High Pressure High Temperature (HPHT) Well Design

The depletion of existing fields & scarcity of easier reservoir targets in Malaysia
have forced the National Oil Company (NOC) to explore new plays such as
deepwater drilling, high pressure high temperature (HPHT) drilling & reopen
onshore exploration block in Malaysia. These strategies have proven to be successful
especially by recent onshore discovery after 24 years by an international operator.
However, it must be emphasised that the operator is unable to drill to deeper HPHT
sand pays that may have high hydrocarbon quantity due to limitations associated
with HPHT conditions such as:
• Narrow drilling window margin between pore & fracture pressures
• Reduced kick tolerance
• Higher probability of operational problems such as lost circulation, stuck pipe
& well control issue
Due to these limitations, HPHT wells often have higher non-productive time (NPT)
committed in resolving operational problems particularly lost circulation & well
control issue in narrow drilling window margin compared to conventional wells that
result in higher economic risk. Thus, there is a requirement to have proper HPHT
well planning & design to maximize safety, eliminate NPT & increase efficiency.
This paper presents the approach in planning & designing optimum onshore HPHT
well design using well design package software based on real field data. Within this
approach, a refined kick tolerance calculation used in casing shoe setting depth
selection is introduced by incorporating the effect of temperature which is dominant
in HPHT well. In addition to that, this paper also presents the optimization of casing
design & wellbore hydraulics that complies with NOC drilling standards to ensure
that this well is able to reach its objective target depth safely & fulfil all of its
objectives. It must be noted that this paper is limited to elements present in typical
Basis of Well Design (BOWD).