Multi-lateral drilling

A well in which there is more than one horizontal or

near horizontal lateral well drilled from a single borehole

Geometry of Multi‐Lateral and Multi‐branched wells

Advantages of Multilateral Wells

1-Higher Production (Ph.A.Charlez 1999): In the cases where thin pools are targeted, vertical
wells yield small contact with the reservoir which causes lower production. Drilling
several laterals in thin reservoirs and increasing contact improves recovery.
2-Decreased Water/Gas Coning (G. Ismail 1996): The position of the laterals within the
producing formation provides enough distance to the water zone and to the gas
zone. Therefore, gas/water conning can be prevented or reduced.
3-Improved sweep efficiency: By using multilateral wells, the sweep efficiency will be
improved and the recovery can be increased due to the area covered by the laterals.
4-Fast Recovery (Ph.A.Charlez 1999): Production from the multilateral wells is higher than
that in single vertical or horizontal wells; hence the reservoir contact is higher in
multilateral wells
5-Decreased environmental impacts: The volume of consumed drilling fluids and the
generated cuttings during drilling multilateral wells are less than the consumed
drilling fluid and generated cuttings from separated wells. Therefore, the impact of
the multilateral wells on the environment is reduced.
6-Saving time and cost (G. Ismail 1996): Drilling several laterals in a single well will result
in substantial time and cost saving in comparison with drilling several wells in the
reservoir.

Challenges and Complexity of Multilateral Wells:
1-The installation and retrieving of some necessary tools during drilling or after
completion of multilateral wells is associated with high risk. These tools may be
whipstocks, packers etc.
2-In drilling multilateral wells, the mother well bore can be cased to control sand
production, however, the legs branched from the mother well bore are open hole.
Therefore, the sand control from the legs is not easy to perform.
3-There is a difficulty in modeling and prediction due to the sophisticated system of
multilateral wells.
4-Construction of multilateral wells is quite complex.
5-Because of complexity of laterals, there is difficulty in stimulation and clean‐up.