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Abstract
Improving drilling performance leading to reduction in Well drilling time and
the associated costs, without compromising the deliverability of the Well, is
the primary objective of drilling engineering. Some of the major challenges
faced by Drilling Engineers include damage to the pay zone while drilling the
reservoir section, lost circulation problems, drilling of hard and abrasive
formations and more. With recent advances in drilling-related technologies,
these issues have been addressed and tremendous time and cost benefits have
been realized.
OMV has been drilling high temperature vertical gas wells up to 4000m in Sindh,
Pakistan. For drilling the reservoir section, OMV Pakistan pioneered the use of
high temperature Formate Brine systems. These are solids free, high temperature
stable drilling fluid systems which incur minimal damage to the reservoir.
Application of these has yielded excellent results in terms of drilling as well
as reducing skin damage.
To combat lost circulation, OMV Pakistan introduced and successfully
implemented the concept of Advanced Engineering Fibers (AEF) mixed in mud to
control the losses in fractured limestone formation. The AEF-mud pill soaks, or
can be squeezed, into the formation and immediately creates a fiber-net barrier
preventing further losses. The successful implementation of this technology is
a landmark achievement in controlling mud losses.
Through optimized bit design and selection process, OMV Pakistan was able to
realize its goal of ‘One Bit per Section’ drilling. Well Sawan-11 was drilled
to a depth of 3415m with a milestone single bit run of 1758m at an average ROP
of more than 25 m/hr. The bit was pulled ‘Green’ with minimal damage to
cutters. This resulted in less drilling time and tremendous cost saving.
This paper presents accomplishments, experience, and lessons learned related to
drilling in the Sindh area where the reduction of drilling time from nearly 3
months to around 3 weeks is an outstanding outcome of the “Pushing The Limits”
concept.
Introduction
The Oil and Gas industry today requires better technologies to tap challenging
reservoirs for sustained production of hydrocarbons in the future. Drilling of
complex wells, such as extended reach, horizontal, multilateral, hostile
environment (HPHT) and the like, has already been witnessed. Yet the focus
remains on drilling similar Wells faster and cheaper without compromising the
Well deliverability. This requires innovation and creativity in technology
development while at the same time, and more importantly, willingness and
commitment from Management to push for change and put new technologies to test.
Only then can these be fully developed and adapted universally for the over-all
benefit of the E&P Industry.
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