CN-122014188-A - Heavy oil development method for breaking through fire flooding interlayer based on stratum adsorptivity combustion improver

CN122014188ACN 122014188 ACN122014188 ACN 122014188ACN-122014188-A

Abstract

The invention discloses a thick oil development method based on a breakthrough fire flooding interlayer with stratum adsorptivity combustion improver. The method comprises the steps of selecting a heavy oil reservoir, identifying and confirming a hypotonic interlayer region, defining a target injection region and an injection well group, injecting a combustion improver composition with stratum adsorptivity into the interlayer region, pre-injecting front air after adsorption is finished, activating the oxidation capacity of a catalytic combustion improver, continuously injecting an ignition agent through the injection well to initiate an in-situ combustion reaction, maintaining gas injection, monitoring parameters such as combustion temperature, product components and the like, and controlling stable propulsion of a combustion front. Wherein the combustion improver composition comprises an oxidant, a combustion improver, an inorganic catalyst, a catalyst with stratum adsorptivity, an emulsifier/surfactant, a polymer adsorbent, a solvent and a pH regulator. By improving the stratum adsorptivity of the combustion improver, the combustion improver is enriched at adsorption sites of the interlayer part, and high-temperature and high-pressure reaction is generated after ignition, so that the interlayer structure is broken through, and the heat channel is opened and combustion waves are stably propelled.

Inventors

MA ZHICHEN
LIU WANJIA
XU ZHENGXIAO
TAO LEI
WEN HAORAN
LI YUHAN
WAN KUNPENG
LI JIAWEI

Assignees

常州大学

Dates

Publication Date: 20260512
Application Date: 20260130

Claims (10)

1. The thick oil development method for breaking through the fireflood interlayer based on the stratum adsorptivity combustion improver is characterized by comprising the following steps of: (1) Selecting a developed heavy oil reservoir: (2) Identifying and confirming a hypotonic interlayer region in an oil reservoir, defining a target injection region, and dividing an injection well group by using an original injection well pattern; (3) Injecting a combustion improver with stratum adsorptivity into the interlayer region, and after the combustion improver is adsorbed, pre-injecting pre-air to activate the oxidation capability of the catalytic combustion improver; (4) Continuously injecting an ignition agent through a gas injection well to initiate an in-situ combustion reaction, wherein the ignition agent is one or a mixture of two of air and oxygen; (5) Maintaining gas injection, monitoring combustion temperature and product components, and controlling stable propulsion of a combustion front; The combustion improver with stratum adsorptivity comprises an oxidant liquid and a fuel emulsion, wherein the oxidant liquid comprises an ignition oxidant and a polymer adsorbent, the polymer adsorbent is hydrolyzed polyacrylamide, and the fuel emulsion comprises fuel, an emulsifier and a catalyst.
2. The method for developing thick oil for breaking through a fireflood interlayer based on a formation adsorption combustion improver according to claim 1, wherein the ignition oxidizer comprises one or more of potassium permanganate, ammonium nitrate, potassium nitrate, hydrogen peroxide and potassium chlorate.
3. The method for developing thick oil for breaking through a fireflood interlayer based on a stratum adsorptivity combustion improver as claimed in claim 1, wherein the fuel is diesel.
4. The method for developing thick oil for breaking through a fireflood interlayer based on a formation adsorption combustion improver as claimed in claim 1, wherein the catalyst comprises one or more of an inorganic salt catalyst and a nano catalyst with formation adsorption, the inorganic salt catalyst is metal chloride, and the nano catalyst with formation adsorption comprises one or more of nano Fe 2 O 3 , nano SiO 2 and nano Co 3 O 4 .
5. The method for developing thick oil for breaking through a fireflood interlayer based on a formation adsorption combustion improver as in claim 1, wherein said emulsifier comprises one or more of complex petroleum sulfonate, cocamidopropyl betaine, sodium dodecyl benzene sulfonate, and rhamnolipid.
6. The method for developing thick oil for breaking through a fireflood interlayer based on a stratum adsorptivity combustion improver, which is characterized by comprising a solvent and a pH regulator, wherein the solvent is water, the pH regulator is hydrochloric acid, and the pH of the combustion improver is 4.0-6.0.
7. The method for developing thick oil for breaking through a fireflood interlayer based on a stratum adsorptivity combustion improver as claimed in claim 6, wherein the combustion improver comprises, by mass, 10-30% of ignition oxidant, 0.5-2% of polymer adsorbent, 20% of fuel, 2-3% of emulsifier, 0.01-0.3% of catalyst, 0.1-3% of pH regulator and the balance of water.
8. The method for developing thick oil for breaking through a fireflood interlayer based on a stratum adsorptivity combustion improver, which is characterized in that the injection mode in the step (3) is to inject an oxidant liquid first and then inject a fuel emulsion, the intermittent injection lasts for 3-6 hours each time, the injection pressure is 1.1-1.3 times of the stratum pressure, the injection rate is 20-50 m 3/h/well, the total injection amount is 0.2-0.5 PV, and after the injection is completed, the well is closed and kept still, so that the stratum is imbibed for 5-7 days.
9. The thick oil development method for breaking through the fireflood interlayer based on the stratum adsorptivity combustion improver, which is disclosed in claim 1, is characterized by comprising the specific steps of continuously injecting mixed gas of oxygen and air through a gas injection well, wherein the gas injection quantity is more than 2 PV, the injection pressure is less than the oil reservoir breaking pressure, the injection speed is 500-1000 m < 3 >/h, monitoring the underground temperature and the reaction in real time by utilizing a temperature probe and a pressure monitoring device in the initial stage of ignition reaction, and performing secondary ignition near the interlayer when the combustion front reaches near the interlayer to form a high-pressure combustion environment so as to ensure the interlayer to break.
10. The method for developing thick oil for breaking through a fireflood interlayer based on a formation adsorption combustion improver as claimed in claim 1, wherein the temperature of the combustion front in the step (5) is maintained within the range of 350-650 ℃, and the advancing speed of the combustion front is controlled within the range of 0.5-2.5 m/h.

