The Importance of Investing in Quality Well Cementing

Well cementing, a key service inherent to well construction, plays a vital role in all phases of a well’s development and life cycle, regardless of depth. There are many types of cementing, including primary cementing.

Primary cementing is the process of placing cement into the annular space between the casing and wellbore to insure a complete and permanent hydraulic seal (Figure 1). The objectives of primary cementing include:

1. Providing effective hydraulic isolation for each of the well’s segments
2. Protecting the environment
3. Providing isolation throughout wells that could contain shallow aquifers, hydrocarbons and water reservoirs
4. Supporting the casing’s weight
5. Slowing down the process through which the casing is corroded by well fluids and other fluids injected during stimulations
6. Preventing the collapse of unconsolidated formations

The main challenge is to achieve effective hydraulic seals in areas that manage pressurized fluids. To achieve this, improving the displacement of drilling mud from the segment of annular space that will be cemented is indispensable. This allows a good, 360-degree adherence between the casing and the wellbore, with no canalizations in the cement layer and with a full pour. While it may look easy, success requires proper planning, design and use of hydraulic fluid displacement and centralization simulators.

Well cementing in the oil and gas industry is known as a “commodity” solution and many companies have entered this line of service. This has created more competition but not under the same scenario. Many companies do not have the abilities, expertise and technologies necessary to provide a quality service. Achieving an appropriate hydraulic seal can protect and support the casing and can function as the first line of defense for the well's integrity, one that performs to standards throughout all of the well’s activities and drilling phases, termination, production and maintenance.

Recently, the price for cementing services has dropped. This is due to the strategies used by clients and to a price war between companies because of the amount of competition that exists. This has worsened with the fact that companies assume this to be a “commodity” service that can lead to a great number of failures, including:

• Float equipment failure
• Early cement setting
• Failed integrity tests
• Cement lacking consistency
• Auxiliary equipment failure
• Inappropriate cementing designs
• Inappropriate centralizations

As seen in Figure 2, these failures have been detected in equipment, personnel, materials and systems. 

Inadequate investment in cementing causes failures; to fix these failures can be very complex and expensive, not to mention that it makes it practically impossible to comply with the project’s original objectives, which then lead to other issues:

• Delays in the incorporation of reserves and production
• Increase in costs to cover remediations, tools and drilling equipment
• Lost circulation
• Blowouts
• Environmental damage

This is why the design, preparation and execution of this service must always be customized to the specifications and needs of each well. This is determined by expert personnel and by implementing the best quality of service. The objective is to establish a process of continuous improvement that can document all lessons learned in order to reduce risk.

Cementing work is of great importance because it represents the principal barrier between a formation and the surface, thus ensuring the integrity of the well from the design stage and throughout its life cycle. This includes its maintenance, abandonment and decommissioning. As a result, zone isolation needs to be effective. One of Repstim’s missions is to make sure that all its work is designed and executed using the best practices, norms and standards in the oil industry.