ABSTRACT
A major drawback of directional and horizontal well drilling is the
numerous complex computations required to be done while planning a well.
These computations are very stressful and time consuming especially
when done manually.
One of the objectives of this study was to develop a user friendly
Excel Spreadsheet program that would make the computations of these well
trajectory parameters easier, faster and accurate.
An Excel Spreadsheet program was developed employing the Minimum
Curvature method (and for other five methods) for wellpath design and
planning. This would help increase the usage of these trajectory methods
especially the Minimum Curvature method.
The program is able to provide pictorial views both in the vertical
and horizontal plane of the trajectory of the drilling bit’s position in
the wellbore. This would therefore help to minimize risk and
uncertainty surrounding hitting predetermined target. This is possible
because deviations can easily be detected and the necessary directional
corrections or adjustment be initiated to re-orient the drilling bit to
the right course before (planning process) and during the drilling
operations.
CHAPTER 1
FORMULATION OF THE PROBLEM
1.1 Introduction
Directional drilling is the science and art of deviating a wellbore
along a planned course to a subsurface target whose location is a given
lateral distance and direction from the vertical (Bourgoyne et al,
1991). Directional drilling and horizontal wells represent an efficient
way to achieve or hitting special targets that may or are very difficult
to reach using vertical wells (Tarek, 2000). Directional drilling is
relatively done to increase production rates, control water and gas
conning, control sand production and increase recovery rate (Bourgoyne
et al, 1991). There are many reservoirs which can not be tapped by
vertical wells or would be uneconomical to exploit with vertical wells
(Bourgoyne et al, 1991). Other reservoirs are also characterized by
vertical permeability or the pay zones may be very thin and producing
with vertical wells would require quiet a number of them which would
make vertical wells to be very uneconomical in such situations. The
application of vertical wells in such formations could also result in
lower ultimate recovery (Tarek, 2000). In such low permeability
formations, the only way out is to use directional and horizontal well
technology which has over the years proved to enhance ultimate recovery
(Bourgoyne et al, 1991). Due to the more economical nature of
directional and horizontal wells over vertical wells in most cases, they
are mostly the preferred technology in offshore drilling technology
(Bourgoyne et al, 1991).
1.2 Problem Definition
A major drawback of directional and horizontal well drilling is the
numerous complex computations required to be done ahead of time before
drilling resumes and also during drilling operations (Sawaryn, 2005).
These computations become very stressful and more complex when done
manually. The programs available in the market used for these
computations are usually very expensive to acquire, but the development
of a user-friendly Excel Spreadsheet program which employs the Minimum
Curvature method for wellpath planning would help minimize the stress
and time in executing these complex computations. More importantly, an
Excel Spreadsheet program is very flexible and can easily be modified or
updated at any point in time to meet the needs of the industry.
This study seeks to use the Minimum Curvature Method to design well
path using Excel Spreadsheet to determine the optimum well path
parameters. This would help reduce risks and uncertainty or prevent
deviation from target, minimise non-productive time and reduce drilling
cost. This would therefore enhance planning process and maximizing
return on investment.
1.3 Objectives of Study
The objectives of this study are:
1. To develop a user friendly Excel Spreadsheet program that
will make the computations of well trajectory parameters easier, faster
and accurate.
2. Use the Excel Spreadsheet program to evaluate and compare
some of the survey calculation method available for the industry.