The invention concerns a bottle for liquid/gas especially suited for transportation of samples.

By oil and gas production automatic samplers are sent dovm to the well for collection of samples. The samples are trans¬ ferred to transportation bottles which are sent to the laboratory for analysis. Samples from oil/gas-separators are also transferred to transportation bottles for transportation to the laboratory. Some samples are stored for many years, and these are ment to be stored in the transportation bottles under a fixed pressure.

It is very important that the bottles are clean, sterile and free of air to get representative samples. Previously several different procedures were used to get rid of the air. The most commom process is first to evacuate the bottles and then fill them up with mercury. By filling in oil/gas the mercury will be replaced, and an extra bottle for collection of this is necessary. Mercury is poisonous, and prohibition of use of this has already come in some countries. It is expected that use of this also can be forbidden in several other countries. Bottles filled with mercury are also very heavy to handle. The mercury also represents an investment.

Another method is just to evacuate the bottles by use of a vacuum pump. By this method one cannot be sure that all air is removed from the bottle. Water has also been used to replace air in the bottles. By use of water a strange element

is added to the sample. It is therefore an advantage to use water from the well where the sample was collected. This seems very bothersome.

It is also known a method where oil and gas are blown through the bottle until all air is removed and a representative sample is obtained. This is a bothersome and risky method, and it is for example not suited when a limited sample should be transferred.

The object of the invention thus is to develop a tran¬ sportation bottle which does not add strange elements to the samples and at the same time replaces the air in an easy way. It is further important to get a bottle which makes possible a quick and secure sampling of representative samples. The equipment must be safe and easy to use for those who shall handle the bottle.

These and other objects of the invention are obtained with the apparatus described below, and the invention is further defined and characterized in the following claims.

As the main features the transportation bottle consists of a body with two hemispherical inner faces fixed to each other with a hemispherical membrane with flange fixed between the two parts of the sphere. The transporation bottle can even¬ tually have an inner lining. Before transference of the samples to the transportation bottle the membrane is lying tightly to the one of the inner hemispherical parts. The bottle is equipped with a valve in each end. By filling of the bottle the valve leading to a counter pressure medium first is opened, and for example water pours in and fills the bottle from the side with no membrane. The bottle is filled with water until a pressure large enough to ensure that the membrane is forced against the inner wall of the bottle. The valve on the water side is closed. The bottle is then fixed

for example to an oil/gas separator, and the valve on the side leading to oil/gas is opened. This will not involve any reaction to the membrane because the pressure on the water side will resist the oil/gas pressure. First when the valve on the water side is opened, the water will be forced out, and the sample will fill the bottle as the membrane reverses round a weakened point until it is dragging on to the opposite inner wall of the bottle. When this has happened, the bottle is filled with oil/gas. Both valves will then be closed.

Other features of the invention is described more in detail below and is also shown in the figures 1-3.

Figure 1 shows a principle sketch of the sample bottle.

Figure 2 shows a sample bottle with inner lining.

Figure 3 shows inner lining with membrane and end pieces.

The bottle 1 shown in figure 1 consists of two hemispherical parts 2, 3 which can be fixed to each other. In figure 1 the two half parts of the bottle are equipped with a flange 4 where the membrane 5 also functions as a packing 14. How the two parts of the bottle are fixed to each other is not essential if it is obtained a tight connection. The broken line 5* shows the membrane in reversed position. The bottle is equipped with end pieces 6 with throughgoing holes 13 and valves 7 in each half part. The membrane can be made of different materials. For less flexible materials as for example metals, it is important on account of the reversion to have a weakened point on the membrane which is more flexible. This will function as a starting point for the reversion and effect that the membrane is uniformly reversed.

With more flexible materials such as for example rubber, this will not be necessary. The choice of the materials in the bottle must be adapted to the samples it shall be used for.

