Northern Lights over Sakhalin shelf
September 27, 2013
Gazprom has a unique experience of operations on the Russian continental shelf. Today we would like to acquaint you with a complicated process of marine drilling. During the 2013 navigation period Gazprom is drilling two exploratory wells at the Yuzhno-Kirinskoye field offshore the Sea of Okhotsk (Sakhalin III project). We visited the Severnoye Siyaniye (Northern Lights) semi-submersible drilling rig (SSDR) – one of the several rigs constructed over the last years on Gazprom’s order at Vyborg Shipyard.
We got to the site in the same way, as do the shift workers who work there. Our journey started from the port of Korsakov not far from Yuzhno-Sakhalinsk.
Before getting onboard the Fos Universe ship of a Panamian company we had to go through customs and border control as well as all the procedures required for crossing the state border, as the operations area we were heading for was located outside the Russian territorial waters.
The crew was mostly Indonesian. All of them were very friendly and we had no difficulties communicating even in our broken English.
We were to ride this ship for a bit more than a day, as the way from the port of Korsakov to the Yuzhno-Kirinskoye field is long, namely 824 kilometers or 445 nautical miles.
At first, it all seemed to be a fascinating sea cruise. Photo: press tour participants.
But it turned out to be nothing of the kind… After departing the Aniva Bay and entering the Sea of Okhotsk the ship started rocking back and forth.
Most of us preferred to endure those not too pleasant feelings in such cabins.
And somebody was watching movies in the local cinema hall.
A special mood was set by our seacook Yury Stakhov who appeared to be an artist by trade. He found himself on the vessel seduced by the romance of the sea.
Yury cooked the most delicious dishes for us. He was invited specially for the Russian shift workers whose stomachs are not used to Asian cuisine. Unfortunately, we didn’t want to eat that much due to the ship motions.
The storm (which, in fact, can hardly be called a storm in terms of the Sea of Okhotsk) was rated by the local seadogs at about force 3. For the moody Sea of Okhotsk force 8 storms are not uncommon, and sometimes there are even force 10 storms. However, Severnoye Siyaniye is designed to operate in harsh climatic conditions, and that is why it doesn’t stop its operation even when the sea is very high.
And finally this immense facility appeared on the horizon like a mirage.
The platform arrived at the drilling site from the port of Kholmsk (Sakhalin Region) with the help of two tugs. As the floating rig is power-propelled, it can also move by itself. It takes from 2 to 4 days to install such an SSDR depending on the conditions, and the process is very painstaking.
During this process the platform is towed into position by two steamships. Specialists accurately locate the positioning point by satellite according to the preset coordinates that are determined as part of a survey procedure.
Before the SSDR is installed, the seabed is investigated by remotely operated vehicles (ROV), or robots in other words, in order to exclude the presence of scrap metal, shipwrecks, boulders and gravels that could appear in the time period between the survey procedure and the rig installation.
These robots are engaged in the drilling process, too. They are also used for continuously monitoring the wellhead condition.
With the help of the tugs the SSDR is positioned in relation to cardinal points based on the results of meteorological studies and is fixed by 8 anchors weighing 15 tons each – two anchors for each of the platform angles.
The platform also acts as a mini-port serving up to 3–4 vessels a day. Ships do not moor at the platform – they need to have the system of dynamic positioning.
By the way, before our arrival one of the vessels couldn’t unload because of the high sea and had to float nearby for several hours waiting for the sea to calm.
We had to ascend from the ship to the platform almost as big as a football field and as high as a 43-storey house (the platform height from the lower part of the pontoon to the top of the derrick is 128 meters) in a six-seat basket.
In the local slang it is called a ‘frog’. It was a bit scary – after all, it is not a ride in an amusement park where such baskets are securely fixed.
A lifting crane picked up the basket, raised it high in the air…
…and delicately put it down in the center of a helideck where we were heartily welcomed by the crew.
The Severnoye Siyaniye SSDR is capable of constructing exploratory and production wells in the temperature range between −30 to +45 °C. It can drill wells up to 7,500 meters deep at sea depths from 70 to 500 meters. Currently, Severnoye Siyaniye is drilling its first exploratory well 3,200 meters deep.
The aim of drilling is to prove the reserves and update the geological structure of the Yuzhno-Kirinskoye field. The sea depth in this region is about 146 meters.
Severnoye Siyaniye is managed by two men. The SSDR Head Alexander Demchenko (right) manages the crew from the moment of positioning the SSDR at a drilling site till the moment of repositioning. When the drilling rig changes its location, the whole drilling crew goes ashore, and only the runner crew stays. Marine operations start (towing, mooring and weighing, independent relocation) and the SSDR Captain Valery Solomatin (center) takes the lead. On the left of the photo is Sergey Sitnik, Head of the PR and Media Relations Group at Gazflot.
First off is a safety meeting. It was conducted by Second Mate Andrey Burkov.
There are four lifeboats on the SSDR to carry 64 people each. That is to say, there are twice as many places available compared to the permissible number of people on the platform in order to evacuate the personnel from one of the boards if necessary.
In addition, there are 8 inflatable liferafts to carry 35 people each. In case of alarm every crew member has to put on a drysuit and a life vest and before boarding a lifeboat to turn over a tag with its vessel number so that once the crew has boarded the lifeboats, it would be clear who is to be searched for on the platform before the evacuation.
A lifeboat is basically a capsule that can go through fire. Its fuel tank is sufficient for 24 hours of run-time without refueling, and it can move at a speed of 6 knots and tug rafts, too. There are all the things needed in a lifeboat, namely, a survival kit, an emergency kit, a wireless station, etc. Photo: Gazprom’s Press Service representative Dmitry Martynenko.
