The Jasmine Field sandstone reservoir described in the paper is highly compartmentalized, has a sand thickness of about 30-40ft, reservoir pressure is supported by a strong aquifer, and most wells have high productivity. However, in the particular fault block of interest, a gas cap is present, which is normally not present in other fault blocks. This reduces the oil sand thickness to about 20 ft, with a big gas cap above and water below. To efficiently produce the oil rim in this area, a horizontal well was required, with an electrical submersible pumps (ESP) to aid lift. Since ESPs don't typically handle gas very well, the challenge was to ensure the well is economic by preventing premature gas breakthrough, and hence increase oil recovery. The Autonomous Inflow Control Device (AICD) is an active flow control device that delivers a variable flow restriction in response to the properties (viscosity) of the fluid flowing through it. Water or gas flowing through the device is restricted more than oil.When used in a horizontal well, segmented into multiple compartments, this device prevents excessive production of unwanted fluids after breakthrough occurs in one or more compartments. The JS-06 well was drilled with almost 2000 ft horizontal length within the original thin oil column, with gas on top and water below. AICD flow loop testing, performance modelling, candidate selection, and completion design for this well was focused on gas production control, given that gas production was the main concern. Post implementation and production, gas production has been controlled very well compared to the base case conventional completion. The gas oil ratio (GOR) observed from nearby wells was within the normal production range, which has allowed more oil to be produced from the JS-06 well. The production results observed were consistent with modelling and laboratory flow testing, thereby increasing confidence in the methods employed in designing the AICD completion for the well and in AICD modelling and candidate selection. The successful implementation of AICD in this well has opened up another similar opportunity, which are currently being evaluated for the same application

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.

This paper describes the successful application of Autonomous Inflow Control Device (AICD) technology in the Nong Yao oil field located in Block G11/48 within the Gulf of Thailand. Water injection in the Nong Yao field, is often into unconsolidated sands drained at different depletion levels. This can lead to formation failure and the transportation of sand back through the annulus and tubing. This AICD bypass valve technology provides a solution by only allowing injected water into the formation but not in the opposite direction hence preventing downhole crossflow. An AICD Bypass Valve was installed into two injection wells that were completed as Multi Zone Completions (MZC). It was planned that multiple zones would be opened simultaneously to provide ongoing waterflood support. The expectation was that the AICD technology would prevent crossflow between zones, due to pressure difference during any injection shutdowns, thereby eliminating the chance of formation failure and transportation of sand from the reservoir into the annulus and tubing. At first, these reservoirs were produced through depletion, and waterflood of these reservoirs did not commence until reservoir pressures had reached between 5.5–7.0 ppg. This led to differential depletion across these reservoirs, hence increasing the risk of downhole crossflow immediately upon any injection shut down, which may come with sand production resulting injectivity impairment. This has been observed across other wells in the field not fitted with AICD Bypass Valves. The concept of the AICD Bypass Valve is that the device requires a positive injection pressure differential to activate and open and allow fluid to pass through and it will close if the well is shut in due to a drop in the required pressure for valve activation. Since the installation of AICD Bypass Valves, these wells have been shut in multiple times due to platform shutdowns for rig mobilization and each time no drop in injectivity has been observed on restart, and sand production has been observed as predicted. AICD Bypass Valves were installed into two new injection wells in the Nong Yao field, providing a low cost alternative to recompletion or redrill that may be required, if screens become plugged due to sand production triggered by crossflow between reservoirs during well shut-in. This has provided more reliable production for the field and the success in this project means that more AICD Bypass Valves will be planned for future MZC, for injection wells in unconsolidated sand.

The completion of a highly deviated well involves overcoming significant deployment challenges during the drilling operations that require precise and effective conveyance and intervention. The conventional slickline intervention is unsuitable for wells with more than 60° deviation. The operator has sought to implement efficient, reliable and cost-effective deployment methods in delivering injector well. Thus, the operator decided on the e-line tubing tractor conveyed with e-line key and an e-line stroking tool. A tubing tractor and mechanical key and stroker were used to convey the wireline key in highly deviated wells. The key and stroker tools are latched into the sliding side doors (SSDs). They will activate open or close SSDs by down-strokes or up-strokes. In particular, the SSDs are closed when it is required to pressure up the tubing to set the packers. After the packers are set, an integrity test is conducted to confirm zonal isolation. Finally, the SSD is shifted open by the tubing tractor and a low rate injection test is performed to confirm the status of the SSD before handover the well. The operation had successfully installed multiple zones injection completions (MZC) in a highly deviated well and complemented the new completion design for the sand control in water injection well. The e-line tubing tractor and well key/stroker tools have met all operational and budgetary expectations. The traditional intervention methods in highly deviated wells, such as coil tubing, can be costly and potentially infeasible due to a footprint constraint on the drilling rig. The completion was successfully installed without any HSSE issues and the lesson learnt was recorded for future interventions when a change of injection zones is required. For a water injector completion design, equipment was selected based on reservoir requirements i.e. sand control, injection rates and pressure, etc. The goal was to prevent sand from flowing into the tubing when water injection is temporarily paused. To address this concern, the team designed and implemented a cost- effective Autonomous Inflow Control Device (AICD) with bypass valves equipped with SSDs for injection zone selectivity. This first well has been on injection for more than two years with no sand observed in the tubing or declines in the injection rate. The e-line tubing tractor and well key/stroker tools enabled the success of this operations and should be an option for completions in highly deviated wells. Additionally, this is the first time an AICD with bypass valves has been installed for a water injection well in the Gulf of Thailand. The success achieved with this operation in the Nong Yao field provides operators with a new solution for dealing with the water injection in the unconsolidated reservoirs.

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.