API RP 13B-2:2005 pdf download
API RP 13B-2:2005 pdf download.Recommended Practice for Field Testing of Oil-based Drilling Fluids.
A.1 Principle
A.1.1 Experience has shown that some drilling fluids tend to develop excessive shear strength under static condilions. especially at elevated temperatures. Excessive shear strength results in high pump pressures to break circulation”, and can result In loss of returns. High shear strength can also cause difficulties In logging, perforating and other “downhole” operations.
A.1 .2 The technique described in this annex can be used to determine this tendency and to estimate the extent to which the drilling fluid will develop excessive shear strength. This shear strength measurement is normally made on a static, heat-aged drilling fluid sample. Ageing temperatures are therefore selected to be near the estimated bottomhole temperature of the well. Ageing cells or vessels meeting the pressure and temperature requirements for the test are required.
A.2 Apparatus
a) Stainless steel shearometer tube, having the following characteristics:
1) Length: 89 mm (3,5 in);
2) Outside diameter 36mm (1.4 in);
3) Wall thickness: 0,2 mm (0,008 in).
NOTE A slight outside taper on the bottom of the shear tube has been found to improve reproducibility of the test results.
b) Platform for weights.
C) Set of weights, in gram increments.
d) Ruler, graduated in millimetres (Inches).
A.3 Procedure
A.3.1 Place and balance the shear tube carefully on the surface of the aged sample that has cooled to room temperature. It may be necessary to shift the weights on the platform to ensure that the tubWs initial penetration mto the drilling fluid is vertical. If a crust develops on the heat-aged sample, this crust should be gently broken before setting the shear tube in place for the test.
A.3.2 Carefully place sufficient weights on the platform to start the downward movement of the shear tube. Unless too much mass is added, the tube will stop its downward travel at the point where the shear strength of the aged drilling fluid against the surface of the tube is sufficient to support the applied mass. It is desirable to submerge at least one-half the length of the tube.
B.1 Principle
This procedure measures the amount of oil from cuttings generated during a dnlling operation. It is a retort test, which measures all oil and water released from a cuttings sample when heated in a calibrated and properly operating retort instrument
A known mass of cuttings Is heated in the retort chamber to vaporize the liquids associated with the sample. The oil and water vapours are then condensed, collected and measured in a prects.on.graduated receiver.
NOTE Obtaining a representative sample requires special attention to the details of sample haniJing (location, method. frequency). The sampling procedise Wi a given area may be specilled by local Or governmental rules.
B.2 Apparatus
a) Retort Instrument
1) Retort assembly, which includes a retort body, cup and lid with a volume of 50 cm3 (accuracy i 0.25 cmi). constructed of 303 stainless steel, or equivalent.
2) The retort cup volume with lid should be verified gravimetrically. The procedure and calculations are given in annex J.
3) Condenser, capable of cooling the oil and water vapours below their vaporization temperatures
4) Heating jacket, nominal power 350 W.
5) Temperature controller, capable of limiting temperature of the retort to 500 C ±40 C (930 F ± 70 F).
b) Liquid receiver (TC), specially-designed cylindrical glassware with rounded bottom to facilitate cleaning and a funnel-shaped top to catch falling drops, meeting the following specifications.
