Effective zonal isolation in wellbores with a challenging mud removal environment is well known to be very difficult to achieve. In wells at the technical limits of Non- Aqueous Fluid (NAF) removal prior to cement placement, cement bond quality and hydraulic isolation can be compromised by leaving channels behind the casing, which can result in several long-term well integrity issues. An Interactive Cementing System (ICS) is developed through special experimental methodologies to mitigate mud channeling issues and improve zonal isolation, by immediately interacting with any residual mud channels left in the well after cement is in place, hence reducing the permeability of mud channels and sealing off microannulus gaps. Casing centralization is considered to have the greatest influence on mud removal efficiency because it directly affects the flow movement on each side of the wellbore. Mud removal has been studied from numerical simulations, laboratory experiments, and field results, and these show that good mud removal can be achieved only when adequate casing standoff is achieved during cementation. In modern wells where there are many operational restrictions and limitations, especially in highly deviated and horizontal wellbores, final cement designs may not allow good casing standoff and thus not all of the best practices for effective mud removal can be applied. The objective of the innovative cement system is to have a design that interacts with residual mud in the annulus to "fix" the channels, thereby enhancing cement bond quality and zonal isolation. Two detailed case histories of the application of this technology in the development campaign showed visible improvement in cement bond logs using the ultrasonic imaging tool as compared to offset well that was cemented using a conventional cement system. After two successful implementations, the ICS was selected as the cement system of choice for wells with challenging mud removal.

This paper will discuss completion design and the deployment method of sand control for multi-zone completion wells in the Nong Yao field. The discussion will cover sand control and completion techniques from given reservoir characteristics, in combination with the production strategy. Operational challenges from offset wells will be discussed. The Production strategy for the field required careful consideration for the unconsolidated nature of the reservoirs. An effective drawdown strategy is required as Electrical Submersible Pumps (ESPs) are deployed for artificial lift. The teams designed and implemented a cost effective multi-zone completion (MZC) with selectivity and sand control. The completion was designed to fit in a 7" 23# casing and is comprised of a lower and an upper completion. The complexity of the lower completion; 4" sand screen as outer string, internal 2-3/8" tubing with sliding side doors (SSDs), seal bores and packers, made deployment a challenge with a hydraulic workover unit due to the limitations of stroke length and gin pole. The completion equipment were selected based on workover operations pipe handling constraint, i.e. stroke length, gin poling hanging weight. As the workover stroke length is only 10 ft., R2 range screen and blank pipe was selected instead of the typical R3 range to prevent screen damage when passing through the stationary slip of the workover unit. Moreover, the total screen length combined with blank pipe has to be designed to meet the sand control objectives and stay within the gin pole hanging weight limitation. The lower completion was completed for selective production zone by zone, and was followed by an upper completion (Y-Tool and ESPs) to produce the hydrocarbons. The first well completed as a MZC with selective sand control has been on production for more than six months with no sand checking the base sediment and water (BS&W), even though the well has produced at high water cut and at relatively high rates. This observation shows that the implemented completion design along with production start-up strategy is working well. This same strategy is being applied in future wells.

This paper describes a pilot program for the application of an Autonomous Inflow Control Device (AICD) by retrofitting an existing ICD completion for reservoir optimization. New drill horizontal wells were required to be completed with AICD's to enhance recovery with existing ICD completion materials in inventory desired to be used. The workflow for establishing the decision change from ICD to AICD completion and the completion design process change is discussed. The well program was selected to demonstrate the effectiveness of AICDs in the Jasmine asset, a current field development in Thailand. ICD screens had previously been purchased for a different application but were unused. To reduce overall project cost and asset inventory, a method of utilization the existing ICD screens was strongly desired. An evaluation was done, followed by design and development of a manufacturing process to retrofit the ICD screens with larger sized AICD housing. Furthermore, overall completion design was implemented to ensure a smooth deployment and optimized production benefit. Multiple joints of existing ICD screens were successfully retrofitted with AICD technology locally within the region. The operator was able to reduce current inventory book levels by 20% that resulted in a direct cost saving of 40% comparing to new AICD screen cost. The field deployment of the retrofit completion was a success without any operational issues. Despite the improved productivity and uplift in reserve recovery associated with horizontal wells, reservoir heterogeneity can cause uneven production and early water and gas breakthrough from portions of the wellbore. The AICD delivers a variable flow restriction in response to the properties (viscosity) of the fluid with water or gas flow restricted. With multiple segmentation along the horizontal section in this application, excessive production of unwanted gas and water have been limited. Installed in late 2017 and another application in 2018, production from the wells have exceeded expectation, with an uplift in recovery.

