Sea Stories
Mud Boats In Mexico
Tidewater operates over 50 boats out of Ciudad de Carmen and Paraiso
in the Bay of Campeche in Mexico. A mud boat delivers mud, drill
water, chemicals, diesel, and supplies
to platforms, rigs, and vessels. The oilfield is
owned and operated by Petroleos Mexicanes, PEMEX, the national
oil company of Mexico.
Mud is probably the most important component used in drilling a well. Due
to the viscosity and density of the mud, it enhances the drilling rate,
cools the drill bit and returns the drill bit cuttings to the surface
as the well penetrates the earth. In addition mud also coats the side
of the hole with properties that inhibit the hole from caving in. But
most important is the weight of the mud. The mud needs to weigh enough
to hold back the pressure of a well coming in when you drill through
the producing zone, but not weigh so much that the mud is lost to the
porosity of the producing zone. The weight of the mud is controlled by
its density. Additives help all of the required mud properties in
different ways. It is a science and an art – it is a multimillion
dollar industry. There is so much science (and art) surrounding
drilling mud.
Mud boats are supply boats with specialized equipment and modifications
allowing the vessel to make and transport drilling mud and drill water.
Mud boats in Mexico are usually over 200 feet long.
I commanded the Man O' War which is 220 ft. by 48 ft.
They typically have two engines
totaling 3800 hp to 6000 hp. They have a bow thruster enabling
sidewards movement.
The pictures on this page are cropped from a full size picture which
gives a better perspective to what is being shown. To see a picture
full size, simply click on the picture and it
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The Man O'War is a 1971 Halter Bollinger Shipyard Boat, well built and
suited for her tasks. She has a gross tonnage of 1124 international
tons and 498 domestic tons. Her max displacement is 2,413 long tons
which is 5.3 million pounds and has a max draft of 13 ft. 5 3/8 in.
Her high smoke stacks are called North Sea stacks and are able to
withstand significantly worse weather than the low stacks. Her deck
is loaded with chemicals used to make mud.
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The Man O'War is a DP 1 boat (dynamically positioned). However the
client is not willing to pay for the use of the DP system. We can
use it even though we have a fully functional DP system on board.
The forward helm is laid out well. All of the controls and electronics
are within easy reach. To port is one radar and alarm panel.
The digital fathometer is aft of the alarms.
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In the center are the helm controls, auto pilot, DP controls, engine
throttles, bow thruster throttles, magnetic compass
and emergency engine shutdowns. She has a gyro for the DP system but
there is no read out at either helm.
On the starboard side are a myriad of radios, GPS, second radar, AIS,
and the ship's voice powered phone.
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To the left is a view of the autopilot and DP system controls.
To the right is the steering control panel. There are two hydraulic
steering pumps to choose from. The rudders can be controlled
independently of jointly. They can be controlled from one of two
joy sticks, the wheel, the autopilot or the DP system. Quite a nice,
complex system.
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The aft helm station has most of the same features as the forward station.
It has more display information regarding the dynamic positioning system
as much of the DP work is done with the stern to the platform or rig.
Most of our working hours are spent on the aft helm.
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There are 25 persons on board, 14 crew, 10 mud contractors, and one
PEMEX rep. Consequently space is at a premium. This is the captain's
quarters. A bit small, having been converted from an electrical
closet/lounge. But it is the only private room on the boat. The
old captain's quarters is a four person room and is used by the
three chemical engineers.
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We are moving into position alongside a jackup rig in order to pump
new mud and receive old mud or deliver or receive chemicals. Although
we are much bigger than the oilfield workboats we have to get in closer
to the structures to place the hoses correctly. This takes some getting
used to.
There always seems to be some appendage sticking out from the structure
making our job more challenging. Here you see the flare. We could
easily damage it and the superstructure of our boat if we weren't careful.
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Here we are moored with a single line to a fixed platform with our
hose pumping mud up to the drilling rig's tanks.
