Keith Boyle
Shell Canada Limited
ABSTRACT
It has long been recognized that defining a flowing profile in a well producing three phases from a small interval (less than 50m) is extremely difficult with current production logging tools. The difficulty arises from the limited number of measurements that can be made with the current spinner, gradiomanometer, capacitance, pressure and temperature tools. The recent introduction of the oxygen activation technique to detect water flow brought with it an independent measurement of water-phase velocity. This data, when combined with traditional production log interpretation and surface measurements, can theoretically be used to accurately define a three phase flowing profile. Unfortunately, .recent field experience has shown that the water phase velocity derived from an oxygen activation log does not correlate to the traditional spinner interpretation or to surface measured rates in the presence of multi-phase flow. Two wells were logged using an oxygen activation log and a conventional production logging suite (spinner, gradiomanometer, pressure, temperature and, in one case, a water cut meter). The wells are part of a hydrocarbon miscible flood, which have recently experienced solvent breakthrough. The reservoir is a multi-layered reef, and the logs were run to identify which layers had solvent breakthrough. The wells produce between 500 - 700 m3/d total fluids @ 90% water cut (W.C.) with a gas-oil-ratio of 2000 - 3000 m3/m3. In one well the oxygen
activation log results correlated very well with the production log interpretation in a low flow rate/single phase interval. In the higher flow rate/multi-phase section, however, the water velocity from the oxygen activation log was substantially higher than that calculated from a traditional production log interpretation. In logging the second well the two techniques did not correlate well in the low flow/single phase interval, but there was a better relationship in the higher flow rate/multi-phase interval. In both instances there was not a consistent trend between the oxygen activation data and the traditional production log interpretation. This disparity implies that the results are dependent upon the flow regime and flowing mechanics.