This paper describes the optimization of a well placement in a 4 m thin complex sand reservoir, using a point-the-bit rotary steerable system, real-time LWD imaging, and 3D geosteering software in well Chermingat A02 drilled by Newfield Peninsula Malaysia Inc. Real-time, at-bit gamma images 1 m from the bit proved crucial in providing early structural interpretation for geosteering decisions. Higher resolution density images further refined the structural interpretation. A geosteering consultancy service, based in the customer's office, provided the subsurface team with guidance throughout the geosteering process, which led to the successful delivery of the well objectives. The advanced, intuitive 3D geosteering software was used to create a geological model based on offset data and geological surfaces. This local geological model was updated continuously throughout the drilling process, based on the best match between modeled and actual logging-while-drilling (LWD) sensor responses, to reveal local bed dip, bed thickness, and faults. Changes in the well trajectory were seamlessly communicated to the directional drillers on-the-fly by means of a two-way down linking system to the point-the-bit rotary steerable system, while on-bottom drilling ahead continued with no drilling interruptions. This new level of efficiency, using at-bit images immediately integrated into an intuitive geological modeling package with full support from the geosteering advisors, resulted in rapid geosteering decisions with no downtime waiting for a decision from town. The team achieved 500m (1,640 ft) MD of high quality reservoir, thus meeting the objective of the original well plan. This strategy and operational efficiency resulted in a cost savings of ﹩812,000 (USD). The methodology, lessons learned, and experience gained from this well were applied successfully in the next drilling campaign in East Belumut A02 and in subsequent wells on the East Belumut platform. Introduction The Chermingat field is located in the Malay basin offshore Trengganu, Malaysia (Fig. 1). Newfield Peninsula Malaysia Inc. planned three wells in 2007 to produce oil from the Chermingat field. One of these wells, the Chermingat A02, was planned as a horizontal well to penetrate the J18 reservoir and the maximize drainage of this production zone. Traditional geometric wellbore placement in extended horizontal wells within the target pay sand can be particularly challenging because the ellipse of uncertainty at the toe of the horizontal section can be as much as 5 to 7 m. This challenge is exacerbated in thinner pay zones, especially when the uncertainty in the geological earth model is high. The true vertical depth (TVD) uncertainty at the total depth (TD) of this well is 3.19 m. Various methods and tool applications were reviewed to determine the best and most efficient way to deliver these wells online for oil production. The Chermingat A02 well plan, after numerous iterations, was deemed particularly challenging in terms of drilling and geological understanding. The Geo-Pilot® XL point-the-bit rotary steerable system and an at-bit gamma-ray imaging tool, (ABG™) system, in combination with the intuitive Stratasteer®3D geosteering service, were deemed fit-for-purpose to assist in delivering optimum wellbore placement in the 4 m thin J18 reservoir. Case Study: Chermingat A02 The target production sand, J18, is a 4 m thin sand in the Chermingat field. The J18 sand is a distal tidal flat depositional environment; the sand thins to somewhat shaly in part toward the toe of the horizontal.

