SYNERGISTIC TEAMS
The need to get a better economic return
from our producing properties and fields is greater than ever.
Gas prices are down, rig count is down and some operators are
disposing of their U.S.A. properties and investing in other countries.
The buyers of these "cast off" properties anticipate generating
as high a return on these properties as the seller hopes to
achieve in other countries and apparently is being very, successful
of it using synergistic teams. We think, that the same opportunity
exists for the seller.
The synergistic team brings together, professionals of all
disciplines that pool ideas and compliment each other to find,
develop and produce an oil and gas property. With the interactive
exchange and flow of ideas, the views and needs of the professionals
with the most information on the property are shared and solved
quickly. Better results are produced in less time because information
flows in many directions at one time and all the professionals
are working on the solution at the same time.
APPLIED PETROLEUM ENGINEERING
For The Non-Petroleum Engineer
Subsurface Consultants will conduct
it's "Applied Petroleum Engineering for the Non-Petroleum Engineer" course
in Dallas on November 14, 1991. This course is designed for
the non-petroleum engineer and covers basic petroleum engineering
in laymen't terms and focuses on using volumetric and performance
techniques to evaluate oil and gas properties. A course manual
with explanations, graphs, charts and sample problems are included.
HORIZONTAL WELL RESULTS
Subsurface Consultants & Associates, Inc. recently generated
the graph in the following figure 1 to show the rate of increase
from a horizontal well with various lateral lengths for different
drainage areas. This graph is for a well in a homogenousisotropic
sand with no fractures. To use the curves in Figure 1, the
evaluator must determine the drainage area of a representative
vertical well for the area of interest. The deliverability
improvement for a horizontal well with various lateral lengths
is read from the appropriate drainage area curve in Figure
1. Most often reservoirs exhibit different rock characteristics
in the vertical and horizontal directions, i.e., are not homogenous
and isotropic. The greater the difference in perameability
in tyhe vertical and horizontal directions the smaller the
increase in deliverability acheived by a horizontal well. The
curves in figure 2 can be used to estimate the impact of difference
in the vertical and horizontal permeability for the reservoir
being evaluated. For example, a 500 foot horizontal lateral
in a 20 acre drainage pattern would result in a 4.7 fold in
crease in deliverabliity over a vertical well in a homogebour
isotropic sand (Figure 1). If the vertical to horizontal permeability
is 0.1, the increase is reduced, but is till about 3.7 (Figure
2).
QUICK LOOK TECHNIQUE
Odd Number of Countours
A basic rule of contouring is that ALL countours on a continous
surface must close or end at the edge of the map. This rule seems
so obvious and simple that no one could break this rule of contouring.
Figure 3 is a relatively simple structure map with a few faults.
Consider the area to the right of the major down-to-the-east
fault. Is there a contouring problem? Starting at the 10,300
foot contour, try to go around the small finite fault and return
to the 10,300 foot contour. Can it be done? The answer is no.
Five contours terminate against the finite fault; therefore,
a contour is dangling. In other words, one contour does not close.
One contour is missing. All contours must close. There must be
an even number of contours around a finite fault such as the
one shown in Figure 3. This type error is very common. A quick
way to check a map with a small fault which dies in both directions
is to count the number of contours intersecting or terminating
against the fault. If ther is an odd number of contours, the
construction is wrong. This may be a minor mapping bust, but
if you find several on one map, it may be time to quesiton the
accuracy of the map.
ERRATA
To all purchasers of the mapping test
"Applied Subsurface Geological Mapping"
by Tearpock and Bischke.
The three-dimensional equation (4-6)
on page 72 in the text for co nverting measured log thickness
to true vertical thickness is in error. We thank Charles R.
Berg for bringing this to our attention. The equation shown
below is the corrected equation (4-6) and should replace the
old equation for all computations. The corrected equation was
first presented in 1958 by Setchell (Setchell,J., 1958, A Nomogram
for Determining True Stratum Thickness; Shell Trinidad, EP
28884, Abstract in PA Bulletin, No. 127/128, May/June 1958,
N.V. DeBataafache Petroleum Maatschappij, The hague, Production
Department, p.8.) and has been used successfully for over 33
years.
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