Production Assurance

Everything You
Need to Know

• What is CARBO offering for Production Assurance applications and how do they work?
  

  CARBO offers a range of proppants impregnated with production assurance chemistries grouped under the GUARD technology platform. They are placed as a part or a hydraulic fracture, fracpack or gravel pack treatment and released the impregnated chemical over time as production stream flows past it. In this manner they prevent the precipitation of deposits that may impair production from the formation to surface facilities. CARBO currently provides SCALEGUARD to prevent carbonate and sulfate scales, SALTGUARD for halite inhibition, ASPHALTENEGUARD for asphaltene prevention and is working on incorporating additional chemistries.

• What are the key components of the GUARD technology Production Assurance platform?

  The GUARD technologies enablers are a porous ceramic proppant engineered with interconnected porosity to maximize impregnated volume, infusion methods tailored to the specific chemicals being impregnated, and an innovative controlled release membrane for extended protection time.

• How do the economics of GUARD Production Assurance platform proppants work, how much more expensive than regular proppants are they?

  SCALEGUARD, SALTGUARD, ASPHALTENE GUARD and the concept of the GUARD platforms in general is providing add-on functionalities to that of regular proppants. In a frac application for example a GUARD proppant will act both as a regular proppant to mechanically support the frac and provide a conductive path, as well as inhibiting precipitation of damaging materials. As such they help lower the total cost of completing and assuring production by performing two functions in one job, rather than doing two separate treatments.

• How are the properties of GUARD proppants affected by using a porous ceramic substrate, how are crush and conductivity affected?

  The porosity of the ceramic substrate is engineered to be finely grained and evenly distributed within the pellets to minimize its impact on physical properties. The type of substrate and internal porosity are designed so that the finished product matches the properties of the base proppant it will be blended in.

• What type of scale inhibitors are available in SCALEGUARD, which one should I use, can CARBO advise?

  SCALEGUARD is available with phosphonate or polymeric scale inhibitors. Both are effective to prevent carbonate and sulfate scale deposition, the selection of the adequate inhibitor depends on well conditions, most noticeably BHST and water chemistry. CARBO can advise on proper scale inhibitor selection upon provision of a well dataset.

• Can I use my own preferred scale inhibitor instead of the ones in SCALEGUARD standard offering?

  Yes, we can use alternative scale inhibitors. Tailoring will involve impregnation and elution (release) validation testing.

• How is a SCALEGUARD job designed, what information is required, what inhibition times can be achieved?

  SCALEGUARD is designed based on well conditions, including.
  – Well completion schematic.

  – Produced water analysis, pH and CO2 content. This should be provided for each zone if there are multiple zones being produced commingled, and injection water analysis, as well as injection water if it is a waterflood.

  – Basic reservoir data: K, BHST, Pr, Frac gradient or closure pressure. Bottom hole Pwf and wellhead WHP production pressure.

  – Expected gas (MMSCFD), oil (BOPD) and water production profile (BWPD or BBL/MCFD) and desired treatment duration.

  – Frac, or sand control completions: frac/gp/fp dimensions, type of proppant and mesh size, proppant volume. Acidfrac wells: Pump schedule with acid types and volumes, pump rates utilized.

  With this data CARBO determines the scaling tendency, MIC requirement and amount of SCALEGUARD required to achieve the desired protection time which is added to the regular proppant as a percentage of the planned job volume. Typical SCALEGUARD fractions vary between 5% and 20% of the total proppant volume.

  The duration of the inhibition time is determined by the balance between SCALEGUARD placed and water production. Multiple year protection has been achieved as published in paper SPE-172792 and also planned for the life of the well (>20 years) as referred to in paper SPE-179882.

• How can GUARD chemical residuals be monitored in produced water?

  Periodic sampling and analysis can be routinely performed for monitoring residuals.  Typical monitoring is done during flow back, then 30 days, 60 days and 90 days after the well has been turned on to production, then sampling is done once a quarter.  Sample analysis can be done at standard oilfield labs, or sent to CARBO for testing.

• What happens if water production is expected several months or years after the frac is placed in the initial completion? What if the well is shut-in for a long time before flowing it back? Will SCALEGUARD be wasted?

  SCALEGUARD only releases in contact with water, as such it will not be produced or wasted until water breakthroughs. This is actually a useful feature that helps manage the uncertainty of the onset of scaling issues and need for treatment as reported on paper SPE-195326. In the case of prolonged shut ins prior to flowback the product would reach a state of equilibrium and the solution would stabilize and not continue to dissolve the inhibitor.

• What happens when all the inhibitors in SCALEGUARD are produced? Can it be recharged? Will voids be left in the proppant pack?

  Once all inhibitors are dissolved SCALEGUARD will continue to act as a regular proppant only. The porous substrate will maintain its integrity and no voids will be formed in the proppant pack. The inhibitor cannot be recharged down the hole.

• Can SCALEGUARD be used in acidfracced completions?

  Yes, SCALEGUARD can be included in the gel sweeps in acidfrac jobs as a scaled inhibitor carrier and slow controlled release agent. It will be placed and held deep into the engraved frac faces for long term slow release and scaling protection.