CN-122014233-A - Thickened oil fireflood communication judging method

CN122014233ACN 122014233 ACN122014233 ACN 122014233ACN-122014233-A

Abstract

The invention relates to a thick oil fireflood communication judging method which comprises the steps of S1 judging whether initial communication is established according to a schematic diagram of pressure change along with ignition time after ignition of an injection well, entering S2 if the initial communication is established, carrying out on-site regulation and control if the initial communication is not established, S2 judging whether low-level communication is established according to a schematic diagram of N 2 content along with ignition time in flue gas produced by surrounding production wells, entering S3 if the low-level communication is established, carrying out on-site regulation and control if the low-level communication is not established, judging whether high-temperature communication is established according to a schematic diagram of CO 2 content along with ignition time in flue gas produced by surrounding production wells, entering S4 if the high-temperature communication is established, carrying out on-site regulation and control if the high-temperature communication is not established, judging whether effective communication is established according to a schematic diagram of oil production along with time after ignition of the surrounding production wells, and proving continuous stable oil production if the effective communication is established, and carrying out on-site regulation and control if the effective communication is not established. The method defines the single well regulation and control direction, further changes the firing direction of the firing line, and improves the overall development effect of the fire flooding.

Inventors

LI DONGXU
ZHOU HUAFENG
ZHAO CHANGHONG
Aizimaitijiang Erikny
QIN YUAN
WANG YU
ZHAO YUHAO
ZHONG WU
Liao Botou
LI GUOHUA

Assignees

中国石油天然气股份有限公司

Dates

Publication Date: 20260512
Application Date: 20241111

Claims (16)

