Method for producing heavy oil by generating solvents in situ in the reservoir

Patent metadata

Field	Value
Publication number	US-2022205345-A1
Application number	US-202117536130-A
Country	US
Kind code	A1
Filing date	Nov 29, 2021
Priority date	Dec 31, 2020
Publication date	Jun 30, 2022
Grant date	—

Abstract

The disclosure relates to a method for producing heavy oil by generating solvents in situ in the reservoir, an electric heating device is used to heat up the crude oil in the reservoir near the wellbore to the target temperature. Chemical reaction additives are injected into the heating section to meet the preset reaction conditions for the high temperature thermal cracking and aquathermolysis of crude oil, so as to generate light hydrocarbon components and gases. Under the effect of heat and gravity, the light hydrocarbon components and gases rise to the steam chamber. The light hydrocarbons and some gases that move to the vapor-liquid interface of the steam chamber are dissolved in the crude oil to reduce the viscosity of crude oil and increase the production rate of crude oil.

First claim

1 . A method for producing heavy oil through solvents generated in situ in a reservoir, comprising the following steps:
run a guiding conduit to the rear end of a horizontal section in a liner of a horizontal producing well located at the lower part of the reservoir; run a coiled tube with a pre-installed heater to the horizontal section from a conduit, where the heater is arranged at the terminal end of the horizontal section; place and expand a thermal packer in an annulus between the liner and the conduit in the horizontal section, to separate the annulus of the horizontal section into two disconnected independent well sections, a production section in the uphole section and a cracking reaction section in the downhole section, wherein the coiled tube with the heater is arranged in the cracking reaction section; turning on a power supply and input electric power to the heater to heat up the reservoir near the wellbore; monitor the wellbore temperature with a thermocouple or an optical fiber in the coiled tube, add one or more chemical reaction additives to the cracking reaction section through the conduit after a surface temperature reaches a target temperature of 200-450° C., to enable the high temperature thermal cracking and aquathermolysis reaction of the crude oil; turn on the a downhole pump to lift the mixture of crude oil and condensed water to the ground through the production tubing after the bottom hole pressure and the temperature of production section reach the preset values.

2 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 1 , wherein a cable, the thermocouple or an optical fiber for temperature monitoring and the downhole heater are installed in the coiled tube.

3 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 1 , wherein the electric heating method is applied for the cracking reaction section, i.e., heat conduction type resistance heating or induction type electromagnetic field or microwave.

4 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 2 , wherein the surface temperature of the heater is set according to the optimum thermal cracking and aquathermolysis temperature of crude oil, and changes within 200-450° C.

5 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 1 , wherein the chemical reaction additives injected into the conduit are selected from one or any combination of hydrogen, oxygen, air, water and metal ion catalyst.

6 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 5 , wherein the type of chemical reaction additives injected and the injection rate are determined by the crude oil component, parameters for cracking reaction kinetics and operating pressure of steam chamber.

7 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 6 , wherein the operating pressure of the steam chamber is maintained at 2.0-5.0 MPa.

8 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 1 , wherein the crude oil in the cracking reaction section comes from the crude oil drained from the upper reservoir along the vapor-liquid interface of the steam chamber, crude oil is cracked in the cracking reaction section, light hydrocarbon components and gases flow back into the steam chamber, upgraded oil and condensate are produced through the production section.

9 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 1 , wherein in the high temperature cracking process of crude oil, while the light hydrocarbon components and non-condensable gases are generated, the heater continuously heats up the reservoir and the condensed water in the near wellbore formation is heated to generate extra steam and replenish energy for the steam chamber.

10 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 1 , wherein in the original reservoir or the reservoir after steam huff and puff, the operating pressure of cracking reaction section in the producing well is equal to or slightly higher than the current reservoir pressure.

11 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 1 , wherein the light hydrocarbon components refer to the saturated hydrocarbons with the carbon number less than 10, and the non-condensable gas refers to CO 2 , N 2 , O 2 , H 2 , CO, CH 4 , H 2 S or their mixture.

12 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 1 , wherein the fluid temperature entering to the downhole pump is less than the saturated steam temperature at bottom hole pressure to ensure that the fluid does not flash.

13 . The method for producing heavy oil through solvents generated in situ in the reservoir according to claim 1 , wherein the chemical reaction additives enter into the annulus of the production liner via the guiding conduit inlet of the cracking reaction section and then into the formation via the production liner; and the fluid in the production section enters into the production liner and is lifted to the ground via the downhole pump, realizing the whole process of injection and extraction in the same wellbore.

Assignees

• Univ Southwest Petroleum

Inventors

• Jiang Qi
• Liu Jiali
• Wu Fangjie
• Huang Siyuan
• Yu Chunsheng
• Zhou Xiang
• Wang Zhibin
• Zhang Yang
• Huang Ke
• He Jie

Classifications

• E21B43/2408 Primary

  SAGD in combination with other methods · CPC title

• E21B43/16

  Enhanced recovery methods for obtaining hydrocarbons · CPC title

• E21B36/04

  using electrical heaters · CPC title

• E21B43/241

  combined with solution mining of non-hydrocarbon minerals, e.g. solvent pyrolysis of oil shale · CPC title

• E21B47/06

  Measuring temperature or pressure · CPC title