Page 207 - Primer on Enhanced Oil Recovery

EOR on site implementation 195

analysis and equipment manufacturing for analysis field is dominated at the
moment by three companies:

Vinci Technologies
Chandler Engineering

Core Laboratories

16.2.2 Core analysis
To determine the permeability of reservoir liquids through formation rock at the reservoir
conditions it is necessary to account carefully for several factors. These are: lithostatic or
rock pressure, pore pressure and temperature. For creation of these conditions there are
automated reservoir conditions modeling systems (equipment). The systems are designed
and build for core research under conditions simulating reservoir. The analysis in general
can be done in a wide range of specified values of pressures and temperatures.
All core studies can be divided into two large groups: standard and special core
analysis.
Standard core analyzes are carried out in order to determine the parameters nec-
essary for calculating geological reserves of oil and gas. This include oil and water
saturation, porosity, permeability, pore size distribution, saturation distribution pat-
tern over OWC (oil-water contact angle values).
Special core studies are carried out in order to obtain reliable baseline data for
hydrodynamic modeling of deposits: relative phase permeability during two- and
three-phase filtration; oil displacement factors with water, accounting for driving/
dissolved gas and various injected chemicals.
The main manufacturers of core analysis systems are:

Vinci Technologies
Coretest Systems
Core Laboratories

16.3 EOR implementation

After conducting a hydrodynamic simulation and obtaining positive results for the
proposed EOR in the pilot area, the project proceeds to the full implementation.
Usually, a pilot site with an injection well (typically a 5 7 point system is used)
with surrounding production wells (see Fig. 16.2) is taken at the field.
In order to monitor and evaluate the process and determine the mechanism
before and after the start of the event, a number of necessary studies are carried out
at the wells. Before the start of the event, production logging studies are carried out
at the production well to assess the vertical sweep efficiency.
The process influence efficiency should be assessed by collecting and comparing
data on all processes. Usually Production Logging (so named PLT, where T can stand
for Technique or Tool) is implemented and employed. With certain periodicity PLT
logging studies need to be repeated at all well (exploration, injection, production) (see
a log examples at Fig. 16.3).