Multilateral Drilling & Completions

Multilateral Drilling & CompletionsBy: Syed Zeerak Abbas Abdi

What is Multilateral Drilling? Is a type of drilling process that ultimately

leads to the creation of a multilateral well. Laterals=roots of a tree https://www.youtube.com/watch?v=-L4120-

o4nU

History of Multilateral Drilling First multilateral well drilling in 1953 by

Soviet engineer, Alexander Mikailovich Grigoryan.

Consisted of 9 laterals that extended up to 300 meters.

Cost 1.5 times more than a regular drilling job. Production saw a 17 times increase relative

to the average in that formation. Research and development increased in

1993 aided by the computer.

Drilling (Continued) Multilateral drilling is similar to directional

drilling, and can be done in 2 ways. A whipstock is installed at the desired depth

and is used to guide the milling assembly. The milling assembly cuts the casing and

cementing and allows the drilling assembly to drill the lateral.

Milling can be done without the use of a whipstock, as shown in the previous video. The use of a whipstock is preferred

because it removes hassle of dealing with cement plugs.

https://www.youtube.com/watch?v=IwKdRgLgkms (1:50, 2:16)

Multilateral Completions Add support to lateral through casing &

cementing. Provides stability and reduces risk of

collapse. Classified into 6 levels of increasing stability

by TAML (Technology Advancement of Multilaterals).

Completion solutions provided by service companies such as Schlumberger, Halliburton, and Weatherford.

Intelligent Completions are a necessity now.

TAML Levels

Intelligent Completions Combination of sensors, valves, packers,

and fiber optics that allow remote control of production.

Necessary for off shore multilateral production.

Expensive but highly recommended for zonal isolation.

Multilateral Configurations Laterals can be drilled in various directions,

or configurations. Dual Opposed: laterals drilling in the x-

plane, opposite to each other Useful in naturally fractured formations of

low permeability. Vertically stacked: laterals drilled in the

y-plane, one above the other. Useful in layered reservoirs.

Example of Configurations

Benefits Dramatic increase in production.

The first multilateral well saw a 17x increase in production.

Re-entry allows previously unfeasible reservoirs to be produced from.

Multiple laterals allow for coupling of production from a series of nearly-depleted laterals.

Very low surface impact. Make for good test wells.

Drawbacks TAML Level 3 & higher completions are very

expensive, limiting multilateral drilling to larger companies.

Intelligent completion solutions are custom-designed for each well, leading to long wait period relative to drilling time.

Large amount of interdisciplinary work requiring the usage of both drilling and completion teams.

Difficult to service and repair old multilateral wells.

Conclusion Slowdown in research & development due

to low oil prices. Very beneficial, but come with a high initial

cost and require engineering expertise across multiple teams.

Key to produce from large & offshore reservoirs

Make uneconomical ventures a possibility. Intelligent completions give engineers more

control than ever.