Reko Diq's discovery was big news by itself, some $500 Billion worth. An oil discovery like this would be phenomenal if your estimates are correct. I wouldn't be surprised if Chinese were involved and showing interest not only in CPEC but surveying Arabian sea from Coast of Karachi up to Oman Basin. Any European or Russian involvement would bring more competition though. To summarize the whole concept of Oil Drilling, the process and devices used are outlined below:
1. A Gravity meter, to find subtle gravitational fluctuations that might indicate a subterranean flow of oil. Its best to check for other resources also, like natural Gas so usage of Sniffer equipment (any type) to detect traces of natural gas in seawater.
2. Magnetic survey equipment, to scan for any magnetic anomalies that could form underground traps, since certain rocks affect the Earth's normal magnetic field.
3. "Sparking" method can also be used for this purpose; ending shock waves down through the water and into the ocean floor which can reach to a change in rock layers, and bounce back up showing possible traps.
4. A mobile drilling platform can perform exploratory drilling which could be ship-based or towed on a different vessel. Usually the drilling is done for a "core sample", for this purpose four exploratory wells are drilled where possibility of deposits are detected. This process could take 2-3 months to obtain a core sample.
5. When the signs of petroleum show up, its called a "show". When a show has been reached, the drilling stops to carry out more tests to check the quality and quantity of oil.
6. Once satisfied with findings, the next stage is drilling of a "Production Well". This could be straight drilling vertically downwards or at an angle, called Directional Drilling. The well should last for up to 20 years. For reliability of oil drilling, platforms are fixed directly to the ocean floor using either metal and concrete foundations or tethering cables. There could be multiple wells (50+) under one platform. If wells run dry, the platforms can become a relay or hub for new or other platforms nearby.
7. A little bit about "Template". Template is a steel frame with slots for each well and supporting legs. It is lowered down and anchored to the sea floor. A template is used in order to easily tie in production from several wells. A "Sub-sea drilling Template" ensures accurate drilling as it connects the drill site to the platform. It resembles a large metal box with holes in it to mark the site of each production well.
8. A "Drill String" is composed of multiple drill pipes screwed together as wells often have to sink deep down into the Earth's crust. A turntable on the platform rotates the drill string and, at the other end, a drill bit grinds through the Earth. A "Marine Riser" is flexible tube used to descend equipment between the platform and the ocean floor. The equipment is generally drill bit, which is used to grind through the Earth and may need replacements.
9. "Drilling mud" constitutes thick, viscous fluid consists of clay, water, Barite and a mixture of special chemicals used to lubricates the drill bit, seal the wall of the well and control pressure inside the well. Also, as the drill bit shreds rock, the resulting fragments become suspended in the mud and leave the well in the rising, return flow. On the surface, a circulation system filters the mud before sending it back down the well. Drilling mud acts as the first line of defense against high subterranean pressures.
10. A blowout prevention system (BOP) seals the well with hydraulic valves and rams and reroutes the surging well fluids into specially designed containment systems as there is a a high risk of a blowout of fluid from the well.
11. The process of Drilling is as follows:
The initial surface hole, descends from several hundred to several thousand feet. Drill string is removed and send down hollow segments of metal pipe called "Casing". When its cemented into place, this conductor pipe barrier lines the hole and prevents leaks and caving. Then a drill bit digs the well even deeper. A Drill bit bores the rest of the way to the petroleum deposit. This final stretch is called the "bottom hole", and is lined with intermediate casing. Throughout this process, a device called a "Packer" travels down the well, expanding against the walls to ensure everything is sealed.
12. Once the drill hits petroleum, a final bit of casing called a "Production Casing" goes down to the bottom of the shaft. This section of casing terminates in a solid cap, closing the well off from the surrounding petroleum reservoir. This allows the oil and gas to reach the surface under less pressure, and not like a blasting geyser.
13. Rising up to the platform is a mixture of crude oil, natural gas, water and sediments. Most oil refinement takes place onshore, but oil companies sometimes use converted tanker ships to treat and store oil at sea.
14. Natural gas is of two types: wet and dry. Wet natural gas contains various vaporized liquids, and these have to be filtered out before it can be transported elsewhere. Dry natural gas, on the other hand, is free of these pollutants. At this point, undersea pipelines and oil tankers transport the separated oil and natural gas to onshore storage and treatment plants.
15. Drilling Platforms
(MOBILE):
Drilling Barge: Mostly used for shallow drilling in non-ocean waters.Tugboats tow the platform out to the site, where anchors hold it in place. However, given that drilling barges basically just float on the surface, they're only suitable for calm waters.