1. The thick oil fireflood communication judging method is characterized by comprising the following steps of: S1, acquiring a schematic diagram of the pressure change trend of the injection well along with the ignition time after ignition, judging whether the injection well is in initial communication with surrounding production wells or not according to the acquired schematic diagram of the pressure change trend of the injection well along with the ignition time, and entering a step S2 if the initial communication is successfully established; S2, acquiring a schematic diagram of the change trend of the nitrogen content in the produced flue gas along with the ignition time after the surrounding production wells are ignited, judging whether the injection well and the surrounding production wells are in low-level communication according to the acquired schematic diagram of the change trend of the nitrogen content along with the ignition time, and entering a step S3 if the low-level communication is successfully established, wherein if the low-level communication is not successfully established, the surrounding production wells are required to be subjected to field regulation and control; S3, acquiring a schematic diagram of the change trend of the carbon dioxide content in the produced flue gas along with the ignition time after the surrounding production wells are ignited, judging whether the injection well and the surrounding production wells are established to be high Wen Liantong according to the acquired schematic diagram of the change trend of the carbon dioxide content along with the ignition time, and entering a step S4 if the high-temperature communication is successfully established; s4, acquiring a schematic diagram of the change trend of the oil production with time after the surrounding production wells are ignited, judging whether effective communication is established between the injection well and the surrounding production wells according to the acquired schematic diagram of the change trend of the oil production with time, if the effective communication is successfully established, starting stable continuous oil production of the production wells, and if the effective communication is not successfully established, carrying out on-site regulation and control on the production wells.
2. The method for judging fire drive communication of thickened oil according to claim 1 is characterized in that in the step S1, the method for acquiring the schematic diagram of the pressure change trend of the injection well along with the ignition time after ignition is that the pressure value is read according to an automatic control device arranged at the wellhead of the injection well, and a graph of the pressure change trend of the injection well along with the ignition time after ignition is obtained according to the read pressure value and the corresponding ignition time.
3. The method for judging whether the initial communication is successfully established or not according to claim 1, wherein in the step S1, if the surrounding production wellhead begins to produce gas, the pressure of the injection well is reduced, the initial communication is proved to be successfully established, and if the surrounding production wellhead does not produce gas, the pressure of the injection well is not reduced, the initial communication is not established successfully.
4. The method for determining the time when the initial communication is successfully established according to claim 1 or 3, wherein the method is characterized in that a schematic diagram of pressure change after ignition of an injection well is analyzed, when the pressure begins to drop for the first time, a pressure release point is indicated to begin to appear, and the ignition time corresponding to the pressure release point is the time when an underground live wire begins to advance to surrounding production wells, and is also the time when the injection well and the surrounding production wells establish the initial communication.
5. The thick oil fireflood communication judging method according to claim 1, wherein in S1, if the initial communication is not established successfully, the specific method for carrying out on-site regulation and control on the surrounding production wells is that firstly, normal well opening production of the injection well and the surrounding production wells is ensured, and then, the parameter regulation is carried out on the surrounding production wells at the same time, so that the production fluid of each production well is within +/-3 tons until the initial communication is established successfully.
6. The thick oil fireflood communication judging method according to claim 1, wherein in the step S2, the method for acquiring the schematic diagram of the change trend of the nitrogen content in the produced flue gas along with the ignition time after the ignition of the surrounding production wells is characterized in that after the ignition, the gas components at the wellhead of the surrounding production wells are monitored through a gas chromatograph to acquire nitrogen content data, and the change trend graph of the nitrogen content along with the ignition time is acquired according to the acquired nitrogen content data and the corresponding ignition time.
7. The method for determining whether the low-level communication is established successfully in step S2, wherein the method is characterized in that if the nitrogen content is greater than 0%, the low-level communication between the injection well and the surrounding production well is proved to be established successfully, and if the nitrogen content is not found in the components, the low-level communication between the injection well and the surrounding production well is not established.
8. The method for determining whether the low-level communication is established successfully according to claim 1 or 7, wherein the method is to analyze a schematic diagram of a trend of nitrogen content in flue gas produced from surrounding production wells, and the ignition time is when the N2 content in the gas component is greater than 0%, i.e. the time when the underground fire line is smoothly pushed to the surrounding production wells, and is also the time when the low-level communication is established between the injection well and the surrounding production wells.
9. The method for judging the thick oil fireflood communication according to claim 7, wherein in S2, if the low-level communication is not established successfully, the specific method for carrying out on-site regulation and control on surrounding production wells is that firstly, parameter regulation production is carried out on the wells with no nitrogen content and the production wells with adjacent nitrogen content of more than 0 percent, and if the parameter regulation is not effective, steam injection throughput effect introduction measures are carried out on the wells with no nitrogen content until the low-level communication is established successfully.
10. The thick oil fireflood communication judging method according to claim 1, wherein in the step S3, the method for acquiring the schematic diagram of the change trend of the carbon dioxide content in the produced flue gas along with the ignition time after the surrounding production wells are ignited is that monitoring the gas components at the wellhead of the surrounding production wells through a portable smoke analyzer after the ignition to acquire carbon dioxide content data, and the graph of the change trend of the carbon dioxide content along with the ignition time is acquired according to the acquired carbon dioxide content data and the corresponding ignition time.
11. The method for determining whether the high Wen Liantong is successfully established in step S3, wherein if the carbon dioxide content is >10%, the method for determining whether the high Wen Liantong is successfully established between the injection well and the surrounding production well is proved, and if the carbon dioxide content is <10%, the method for determining whether the high Wen Liantong is successfully established between the injection well and the surrounding production well is not established.
12. The method for determining whether high temperature communication is established successfully according to claim 1 or 11, wherein the method is to analyze a schematic diagram of a trend of carbon dioxide content in flue gas produced from surrounding production wells, and the ignition time is when the carbon dioxide content in the gas component is >10%, i.e. the time for achieving high temperature combustion in the direction of the production well, and is also the time for establishing high temperature communication between the injection well and the surrounding production well.
13. The method for determining thick oil fire flooding communication according to claim 11, wherein in S3, if high temperature communication is not successfully established, the specific method for performing on-site regulation and control on surrounding production wells is as follows: And (3) adjusting parameters of the wells with carbon dioxide content less than 10% and the adjacent production wells, and simultaneously performing casing pressure valve control production or direct well closing on the well with highest gas production in the production report in the surrounding production well group, so as to ensure that the fire wire is uniformly pushed in the weaker combustion direction until the high Wen Liantong is successfully established.
14. The method for determining whether or not effective communication is established successfully in step S4, wherein when the water content of the production well begins to drop and remains stable at 60-80% while the wellhead production begins to continue to produce oil stably, the method for determining whether or not effective communication between the injection well and the surrounding production wells is successful is verified, and if the standard is not met, the method for determining whether or not effective communication between the non-injection well and the surrounding production wells is not established.
15. The method for determining the time for successfully establishing the effective communication according to claim 1 or 14, wherein the method comprises the steps of analyzing an oil production diagram of surrounding production wells, and when the oil production starts to rise, proving to enter a flue gas flooding stage, wherein the ignition time is the time for establishing an oil wall in the direction of the production well and stably advancing, and is the time for establishing the effective communication between the injection well and the surrounding production wells.
16. The method for judging fire flooding communication of thickened oil according to claim 1, wherein in the step S4, if effective communication is not established successfully, the specific method for carrying out on-site regulation and control on surrounding production wells is that through carrying out throughput and efficiency guiding on the production wells, a live wire is pulled to burn towards the direction of the throughput and efficiency guiding well until effective communication is established successfully.

