Radium from underground brines concentrates in oilfield scale and sludge — and the numbers are stark. Here’s a practical playbook to monitor, handle, and dispose of NORM in produced‑water systems without losing control of safety or compliance.
Oil‑field produced water (PW, the water brought to surface during oil and gas production) often carries dissolved Ra‑226/228 (radium isotopes from uranium/thorium decay) that co‑precipitate as barium–strontium sulfate scale or sludges. OSHA data estimate ~17.8 Bq/g (becquerels per gram, a unit of radioactivity) Ra average in scale, up to ~14,800 Bq/g, and ~2.8 Bq/g in tank sludge (www.researchgate.net). By contrast, drinking‑water limits are ~0.185 Bq/L (5 pCi/L, picocuries per liter) total Ra (www.scribd.com).
In high‑chloride brines, substantial Ra can stay dissolved; when that water is brought to surface and treated, scale and sludge trap Ra and naturally occurring radioactive material (NORM). The outcome can be large waste streams: one Gulf operator in the early 1990s stockpiled over 2,300 barrels of NORM solids from cleaning operations — wastes that “present a health hazard and waste‑management problem” (www.ogj.com; www.ogj.com).
Produced‑water radium and scale formation
Scale on well tubulars and separators concentrates Ra as barium–strontium sulfate, a hard mineral deposit. In practice, PW with high chloride can dissolve substantial Ra; when brought to surface and treated, scale/sludge traps Ra and NORM (www.scribd.com). A formal NORM survey plan should map every equipment item where scale/sludge can accumulate — separator tanks, heat exchangers, pig traps, pits, etc. (www.scribd.com).
That survey map should follow the water through the entire treatment train. In practice, that can include oil‑removal skids and sumps that handle PW solids and emulsions; these unit operations become routine inspection points as part of the NORM plan (oil removal). Clarifier basins and sludge sumps that consolidate fine solids are also logical locations to trend for accumulation (clarifier).
Survey plan, instruments, and thresholds
Periodically (annually or before major cleanouts), trained staff scan mapped locations with radiation instruments. Instruments include γ‑dose ratemeters and surface contamination probes. High‑sensitivity GM (Geiger‑Müller) or scintillation detectors are used at 1–2 m from equipment to spot elevated external dose rates: even a small rise above background (sea‑level background ~0.05 µSv/h, micro‑sieverts per hour, a dose‑rate unit) can flag hidden NORM deposits (www.scribd.com).
A reading “greater than twice background” is treated as contamination (www.scribd.com). Surfaces suspected of contamination are measured with β/γ contamination counters or smeared and counted to estimate Bq/cm² (www.scribd.com; www.scribd.com).
Instrument practices matter. Use intrinsically‑safe, explosion‑proof detectors suited to NORM (e.g., thin‑window β/γ probes). Note α (alpha) is usually irrelevant in these conditions: “oil film ~50 µm stops α” (www.scribd.com). Detectors are calibrated for NORM isotopes, but readings are typically in counts/sec (cps) since mixed spectra cannot be converted precisely (www.scribd.com).
Scan geometry, trend data, and dosimetry
Survey strategy: perform external dose‑rate scans around equipment to find hot spots, measuring at the equipment circumference for contamination screening and at 1 m from centreline for worker‑dose assessment (www.scribd.com). Mark and sample any area exceeding baseline.
Personal dosimetry and logs are standard: workers wear dosimeters (electronic or TLDs) and log tasks. Dose ratios and spot readings help ensure exposures remain ALARA. Over time, trend data matter: dose rates near background imply scale levels are low; significantly higher readings (even a few µSv/h) trigger decontamination plans. Rising dose rates at separators can predict when routine cleaning is needed.
Work zones, ground covers, and PPE discipline
When working on NORM‑contaminated equipment, controls are tight. Establish a fenced boundary with radiation warning signs (trefoil symbol) around any maintenance site; boundary size should match contamination level and be just large enough to do the job safely; only essential, trained personnel enter (www.scribd.com; www.scribd.com).
Place impermeable liners or drip pans under all pipes, tanks, or pumps being opened. This “floor cover” (often bright yellow/blue PVC sheeting) catches spills or debris — oil plus NORM sludge — during cleaning; treat liner and catchment as contaminated (www.scribd.com; www.scribd.com).
PPE and decontamination: workers wear coveralls, gloves, and possibly respirators. Upon exit, hot PPE is surveyed and either bagged for disposal or washed if needed. Remove and contain any clothing or rags as NORM waste (www.scribd.com).