Jack-up: This rig resembles a drilling barge, when this platform reaches the drilling site, it can lower three or four massive legs into the water until they touch the bottom. At this point, the legs lift the platform out of the water. This provides a much more stable environment from which to drill, as the legs stabilize the platform against winds and lift it above pitching waves. The design has its limits, however, as deeper waters require impractically large legs.
Submersible Rig: This drilling platform combines some of the properties of drilling barges and jack-ups. Only in this case, the production facilities are elevated on stilts hundreds of feet above pontoon like barges. After reaching the drill site, the crew floods the barges with water. The barges sink until they rest on the sea or lake floor, while the platform remains elevated above the water on stilts. In effect, the crew sinks the rig into order to anchor it. When the time comes for the rig to relocate, the crew pumps the water back out of the barges, causing them to float back up to the surface and push the stilted platform back up into the air. Like the jack-up, this platform is limited to shallow waters.
Semi-Submersible Rig: This platform is much like a submersible rig, except it's designed to work in much deeper waters. Instead of sinking until its lower hull rests on the seafloor (which, in deeper waters, would drown everyone), it simply lets enough water in to lower it to appropriate operating heights. The weight of the lower hull simply stabilizes the drilling platform, while massive anchors hold it in place.
Drill ships: This is essentially an oceangoing vessel with, a drilling platform in the middle. The drill string extends down to the ocean floor through a moon hole. Drill ships operate in very deep water and often have to ride out rough sea conditions. They use dynamic positioning equipment to keep aligned with the drill site. This equipment uses satellite information and sensors on the sub-sea drilling template to keep track of the drilling location. Using this data, electric motors on the underside of the hull constantly move the ship to keep it lined up with the well.
16. Drilling Platforms
(FIXED):
Fixed platform: These platforms are extremely stable, despite the fact that the concrete base isn't even attached to the seafloor. It simply stays in place due to all the weight above it. However, at depths greater than 1,500 feet, the design begins to become more impractical due to material costs.
Compliant tower: These rigs take the basic idea of the fixed platform and make it viable to operate in depths of 1,500 feet to 3,000 feet (457 meters to 914 meters). The design achieves this by relying on a narrower tower of steel and concrete. But while fixed platform designs are rigid, compliant towers are designed to sway and move with the stresses of wind and sea and hurricanes.
Sea Star platform: The Sea Star platform is basically a larger version of the semi-submersible design. The production facilities sit atop a large submersible hull on a tower. When the lower hull fills with water, it sinks to a lower depth, providing stability while keeping the facilities high and dry. The Sea Star is connected to the ocean floor by tension legs.
Floating production system: These platforms can take the form of either floating semi-submersible platforms or drill ships. The basic idea behind their design is that, once the well has been drilled, much of the production equipment can be mounted on the seafloor and the petroleum pumped to the surface facilities through flexible risers. Meanwhile, the platform or ship stays in position with anchors or a dynamic positioning system. This approach allows oil companies to reach depths of up to 6,000 feet (1,829 meters).
Tension leg platform: This platform is bigger sized version of the Sea Star platform, except the tension legs extend from the ocean floor to the platform itself. It experiences more horizontal motion and a certain degree of vertical motion, but it allows oil companies to drill at depths of up to 7,000 feet (2,134 meters), well over a mile (1.6 kilometers) beneath the waves.
Sub-sea system: This approach takes the idea of mounting the wellhead on the sea floor and applies it to even greater depths -- 7,000 feet (2,1334 meters) or more. Once the well has been drilled by a surface platform, the automated systems transfer the oil and natural gas to production facilities by either risers or undersea pipelines.
Spar platform: Capable to drill a hole at a depth of 10,000 feet (3,048 meters). With this design, the drilling platform sits atop a giant, hollow cylindrical hull. The other end of the cylinder descends around 700 feet (213 meters) into the ocean depths. While the cylinder stops far above the ocean floor, its weight stabilizes the platform. A network of taunt cables and lines trail out from the cylinder to secure it to the ocean floor in what is called a lateral catenary system. The drill string descends down through the length of the cylinder's interior and down to the ocean floor.
Following are the figures of oil reserves in terms of millions of barrels for top 20 countries.
Country Reserves (millions of barrels), 2017 US EIA
1. Venezuela = 300,878
2. Saudi Arabia = 266,455
3. Canada = 169,709
4. Iran = 158,400
5. Iraq = 142,503
6. Kuwait = 101,500
7. United Arab Emirates = 97,800
8. Russia = 80,000
9. Libya = 48,363
10. United States = 39,230
11. Nigeria = 37,062
12. Kazakhstan = 30,000
13. China = 25,620
14. Qatar = 25,244
15. Brazil = 12,999
16. Algeria =12,200
17. Angola = 8,273
18. Ecuador = 8,273
19. Mexico = 7,640
20. Azerbaijan = 7,000
