What risks are present when drilling a well?

What risks are present when drilling a well?

The most prevalent drilling hazards include geological faults and structures, pipe sticking and drill pipe failures, lost circulation, borehole deviation, pipe failures, borehole instability, formation contamination, hydrogen sulfide or other gas, hydraulic fracturing, buried valleys, and man-made features (Mitchell …

What is the advantage of under balanced drilling?

5.3. UBD is considered a drilling method to protect the reservoir by reducing formation damage during the operation. Although original impetus of UBD was reducing mud loss, which is an immediate safety issue, the most significant benefit of UBD is in keeping the reservoir integrity intact.

What is the difference between over balance and under balance?

If hydrostatic pressure in a well is higher than the reservoir pressure, the difference is called overbalance pressure, or simply overbalance. Conversely, if reservoir pressure is more than hydrostatic pressure, the difference is called underbalance.

Why underbalanced drilling technique is not suitable in the case of directional drilling?

Directional drilling equipment can have limitations on UBD. Hydraulic operated tools cannot be used in underbalanced wells, and if a gasified system is used, the measurement while drilling (MWD) pulse systems may not work.

How is a risk assessed?

What is a risk assessment? Risk assessment is a term used to describe the overall process or method where you: Identify hazards and risk factors that have the potential to cause harm (hazard identification). Analyze and evaluate the risk associated with that hazard (risk analysis, and risk evaluation).

Can drilling cause fire?

The possibility of a fire and explosion on a drilling site is always there, no matter whether the source of fuel is from the ground or from the equipment. Being ever vigilant for open sources of fuels and ignition will prevent the unfortunate from happening.

What is balanced drilling?

Underbalanced drilling, or UBD, is a procedure used to drill oil and gas wells where the pressure in the wellbore is kept lower than the static pressure of the formation being drilled. As the well is being drilled, formation fluid flows into the wellbore and up to the surface.

What is under balance?

1. n. [Drilling] The amount of pressure (or force per unit area) exerted on a formation exposed in a wellbore below the internal fluid pressure of that formation. If sufficient porosity and permeability exist, formation fluids enter the wellbore.

What is the difference between overbalance and under balance drilling?

Underbalanced drilling, or UBD, is a procedure used to drill oil and gas wells where the pressure in the wellbore is kept lower than the fluid pressure in the formation being drilled. In conventional, or “Overbalanced”, drilling fluid is pumped into the well shaft at pressure higher than in the reservoir.

What are the 3 types of risks?

Risk and Types of Risks: Widely, risks can be classified into three types: Business Risk, Non-Business Risk, and Financial Risk.

What is a risk assessment in construction?

Risk assessments comprise the identification of risks, the evaluation of associated risks and the determination of appropriate control measures. Many activities on a construction site are hazardous by nature and will require a full assessment of risk.

What is blowout in drilling?

A blowout is the uncontrolled release of crude oil and/or natural gas from an oil well or gas well after pressure control systems have failed. Modern wells have blowout preventers intended to prevent such an occurrence.

What do you need to know about underbalanced drilling?

Unsourced material may be challenged and removed. Underbalanced drilling, or UBD, is a procedure used to drill oil and gas wells where the pressure in the wellbore is kept lower than the static pressure then the formation being drilled. As the well is being drilled, formation fluid flows into the wellbore and up to the surface.

What happens when a well is under balanced?

In under-balanced drilling, if the under-balanced state is maintained until the well becomes productive, invasion does not occur and formation damage can be completely avoided. Increases rate of penetration (ROP).

What are some of the risks associated with drilling?

These include loss of material, such as drilling equipment and fluids, and loss of drilling process continuity, called non- productive time (NPT). These losses are incurred while searching for and implementing remedies to drilling problems. Avoiding drilling problems cuts finding and development costs and allows

How does a rotating head work In underbalanced drilling?

In underbalanced drilling, however, there is a ” rotating head ” at the surface – essentially a seal that diverts produced fluids to a separator while allowing the drill string to continue rotating. If the formation pressure is relatively high, using a lower density mud will reduce the well bore pressure below the pore pressure of the formation.