A Prospective Method to Increase Oil Recovery in Waxy-Shallow Reservoir
Waxy oil has been the main characteristics of The X field. Initial screening criteria studies indicated that cyclic steam stimulation (CSS) would be the optimum option because favorable reservoir condition. Based on this method we would like to know how much oil gain and the effect of steam for the stimulated and surrounding well. The injection of steam was done for 7 days followed by 14 days of soaking period. 39,000 liter of Marine fuel oil was used to generate steam for stimulation with an average produce steam quality about 80%. Average of 255 MMBTU of steam was injected each day with total steam injected was about 1.7 BBTU. The oil production was increased four times from 5 bopd into 21 bopd. Proper well candidate and high permeability are some reason for this method successfully increase oil production. Additional heat from steam reduced the damage near wellbore due to wax deposition. This is verifying by increasing productivity index from 3 bbl/psi to 4 bbl/psi. From results and observation data, this method can be a platform for typical shallow depth reservoir with high paraffinic content especially other reservoir in Sihapas formation.
Study on the effect of wellbore heat capacity on steam injection well heat loss
The accurate calculation for heat loss from steam to formation in steam injection well is of great importance for enhanced oil recovery (EOR) in the thermal recovery process for heavy oil. In this study, a novel heat loss model with consideration of wellbore heat capacity was set up and the heat loss was simulated by the new model. Finally, this paper focused on the effect of wellbore heat capacity on wellbore heat loss with times, and the steam injection conditions was also regarded to study on the influence of wellbore heat capacity on heat loss. It was found that the wellbore heat capacity had an obvious influence on the wellbore heat loss, especially at early stage of steam injection. Consequently, the new heat loss model could solve the problem of low precision for heat loss calculation at early injection time caused by the conventional model due to ignoring wellbore heat capacity. Furthermore, the heat loss would decrease with the increase of wellbore heat capacity, and the effect of wellbore heat capacity on heat loss became significant with increase of steam injection pressure.
A Successful In-Situ Combustion Pilot In The Midway-Sunset Field, California
This study presents a case history of a technically and economically successful dry in situ combustion pilot conducted in a thick, moderately dipping, heavy oil reservoir located in the Midway-Sunset field in W. Kern County, California. The pilot was situated near the oil-water contact with a heterogeneously depleted area updip in the regionally extensive, homoclinal Potter Sand of upper Miocene Age. With less than 15% of the original oil-in-place produced, reservoir and production analyses indicated the impending demise of economic cyclic steaming. This trend, coupled with poor results from laboratory steam-drive tests and minor water encroachment problems in the field, led to the consideration of in situ combustion as the most reasonable mechanism for recovery of the remaining oil reserves. Air injection into the arbitrarily delineated central Potter Zone began in Jan. 1972. Production analysis and an extensive coring program following 3-1/2 yr of operation indicated nearly 80% of the original oil-in-place had been recovered from the initial pilot pattern. Two additional patterns were fired, one of which was a former steam-drive pilot which gives a basis for comparison of the 2 enhanced recovery methods in this reservoir.