GB1363206A - Continous recording viscometer - Google Patents

Abstract

1363206 Measuring mud properties TEXACO DEVELOPMENT CORP 27 Nov 1972 [20 Dec 1971] 54630/72 Heading G1N Apparatus for continuously measuring viscosity related properties of mud during a drilling operation comprises a pair of rotational viscometers 30, 40 operating at different speeds, their outputs being combined to give the desired property. In Fig.1 a pump 28 supplies mud to the viscometers from the inlet or outlet of drilling well 10 depending on the position of valve 26, the well and its mud supply being otherwise conventional. The viscometers rotate at 300 and 600 RPM respectively, and the mud is supplied via a conical baffle and a perforated plate to render its flow uniform, Figs.3 and 4 (not shown). Four properties may be measured by combining the viscometer output signals V 300 and V 600 , the properties being plastic viscosity, given by Á p = V 600 - V 300 , yield point Y, given by Y = V 300 - Á p , apparent viscosity Á a , given by Á a = ¢ V 600 , and finally the onset of flocculation which may be observed from the ratio Á p ¸Y. These properties are obtained in Fig. 5, (not shown) where resistors 76, 77 and 78 are respectively of R, R, and 2R. By reference to the equations above it will be seen that Galvo 1 displays Á p , Galvo 4 the flocculation ratio, Galvo 2 shows Y, and Galvo 3 shows Á a . These signals may be recorded on a chart as a function of time, or as a function of drilling depth, or of both, the depth being measured by a device 19, Fig.1, linked to the drill string suspension.