| Abstract | Increasingly, oil and gas companies are prospecting and producing in areas that relatively recently
would have been considered uneconomic or even impossible to explore. This includes operating in
ever deeper waters and moving into more remote and hostile environments. Over the past 30 years,
offshore drilling has progressively been pushing back the frontiers of technology. Water and drilling
depths have increased dramatically as the search for hydrocarbons has moved towards the outer
edge of the world’s continental shelves. This search has also advanced to some of the earth’s most
remote, extreme and often vulnerable environments, including the Arctic.
Both the costs and the risks of offshore drilling increase in deeper waters. The issues faced are
significant and complex. To fully understand why deepwater introduces new complications and
challenges, we need also to understand the technical difficulties involved in drilling in extreme
environments.
This report will examine the d e e p w a t e r w e l l p l a n n i n g a n d c h a l l e n g e s i n v o l v e w i t h
t h i s a c t i v i t i e s .
The first part of the report will provide an overview of deepwater well planning processes and
techniques and in particular the technical and operational challenges facing in deepwater. Drilling
rig selection and riser design may be the most critical part of well planning, because rig
selection involves with the 30-40% cost of the total drilling period, and riser design involves
with the metocean challenges. Drilling fluid system design is another important event in case of
deepwater drilling due to narrow pore pressure and fracture gradient window.
The second part of the report contains technical, financial and SSHE challenges involve with
deepwater drilling. Pore pressure and fracture gradient prediction is a major geological
challenge of the deepwater because of narrow window in deepwater. Mooring and station
keeping is a challenge for rig positioning. Vortex Induced Vibration (VIV) is a major challenge
for riser design.
Financial challenges involve with rig rent and long lead item (LLI) cost in deepwater.
Deterministic approach is not allowable in case of cost estimation because of the volatile oil
price which can change the rig rent, LLI cost, and third party cost. A Probabilistic approach is a
best suited method for cost estimation. Logistic challenges involves due to distance and variable
sea condition.
Security, Safety, Health, and Environment (SSHE) is also a major challenge for deepwater due
to small area of working place and remoteness of the drilling site. In case of unwanted event
well control is a difficult things to manage, and almost impossible for relief well. |