GEOPHYSICS INTERPRETATION OF SUBSIDENCE MEASUREMENTS [PHASE 1]

Cel

This project consists in measuring subsidence movements induced by pressure charges associated to reservoir depletion in view of evaluating that depletion. These subsurface movements are then converted into reservoir pressure charges versus space and time using a F. E. model of all relevant layers i. e. overburden, reservoir and underburden. Finally this pone pressure map is converted into a permeability map in both reservoir and aquifer.
- Bad weather has induced trouble with tiltmeters.
- 3 surveys carried out by IGN have pointed out a subsidence of 1 cm/year. Converted into pressure variations, this subsidence has allowed to derive a pressure map in accordance with production history and geology.
Before the method can be applied at larger scale it is necessary to prove that the pressure variations in the reservoir provoke movements that can be detected from the subsurface.
The present project thus consists :
- in a first step, in measuring the subsidence generated by the production of a well within the VILLEPERDUE reservoir (operated by TOTAL-CFP, partner TRITON),
- in a second step, in deducing thereby the possible distribution of the pressure variations existing within the pay zone area
PHASE 1- MEASUREMENT OF SUBSIDENCE MOVEMENTS
The VILLEPERDUE field is formed by a carbonate reservoir located in the upper layers of the DOGGER. The production layer is located at a depth of about 1 850 m.
- a first step, performed on a "versus structure" (Hautefeuille) will allow to optimize the display of the tiltmeters around HFE1 well,
- a second step which will allow to implement benches a sine crossing both Villeperdue and Hautefeuille structures
This phase will include the following tasks :
- layout of inclinometres
- postioning of level beacons
PHASE 2 - ELABORATION OF A NUMERICAL MODEL
This step will include :
- Evaluation of the deformation generated by placing well HFE1 on prodution using tiltmeters
- Measurement of a cross section of the subsidence bowl using optical devices.
PHASE 3 - INTERPRETATION OF MEASUREMENTS
Tasks related to this phase only began when a significant subsidence had been outlined. These tasks allowed the plotting of a map of the pressure variations around the well in relation to the time. They included :
a) Development of a method of numerical resolution of the reverse problem in which the subsurface movements are the data enabling the pressure variations within the reservoir to be defined.
b) Determination of the mechanical properties of the entire deformable massif (analysis of the logs and drilling parameters - laboratory measurements).
c) Interpretation of the inclinometry measurements and the level curves, first by means of aradial symetry model and second with the aid of a three-dimensional model.

Program(-y)

ENG-HYDROCARB 2C - Programme (EEC) of support for technological development in the hydrocarbons sector, 1986-1989

Temat(-y)

1.5 - IMPROVED OIL RECOVERY

Zaproszenie do składania wniosków

Data not available

System finansowania

DEM - Demonstration contracts

Koordynator

GERTH

Wkład UE

Brak danych

Adres

232 AV. NAPOLEON BONAPARTE
92500 Rueil Malmaison
Francja

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