Figure 2 shows an especially preferred design of the bottle. Here the bottler consists of a body with an inner spherical face. This design is screw threaded 8 for screwing together the two halves 2, 3 of the bottle. The bottle is equipped with an inner metal lining 9. In this case the lining forms the packing and the outer bottle take up the pressure forces. The materials in the outer bottle 2, 3 have high solidity. The test pressure is 1500 bar, and the working pressure is 700-abar. It is preferably used acid proof steel in the lining and it has a thickness in the order of 1 mm. The membrane 5 whicn also can be made of the same material, is firmly welded between the two halves of the lining. Both the metal lining and the membrane is equipped with a small flange 10, 14 in which they are welded together with the flange of the mem¬ brane 14 between the flanges of the two halves of the lining. This also works as a packing between the two halves of the bottle 2, 3. The membrane has a thickness in the order of 0,4 mm. It has also been tried membranes made of aluminium with great success. It is important that the membrane is quite even and smooth to ensure a uniform reversion. For tϊis object the membrane also has a weakened point which will cause that it easier will begin to reverse uniformly under influence of pressure. In the figure the membrane is shown with a plane part 11 which forms the weakened field. The shown design of the bottle in figures 2 and 3 has end pieces 6 with throghgoing holes 13 which are welded to the inner metal lining 9 for fastening of valves. The end pieces and the lining makes a replaceable unit. ^' After production of the inner lining, it is tested with helium for control of the tightness. When all parts of the bottler are assembled the test with helium is again performed for control of valves/end pieces. Finally, pressure test is performed. In figures 2 and

3 the end pieces are shown with a plane region 12 at that end which come into contact with the membrane for better to take up the pressure from the membrane. Lining with end pieces and membrane as shown in figure 2, is meant to be used once. It has, however, been shown by experiments that the membrane can be reversed backwards and forwards several times without any indications of leakage.

The volume of the shown bottle is about 0,7 1, but it can be made in several sizes as required.

Before the bottle shall be filled with for example oil/βas-samples either from a separator or from a sampler, it must be emptied for air. The bottle 1 is assembled with the membrane dragging onto the lining 9 in the one half of the bottle in such a way that the membrane drags on the inner face of the end piece. The valve 7 at the opposite side is opened for a counter pressure medium which as as example can be water. Other fluids can also be used. The bottle is filled with water of known origin until a pressure large enough to ensure that the membrane is pressed against the inner wall of the container. (This can be controlled by help of X-ray). The valve leading to water is then closed. The bottle is then fixed to the place for taking samples, and the valve leading to oil/gas will be opened. It is preferably used displacement bodies in the hole 13 in the end piece on the oil/gas side to ensure a little volume of air in the end pieces as possible. The bottle is now completely filled with water, and the pressure of the water will resist the pressure of the oil/gas. First hen the valve leading to water is opened, the membrane begins to reverse as the water is pressed out, and oil/gas pours in. The water drained off will at any time give an indication of how much of the sample which is filled into the bottle. It is very important that the membrane has a uni¬ form thickness and is equipped with a weakened field which will cause a start of the reversion and also a uniform

reversion. With a thickness of the membrane of 0,4 mm, and in this case a diameter of 110 mm, the pressure necessary to obtain reversion is about 0,3 bar. The bottle is filled with oil/gas, and the valve is closed. The sample is now ready for transportation to the laboratory for analysis. Next time the bottle will be used, it will be equipped with a new inner lining with end pieces and membrane which in advance is tested for tightness (tested with helium), filled with water and pressure tested.

In the figures there are shown transporation bottles which are spherical or have an inner spherical face. These are designs which are especially preferred for high pressures. The principle, however, is also usable with lower pressures and other types of samples. Then other designs of the bottle can be actual, for example ^' an elliptical design. If for example a rubber membrane is used one is more free to choose the design of the bottle.

By this invention one has achieved a bottle of a construction which makes possible a rapid and secure transference of clean samples and where the bottle also is especially suited for transportation of the sample to the laboratory for analysis. The bottle is not only suited for sampling of oil/gas samples, but is also generally useful for sampling of other fluids where clean samples is important.