After the safety meeting we got acquainted with the operating process. The photo shows the master control room or, as sailors call it, the captain’s bridge. On the left is Chief Mate Dmitry Karpov, on the right – Second Mate Andrey Nikolichev.
Deputy Chief Engineer Roman Okishev (Gazprom Geologorazvedka) says that sea soils are not more complex than, for instance, in Western Siberia. The main difficulty is that in the sea one can’t see either a downhole (well bottom), or a well mouth (its top). This problem, as we have already mentioned, is solved by remotely operated vehicles that make it possible to see everything under the sea on the drilling rig monitors.
Different diameter casing pipes are used during well construction (the deeper into the well, the smaller the pipe diameter, as the well design resembles that of a telescope).
A huge crane takes pipes from racks and delivers them to the rig floor. The pipes are made of a very thick metal specially used for deep-well drilling.
At first, a pilot wellbore of the smallest diameter is drilled (215.9 millimeters) about 600 meters deep. It is aimed at proving the presence of near-bottom gas and determining the setting depth of the first casing column.
If the pilot wellbore drilling goes well, drilling starts for 762- or 914-millimeter casing pipes of the first casing column. Then the column is lowered down the hole and is cemented in place, and drilling for a smaller diameter column starts deeper, and so on.
The photo shows the so-called spider, which holds one pipe with one ‘tentacle’ and grabs another one with the second ‘tentacle’ twisting them together. It all takes place during two minutes approximately. In industry slang several twisted drill pipes are called a DP stand. In our presence drilling tools were lowered 1,750 meters deep with the help of DP stands.
6th grade driller assistants Shamil Uvaisov and Sergey Potapov are pulling down the hand-held slips that additionally clamp the pipe in order to fix it in the rotor.
Drilling data is displayed in the driller’s cabin where looking at the monitors he controls the bit (a rock destruction tool) load, the desired drilling speed, etc. The photo shows 8th grade driller Evgeny Tkachenko controlling the exploratory well drilling process.
Drillers control the process with a joystick as if playing a computer game and talking on the two-way. Every day about 200 meters is drilled. Photo: 8th grade drillers Sergey Makarov (front) and Evgeny Tkachenko (back).
In another platform compartment the geological and technical research specialists monitor sensors placed all over the drilling site to control the technological parameters.
Their task is not to miss indicators of abnormal gas blowout. Although during the whole drilling process there is drilling fluid in the well, which creates back pressure in the wellbore. Photo: geological engineer Alexander Khaustov (front) and geophysical engineer Viktor Balaba (back).
During the drilling process much sludge is brought to the surface from the soil together with the drilling fluid which is then desludged through a special vibrating shaker (in the photo).
When desludged, the drilling fluid is once more pumped into the well with the help of the pumps you can see in the photo.
To preserve the fish and mollusk breeding areas and not to muddy the bottom waters all the sludge as well as other waste is taken away in containers to a special onshore disposal base.
Once the well is drilled and geophysical research is conducted, the production column is set and well testing begins. Perforators are lowered into the column to chamber holes in its sides. Then well pressure is reduced, gas inflow is induced and equipment onboard the SSDR records the gas flow rate (volume of gas produced from the well per unit time) and gas parameters. After the end of testing the drilling fluid is pumped into the well and gas is squeezed back into the formation. If there are several potentially productive horizons in the formation, the testing is conducted from bottom upwards.
Photo: Chief Engineer for Shipboard Equipment Yury Chernov and Auxiliary Operator for Boiler Equipment Viktor Grigoryev monitoring the operation of respective SSDR systems.
An offshore well geometry is represented by casing columns run in and cemented consecutively from a bigger diameter to a smaller one. The annular space at the wellhead is sealed with the help of special sealing rings. Photo: Weatherford service company representative checking the hydraulic tongs.
Once the drilling is finished and all the necessary data is obtained, cement plugs are placed in the spots where the perforator worked, drilling fluid is pumped into the well and a corrosion cap is placed on the wellhead. It serves as a safety valve allowing no gas discharge like a cork in a bottle of champagne. In addition, anti-sweep protection is installed on top in case of vessels passing, boulders and stones hitting. Photo: cementing unit.
All the blowout prevention equipment nippled up on the wellhead rises from 1.8 to 2 meters above the sea level. Photo: Andrey Ivlev, Chief Engineer for Subsea Wellhead Equipment at Severnoye Siyaniye SSDR.
Work on the platform is not easy and the workers need to eat well. That is why all sorts of dishes are cooked here with no emphasis on anything particular, as the crew is multinational. Breakfast, lunch and dinner are scheduled, but if anyone gets hungry, he won’t be left without a sandwich and tea. The cooks work around the clock in two shifts. Photo: 5th grade cook Yury Gomenyuk serving lunch at the SSDR galley.
A shift lasts for a month and that is why comfortable conditions are created on the platform. There is a lounge, a gym, a cinema hall, a sauna and, of course, a medical room. Photo: ship’s doctor Evgeny Siver.
Ready to leave the platform, we suddenly saw a smiley face in the engine space where the main diesel-driven power generators are situated. A kind of a farewell boost of energy for us.
And so our tour to Severnoye Siyaniye ended. We are going home, while the drilling rig crew is to finish the construction of the exploratory well at the Yuzhno-Kirinskoye field.
The gas of the Yuzhno-Kirinskoye field, with its current C1+C2 reserves estimated at 563.9 billion cubic meters of gas and 71.7 million tons of gas condensate, is to be delivered to the Far East for gasification purposes as well as to an LNG plant to be constructed near Vladivostok. Photo: gas carrier fueling up with liquefied natural gas (LNG) at the Sakhalin LNG plant.