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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OMV Pakistan applied an original design of Genesis XT fixed cutter bit with improved features for bit stability to drill the 8.5" section of Sawan-11 development gas well in southern Pakistan. Multiple vertical wells were drilled in this field with similar parameters and operating conditions. Latest proven technology was applied successfully to drill the 1760m of 8.5" section with record ROP of 25 m/hr which is more than twice as fast compared to previous wells records. Instantaneous rates in excess of 70 m/hr were also recorded while drilling this section. This section was previously drilled with multiple bit runs using multiple roller cone and PDC bits. Later, this was reduced to 2–3 PDC bits and now the complete section has been drilled with one PDC bit (HC 606Z). Dull grading comparison with bits used in the offset wells will also be discussed. The lithology of the drilled section consists of Ranikot formation (dominating claystone with inter bedded sandstone and siltstone). Throughout this zone bit stability and optimized drilling parameters of the bit were key factors affecting its performance. Below this zone Upper Goru (UG) and Lower Goru (LG) formations are found. UG Member mainly consists of marl with streaks of limestone having an UCS of > 35 kpsi in its contact with the Ranikot formation. This type of formation is generally the most difficult to drill. LG Member comprises of claystone and siltstone with occasional traces of pyrite having UCS of 20–25 kpsi. Towards the end of section, last 400m witness increased percentage of abrasive siltstone which affects cutter's sharpness and reduces the ROP. Offset data conforms that around this point bits quit drilling. However, at Sawan-11 bit maintained its sharpness and good ROP till the end of this section. Introduction Over the past few years, the degree of difficulty and cost of drilling an oil & gas well have increased globally. With the recent oil & gas price hike, exploration and development operators have expanded their operations substantially around the globe. With the help of advanced drilling technologies like RSS, MPD, etc. and high performance drilling fluids although sometime help and prove their worth. Nevertheless, if the drilling bit is not of appropriate design, then these advanced systems and technologies can't help drilling a well efficiently and economically. OMV has been drilling gas wells in the Middle Indus basin of Pakistan since 1994. Drilling in this area is very challenging due to inter layered geological sequence that consists of clay, shale, limestone, with sand and siltstone (Figure 1). Wells are normally drilled vertically through these geological sequences which provide significant challenge to the bit performance. Previously OMV has attempted to drill these wells using roller cone, tungsten carbide inserts, and polycrystalline diamond compact (PDC) bits. But this required a lot of patience and extra rig cost due to low ROP. Many operators and bit companies have reported that PDC bit in general performs well, produces better ROP and usually drill more meters than tricone bits [1,2]. Yet the cutters on the PDC drill bits normally wear out quite easily due to excessive torque. This mostly occurs when the cutters encounter any hard and abrasive formation. This process makes the PDC cutters flat, dull and unable to penetrate the rock efficiently. Nevertheless, recent PDC drill bit cutter and design technology have made it possible to drill thru some of the very hard, abrasive and interbedded formations having UCS of >30 kpsi [3,4,5].