Well test interpretation in heterogeneous reservoirs with skin and afterflow: Some new theoretical solutions and general field experience

Conference · Sat Oct 01 04:00:00 EDT 1983 · Soc. Pet. Eng. AIME, Pap.; (United States)

OSTI ID:5293935

Nikoh, H

Some new analytical solutions for dimensionless pressure vs. dimensionless time are presented. It is demonstrated how these new solutions, together with existing ones, can be used for unravelling reservoir heterogeneity patterns, quantitative interpretation of selected field tests, and well test design. The field tests cover both naturally fractured carbonates and layered sandstones. Two examples of well test interpretation in naturally fractured formations reinforce the conclusions of other authors, namely that well test interpretation based only on 2 parallel semi-log straight lines is questionable in cases with afterflow. The new analytical solutions refer to stratified and heterogeneous systems with interlayer crossflow. In both cases after-flow and skin factor are included. It is shown how the type curve can be used in certain long pressure build-ups to gain information on the average reservoir pressure in a stratified system. In the pressure behaviour of a heterogeneous system with interlayer crossflow, there is often quite a long transition zone before the system behaves like a single reservoir. This requires careful planning of test duration. In particular, the early part of the transition zone, looked at in isolation, may give a false impression of pressure stabilisation, which could lead to the interpretation of small drainage areas or a gross over-estimation of the system permeability.

• Research Organization: Shell EP Laboratories
• OSTI ID: 5293935
• Report Number(s): CONF-8310121-
• Conference Information: Journal Name: Soc. Pet. Eng. AIME, Pap.; (United States) Journal Volume: SPE11964
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200 -- Petroleum-- Reserves
Geology
& Exploration
020300* -- Petroleum-- Drilling & Production
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
030300 -- Natural Gas-- Drilling
Production
& Processing
ANALYTICAL SOLUTION
FLUID FLOW
FLUIDS
FRACTURED RESERVOIRS
HETEROGENEOUS EFFECTS
NATURAL GAS WELLS
OIL WELLS
PATTERN RECOGNITION
RESERVOIR FLUIDS
RESERVOIR PRESSURE
RESERVOIR ROCK
ROCK-FLUID INTERACTIONS
STRATIFICATION
TESTING
WELLS