Waste labeling, sampling, and segregation
Drums labeled “NORM Waste” must be staged in a restricted area (“Caution: NORM”). All scrap tubing, filters, rags, or sludge from cleaning are placed in labeled, sealed drums or bins; a representative sample of each batch of waste is analyzed for activity. Any item (e.g., a spent pump) that reads >2× background or shows removable contamination is tagged and segregated as radioactive waste (www.scribd.com; www.scribd.com; www.scribd.com).
In practice, no NORM solid or liquid waste is simply dumped. After draining a separator, the sludge liner and sump are cleaned, and the slurry is pumped into drums. Industry guidance (Figure 13) shows stacked labeled drums of oil‑field NORM waste awaiting disposal (www.scribd.com). French workboat codes and industry best practices similarly mandate bagging versus vacuuming and double‑checking all tools before leaving the zone.
Operationally, that can include collecting spent filters from produced‑water skids into closed containers as part of the same drum‑and‑label workflow (cartridge filter).
Disposal pathways and graded isolation
Disposal follows a graded approach: higher‑activity wastes require deeper isolation. U.S. guidance (API/USGS) depicts that very concentrated NORM “must be completely isolated (e.g., deep salt domes or Class A wells),” whereas low‑activity wastes might be buried or landfilled (www.scribd.com).
Deep well injection is common: many “drilling‑waste” injection wells can accept produced water and even sludges. In offshore Louisiana (one of few U.S. regions with NORM regs), operators were allowed to pump NORM‑contaminated cuttings into a depleted reservoir via hydraulic fracturing; approval required modeling to show fractures stay short, particles do not migrate beyond the zone, and radiation is shielded by rock (www.ogj.com; www.ogj.com). This method reuses existing oil wells and is highly effective: since the radium is bound in insoluble sulfate scale fragments, it stays trapped in the formation (www.scribd.com). In general, reinjecting NORM‑laden fluids into depleted zones or deep disposal wells (MD wells) is often the most practical and safe option, provided well integrity is assured.
Landfill or surface disposal can be permitted for low‑activity waste: the API disposal chart shows surface spreading with dilution as a low‑isolation option for mildly radioactive shale dusts (www.scribd.com). Many countries set strict limits. In Indonesia, any NORM waste is effectively “radioactive waste,” so disposal in a general landfill is normally forbidden without a radiation license. (By contrast, some nations allow <10 Bq/g soil‑application limits under exemption rules — Indonesians must follow clearance criteria in BAPETEN standards.)
Metal recycling is feasible after decontamination (acid flushing or mechanical scraping). If clearance levels are met, metal can be recycled; if not, it must be managed as waste. In practice, NORM‑hot equipment is sent to a licensed radioactive waste handler. In some countries, scrap that accidentally hits customs triggers radiation alarms — reinforcing that any scale must be removed first.
Licensing and oversight in Indonesia
Regulatory compliance is mandatory. In Indonesia, BAPETEN rules (Perka 9/2009 and 16/2013) require operators to perform Radiation Safety Analyses and obtain licenses for any on‑site TENORM storage (conferences.iaea.org). As of 2020, fewer than 20 TENORM licenses had been issued in Indonesia (inis.iaea.org).
BAPETEN and the KLHK Ministry now jointly oversee TENORM waste under a 2017 MoU (www.bapeten.go.id). Any sludge or equipment with elevated Ra must therefore be tracked as radioactive waste (with controls similar to a nuclear installation).
Measured outcomes and operating triggers
These measures reduce risk. Requiring a 2×‑background rule and drum containment means that essentially no detectable radium leaves a NORM area. Industry audits (e.g., by IAEA/IRPA) have found that following such practices keeps worker doses near natural background and prevents environmental contamination. In Texas and Louisiana, tightened enforcement and disposal rules since the 1990s have eliminated NORM‑related scrap metal incidents and restricted radium spread (www.ogj.com; www.scribd.com).
Companies should establish quantitative triggers — for example, 0.05–0.1 µSv/h as a “scan” level and 2× background as contamination — and contract licensed waste handlers. Using these data‑backed practices, supported by IOGP/IAEA guidelines and local law, minimizes dose and keeps NORM out of the public domain (www.scribd.com; www.scribd.com).
In practice, those NORM controls sit alongside the site’s water‑treatment operations. That can include routine maintenance of membrane or filtration stages used for water quality, which are surveyed and documented under the same plan (ultrafiltration). Ancillary equipment for water‑treatment skids is managed the same way for access, labeling, and waste logistics (water‑treatment ancillaries).
Source notes and references
All recommendations and data are drawn from authoritative industry and government reports: www.scribd.com; www.scribd.com; www.scribd.com; www.scribd.com; www.scribd.com; www.scribd.com; www.ogj.com; www.scribd.com; conferences.iaea.org; inis.iaea.org; www.bapeten.go.id.
