Effect of earthquake on oil.
Earthquake has caused complete devastation in Venezuela. More than 10 thousand people are estimated to have died. The number may also be higher. Government agencies are busy assessing the damage. It may take a few days to get the correct picture. The devastation is huge. There are a large number of oil wells in Venezuela. It is suspected that damage has occurred here also. There may also be loss of life. Let us understand to what extent oil wells are affected by earthquakes. What is the scientific viewpoint regarding this?
Earthquake is a sudden release of energy inside the ground. This energy reaches the surface in the form of waves. There are two main waves. P-wave and S-wave. Surface waves cause long and far-reaching vibrations on the ground. These vibrations damage the infrastructure. Be it buildings, multi-storey buildings, office complexes or oil wells. Everyone suffers loss.
What are P and S waves?
The energy that comes out from inside the ground during an earthquake travels in the form of waves. Among these, P-wave and S-wave are the most important.
- P-wave: It is called primary wave because it reaches first when an earthquake occurs. This wave works like a spring. In this the particles of the land keep oscillating back and forth. This is the fastest moving wave. It can pass through all three mediums, solid, liquid and gas. In the case of oil wells, it also releases oil and water from within. It is usually felt as a light shock or shock.
Situation after the earthquake in Venezuela.
- S-wave: It is called secondary wave because it reaches second after the P-wave. This wave is like a wave or shaking a rope. In this the soil particles wave up-down or right-left. It is slower than the P-wave. It can pass only through solid medium. It disappears in oil or water. But it is more destructive than the P-wave because it shakes the ground harder, causing more pressure on buildings and oil well pipes.
Well structure and sensitivity
An oil well is usually made up of three major parts. Surface heads and wellheads, steel casing and cementing, underground lugs and production zones. Damage to any part due to earthquake can affect the efficiency and safety of the well. It is possible that Venezuelan oil wells may also have been negatively impacted. Its true meaning will be known only when the security agencies complete their investigation. Right now everyone’s attention is on the visible loss of money and people.
direct effect of seismic waves
The moving waves of an earthquake exert direct force on the well. This force works in two ways. Axial and rotational forces can cause bending or breakage of the casing. Surface vibrations can weaken or even break wellhead and pipeline joints. Even small vibrations can cause havoc if the well is old or poorly constructed.
many different dangers
- Bending or breakage of casing: Strong vibration can cause cracks in the steel casing. The cement bond may break. This may change the contact between underground layers.
- Surface Rupture and Displacement: Ground rupture due to earthquake can directly break the well structure. The wellhead may be mis-aligned.
- Liquefaction or soil liquefaction: Due to strong vibrations, sandy soil filled with water can behave like a liquid. Due to this the base of the well may sink. Casing may bend.
- Breaks in pipelines and connections: Pipes and other parts on the surface may break. This increases the risk of leakage and fire.
- Risk of pressure shock and blowout: If marked connections or the well control system is damaged, a blowout may occur in a high pressure field. This could become an environmental disaster.
underground effects and pressure changes
In the event of an earthquake, many types of situations arise inside and outside the ground. Its effect usually appears in the form of loss. Pressure can change the flow path of water and oil. Pore pressure may increase temporarily. Unexpected diversion of oil or gas can affect production. In some situations, earthquakes increase the risk of leakage.
Symbolic picture.
Seismicity and Well Operations
Oil and gas activities themselves can induce earthquakes. This happens when mass production takes place. In the event of an earthquake, faults become active due to change in pressure. Therefore, coordination between seismic risk and well operation is very important.
Environmental and human safety risks
Well failure can lead to oil and gas leakage. It can contaminate land and water sources. There is also a risk of fire and explosion. The safety of nearby settlements and workers may be in danger.
Monitoring and early warning devices helpful
Early warning devices and their monitoring are the most accurate in this matter. It is possible to save a lot by installing some equipment. Instruments such as ground vibration meters, tilt meters, pressure and flow sensors, and fiber-optic monitoring can be helpful. These devices help in quick monitoring and real-time warning after an earthquake.
Design and prevention measures
- Seismic-Rated Wellhead and Connections: Design the wellhead in such a way that it can withstand shocks and rotations.
- Flexible connections and expansion joints: Flexible joints in pipe-lines reduce the risk of breakage.
- Stronger Casing and Better Cement Bonding: Good casing design prevents the possibility of spillage in underground layers.
- Automatic Shut-in System: Keep valves that close the well in case of earthquake. This can prevent blowouts.
- Zone-Based Risk Assessment: It can be beneficial to decide the location of wells by making seismic hazard maps.
Questions raised by Venezuela earthquake
The earthquake in Venezuela has raised many questions. Some main concerns are also included in these. How safe are old field structures? Were monitoring mechanisms adequate? Were emergency response plans active? What will be the temporary and long-term environmental impacts? Answers to these questions will be available only through scientific investigation, recorded data and field surveys. And of course it may take time. Questions are being raised because there are more than 30 thousand oil wells in Venezuela. Of these, about 85 hundred are active. Meaning production is taking place in them. More than 90 thousand people work in these wells.
In simple words, earthquakes have a direct impact on oil wells. The impact largely depends on the well design, seismic intensity and the nature of the local soil. Preparation and modern monitoring is very important. Regular audits and contingency planning should be mandatory for every operator. Everything is off track in Venezuela, which is struggling with poverty and misery, so even thinking about regular audits and emergency planning is meaningless.
Also read: Why was the most devastation caused by the earthquake in Venezuela’s capital Caracas?
