IDENTIFICATION AND CAUSE ANALYSIS OF STEAM CHANNELING IN THE NORTH AREA OF B OILFIELD

Steam channeling generally occurs in the steam stimulation stage of heavy oil reservoirs. It is the interference phenomenon of the fluid injected by the oil well during the steam injection process to the adjacent oil well. Steam channeling of heavy oil is mainly manifested as vapor channeling, hot water channeling and super heavy oil steam channeling caused by pressure conduction. The main hazard of steam channeling is that it can aggravate interlayer and plane contradictions, seriously affect well conditions and reduce thermal efficiency. In this paper, taking the north district of B Oilfield as an example, we systematically analyzed the identification and causes of steam channeling using geology, construction technology, and reservoir development data. The results of the study show that during the steam channeling, the injection pressure suddenly drops, generally about 50%. In the early stage of steam channeling, pressure, output and temperature rise at the same time; in the middle period, temperature and output rise sharply, and later the temperature stabilizes at a constant value. At this time, pressure drops instead. When the steam channeling is serious, the adjacent well is injected with steam, the water production of the channeled well increases sharply, the water cut is close to 100%, and there is a certain amount of steam at the wellhead of the channeled well. According to the steam channeling characteristics of single wells and injection-production well groups, the steam channeling type of this reservoir can be judged as low sand-to-ground ratio control type. The causes of steam channeling include geology, sand control technology and reservoir development. The geological reason is that the reservoir in the target layer is shallowly buried and weakly compacted. The formation dip angle of the target reservoir is 2° ~ 4°, the permeability difference of the A1 layer in the northern zone is 1.0-5.4, and the average permeability difference is 1.6. These factors have a weak influence on steam channeling. The target layer is shallow loose sandstone, oil wells are easy to produce sand, and the current sand control technology is not good. Reservoir development factors mainly include injection-production ratio, steam injection speed, steam injection intensity and steam injection pressure. This research has certain guiding significance for the efficient development of heavy oil reservoirs.