The Oil Field : From Down Hole to the Tank of Your Car
This post is to give some depth to anyone wishing to understand the jobs that the oil field engineer /operator may be involved with at some stage during their career. At the time of this post the maximum depths reached by a drill from which oil and gas may be produced is Deepwater Horizon 35050 ft. and Sakolin-1 40,501 ft. This is to be compared with the maximum known depth of the ocean floor of 36,201 ft,
This post has a thread which starts some 35000 ft below ground and ends as the fuel pours from the filling hose into the tank of your car. The length of the thread needs the support of thousands of operators and engineers belonging to the major oil companies and the support companies. If you are not sure of where to start looking for a job in the Oil and Gas Industry then start at the beginning of the thread and interrogate the internet at each step along the thread:-
A specialist job but the operator or engineer must have some understanding of this activity. It is the act of determining where underground pockets of oil reside deep underground.
When a pocket of oil is determined it is required to determine its pressure and extent. At the centre of a well pad is a concrete box set into the ground into which the Well head will eventualy be placed to evaluate the oil pocket and to flow the pocket, if viable
The rig is the term that is applied to the very significant device that supports the equipment that will drill through the earth and rock below the well cellar
Lay down Area
The lay down area is where all the drilling pipe and equipment is laid down ready to commence the drilling procedure
Drilling is the act of placing a boring tool on the first section of drill pipe. The lifting of the drill pipe onto the drilling table and engaging the kelly ( a device that grips the pipe) and the rotation of the drill into the earth and rock under power. As the drill penetrates the ground further pipe is used to extend the working length of the drill string
When the length of drill string is of length to reach the underground pocket of oil and the drilled hole is lined with steel pipe and cemented into place an arrangement of valves is bolted to the top “conductor pipe”, The wellhead allows various operations to be carried out to promote the flow of oil/gas from the pocket of oil to the surface
The Wireline equipment is a drum of wire onto which, at the free end, is secured specialist tools. These tools used are various but the initial tools carry explosive that are exploded deep down in the well to “perforate” the steel pipe, the wall of which is between the oil and gas under tremendous pressure and the internal of the pipe which has been purposefully filled with a specialist “Mud”.
When the drilling team has perforated the pipe it is the weight of the mud that is restraining the oil from being forced to the surface under its own pressure. At this time, the crew are under their own pressure to make the “first oil” target time. Pipe spools, that have been fabricated to connect the Wellhead to the flow lines ( installed by others to a distant collection point) are installed and the valves restraining the pressure are opened up allowing the Mud to be displaced by the oil from the pocket below ground
The cellar is the void part of the Wellpad (Concrete box) into which the Well head valve assembly sits. Safety valves are accessed by entry to the cellar,
During operation, should problems occur, at the wellhead or to any part of the piping and the emergency shutdown valves installed within the pipe diameter, then the drilling rig or Wireline rig may have to return. This operation is termed a workover
Flow lines are installed from the wellhead to a manifold at which point there may be flows from many flow lines to be transported. The flow lines are made from carbon steel and are generally 4″ or 6″ diameter. They are considered a consumable as little maintenance is done to protect them
A platform is a fabricated steel surface upon which different operations of the gas gathering, treating and onward transportation takes place.
The term “Jacket”, as used in the offshore oil industry, refers to the fabricated structure upon which the Platform rests and to which the platform is secured. The design of the jacket is made to considered shallow water depths and deep water depths. Accordingly, for shallow depths, the jacket will be designed with large diameter steel legs which extend down to the sea bed. At the sea bed, the legs are secured with a number of piles into the sea bed. Other designs of jackets for deep water may be a design using steel cables to secure the jacket to the sea bed and for very deep water designs the use of GPS to control a number of very high powered motors driving large propellers to keep a floating platform “on station” are used.
