Overcoming uncontrolled casing pressure in oil and gas wells

In the summer of 2011, there were over 8000 wells in the Gulf of Mexico which exhibited sustained casing pressure. The bleedoff process, which in requires a high degree of control and huge amounts of money, was ineffective and the high pressure remained in these wells.

Although most cases of SCP are fairly minor, it can be a serious problem which can occur throughout the lifecycle of the well with potentially massive consequences, including:

· Lost hydrocarbons

· Making abandonment increasingly difficult

· Environmental effects

· Impact on the safety of equipment and people working near the site

The causes of this increased pressure can also range widely, however the most common factors tend to be with the cement sheaths, tubing connections, wellhead seals or downhole accessories. These can be due to initial inaccuracies and installation issues or corrosion throughout the lifecycle. As there are an increasing number of aging oilfields, it is no surprise that there are more integrity issues year on year.

The main ways to combat sustained casing pressure are through

· Increased regulation – such as the necessity of having two to three independent and testable well envelopes in each well

· Improving the casing strength

· Constant monitoring and marinating of pressure throughout the well – it should be known/measurable at all times

This is a huge and constant problem which all operators and contractors must accept responsibility for.

If you are interested in hearing more details and case studies of the technicalities of improving well integrity and managing casing pressure, you may be interested in Well Integrity and Intervention World, Middle East 2012.