Mubadala Petroleum conducts a fast-paced drilling program in the Gulf of Thailand, where rapid response resolutions are often required. This paper demonstrates the Remote Operation (RO) approach, which is an integrated approach comprised of people, software, network, and technology to transform operations, and moves analytical activities to safer office-based environments (Figure 1). The approach provides a high level of performance, leveraging global domain expertise, real-time collaboration, data visualization techniques, and intelligent planning within the restrictive context of the COVID-19 pandemic. Figure 1 Remote Operation relevant function RO is the ability to operate a system at a distance. This is an adopted innovation and technology in the oil and gas industry, which is a completely new way of working. The principal concept for introducing the RO approach was to reduce the Personnel on Board (POB) and the HSE exposure, which was particularly relevant during the outbreak of the COVID-19 pandemic. The approach relied on leading-edge digital technology, as the RO was required to handle real-time directional drilling (DD), measurements, and logging while drilling (MLWD). During the implementation, the crew was trained in multi-skilling related to the DD/MLWD function, while working with the necessity of digital technology. Digital transformation is emerging as a driver of sweeping change in the world around us. Today, the Oil and Gas industry has redefined its boundaries through automation and digitalization. The potential benefits of going digital are clear, including increased productivity, safer operations, and significant cost savings. This exercise, it allowed us to reduce the POB on-site by 40% while maintaining both drilling efficiency and service quality. The drilling data can be monitored in real-time. The Remote Operation Center (ROC) has the capacity to execution and montor directional drilling, formation evaluation, programming, and dumping data from various tools. An experienced crew were assigned to the RO team ensuring competencies and familiarity with drilling operation in specific field characterization. This transformation supported our business continuity objectives by reducing the number of people traveling offshore during the COVID-19 pandemic while allowing us to achieve all our drilling performance objectives. In this new environment, following the turmoil of pandemics, this exercise indicates an opportunity to make fundamental improvements to the way business is conducted using the Remote Operations approach. RO takes a significant step towards the future for highly traditional industry. Preparing the industry toward the future may prove to be the most important outcome of the application of RO during the COVID-19 pandemic. The application of RO during the COVID pandemic has confirmed the possibility of more permanent improvements and increased resilience against future pandemics and other challenging events, as well as a new and more effective way of working during normal times.
The Nong Yao field is a marginal oil field that presents many challenges, both geological (thin hydrocarbon column and structural uncertainty due to shallow gas effects) and with well design (shallow depth and unconsolidated reservoirs). The field has been on production for almost five years with water cut in most wells now over 90%. The key to extending field life is identifying new infill locations, with advanced technology required to identify and drill these targets. To improve seismic image and structural definition, the seismic data was reprocessed in 2016, utilizing the latest technologies including Broadband Processing and Full Waveform Inversion. This detected local unswept structures and thin reservoirs allowing for identification of infill targets. New generation hydrocarbon saturation cased hole logs were run in wells to identify swept versus bypassed oil areas. Many infill opportunities required complex 3-D well trajectories and innovative completions. To achieve these objectives, technology such as high build rate rotary steerable systems, advanced real time survey corrections, a multilayer bed boundary detection tool, rotational friction transducer and inflow control devices were implemented. After four years of production, a key well exhibited significantly more production than expected, indicating a much larger reservoir than modelled. However, water cut in this well had reached 98%, so infill wells were required in order to extend production. The reprocessed seismic indicated that the structure extended further to the east of the existing producer than initially modelled. A cased hole saturation log was acquired in an existing well drilled near the planned landing location, which showed that the reservoir was actually swept in this area. Instead, the infill well was landed and drilled in the opposite direction in this eastern part of the structure, keeping the heel away from the water, but providing a much more challenging well path. A high-build rate rotary steerable system, advanced real time survey correction and rotational friction transducer were used to safely deliver this complex 3-D well profile and avoid collision risk from offset wells. The multilayer bed boundary detection tool was then used to ensure the horizontal well stayed as high as possible whilst remaining within the reservoir. Lastly, an inflow control device was installed in the horizontal section to delay water production. The well came online with 0% water cut and is an excellent producer. Similar methods have been adopted at other locations to identify and drill infill targets with great success. Collaboration across disciplines is key, as input is required from the geologist, geophysicist, petrophysicist, reservoir engineer, drilling engineer and completion engineer to identify, drill and produce these infill targets. Implementation of this approach continues to add new volumes and extend field life.
The Well X in Nong Yao field, is an infill-well designed for the Gulf of Thailand which presented several interesting challenges due to its complexity, tortuosity, and potential collision risks with other wells. This paper demonstrates the application of a Real-time Advanced Survey Correction (RASC) with Multi Station Analysis (MSA) to correct the Measurement While Drilling (MWD)'s azimuth. The Well X is a 3D Complex design with a high drilling difficulty index (DDI) at 6.9, high tortuosity of 316 degree, and which has an aggressive build on inclination and azimuthal U-turning well path. The well also creates difficult doglegs severity (DLS) up to 5.5deg/100ft, which is near the limit of the flexibility required to achieve the horizontal landing point. The conventional MWD survey, with proximity scanning with the nearby Well A, demonstrates high risk with a calculated Oriented Separation Factor (OSF) of 1.01. The RASC-MSA method is applied with a clearly defined workflow during execution in real-time and provide significant improvement in calculated OSF. RASC-MSA is applied for every 1,000 ft interval drilling below the 9.625in casing shoe. The workflow ensures that the directional driller follows the corrected survey along the well path and especially in the last 300 ft before reaching the electrical submersible pump (ESP) tangent section. The result from RASC-MSA, indicated a 29 ft lateral shift on the left side of the MWD standard surveys. Without this technique, Well X has a high potential to collide with Well A and Well B (Figure 1) as the actual OSF may less than 1 while drilling. The final 3D Least Distance proximity scanning with Well A shows a minimum OSF = 1.35, which is a 30% improvement compared to the conventional MWD survey. Another nearby well, Well B, indicates a minimum OSF=1.66 and passed the anti-collision OSF rule. In consideration of the drilling efficiency, availability, cost effectiveness and time saving, the RASC-MSA analysis to correct the MWD's azimuth are applied and the separation factor can be improved by 30%. In conclusion, the collision risk management technique applied successfully met the complex challenges of Well X, which was successfully drilled and safely delivered. Figure 1 3D visualization to exhibit the collision issue between Well X and nearby existing Wells A and Well B.
