(Reuters) - Oilfield services provider Baker Hughes Inc (>> Baker Hughes Incorporated) said on Thursday it was in preliminary merger talks with larger rival Halliburton Co (>> Halliburton Company).

A combination would help the companies better cope with weak oil prices. Global crude oil prices have slipped from over $100 in June to less than $80 this week amid excess supply and tepid demand growth.

Despite the market share boost that a tie-up of the No. 2 and No. 3 oilfield companies would bring, the combined entity would only be about half the size of market leader Schlumberger NV (>> Schlumberger Limited.).

Below is a breakdown of the market share of the top three oilfield companies in various services, according to data from Spears and Associates and Cowen and Co.

Company Units Service description Halliburton Baker Hughes Combined Schlumberger

Cementing Preparing and pumping 35 pct 16 pct 51 pct 27 pct

cement into a wellbore to

prevent leaks

Coiled Tubing Includes cleaning and 13 pct 11 pct 24 pct 21 pct

penetrating wellbores,

besides retrieving and

replacing damaged

equipment

Completion Products and services 28 pct 26 pct 54 pct 14 pct

Equipment and used in well completion

Services

Directional Drilling wells at 16 pct 18 pct 34 pct 31 pct

Drilling different angles and not

just vertically to better

reach oil and gas

reserves.

Drill Bits Apparatus used to cut 17 pct 24 pct 41 pct 27 pct

into rock in oil and gas

drilling

Drilling and Fluids used in drilling 25 pct 10 pct 35 pct 36 pct

Completion Fluids bore holes into the

ground and in completed

wells before the start of

production

Hydraulic Drilling technique where 26 pct 13 pct 39 pct 20 pct

Fracturing water, chemicals and sand

are blasted into wells to

extract oil and gas

LWD (logging while Drilling where logging 30 pct 16 pct 46 pct 45 pct

drilling) tools are incorporated

into the drill string,

helping transmit

formation measures to the

surface in real time

Surface Data Helps detect and avoid 15 pct 12 pct 27 pct 29 pct

Logging problems in drilling

Wireline Logging Helps measure properties 16 pct 12 pct 28 pct 44 pct

of an oil and gas

formation through

electrical cables

Below is a breakdown of Baker Hughes' and Halliburton's third-quarter revenues by operating region:

Revenue by region Halliburton

(in $ mln)

North America 4,724

Latin America 1,045

Europe/Africa/Commonwealth 1,464

of Independent States

Middle East/Asia 1,468

Revenue by region Baker Hughes

(in $ mln)

North America 3,155

Latin America 571

Europe/Africa/Russia Caspian 1,114

Middle East/ Asia Pacific 1,077

(Reporting by Swetha Gopinath, Shubhankar Chakravorty and Manya Venkatesh in Bangalore; Editing by Lisa Von Ahn)