Description

Heavy oil development method for breaking through fire flooding interlayer based on stratum adsorptivity combustion improver Technical Field The invention belongs to the technical field of oil-gas field development engineering, and particularly relates to a thick oil development method for breaking through a fireflood interlayer based on a stratum adsorptivity combustion improver. Background In-situ Combustion (ISC), also known as underground Combustion, is an important Enhanced Oil Recovery (EOR) technology, particularly for the later development of heavy and ultra-heavy oil reservoirs. The basic principle of in-situ combustion oil displacement is that under the stratum condition, crude oil in an oil reservoir is used as fuel, air or combined gas is used as combustion improver, and partial combustion of the crude oil is initiated by igniting in the oil reservoir. In the process, light crude oil is heated and distilled, gases such as light oil, flue gas and the like generated by combustion and water vapor formed by water evaporation in an oil reservoir participate in the driving action together, and meanwhile, substances remained after pyrolysis of heavy components generate coke at high temperature and serve as continuous fuel to maintain the forward movement of a fire wire. The multiple action mechanisms of heat released by combustion, superheated steam, flue gas and the like cooperatively drive unburned crude oil to move to a production well, so that the sweep range is enlarged and the recovery ratio is improved. Therefore, the stable pushing and swept volume of the combustion front in the fireflood process has an important influence on the fireflood effect. Reservoir sandwiches refer to relatively impermeable formations distributed within a reservoir or between adjacent reservoirs that are capable of completely blocking or may partially affect the movement of subsurface fluids. The oil reservoir layers can be divided into argillaceous, calcareous and calcareous layers according to lithology, and relative permeability difference exists for surrounding reservoirs. The thickness of the interlayer is smaller, generally more than ten centimeters, thicker interlayer can reach tens of centimeters, transverse distribution is unstable, the distribution area is smaller, the thickness of the interlayer is generally from a few meters to tens of meters, the transverse distribution is very stable, and the coverage area is wide. The interlayers have important influences on the flow, distribution and development effects of oil gas, are low in heat conductivity and poor in permeability, form obvious barriers to air injection, heat conduction and combustion wave propulsion, and are shown as a 'heat barrier' or a 'combustion path blocking body' in the fireflood process, so that the interlayer is one of the important manifestations of reservoir heterogeneity. Since the in-situ combustion technology is studied, the in-situ combustion technology is widely applied to later stages of oil reservoir development due to high oil displacement efficiency, high recovery ratio and wide oil reservoir application range. By igniting the oil layer, the combustion front is pushed forward, and the crude oil is heated, the viscosity is reduced and gas is generated to push the oil to flow. When a thicker or more continuous interlayer is present in the reservoir, a barrier effect is created to the vertical propagation of the high temperature front, which alters the path of the fire drive, causing the combustion front to stagnate or shift in front of the interlayer, ultimately resulting in a reduction in recovery. In addition, the interlayer upper oil layer is difficult to transfer due to heat, the temperature is slowly increased, an effective combustion area cannot be formed, the utilization rate of the reservoir is reduced, the problems of uneven combustion, limitation of an oil production area and the like are caused, and the effect of fire flooding development is greatly limited. Although technicians have achieved significant results in-situ combustion studies, most of the conventional fireflood techniques are applicable to formations with weaker heterogeneity. For stronger heterogeneity, the development blocks with interlayer shielding exist, and the current main means comprise the modes of avoiding an interlayer through well pattern adjustment, using horizontal well cross-layer well arrangement, locally injecting strong gas to enhance penetration and the like, but the methods have complex construction, high cost and poor adaptability, and cannot actively realize the damage and transformation of the interlayer structure. Disclosure of Invention The invention aims to solve the problems that an oil reservoir interlayer can inhibit combustion, so that the combustion front is easy to be blocked, a heat driving channel is not communicated and the recovery ratio is low, and provides a thick oil development method for breaking through the fire dri