Well X is an infill horizontal well designed for the Gulf of Thailand. It is challenging due to the following factors - A long 8 ½ inch open hole section, An extended reach section at horizontal or near horizontal, the presence of loss circulation zones, an Extended Reach Drilling (ERD) ratio of 2.725 and a Drilling Difficulty Index (DDI) of 6.762. The key challenge was to successfully deploy the 7 inch casing across 12,350 ftMD of open hole, with potential loss circulation zones. In spite of these difficulties, the 7 inch casing was successfully landed with the use of an Ultra-High Speed Rotational Reamer Shoe. Historically, losses of circulation have posed significant challenges to well delivery in the Gulf of Thailand wells. In Well X, this is further complicated by a long open-hole section with a step-out of over 10,000 ftMD. It was determined that the successful deployment of the 7 inch casing would require some degree of agitation at the nose, and such a device must be tolerant to the Lost Circulation Materials (LCM) type and the composition of the drilling fluid and the cement. An ultra-high speed rotational reamer shoe was specially configured to meet the LCM requirements in the displaced fluid, for use in deploying the casing. While deploying the 7 inch casing, losses of up to 20 bbls/hr occurred from 7,043 ftMD while running at 15 joints/hr. A loss circulation recipe comprising of 60 bbls of 30 ppb Tiger LCM was mixed and successfully displaced through the customized ultra-high speed reamer shoe to cure losses. The casing was washed down from 10,569 to 11,610 ftMD, filling casing each stand. The 7 inch casing was successfully landed at the target depth of 12,353 feet and subsequently cemented. Drill out operations took 1.5 hours to complete. A formation integrity test (FIT) showed good shoe strength which was later confirmed by the cement evaluation logs. The comprehensive Ultra-High Speed Reamer Shoe was configured with a minimum restriction of 15mm, which is 5 times the diameter of the maximum particle size in the LCM of 3 mm. The tool was designed to tolerate the prescribed loss circulation materials, making it possible to cure the losses while running the casing string. The innovative Ultra-High Speed Reamer Shoe has demonstrated its usefulness by providing a higher probability for successfully deploying the 7 inch production casing over the extended reach section of Well X. The application of this technology can mitigate against non-productive time such as wiper trips or excessive washing down or casing rotation. It has proven to be a reliable technology that can be used in the industry in challenging well designs.
Lost circulation, while cementing, compromises the objectives of cementing an oil or gas well. Losses encountered during cementingcan cause a weak casing shoe, poor zonal isolation, early water breakthrough for an oil producer, as well as increasing the possibility of costly intervention work. Execution of primary cementing operations can be subject to unplanned circumstances; when a slurry is being pumped or displaced and losses are recorded, in most circumstances the operation switches to damage limitation by slowing down the pumping rate. The Nong Yao field (Figure 1)is characterized with an interbedded unconsolidated sand / clay lithology within a highly compartmentalized structure, and as such, well construction operations have encountered unpredictable lost circulation during 7-in. casing cementation (but rarely during the drilling phase). Over 60% of the wells recorded losses during 7-in. cementing; it became evident that a proper loss mitigation plan was necessary to combat lost circulation and improve the probability of successful cementation execution. Although the primary objective is to achieve zonal isolation, equally as important for Nong Yao drilling operations are provision of annulus barriers, slurry compressive strength development, "gas tight" qualities, optimum slurry Thickening Time (TT) to allow for safe batch drilling operations. Figure 1 Nong Yao field localization To overcome the challenges, an "out of the box" approach was essentialwhich yielded two innovative solutions: i) a combination of advanced lightweight cementwith engineered reticular fiber (ERF) systems, which allows safer placement of the cement in the annulus, while minimizing the potential losses; ii) a combination of several lost circulation materials (LCM) in an optimized ratio in an engineered fiber-basedlost circulation weighted spacer package, which has an additional function of preventing and mitigating risk of losses during cementing. This approach was intended to reinforce the loss zones by using the four-step methodology; disperse, bridge, plug and sustain. The severity of lost circulation while cementing was significantly reduced without compromising the abovementioned objectives. This paper will discuss the successful implementation of the new approach solution by integrating different technologies to overcome the challenges of unpredictable losses during cementation. Two case histories from numerous jobs will be discussed with cement post-job evaluation via playback simulations and standard cement bond logs, which validates that the new approach increases the chance of achieving well objectives. Consequently, the risk of unplanned (UNP) operations and costly remedial operations are substantially reduced.
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