Information Technology Reference
In-Depth Information
Fig. 13.9
Borehole reconstruction using triangle strips
Figure
13.10
shows one simple example of this process. Given a pair of sec-
tions, let's call A the upper section indicated by black dots and B the white ones.
From left to right (i.e., from the first arm or control point to the last one), we add to
the triangle strip the first vertex from A and B, in this order (points 1 and 7 in the
figure). Then, we move to the next pair and add the new points from A and B
(2 and 8), and so on until all vertex from both sections are added. The first two
points are added again in the end, so the strip closes the section. Each new point
added after the first pair results in the creation of a new triangle (1-7-2 and 7-2-8,
for example). When the process is over, a small mesh connecting two sections is
created. Applying these steps to all sections it results in a 3D representation of the
borehole. Listing
13.1
describes a pseudo-code for this process.
13.6 Analysis and Information
Study of borehole stability requires not only a deep knowledge of problems'
sources, but it is accurate identification and modeling. When a borehole is drilled
in a nonisotropic prestressed rock, we can note a failure, which is a result from the
reorientation of the stress field and the stress concentration around the borehole
wall. The stability of an oil reservoir is a challenge for specialists of the petroleum
industry; therefore, a correct analysis of this question can reduce the perforation
cost significantly. It can be considering that a considerable time expense to per-
forate a hole is related to the analysis of its stability, which means an annually high
cost.
The caliper tool is used in this purpose for gathering data such as resistivity and
acoustic measures of the borehole wall, as well as diameter for each section. These
data can be used to identify problematic points where tension could lead to the
borehole's collapse.
Search WWH ::
Custom Search