A kind of fire flooding oil extraction crude oil combustion-assistant ignition processTechnical field:
The present invention relates to a kind of particularly ignition process of viscous crude field fireflood exploitation of oil field that is used for, belong to the fire flood technology.
Background technology:
Fire flood is oil reservoir displacement in the oil extraction process, a kind of mode of oil extraction, on existing well pattern, set up exactly with inject flatly well and on every side a well group or well array of forming of many mouthfuls of producing wells serve as the injection well, adjacent well array is for producing the housing in row well pattern of well, inject air and high-temperature steam to injecting well, air is heated to the temperature that can light crude oil in the down-hole, perhaps the living heat of autoxidation in oil reservoir makes oil reservoir reach the process of ignition temperature (being threshold temperature) by air and crude oil, make oil reservoir realize underground combustion, the underground combustion process burns a part of crude oil, produce heat, form viscosity reduction, series of effects such as distillation and produce the driving force of displacement crude oil is impelled crude oil, the gas of water and generation flows into producing well.The key link of fire flood technology is the oil reservoir igniting, because oil composition is very complicated, wherein relatively strong reaction just can take place with oxygen at lower temperature in some active component, and their absorption oxygen molecules generate materials such as alcohol, acid, ketone, aldehyde when temperature is low, form coke class material.Oxidative heat generation improves temperature, and temperature improves makes oxidation more violent, and living heat is more, and this accelerated oxidation reaction can impel temperature to increase sharply.Temperature improves before the arrival threshold temperature, and oxidation belongs to low-temperature oxidation, and coking in the oil reservoir arrives after the threshold temperature, and coking material blazes up, and finishes ignition process.An important boundary of low-temperature oxidation and high-temperature oxydation is exactly that can coking material burn.Low-temperature oxidation is not easy to be converted into high-temperature oxydation, because the living heat of low-temperature oxidation is less, the heat that is generated is by after rock absorbs on every side, and temperature rises less, does not therefore reach threshold temperature.Low-temperature oxidation can take place in very wide temperature range, and makes the threshold temperature of coking material burning, generally more than 430 ℃.
Experimental study shows, this process of oxidation that reaches a high temperature two key factors are arranged, the one, the air injection rate is enough big, the 2nd, the preheat temperature of oil reservoir is enough high, wants the oxidation that reaches a high temperature, and must carry out manual firing and firing temperature more than threshold temperature.
Fire flood oil reservoir ignition method having heaters method, chemical method and steam injection in the prior art.Wherein the heater method is to utilize cable that heater is sent in the oil well air that heating is injected, the air that this method exists injection can not fully contact with heater, often produce the air heat absorption inhomogeneous, cause the too high phenomenon that burns out heater of heter temperature sometimes; Chemical method carries out heat to oil reservoir and drives, though succeed, for heavy crude reservoir, ignition success rate is very low; The steam injection methods of printing is after injecting a large amount of steam more than 350 ℃ by oil well, to inject air again in well, and its shortcoming is to reach threshold temperature to need the long time.
Summary of the invention:
The object of the present invention is to provide a kind ofly can overcome the prior art deficiency the easy to implement and duration of ignition is short, ignition success rate is high fire flooding oil extraction crude oil combustion-assistant ignition process.
Technical scheme of the present invention is as follows.This kind ignition process is to inject high-temperature steam and be the combustion adjuvant of important component with metals such as platinum, palladiums to oil reservoir by injecting well, enters normal ignition process quickly.
This process is as follows with implementation step and technical essential:
1, according to the reservoir geology data existing well set up on the net inject flatly well and on every side the well group formed of many mouthfuls of producing wells or a well array for injecting well, adjacent well array for producing the housing in row well pattern of well;
2, inject a certain amount of high-temperature steam to injecting well, make reservoir temperature reach 210～250 ℃ preheat temperature;
3, in the steam injection process later stage, the crude oil of some is mixed combustion adjuvant by a certain percentage mix, inject oil reservoir with high-temperature steam, inject sufficient air simultaneously continuously.Wherein, it is the combustion adjuvant of important composition that combustion adjuvant adopts with metals such as platinum, palladiums, and its consumption reaches more than the 28.5kg/m by the core intersection requirement, and the air consumption reaches 1.2～1.61000Nm3/min by the core intersection requirement.
Fire flooding oil extraction crude oil combustion-assistant ignition process provided by the invention is easy to implement, and light-off period is short, and the ignition success rate height utilizes it successfully to finish ignition process within a short period of time, helps the production run of fire flood.
The specific embodiment: injecting the construction well group with Liaohe Oil Field 48 certain fire floods of Du is example.
This well group is positioned at 48 of Liaohe Oil Field Du, and straticulate exploration is the tame table oil layers of husky three Du, well group control oil in place 72 * 104T, recovery percent of reserves 23%, core intersection 10.1m, oil reservoir buried depth 950～1020m, at present, strata pressure 1.1～1.5MPa, 53 ℃ of formation temperatures.
This well carries out fire flood displacement construction according to above implementation step to the heavy oil wells oil reservoir, carries out necessary part oil reservoir shutoff before the construction.Then, inject 280m earlier3High-temperature steam (330 ℃ of steam quality 85%, temperature, steam injection rate 23t/h) is at steam injection later stage (about 240m3The time), be oxidizer with the platinum group or the palladium of about 10t crude oil and 850kg powdery, inject well with injection pump with high-temperature steam.Annotated behind the steam with 12Nm3/ min speed is injected air, approximately injects 20 * 104Nm3The time, injection rate can suitably lower, but is not less than 8Nm3/ min.
By observation and sample analysis, judge the stratum combustion case to producing well.Estimate that ratio does not produce high-temperature oxydation combustion reaction minimizing half the time with the sparking mode of combustion adjuvant.