Description

Thickened oil fireflood communication judging method Technical Field The invention belongs to the technical field of thickened oil development, and particularly relates to a thickened oil fireflood communication judging method. Background In the thick oil development, fireflood is an important thick oil extraction mode, a large number of mine tests are carried out at home and abroad in recent years, and the fireflood development main technology is basically mature. However, as the fire flooding mechanism is very complex, the fire flooding combustion has great difficulty in regulating and controlling the fire line, and under the condition of no effective and accurate fire line monitoring means, a method suitable for judging the communication between the high-temperature fire flooding injection and production wells of the waste oil reservoir after the thick oil is injected with steam needs to be searched, and technical support is provided for the fire flooding regulation and control so as to improve the overall exploitation effect of the fire flooding. The general recovery rate of general steam huff and puff exploitation is only 10% -25%, and the total recovery rate after the development of the rotary fireflood can reach more than 60%. In the prior art, the invention with the publication number of CN104612666A discloses a method for describing the fire-flooding combustion front position of a linear well pattern, firstly, according to the definite injection and production well position relation, the injection well ignites an oil layer, then the communication condition of the well is judged by continuously monitoring the change relation of the injection pressure of the injection well along with time in the gas injection process, the acid value among the wells is intermittently measured to judge the fire-line position, the continuous injection of air into the injection well is ensured during fire flooding, the continuous combustion of the oil layer is ensured, and thus the combustion dynamics of the fire flooding and the related parameters of a reservoir are mastered. The method has enough sampling data, extracts oil samples at the same time, has extremely large workload for field implementation, and simultaneously does not need to obtain the oil samples at the same time for subsequent analysis and judgment of manufacturing difficulty. In the prior art, the invention with the publication number of CN104612666A provides a method for monitoring the temperature of the front edge of a live wire. The method comprises the steps of injecting the isotope labeled tracer into the gas injection pipeline when the gas injection well injects gas, injecting the tracer into the bottom of the well along with air, sampling and analyzing the tracer from the production well at fixed time, and judging the combustion temperature of the oil layer by detecting the decomposition products containing the corresponding isotopes. The method is applied to monitoring the combustion temperature of the oil layer in the in-situ combustion ignition process and the production process of the heavy oil reservoir, and can judge the combustion state and the communication state of the oil layer. The technology has the defects that firstly, the tracer suitable for high temperature is very limited, secondly, the tracer is adopted with higher cost, and the monitoring cost for monitoring the temperature of the live wire in one area by using the mode is very high. Disclosure of Invention The invention aims to provide a thick oil fireflood communication judging method for overcoming the technical defects. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The thick oil fireflood communication judging method is characterized by comprising the following steps of: S1, acquiring a schematic diagram of the pressure change trend of the injection well along with the ignition time after ignition, judging whether the injection well is in initial communication with surrounding production wells or not according to the acquired schematic diagram of the pressure change trend of the injection well along with the ignition time, and entering a step S2 if the initial communication is successfully established; S2, acquiring a schematic diagram of the change trend of the nitrogen content in the produced flue gas along with the ignition time after the surrounding production wells are ignited, judging whether the injection well and the surrounding production wells are in low-level communication according to the acquired schematic diagram of the change trend of the nitrogen content along with the ignition time, and entering a step S3 if the low-level communication is successfully established, wherein if the low-level communication is not successfully established, the surrounding production wells are required to be subjected to field regulation and control; S3, acquiring a schematic diagram of the change trend of the carbon dioxide