The field development plan for a Sarawak Shell Berhad operated gas field, located in the South China Sea, offshore Sarawak, Malaysia, specified drilling of horizontal wells into the Tertiary Miocene Carbonate reservoir. The wells were planned as high capacity producers of the Big Bore-Long Casing Flow design. The traditional well design dictated that, prior to entering the reservoir, a casing had to be installed to stabilise the hole in soft shale. The uncertainty of detecting the formation top resulted in premature casing commitment of at least 30 feet TVD above the top of the reservoir and the need to use an expandable liner to cover 300 feet of exposed shale above the reservoir. To obviate this problem, the capability of one of the components in the Logging-While-Drilling tool array, namely the Electromagnetic Wave Resistivity forward modeling technique, was used to detect the top of the carbonate formation (top reservoir), immediately prior to drilling into it. A standard Logging-While-Drilling tool is configured to prioritize Electromagnetic Wave Resistivity forward model response as the carbonate formation top is approached. This configuration, together with an appropriately designed bottom-hole-assembly and well trajectory, enabled the successful implementation of the plan to stop drilling approximately one foot true-vertical-depth above the carbonate top. At this point, a conventional 9 5/8-in. casing string was set at an optimum depth. This eliminated potential well control problems, costly remedial actions associated with lost circulation and inferior cementation of the 9 5/8-in. casing string. Thereafter, the wells were drilled horizontally in a conventional manner, into the carbonate gas reservoir. This paper compares pre-drilling Electromagnetic Wave Resistivity forward modeling of the proposed well trajectory with the actual well data, whilst drilling. The pre-drilling and post-drilling modeled data is presented. The cost savings from employing this technique are variable, ranging from substantial - in the event of a well control situation and attendant high losses - to moderate if the need to set an expandable is eliminated. Introduction Sarawak Shell Berhad operates numerous gas fields in the Central Luconia area located in the South China Sea, offshore Sarawak, Malaysia. The field development plan for the M4 field (Fig. 1) specified drilling of two horizontal wells into the Tertiary Miocene Carbonate reservoir. The wells were planned as high capacity producers of the Big Bore-Long Casing Flow Design. In the Central Luconia area, the drilling of development wells is challenging as frequently mud losses or total loss of circulation are encountered due to karst and fractures in the carbonate reservoir. The carbonate reservoir is overlain by a thick layer of soft shale which needs to be drilled with high mud weight drilling fluids. A 9 5/8" casing string has to be set before drilling into the carbonate reservoir to avoid bore-hole collapse when drilling into the reservoir and the occurrence of severe mud losses. Since the shale section above the carbonate reservoir lacks any geological character or marker beds to help delineate the Top Carbonate; it was common practice to set the casing point at least 30 feet TVD above the Top Carbonate. Subsequent drilling left approximately 300 feet of exposed soft shale along the bore-hole before entering the carbonate reservoir which necessitated the installation of an expandable liner to isolate the soft shale. Therefore, a new methodology was looked for to minimize the length of the open bore-hole shale section. Well Plan and Strategy To set the 9 5/8" casing as close as possible to the Top Carbonate, the Electromagnetic Wave Resistivity (EWR) forward modeling technique is employed to "look ahead" of the drill bit.

fax 01-972-952-9435. AbstractReal time solutions: an innovative approach to making business-time critical driven decisions. It is designed to monitor, support, and optimize operations in real time and remotely to mitigate cost and risk at work sites. The workflows allowed real time monitoring and intervention of the drilling operating parameters from the office which resulted in greater operating efficiency and thus greater financial saving. This technology was instrumental to the Angsi development team's success in drilling Malaysia's longest development well to-date, Angsi-A028ST1 at a total depth of 6,339 meters.Real time well construction workflows begin when real time data on the rig site are gathered and transmitted to PETRONAS Carigali Sdn.Bhd, PCSB office via VSAT link. Data can be accessed via a web-based interface for 24 hours coverage anytime anywhere. The real time data are integrated into a geological and geophysical project database and fed into a 3D visualization tool which amalgamates the planned and current well trajectories within the geological earth model incorporating neighbouring wells with operations data. The simultaneous display of "knowledge-management-cubes" from daily drilling operational reporting software enables the team to review contingency plans and be pre-emptive by the captured lesson learnt.This technology creates multidisciplinary collaborations through the ether space, reducing communication gaps and greatly improving the decision making process. Examples: reducing the number of check trips, shortening the planned TD by comparing the real time data against correlated model, and helping in handling operational problems. The team has greatly benefited from RTO -technologies, people and processes -with a total cost saving of more than USD 1 million. This paper presents the real time system setup, architecture and scope of work in enabling 2D and 3D well visualization and integration. The value-added and the relative cost savings, observations and feedback are also presented

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When logging through certain water-wet sand-shale sequences offshore Malaysia, the thermal neutron porosity measurement from an 8-in logging-while-drilling (LWD) tool exhibits an apparent lack of dynamic range in its sandstone porosity response. Petrophysicists using these data to determine sandstone-silt-shale points were finding that the shale points fell too near the sandstone line to be usable. An extensive nuclear Monte Carlo modeling campaign was performed to address this issue, which indicated that the tool response, while unexpected, was accurate. Modeling verified that neutron logs can exhibit a poor dynamic range just by happenstance, but an accurate assessment of the shale volume fraction [Formula: see text] should still be feasible. Surprisingly, the shale responses for this LWD tool, a smaller LWD tool, and a wireline tool are quite similar, invalidating a common expectation that LWD tools should be noticeably more epithermal in their response, and thus be less sensitive to absorbers in the clays. Modeling the actual shales, based on X-ray diffraction (XRD) analyses of cuttings, revealed the answer. In the wells with a poor dynamic range in the shale response, the quartz content was very high. Simulating the actual XRD-determined shales reproduced the actual log crossplot very nicely. Points in the shale crossplot fall near the sandstone line because the formations are primarily [Formula: see text], with only a small amount of clay. This result explains the response of the LWD tool.