The completion fluids used in oil and gas well operations are critical to the operation of the well. They facilitate the final contact between the reservoir formation and the well bore. The fluids must be compatible with the reservoir rock and be carefully selected to minimize formation damage, ensure the safety of personnel and equipment, and enhance hydrocarbon recovery. The correct selection of completion fluids varies depending on the type of well, the reservoir formation, and the objectives of the completion or workover operation. For more detailed information on the considerations and best practices for selecting completion fluids, learn more here.

Completion fluids are typically brines, mud or gels composed of various salts and dissolved polymers. They are designed to be compatible with the reservoir formation and are usually filtered to a high degree to prevent the ingress of solids into the near-wellbore area. They are also designed to be chemically compatible with the well bore and must have resistance to corrosion. They must be nontoxic, noncorrosive and stable over a wide range of temperature conditions, while remaining in suspension for extended periods of time and providing adequate viscosity at the same time1.

Developing a successful completion fluid begins with the meticulous selection of clear brines that align with the desired density. The design process considers a variety of other factors, including the true crystallization temperature (TCT), the ability to stop gas hydrate formation, corrosion rates, viscosity stability and the pH balance of the system.

Once the rheological properties are established, a series of tests are conducted to evaluate performance under varying temperature conditions. In addition, the system is analyzed to determine its wettability characteristics to avoid causing any formation damage.

The results of these tests allow Newpark engineers to provide clients with a complete completion fluid formulation that aligns with the reservoir specifications and meets their specific operational requirements. This rigorous process includes conducting a series of filtration tests to ensure the completion fluid is free from solids and is capable of resisting shear stress over a wide range of temperatures.

In addition, the completed fluid is screened to make sure it is free of pyrotechnics, paraffin wax and other contaminants that could cause undesirable formation damage. The final fluid is then packaged in a safe and portable package that can be delivered to the field.

Using an effective completion fluid filteration system enables operators to maximize production while maintaining compliance with environmental regulations. The system is custom-designed for each application based on the particular well, formation and the completion fluid being used, with options to include an air-driven diaphragm pump, manual or hydraulic control panel and an integrated pressure gauge.

The most important benefit of a filtration system is its ability to filter completion fluids without losing their viscosity, avoiding clogs and the loss of rheological control. In turn, this enables the well to be completed quickly, safely and effectively with minimal formation damage. This increases production and prolongs the life of the well, ultimately reducing costs. For more information about completion fluids, check out the SPE website for a wealth of articles and technical papers.