Chair 2009 Liongson

DESIGN CAPACITIES OFHORIZONTAL WELL SYSTEMS

Leonardo Q. LiongsonTeam Energy Professorial Chair

in Energy Engineering

Instituteof Civil EngineeringCollege of Engineering

University of the Philippines, DilimanQuezon City, Philippines

6th Engineering Professorial Chair Colloquium 6 July 2009

Aim of the paper:To review and derive the design capacities of horizontal wells(infiltration gallery systems) under the ff. cases:

Part 1: Review for Cylindrical Horizontal Wells(derived in previous Prof. Chair Lectures in 2007 and 2008):

Case 1. A horizontal well below a horizontal recharge boundary in a semi-infinite aquifer (exact solution).(Cases 2 and 3 are variations of Case 1 – not reviewed here).

Case 4. A horizontal well below a horizontal recharge boundary and above a horizontal impermeable boundary in an infinite strip of aquifer (exact solution).

Case 5. A horizontal well below a leaky aquitard layer (silt or clay lenses ) under a horizontal recharge boundary in a semi-infinite aquifer (approx. r<<b).

Case 6. A horizontal well lying below a finite silt or clay lens represented by a doublet or a pair of counter-rotating vortices, under a horizontal recharge boundary in a semi-infinite aquifer (approx. r<<b).

Part 2: Derivation for Rectangular Horizontal Galleries :

Case 1. A rectangular gallery with a filter bed, under constant head.

Case 2. A rectangular gallery without a filter bed, under constant head.

Case 3. A rectangular gallery with a filter bed, under constant recharge rate.

Case 4. A rectangular gallery without a filter bed, under constant recharge rate.

Part 1: Review for Cylindrical Horizontal Wells(derived in previous Prof. Chair Lectures in 2007) – Case 1

Part 1: Review for Cylindrical Horizontal Wells(suggested in previous Prof. Chair Lectures in 2008) – Case 6

Part 2: Derivation for Rectangular Horizontal Galleries -Case 1

Part 2: Derivation for Rectangular Horizontal Galleries –Case 1 vs. Case 2

Part 2: Derivation for Rectangular Horizontal Galleries –Case 2

Conclusion:

This paper has

• reviewed the design capacities of cylindrical horizontal wells (with four (4) cases);

• derived the design capacities of rectangular infiltration gallery systems (with four (4) cases) ;

• Explained the limitations in the asymptotic value of the design capacity of rectangular gallery with filter bed, under constant head, regardless of the length of the gallery.

General Recommendation:

Apply numerical seepage models to extend the results to other 2-D and 3-D layouts and geometries of horizontal wells, guided by the analytical results reviewed and derived in this paper.

THANK YOU !

Chair 2009 Liongson

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