the blockage of the flow by the wellbore itself. Because of the orientation of a horizontal well relative to the anisotropic permeability field, perforation skin models for vertical wells that consider these effects, notably the Karakas and Tariq model, are not directly applicable to perforated horizontal completions. Using appropriate variable transformations, we derived a skin factor model for a horizontal perforated completion that is analogous to the Karakas and Tariq vertical well model. The empirical parameters in the model were determined from an extensive 3D finite element simulation study. The results of the new model show that the azimuth of a perforation (the angle between the perforation tunnel and the maximum permeability direction, usually thought to be the horizontal direction) affects the performance of perforated completions in anisotropic reservoirs. When perforations are normal to the maximum permeability direction, perforations will enhance horizontal well flow compared with an openhole completion (a negative skin factor). But if perforations are in the same direction as the maximum permeability, significant positive skin will result. The new skin factor model provides a clear guide to the shot density, perforation orientation, and level of perforation damage that is tolerable to create high productivity perforated completions in horizontal wells.

AB - Using a combination of analytical calculations and 3D finite element simulation, we have developed a comprehensive skin factor model for perforated horizontal wells. In this paper, we present the mathematical model development, and validation of the model by comparison with finite element simulation results. With the new perforation skin model, we then show how to optimize horizontal well perforating to maximize well productivity. A cased, perforated well may have lower productivity (as characterized by a positive skin factor) relative to the equivalent openhole completion because of two factors - the convergence of the flow to the perforations and the blockage of the flow by the wellbore itself. Because of the orientation of a horizontal well relative to the anisotropic permeability field, perforation skin models for vertical wells that consider these effects, notably the Karakas and Tariq model, are not directly applicable to perforated horizontal completions. Using appropriate variable transformations, we derived a skin factor model for a horizontal perforated completion that is analogous to the Karakas and Tariq vertical well model. The empirical parameters in the model were determined from an extensive 3D finite element simulation study. The results of the new model show that the azimuth of a perforation (the angle between the perforation tunnel and the maximum permeability direction, usually thought to be the horizontal direction) affects the performance of perforated completions in anisotropic reservoirs. When perforations are normal to the maximum permeability direction, perforations will enhance horizontal well flow compared with an openhole completion (a negative skin factor). But if perforations are in the same direction as the maximum permeability, significant positive skin will result. The new skin factor model provides a clear guide to the shot density, perforation orientation, and level of perforation damage that is tolerable to create high productivity perforated completions in horizontal wells.

UR - http://www.scopus.com/inward/record.url?scp=1142303146&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=1142303146&partnerID=8YFLogxK

M3 - Conference contribution

SP - 303

EP - 316

BT - Proceedings - SPE Annual Technical Conference and Exhibition

ER -