Within many of the low permeability gas reservoirs of the world identification and measurement of gas entries is difficult due to the low volume of the flow. Also, in many areas, identification of natural fracturing is important since much of this fracturing is related to better production within the low permeability formations.

During logging operations the Borehole Television Camera (BHTV) is capable of giving a real-time observation of the wellbore by use of a colour television camera mounted on the end of the camera tool assembly. This camera transmits a picture directly to a monitor within the logging truck. Observed oil and gas entries are noted and natural fracturing can be observed. Also, with the BHTV's internal gyroscope the orientation of the observed fracturing can be recorded. Twin VHS videotape recorders record the logging run for a permanent client record.

The Low Volume/High Resolution Flowmeter (HRFM) is used in conjunction with the BHTV in both open and cased hole logging as it is capable of measuring gas flow down to a fraction of an MCF. With the HRFM, flowrate is determined by injecting a tracer gas into the gas flow1 . The dilution of the tracer gas is then measured at a downstream detector. Mass flow is therefore determined by this method rather than the velocity of the gas in the wellbore as measured by conventional production spinner surveys.

Both the BHTV and the HRFM are capable of being run in vertical and horizontal open and cased holes.

You can access this article if you purchase or spend a download.