Zawtika field, Block M9, Myanmar offshore is one of the gas fields that has been developed and been producing since 2013. Two types of well designs have been selected and drilled from platforms; Monobore (Tubingless completion, Gulf of Thailand technique) and Sand control well (cased hole gravel pack). Over the course of production operation many challenges and difficulties have been encountered; one of which is sand production resulting in excessive corrosion and damages to the surface facility and shorten the well life. Hence, sand control completion has been chosen as the main design for field development. During 2013-2014 Zawtika M9 Phase1A sand control wells were drilled with a drilling rig and later completed completion with a 2nd unit hydraulic workover. Though this strategy could bring a well to production soonest, it comes with additional cost and risks; mobilization, stand by, wait on weather, overheads, etc. Up to now, Zawtika M9 Phase1B for sustainable gas production delivery, previous strategy has been adapted for more cost effective operation during an ongoing oil price crisis starting 2014. "One rig strategy" has been implemented with a tender assist drilling rig (TADR). The strategy is to drill all required wells on the platform, then to convert the drilling rig to completion mode and to run sand control completion. Drilling rig has large deck space, high deck load capacity and capability to accommodate 170 people, and sand control equipment can be installed permanently on drilling rig without major impact to drilling operation. The key completion personnel onboard shall relentlessly prepare and commission equipment to perform completion operation right after drilling operation is completed. Ultimately drilling rig can be converted from drilling to completion mode within 3-5 days, compared with a 15 days move of 2nd unit per platform. With this strategy, risk exposure to heavy lift and marine operation reduce significantly. In fact the unpredicted rig stand by due to bad weather in Zawtika M9 Phase1A becomes manageable due to lesser number of rig moves. Sand control completion has been operated efficiently by using rig equipment, space and experienced crews. Many offline operations and activities can be performed concurrently, e.g. cement bond evaluation, wellbore cleanout, packer installation with wire-line, rack back tubular capability, etc. Likewise the drilling rig performance can be continuously optimized and improved. This also eventually extends to running speed enhancement, non-productive time mitigation by proven equipment and crews. With this strategy, the rig has so far completed 3 platforms in Zawtika M9 Phase1B with significant improvement and remarkable record. The total drilling and completion well duration has significantly decreased from Phase1A 18 days to 10 days in Phase1B. Therefore, millions of cost reduction and saving from "One Rig Strategy" claimed.

The operator relentlessly thrives for the minimum well construction cost. Continuous improvement and Innovative approach are the major drives for developing the marginal gas field, Myanmar offshore. Whereas, routine and consistent operations may mask up the operator and leave out many rooms for improvement from operation excellence during the development phase of the project life cycle. PTTEPI successfully started up the second development campaign, Myanmar offshore in early 2016. Since then the team has brought up many ideas to continuously improve the operation and achieve milestones for both safety and performance. This paper will share the best in class for well construction of Myanmar offshore on well design, drilling engineering, rig selection, offline utilization, drilling and sand control practices and fit for purpose procedures. The performance is significantly improved on both drilling and sand control operation which results in total days per well reduction over 50% and 80% for drilling operation and sand control operation respectively. Total days per well for drilling performance on the last platform in 2019 is reduced to 4 days per well compared to 9 days per well when the first development platform was drilled in 2013. Sand Control performance is improved further. Total days per well for Sand Control performance on the last platform in 2019 is reduced to 3.5 days per well (dual-zone completion) compared to 18 days per well when the first development platform was completed in 2013. Recommended practices and well designs are shared as a case study of drilling and sand control operation for Myanmar offshore development. This can be a guideline for another operator to develop oil and gas field offshore Myanmar.

This paper aims to elaborate the strategy for operational and cost efficiency improvement by providing an example of a successful case of rig selection strategy for Hydraulic Fracturing Operation in S1 oil field Thailand. The integrated workflow proposed involves all concerned parties to specify the scope of work, analyze internal and external strengths and weaknesses, evaluate possible scenarios, and identify the procurement strategy. As a case of rig selection for fracturing operation in the heterogeneous sandstone, committing the number of candidates before drilling is impossible. Therefore, the typical criteria for fracturing rig selection consider rig move mobility and flexibility in candidate selection. However, in a proven area, the uncertainty of candidate confirmation is manageable. Reservoir engineers provide the number of candidates in 3 scenarios for sensitivity analysis. SWOT analysis and the market survey reveal the possibility to improve both performance and cost by using a warm-stack skidding rig instead of a truck-mounted rig. The sensitivity analysis by using the historical data of each type, indicates that the number of candidates and rig cost play a significant role in cost saving. As a result of analysis and strategy, the operation performance improvesby 34% (2 months reduction) leading to cost-saving by 1MM USD or 24% of the time-dependent cost.

Drilling narrow window wells conventionally have been well known to cause major wellbore issues to the Operator in the Gulf of Thailand. Therefore, managed pressure drilling (MPD) has been deployed since several years ago to mitigate the drilling problems. To ensure safety and optimize drilling time, it is necessary to identify the actual pore pressure while drilling wells with narrow marginin order to eliminate kick, ballooning and loss events. The use of automated MPD system to precisely control bottomhole pressure (BHP) during connections combined withthe evaluation of bottom up gas trend while drilling enabled the pore pressure to be predicted accurately in almost real-time condition without the need to stop drilling in the Gulf of Thailand. Thus, the narrow window wells were drilled faster with MPD, which was beneficial for the Operator in the area where the fast factory drilling was necessary to make wells more economical. Furthermore, the use of this new method in effectively determining the actualpore pressure provided solutions to the Operator in mitigating wellbore issues at the same time improving drilling timeafter several years of MPD technology implementations. The estimated pore pressure results acquired with the new methodon several narrow window wells were even comparable to the actual wireline logging measurement results. The objective of this paper is to introduce an effective and efficient method in determining pore pressure (PP) while drilling challenging wells with tight reservoir characteristic by utilizing MPD technology in the Gulf of Thailand. In addition, this paper also describes the drilling strategy, detail procedure and lesson learnedin verifying pore pressure with the new method.