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Understanding the Full Spectrum of Fluid Work in Deepwater Well Operations

By Gary Poole | Account Manager/Technical Advisor | April 26th, 2021

Do your service providers, operations personnel, and engineers understand the many variables impacting fluid performance across the entire spectrum of well operations? Do they recognize the profound impact a completion brine can have on cost, performance, safety, and the environment? Based on feedback from the frontline, we have identified a need for greater awareness of the overall impact of a completion brine.

The HSEQ Perspective

Let us begin with a look at the factors impacting health, safety, environment, and quality (HSEQ), because most of us would agree that safeguarding both personnel and the environment is paramount.

A Novel Alternative to Zinc-based Fluids

Forgoing the use of zinc-based fluids should now be the norm given their hazards to personnel and the current environmental restrictions on the use of zinc in practically every offshore field. In the Gulf of Mexico, where modest use of zinc is still permitted, it is reasonable to expect restrictions will grow even more stringent in the years ahead.

Fortunately, TETRA has pioneered a very effective high-density alternative to zinc-based brines—the family of TETRA CS Neptune^® completion fluids. These innovative fluids are zinc-free and formate-free, made with readily available, environmentally benign ingredients, and can be formulated as either monovalent or divalent with densities up to 15.7 and 17.5 lb./gal., respectively. Moreover, the fluids can also be used as working, packer, and reservoir drill-in fluids, so they provide unprecedented versatility compared to other high-density brines on the market.

The TETRA CS Neptune fluids won a Hart Energy Special Meritorious Engineering Innovation Award in 2020, and they are revolutionizing the industry as more and more operators recognize their many benefits.

More Efficient Displacement for Cleaner Results

Today, TETRA offers displacement spacer systems that are formulated specifically for a given well’s conditions, because targeted treatment ensures more thorough hole cleanout and surface preparation. But why has this approach not been widely adopted for cleaning fluid storage pits? In most cases, thousands of barrels of wastewater and detergents are used to clean their surfaces, all without first testing the chemistry of the wash on the synthetic-based mud it is meant to clean away—a textbook example of inefficiency.

The TETRA Advanced Displacement System (TADS) can address this problem. TADS is a 3-phase displacement system designed for optimal wellbore cleaning because it’s tailored to the specific application.

As reported in a number of cases, use of TADS has yielded:

• Significant reduction of filtration time and interface volume losses (down to as little as 3–10 barrels), which cut rig time in half;
• 10-month displacement of zinc bromide down to the seabed wellhead (for a temporary abandonment) with no fill at total depth.
• Brine so clean (35 NTUs), rather than return it for reclamation, the operator kept it for a backup working fluid.

Ultimately, TADS delivers exceptional value because it facilitates brine reclamation and is very effective in reducing disposal and environmental impact.

API Q2 Certification

TETRA is API Q2 certified. We provide behavioral-based training for every rig and service crew member. On a TETRA jobsite, all personnel perform their duties safely and consistently based on approved documented practices. Personnel involved in handling completion brines and additives are outfitted with appropriate personal protection equipment and acid-resistant clothing.

Our commitment to safety and proper procedures pays off: In one recent completion project spanning 12 months and 688,000 work hours, TETRA logged zero HSEQ incidents.

The Operational Perspective

Now let us turn to the operational aspects that impact the efficiency and results of your well operations. Below is a checklist that TETRA can help fulfill.

A Checklist for Success

• Use the appropriate TETRA brines with third-party verification to prevent stress cracking of alloy 125 casing, like our CaBr₂ and ZnBr₂ brines;
• Use a TETRA corrosion-inhibition package with third-party verification that is compatible with commonly used polymers, like our ZnBr₂ brine;
• Identify any buoyancy issues with ball-drop operations;
• Carefully monitor the circulation rate of viscous, high-density brines and never deviate from the designed rate;
• Properly time running brines through the work string and tubing for maximum efficiency;
• Use TETRA pills, like the TETRAFlex^™ cross-lined pill, that are formulated specifically for the downhole equipment and reservoir characteristics to minimize loss of completion fluid;
• Optimize every brine’s pH, crystallization, and salt content, and avoid adding dry powder buffer compounds;
• Use a clay-inhibitor that is based on well mineralogy and will safeguard the porosity of the pay zone;
• Chart filtration data to determine the most prolific ‘signature’ event of the operational phase;
• Carefully manage flowback to collect samples for chemical analysis and for potential reclamation of fluids.
• Adhere to TETRA’s documented pit-cleaning standards to ensure thorough cleaning for uncontaminated fluids;
• Consult TETRA for proper shaker-screen sizes for the different operational phases, from drilling to completion;
• Define procedural mandates and responsible parties for the outside rig station;
• Record and share lessons learned.

TETRA Technologies was founded in 1981 to provide the highest quality completion fluids in the oil and gas services industry. Our portfolio has since expanded to include a wide range of products and services for well operations and hydraulic fracturing, but completion fluids and additives remain one of our core offerings. We stand at the forefront of completion fluid technology, and we stand behind the quality of our products and services and commitment to work safely and deliver the most value to our clients.

Our team is happy to answer your questions or provide detailed information, please email us here.