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.

The objective of this research is to describe the methodology used to drill the most extended reach well (ERD) in the Gulf of Thailand. The Jasmine field is a mature, sophisticated, oil field with many shallow reservoir targets that require a minimum 10,000ft horizontal displacement. As such, the main challenges faced, and the novel technology applied is described in detail by this research. The research is an example of successfully drilling a challenging well, safely and efficiently. The Jasmine C – Well X, is a 3-string design structure with an 11-3/4in top hole, an 8-1/2in intermediate section, and a 6-1/8in reservoir horizontal section. Well X was constructed by utilizing an existing platform well slot. The challenge involved drilling from the top hole to the kickoff point and directional drilling away from the casing stump of the existing well to avoid any collision with nearby wells emanating from the Jasmine C platform. The 8-1/2in hole section was the most important segment as it had to reach the landing point precisely in order to start the 6-1/8in section for GeoSteering in the reservoir section. The 8-1/2in section encountered three challenges that could affect drilling efficiency.Directional Drilling – The complexities of the well profile:The method involved making well inclination (INC) lower than 82deg in the tangent interval in order to reduce the well's tortuosity as much as possible.Hole condition – Hole cleaning and fluid losses control:The method involved the use of Low Toxicity Oil Based Mud (LTOBM) CaCO3 system, the chemical elements in the drilling fluid system could help to seal the high permeable zones.Drilling Engineering – Torque and Drag (T&D) control:The method taked into account the 7in casing run to the bottom of the hole, which the casing driven system did not allow for rotation The well was completed successfully without any additional trips. A Total Depth (TD) was of 13,052ftMD was achieved to reach reservoirs at 3,260ft TVDSS. It was therefore announced in 2019 as a new ERD record for Mubadala Thailand (ERD ratio = 3.26, Directional Difficulty Index (DDI) = 6.95). The top hole and 9-5/8in casing were set in the right depth. An 8-1/2in section was accomplished on the planned trajectory with an average on bottom Rate of Penetration (ROP) at 319 ft/hr. The 6-1/8in section was drilled by geosteering to achieve sub-surface objectives. A total of 2,143ft intervals inside the reservoir was successfully achieved. While drilling, lost circulation events occured, but the mud system was conditioned with Lost Circulation Materials (LCM). Therefore, drilling performance was unaffected. Moreover, the Bit's Total Flow Area (TFA) and Rotary steering systems (RSS) flow restrictor was configured to allow directional drilling at a very low Flow rate of 470gpm. Addition, 30 joints of 5-1/2in Heavy Weight Drill Pipe (HWDP) and 39 joints of 4in HWDP were added into the Bottom Hole Assembly (BHA) to transfer string weight to drill bitsand drill to well TD. As complexities of the well profile were fully aware, the casing was runned and minimized the open hole friction until the casing was deployed successfully. In the Gulf of Thailand, drilling the longest ERD well in a shallow True Vertical Depth (TVD) was clearly groundbreaking and entailed the successful management of the key operational challenges related to identification, job planning, design, technology selection, and implementation. This research illuminates the challenges and technical solutions of long ERD well and serves as an example of what can be achieved in the region and globally.