Summary
The Kansas Class 2 project was a demonstration project in
an Osagian and Meramecian (Mississippian) shallow shelf carbonate
reservoir in west central Kansas. Cumulative production from
Mississippian carbonate reservoirs located beneath a regional
sub-Pennsylvanian unconformity is over 1 billion barrels distributed
over a large number of small to medium size reservoirs. Small
independent producers operate many of these reservoirs. Extremely
high water cuts and low recovery factors place continued operations
at or near their economic limits.
Application of cost-effective reservoir description and management
strategies can significantly extend the economic life of these
mature peritidal carbonate fields and recover incremental reserves.
Equally important is innovative dissemination of the data, methodologies,
and results to foster wider application of demonstrated technologies
by the numerous operators of similar fields throughout the northern
Mid-continent and US. Producibility problems in Kansas Meramecian
and Osagian dolomite reservoirs include inadequate reservoir
characterization, drilling and completion design problems, and
non-optimal primary recovery.
The project entailed integration of existing data, drilling
and coring of three new wells through the reservoir interval.
Descriptive core analysis, petrophysical and petrographic analysis
(e.g. capillary pressure and NMR), calibration of logs and core
data, and integration of existing well data into a computerized
three dimensional visualization/simulation that was used to develop
a digital reservoir model and management plan for the Osagian
and Meramecian rocks at the Schaben site. Analysis indicates
significant potential incremental reserves through targeted infill
and horizontal drilling in this major producing trend.
At the Schaben demonstration site, integrated reservoir characterization
provided the basis for development of a descriptive reservoir
model and the framework for simulation. A publicly accessible
and comprehensive digital reservoir database using existing and
newly acquired data was distributed through the Internet. New
data from the three new wells provided insight into fundamental
reservoir parameters (e.g., core plug NMR analysis to determine
effective porosity and relationship to facies). As part of the
Kansas Class 2 project a number of cost-effective tools and techniques
for reservoir description were developed, modified and demonstrated.
These include:
- a new approach to subsurface visualization using electric
logs ("Pseudoseismic")
- a low-cost easy-to-use spreadsheet log analysis software
(PfEFFER)
- an extension of the BOAST-3 computer program for full field
reservoir simulation.
The Kansas Digital Petroleum Atlas model was used to provide
rapid and flexible dissemination of the project results through
the Internet.
The most significant Kansas Class 2 project results are
- development of an on-line comprehensive digital reservoir
database
- acquisition of additional core, electric log and test data.
- construction of an integrated geologic reservoir characterization
using cost-effective approaches to data analysis
- full-field reservoir characterization and simulation using
publicly available or low-cost software
- identification of potential incremental reserves that can
be accessed through targeted infill and possible horizontal drilling
- development of a regional database for evaluation of potential
for horizontal and targeted infill drilling in similar Mississippian
reservoirs of Kansas
- new models for innovative technology transfer. An improved
understanding of Mississippian subunconformity reservoirs in
Kansas has been developed and new cost-effective techniques have
been demonstrated for the identification of incremental reserves
at the Schaben Field demonstration area and at similar reservoirs
throughout Kansas and the Mid-continent.
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