Measurement-while-drilling assembly using real-time toolface oriented measurements

A method of determining a parameter of interest of a medium proximate to a borehole using a rotating downhole assembly in said borehole, the method comprising:

• (a) obtaining information about a tool-face angle of the assembly during rotation thereof;
• (b) using a directionally sensitive evaluation device for obtaining measurements indicative of the parameter of interest, said measurements being obtained separately over a plurality of specified time intervals;
• and
• (c) . representing the directionally sensitive measurements by a series expansion that includes a sinusoidal variation with the toolface angle.

An apparatus for determining a parameter of interest of a medium proximate to a borehole;

• the apparatus comprising:
• (a) a bottomhole assembly (BHA) conveyed in the borehole;
• (b) an orientation sensor which obtains information about a tool-face angle of he BHA during rotation thereof;
• (c) a directionally sensitive evaluation device which obtains measurements indicative of the parameter of interest;
• and
• (d) a processor which represetnts the directionally sensitive measurements by a series expansion that includes a sinusoidal variation with the toolface angle.