The oil and gas industry is facing notable challenges in 2016. Overproduction has driven oil prices down, renewable and green energies are on the rise and new exploration rules are limiting where oil producers can drill. To combat these challenges, producers are innovating drilling, extraction and production techniques with the goal of improving efficiency and minimizing costs. The following three techniques ensure optimum well productivity and are experiencing heavy adoption by oil producing countries around the world.
Enhanced Oil Recovery
Enhanced oil recovery (EOR) is a combination of techniques used to increase the amount of crude oil extracted from an oil field. Also known as tertiary recovery, EOR can increase well productivity by 75% and is usually employed in fields with low permeability or heavy oil. As EOR is expensive, it will only be approved for a field following heavy evaluation. Enhanced oil recovery utilizes one of three primary techniques:
- Thermal recovery, also known as steam injection, uses steam to thin oil and improve flowing ability. Steam is applied to a reservoir multiple times, reducing viscosity and surface tension and increasing oil permeability. Thermal recovery has been in use since the 1960s and now accounts for over half of all EOR projects in the United States.
- Chemical injection involves injecting polymers into a reservoir to reduce surface tension and improve flowing ability. Other chemicals such as alkaline or caustic solutions can be used. The chemicals used in this process can be very costly and may adsorb onto the rock within the reservoir. As a result, less than 1% of all EOR projects in the U.S. feature chemical injection.
- Gas injection, also known as miscible flooding, is the most commonly used form of EOR and involves injecting natural gas, carbon dioxide or nitrogen into the reservoir. The gas either expands throughout the reservoir, pushing oil out, or dissolves and mixes with the oil resulting in improved flowing ability and reduced viscosity.
The majority of wells drilled for oil are vertical wells i.e. drilled straight down. However, this is not always the optimum method for extracting oil and drilling at other angles can often result in greater well productivity. Directional drilling has been in use since the 1920s, and while the technology has improved it still retains the same concept of drilling in multiple angles to gain better access to oil reserves, enabling greater well production. Directional drilling benefits include:
- Access to targets unreachable by vertical drilling, such as those under residential areas or parks.
- Increase well production using a single drilling pad, reducing the surface footprint of the drilling operation.
- Increase well production from a single target by accessing a greater area of the reservoir.
- Increase well production from a fractured reservoir by accessing the maximum number of fractures.
- Can be used to relieve pressure or seal wells which have become out-of-control.
- Suitable for installing underground utilities, such as gas and electric lines, where excavation is not possible.
Hydraulic Fracturing and Acidizing
Tight oil is the name given to oil reservoirs located in extremely impermeable rock formations. While conventional rock formations can be drilled with relative ease, tight oil formations require secondary production methods such as hydraulic fracturing and acidizing to access the oil.
- Hydraulic fracturing, commonly known as fracking, involves breaking tight oil rock formations through use of high-pressure fracking fluids. The pressurized fluid is injected into a well, creating cracks in the rock formation and resulting in a greater flow ability. Fracking is a highly controversial method for oil extraction due to the potential impact it can have on the local and global environment. Opponents of fracking suggest hazards including ground and surface water contamination, noise and air pollution and the triggering of earthquakes can all be caused by hydraulic fracturing.
- Acidizing involves pumping acid into a well to improve rock permeability. Matrix acidizing improves permeability by dissolving sediment within rock formations, enlarging pores and increasing flow ability. Fracture acidizing utilizes the same method as hydraulic fracturing, but with a highly pressurized acid instead of fracking fluids. This method dissolves sediment and enlarges pores while also physically fracturing the rock formation.
Although some of the above techniques have been in use for close to 100 years, advances in drilling technology have improved the capabilities and the cost-effectiveness of these methods. As an increasing number of oil producers look for ways to minimize costs and maximize profit, innovating existing techniques takes a central role in oil operations. The global oil and gas industry no longer has the same stake in the world’s energy supply it once had, and must evolve if it wishes to maintain its place as a leading global energy supplier.
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