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I find the night work to be the most interesting. We work 24 hours a
day. Here we are moored to a platform alongside a semi-submersible
work barge also moored to the same platform. The barge is used to lift
our hoses to the platform and to carry personnel to and from the
platform. The barge also performs a variety of construction work
for the platform.
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The barge, Semi 1, is a dynamic positioned vessel and can safely get
very close to other platforms and vessels. Its DP system is working.
Passengers on the personnel basket stand outside of the basket on a
wooden ring. You can imagine what the ride must be like, especially
at night. The view is fantastic. It is better than any Disneyland
ride I have been on.
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We wanted to transfer diesel to another boat. Neither of us had DP.
The seas were too high to tie up to each other. We anchored on 7
shots of chain in 60 feet of water - that's 630 feet of chain giving
a scope of 10 to 1. The other vessel then tied to us stern to stern
with one line on opposing corners. This was very stable.
We pumped diesel to the other vessel with no difficulty at all.
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Most afternoons and evenings in the tropics in the summer and fall
we tune one RADAR for squall watch. These squalls come up pretty
fast and move fairly quickly. The lightening and torrential rains
make work very unpleasant. The accompanying winds and seas making
mooring much higher risk.
This was one particularly nasty squall which came in very quickly
on us. We had about one hour from the time we identified it on RADAR
till it was on top of us.
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We began asking the rig to let us go (hoses and lines) about 45
minutes before the squall came. They refused so they could finish
the work. When the squall finally hit, they realized what a
mistake they had made. We were able to get free without incident
as the downpour began.
Hopefully they learned from this and there won't be a next time.
But if there is, I will be ready with saws and axes to free us
from the hoses and lines. The guys on the rig are usually pretty
clueless about boats and risks.
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Chancey Lee Ramon is my Chief Mate. He is from Honduras. He has
been handling boats for over forty years of his life. Needless to
say, he is an excellent boat handler. However, there are more
aspects to the job of Chief Mate than just handling boats.
Ramon Zablada is my Chief Engineer. He is from Honduras. He has
been on boats for over 40 years as well. We never had an engine
problem during my entire assignment to the Man O'War with Ramon.
He knows the value of preventive maintenance.
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Safety Drills and safety training are very important. Two AB's are
suited up to fight a simulated fire on the aft deck. All STCW training
is supposed to be standardized world wide. However, none of my QAB's
had ever put on fire fighting suits before. In the United States, you
can get an STCW certificate without fighting a real fire in full gear.
This is true for both Mexico and Honduras.
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Everyone on board enjoyed participating in the drills. We are
required to do a fire drill every two weeks and an abandon ship
drill every two weeks by US regulations (46 CFR Subpart L - OSV's).
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After the drills we all meet in the pilot house for a lesson on safety.
This day we had 3 - one on aft deck safety, one on load lines and
stability and one on safety around mud operations.
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There is a lot of science to properly making drill water and mud.
Here the chemical engineers are testing the salinity of the drill
water. This determines the weight (density) of the water. Given
the depth of the hole may be one to three miles deep, the salinity
has to be very accurate so you don't have too much or too little
weight when drilling through the producing formation.
The PEMEX engineer is verifying the density of the drill water.
You can see how serious everyone takes these measurements. A
million dollar well can be damaged or destroyed by having the
wrong water or mud weight. Worse yet, if it is too light, a blow out
could occur which could create major environmental oil pollution.
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Sacks of chemical additives are stored on the stern for the
drill mud and drill water.
Here are some of the types of equipment used in the creation of the
mud and drill water.
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These four tubes are the tops of the mud tanks. Each tank can store
75 cubic meters of mud. This could be as much as 100 tons of mud in each tank.
This is one of two tubes which are the tops of the drill water tanks.
Each drill water tank can hold over 11,000 gallons (over 47 tons
each) of drill water.
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