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API RP 13B-2 Recommended Best Practise For Measuring Oil Based Drilling Muds

Test Equipment for API RP 13B-2 – Salunda Limited

The recommended practise for testing oil based drilling muds is outlined in the American Petroleum Institute’s (API) Recommended Practice 13B-2 document (API RP 13B-2).

The Salunda MudChecker drilling fluid analyser is an innovative new technology which provides API equivalent measurement results covered in section D and E through a simple two step measurement process which greatly reduces the time taken to determine the characteristics of oil based drilling mud, whilst ensuring accurate, repeatable results.

API Standardized Oil, Water & Solids Concentrations (Section E)

API standardized retort

Section D of the documentation outlines the API standardized practise for determining the oil, water & solid composition of the drilling fluid sample.

The API currently recommends the heating of a measured sample of drilling mud in a retort oven until the liquid elements are vaporized. These vapours are then condensed and collected in a graduated liquid receiver. Volumetric measurements are expressed as percentages of oil, water & solids, these are calculated from the total volume of the starting sample and the condensed liquid volumes of oil & water in the graduated liquid receiver.

The hand-held MudChecker drilling fluid analyzer provides a far quicker and safer alternative to this via the use of an accurate electronic measurements which greatly reduces the amount of time required to carry out a measurement, yet produces the same results. The measurement process takes a maximum of 5 minutes to be carried out with all results being recorded electronically along with a date and time stamp, providing the user with traceability of measurements in the event of an audit.

API Standardized Alkalinity, Chloride Concentration & Calcium Concentration (Section E)

API Recommended Titration Practise

Section E of API RP 13B-2 covers chloride concentration and calcium concentration measurements this is carried out via a chemical titration which involves the use of various pieces of laboratory equipment and chemicals in a process that is very susceptible to erroneous results due to user interpretation and human error.

The process involves taking a known volume of deionized water and propylene glycol propyl which is added to a 250ml conical flask. Drilling mud is then added (dilute sulphuric acid may also be added to counteract lime in the mud sample). Potassium chromate indicator solution is then added before swirling to disperse the mud and extract the chloride ions. A burette is then filled with silver nitrate solution and added slowly to the conical flask until the solution starts to turn pink. A series of 1ml aliquots of silver nitrate are then added, with the flask swirled after each addition. Results are recorded to the nearest 1ml when the sample changes from yellow to pink. The mud salinity (in mg CL-ions/litre mud units) represents the value in ml multiplied by 1000.

MudChecker drilling fluid analyser provides a salinity measurement as part of a two-step process, the measurement is electronic meaning results are far more repeatable than those taken via a titration. This process involves adding 5ml of drilling fluid to 205ml of Salunda DSX7 dilution solution and blending. The hand-held probe is then inserted into the blended solution, an electronic salinity measurement is then taken after which results can instantly be recalled within the accompanying MudChecker software, significantly reducing the time taken carry out a titration measurement.

The MudChecker measurement process is not only far quicker than the recommended retort & titration process but is also far safer with no chemicals or heating elements required. The electronic measurement process ensures consistency between measurements with results being very repeatable, this makes the device ideal for tracking drilling fluid composition which can be particularly useful when drilling through complex formations.

For further information, case studies, validation data and product videos visit the MudChecker product page:

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