GB2483273A

GB2483273A - Tank floor funnelling

Info

Publication number: GB2483273A
Application number: GB1014583.7A
Authority: GB
Inventors: James Dallas
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-09-02
Filing date: 2010-09-02
Publication date: 2012-03-07
Also published as: GB201014583D0

Abstract

The invention relates to funnelling the bottom of a drilling mud tank without structural alterations. A funnel 2 is created on the tank floor using blocks (1, figure 4) of an oil resistant material such as plastic. Preferably the floor is tapered towards a single point so as not to create a ditch in the tank floor. A suction pump 4 may be positioned at the top of the tank and connected to a suction pipe 5 and a discharge pipe 6. Funnelling the floor of the mud tank eliminates the need for personnel to enter the tank to clean it out.

Description

Tank Floor funnelling.

This invention relates to a method of cleaning drilling mud tanks without need to have Personnel entering them.

This invention relates to forming a funnel on the floor of a flat bottomed mud tank.

The funnel will be formed using tapered blocks of plastics, materials such as polyurethane, fibre glass, -Teflon or any material suitable for this purpose.

The blocks will be made of a rigid construction, and will be oil, chemical, and heat, resistant, and of a manageable weight.

There are numerous reasons for creating a funnel on the bottom of mud tanks. For example a funnel will completely empty the tanks of all drilling fluid. The tanks can be rapidly cleaned without the need for personnel entering them. And all existing tank cleaning machines that are on the market will become fully effective, as most of them were ineffective on flat bottom tanks.

Drilling mud is the fluid that is used to drill a well, the fluid can be either a water based fluid, or it can be an oil based fluid, the fluid is used to cool the drilling bit, create a wall cake to support the well, and to carry cuttings up to the surface and over shaker screens where the fluid is separated from the cuttings, this is its primary use.

The mud is pumped around the well in a closed loop system, starting from the mud tanks, the mud is pumped to the bottom of the well, and back up into the mud tanks, This is where the problems start, most of the mud tanks on semi submersible, jack ups, and drilling platforms, have flat bottoms.

Drilling mud can be stored in these tanks for months depending on the well geology, and depth.

The mud is weighted with powdered rock called barites, the barites is supported in the mud with viscous materials.

Over a period of time drilled solids, and barites fall out of suspension and settle on the bottom of the tanks, where it can build up to a couple of feet.

When a well has been completed the drilling mud is offloaded from the mud tanks to a supply ship, then tank cleaning begins. An average tank bottom measurement is around (14ff) by (loft).

As a result of the tanks having flat bottoms it is extremely difficult and time consuming jetting a build up of solids with water, along the floor of the tanks into a suction point.

This has been an ongoing problem for a long time, although a few drilling operators had the foresight to have a slope built into their mud tanks during the rigs construction faze. All were built with a single slope in them; this single slope created another problem as it formed a ditch on the tank floor, along the length of the slope.

Solids are easily moved from the surface of a slopped tank floor with a jetting lance, but it is extremely difficult removing solids from along the ditch.

Funnelling the floor of the mud pits will address all of the existing problems associated with flat bottom tanks.

Problems with flat bottom tanks, Oil operators, and drilling contractors, are looking for a non entry tank cleaning system. This is still not available.

Personnel will always have to enter tanks with flat bottoms to clean them out.

Large volumes of drilling fluid remain on the floor of flat bottom tanks when drilling fluid is pumped back to the supply ship at the end of a well.

Present day tank cleaning machines are ineffective in mud tanks with flat bottoms.

The invention will now be described solely by way of example and with reference to the accompanying drawings.

Figure 1 shows a flat bottomed mud tank, with man way hatch, and a suction sump.

Figure 2 shows a mud tank with a sloping bottom, a ditch, and man way hatch.

Figure 3 shows a mud tank with a taper block funnelled floor, man way hatch, suction pump.

Figure 4 shows a mud tank with a tapered block funnelled floor, and pre cast tapered plastic blocks, numbered for assembly.

Figure 5 shows installed block funnelled floor.

Figure 1 shows a flat bottomed mud tank 3 where the solids accumulate, 2 is the suction sump, solids are jetted along the flat floor into the sump, us the man way hatch.

Figure 2 shows a mud tank with a single slope 3 and cutaway 5 with a ditch 2 and a suction sump 4, the suction sump is located in the centre of the tank, the tank is jetted from the man way hatch 1, as can be seen from the drawing it is extremely difficult, and time consuming, cleaning tanks of this design without entering them.

Figure 3 shows a block funnelled mud tank floor 2 tapering towards a suction sump 3.

A suction pump 4 is positioned on top of the tank and is connected to 5 a suction pipe, and a discharge pipe 6.

Figure 4 shows a stack of numbered blocks I prior to installing, and 2 the installed numbered blocks.

Claims

Claims 1. Funnelling the bottom of drilling mud tanks without structural alterations. A funnel can be created on the tank floor using blocks of plastic, or any suitable oil resistant material. The funnelled deck can be installed on location.
2. The funnelled deck can be installed in a couple of days without delays in the day to day drilling operations.
3. The alternative to the blocked funnel deck, would require major structural alterations to be carried out over a couple of months, and lost operating revenue.
4. Will eliminate the requirement for personnel to enter the tanks for cleaning.
5. Will eliminate dead volume, this is a volume of drilling fluid that is left in all flat bottom tanks.
6. Will dramatically reduce lank cleaning times
7. Will reduce the number of personnel required for tank cleaning
8. Funnelling the tank floor will not create a ditch, as all angles are tapered to a single point on the floor, unlike a tank with a single sloop along one side of a tank creating a ditch, and the problems this causes.