Tag: petroleum survey

Procedure of Calculations Using Density, API & Relative Density

Marine Surveyor Information 1602282

 

Working with Density at 15°C in air:
1) Observed Ullage – apply corrections – get Corrected Ullage
2) Observed Interface – apply corrections – get Corrected Interface
3) From Corrected Ullage, find Total Observed Volume TOV (in cubic metres)
4) From Corrected Interface, find Volume of Water (in cubic metres)
5) TOV – Water = Gross Observed Volume (GOV) of Cargo (in cubic metres)
6) Use Density at 15°C and Observed Temperature (°C) and find Volume Correction Factor (VCF) from Table 54
7) Gross Standard Volume (GSV) = GOV x VCF (cubic metres)
8) Weight Correction Factor (WCF) = Density at 15°C in vacuum – 0.0011 (or the Density at 15°C in air)
9) Weight in Air (Metric Ton) = GSV x WCF(Density at 15°C in air)
10) Weight in Vaccum (Metric Ton) = GSV x Density at 15°C in vacuum
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Petroleum Calculation Series: Wedge Formula

marine-surveyor-wedge-formulaAs I have requested by comments to post about Wedge Formula of liquid cargo measurement, herewith the article collected from internet

What is Wedge Formula?
Wedge Formula is calculation to determine the small quantity of liquid or non liquid cargo (On Board Quantity – OBQ or Remaining On Board – ROB) on cargo tanks, where it should fulfill the following conditions :
– The vessel has huge trim, but there is no trim correction value available on the tank table,
– The liquid or cargo on tank is not touch one or more of the tank bulkheads,
– Observed sounding tanks at several points to ensure the cargo is not touch one of the tank bulkheads,

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Gas Tanker: Specimen of Calculation

marine cargo ship surveyors

The following example demonstrates the typical procedure outlined using the standard temperature of 15°C as applied to cargo in a ship’s tank.

Measurement data — Tank No.3 port
Product — Propane
Gauge reading of liquid depth  ………………………………….. : 10.020 metres
Ship’s trim ……………………………………………………………. : 2.0 metres by stern
Ship’s list …………………………………………………………………. : 0.5° to port
Mean temperature of liquid ……………………………………….. : – 43°C
Mean temperature of vapour………………………………………. : – 38°C
Vapour space pressure ……………………………………………… : 59 mbarg
Molecular weight of liquid …………………………………………. : 44.097 given by
Density of liquid at 15°C ……………………………..…………….. : 511 kg/m3 shore
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Gas Tanker Calculation Procedures

marine cargo ship surveyors

Independent cargo surveyors are often employed by cargo buyers or sellers and the survey companies provide personnel to check cargo operations and cargo quantities both on board ship and within terminals. Such activities can include cargo measuring and cargo sampling.

During cargo operations, it is important to maintain a log of events. Ship’s officers and shore personnel should ensure that their time records are in agreement and that, when independent cargo surveyors are used, similar times are recorded in the Surveyor’s Time Sheet.

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Petroleum Calculation Series: Gas Tanker Principal Products

marine cargo ship surveyorsThe hydrocarbon gases methane, ethane, propane and butane may be regarded principally as fuels, the LPGs are also important as feedstock in the production of the chemical gases.

Liquefied Natural Gas (LNG)
Natural gas is transported either by pipeline as a gas or by sea in its liquefied form as LNG. Natural gas comes from underground deposits. Its composition varies according to where it is found but methane is by far the predominant constituent, ranging from 70 per cent to 99 per cent. Natural gas is now a major commodity in the world energy market and approximately 73 million tonnes are carried by sea each year. This is expected to increase to 100 million tonnes per year by the end of the millennium.

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Software: Bunker Survey and Petroleum Calculation

marine cargo ship surveyors

I have added some software relate to oil calculation. The software are:

1. BunkerCal
A Bunker Tank Sounding calculation program. Bunker survey calculation for tank sounding report based on ASTM Table 54B .
Follow this link to know more http://www.sevensurveyor.com/software/surveysoft-marine-surveyor-software/

2. OilCal
A Petroleum calculation program. For shipboard survey with calculation and ullage report based on ASTM Table 6A, 6B, 54A and Table 54B.
For more info check here: http://www.sevensurveyor.com/software/surveysoft-marine-surveyor-software/.

Hope the software is useful. Please try it and drop your comment here.

Regards,
Surveyors

Petroleum Calculation Series: Shipboard

marine cargo ship surveyors

The shipboard loading survey is conduted to get the quantity loaded onboard the vessel with measurement of cargo tank. The sounding or ullaging are performed to obtain the level of oil and free water on each tank. The obtained oil level data were calculated by using ship tank table to get TOV and total free water.

Data required for Crude Oil Survey:
– Tank Number
– Tank Reference Height
– Dip innage (sounding) or ullage
– Free water dip (FW)
– Oil temperature (C or F)
– Oil density or API
– BS&W volume in % (as per analysis result)
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