Method of monitoring unconventional hydrocarbon exploration and development sites

Patent metadata

Field	Value
Publication number	US-9810064-B2
Application number	US-201514670940-A
Country	US
Kind code	B2
Filing date	Mar 27, 2015
Priority date	Apr 7, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

The present invention is a method of monitoring recovery site hydrocarbons (HC) using an unconventional method which permits quantifying the HC present in zones above the exploration and development zone. The method according to the invention is based on the adjustment of a model describing the gas concentration as a function of time, using in-situ geochemical analyzes of rare gases and, when appropriate, of injected gas used for fracturing, contained in fluid phases of subsoil samples. By use of rare gas analysis, the method according to the invention allows anticipation of hydrocarbon leakage above the exploration/development site.

First claim

The invention claimed is:

1. A method of monitoring an underground formation to recover hydrocarbons using simulation and drilling and at least one rare gas present in the underground formation, comprising:
a) selecting a diffusion model of the at least one rare gas and a diffusion model the hydrocarbons to be recovered with each model including an evolution of concentration as a function of time and depth and a diffusion coefficient;
b) taking at least a first sample of fluid present in a subsoil zone which is being monitored that is located above the underground formation prior to recovery of the hydrocarbons by using a downhole sampler and measuring a concentration of the at least one rare gas within the first sample of the fluid;
c) fracturing the underground formation;
d) at least one of during and after recovery of the hydrocarbons, taking at least a second sample of the fluid present in the subsoil zone and measuring a concentration of the at least one rare gas within at least the second sample;
e) repeating d) at different times;
f) determining when the concentration of the at least one rare gas increases in the at least a second sample from the concentration of the at least one rare gas in the first sample and modifying the diffusion coefficient of the diffusion model of the at least one rare gas to be coherent with the increased concentration of the at least one rare gas in the at least a second sample and determining a ratio between the diffusion coefficient before modification and the modified diffusion coefficient; and
g) incorporating the ratio into the diffusion model of the hydrocarbons to be recovered and thereafter determining from the diffusion model of the hydrocarbons incorporating the ratio an amount of hydrocarbons in the subsoil zone that can be recovered at a time t.

2. A method as claimed in claim 1 , wherein the subsoil zone is an aquifer.

3. A method as claimed in claim 1 , wherein leakage of the hydrocarbons to be recovered from the underground formation is detected using an amount of the hydrocarbons which are determined to be recoverable in the subsoil zone.

4. A method as claimed in claim 2 , wherein leakage of the hydrocarbons to be recovered from the underground formation is detected using an amount of the hydrocarbons which are determined to be recoverable in the subsoil zone.

5. A method as claimed in claim 1 , wherein the fracturing is performed by injecting gas.

6. A method as claimed in claim 5 , wherein an amount of fluoropropane which is injected into the monitoring zone or an amount of helium present in the monitoring zone at the time t is determined by incorporating the ratio into the diffusion model of the hydrocarbons.

7. A method as claimed in claim 6 , wherein the injected gas comprises at least one rare gas.

8. A method as claimed in claim 5 , wherein the injected gas comprises at least one rare gas.

9. A method as claimed in claim 8 , wherein the at least one rare gas comprises at least one of helium and argon.

10. A method as claimed in claim 5 , wherein the injected gas comprises fluoropropane or helium.

11. A method as claimed in claim 1 , wherein the hydrocarbons contain methane.

Assignees

• Ifp Energies Now
• Ipf Energies Now

Inventors

• Garcia Bruno

Classifications

• G01N33/241

  for hydrocarbon content · CPC title

• G01N33/0036

  specially adapted to detect a particular component (physical analysis of gaseous biological material G01N33/497) · CPC title

• E21B49/088 Primary

  combined with sampling · CPC title

• E21B43/168

  Injecting a gaseous medium · CPC title

• E21B47/1015

  Fixed Constructions · mapped topic