The facilities on a platform will depend on the platform’s location in a network of platforms. There are a number of processes required on a platform to (a) ensure the oil flow to the platform, (b) to remove the water content from the produced oil and, as the pressure drops along the flow line route, associated gas in the oil separates from the oil and this associated gas in many cases needs to be handled in a dedicated transportation pipe line. These activities need a number of drums, separating devices and chemical systems (loosely termed “pots and pans” in the industry)
A launcher is a device which allows the insertion of a multi purpose device into the transportation pipeline which carries the oil or gas to the next facility. This multi- purpose device is mainly used to sweep the transportation lines of any “materials” that drop out of the main flow of oil or gas. In the oil transportation line water will drop out of the main flow as well as sand etc and in the gas transportation lines a petroleum condensate will drop out of the main flow. This separation can lead to the pipeline flow being chocked and this is the purpose of the sweeping to prevent throttling of the main flow. Another purpose of the device is to monitor for any corrosion or thining of the pipeline walls, leading to loss of containment
Under sea Transportation Lines
The main production of Oil and Gas can be through one pipeline or two dedicated pipelines, one for oil and one for gas. The criteria for designing one or two is dependent on flows and the overall network of facilities. The Transportation Lines can vary in size from 8″ upwards and as the line is joined by other lines the ongoing size will be increased to very significant diameters eg 16″ > 24″ > 36″ > 48″
A receiver is the device which is required to complement the Launcher. One device is used to install the sweeping/ monitoring device, the other is to remove the sweeping/ monitoring device from the pipeline. Clearly, each diameter of pipeline will have its own pair of sweeping/ monitoring insertion and extraction devices. Note that accessing the receivers has to be done with exteme caution as hazardous materials (pyrophoric iron sulfide) can be swept into the receivers. When entering the receiver the debris must be kept wet at all times and it should be understood that hydrogen can be released from the debris if the debris is allowed to dry
The term “gathering stations” is used when a number of major producing pipe lines are brought to one point. Major storage facilities are generally incorporated at gathering stations and the process of conditioning the produced gas and oil may be done at Gathering stations
Refinery plant, LNG plant
As stated previously, there could be production from a number of wells which may be separated into streams of Oil and Gas. The oil is routed to a Refinery and the gas is routed to a Liquid Natural Gas (LNG) facility. These two processes are at the extreme ends of the range of temperatures, the LNG process being very cold and the refinery process being very hot.
Crude Oil can be routed to a producing countries coast line were it can be treated before it is shipped to a destination country or it can be treated (refined) in the producing country. LNG can be routed to a countries coast line were it is normally treated and reduced in volume by lowering its temperature to -200 degrees centigrade. Both the mass storage of oil and gas is achieved by having massive storage tanks fabricated to store the product. These tanks are situated adjacent to a Marine Terminal were Oil and Gas Tankers berth to be loaded with oil and gas for exportation
Over many years the capacity of oil and gas marine tankers has risen dramatically, of course, such increases in size are generally accompanied by a slide in the oil price which results in marine tankers being mothballed and placed in storage. The biggest size of marine tanker designed and constructed was Seawise Giant a ULCC supertanker and the longest ship ever built. It possessed the greatest deadweight tonnage ever recorded. Fully loaded, its displacement was 657,019 tonnes (646,642 long tons; 724,239 short tons), the heaviest ship of any kind, and with a laden draft of 24.6 m (81 ft), it was incapable of navigating the English Channel, the Suez Canal or the Panama Canal. Overall, it was generally considered the largest ship ever built.
With larger ships having deeper drafts, mooring the tanker near to an on/off loading facility required a new approach, The company Single Bouy Mooring was founded and, known as SBM, became a leader in the production of offshore floating connection points at which tankers could connect flexible hoses to/from and either load or off load crude or refined products.
Cross Country Strategic Pipelines
A network of major pipelines has been developed across many countries to ensure the availability and flexibility of fuel supplies. The UK has a major network of linked pipelines that can transport oil from various points on the South Coast to various points in the Midlands and the North or England
Distribution Centres and Road Tankers
All the countries of the World need a supply of oil and gas for their power requirements. Oil and gas may be imported as a refined product or may be imported as a crude product. Either way, a refined product is needed to be distributed to the network of Consumer Petrol Stations and this is done by fleets of Road Tankers. It is not widely understood but all the major Oil Companies share their products and facilities under various deals made between the companies. Accordingly, all the propaganda about the pros and cons of Fuel A vis Fuel B across the advertising media and how many more miles per gallon Fuel A achieves over Fuel B, over the bar at the local pub, is not understanding that , for example, a Shell badged tanker can stand under the same loading hoses as a Texaco badged Tanker which is standing under the same loading hoses as a British Petroleum Badged Tanker. The same fuel is loaded into each tanker belonging to different companies and the only difference in the fuel, as the tankers role out the gate, is a small injection of Redex or similar and /or colouring , which is made a big point of when the advertising people use their charm
Consumer Petrol Stations
Drivers need to have points at which they can take fuel into their cars petrol tank. Most are aware of these fuel purchasing outlets where petroleum and/or diesel fuel can be obtained.
Diesel of Petrol. Make the correct choice
The reader will probably know of this already but it is very easy to be distracted and to start to fill you car, or a hire car, with Petrol when the correct fuel for the engine is diesel. (or Diesel instead of Petrol) . It may not be realised at first but on starting the engine it is clear all is not right as the noise from the engine is “unusual”. At that time it may be realised that a mistake has been made. If so , get the AA or RAC or Green Flag to the car so they can organise the draining of the incorrect fuel. If of course it is not realised that a mistake has been made and the car is continued to be driven the owner can expect a large bill to repair the car before to long