This paper summarizes the challenges faced during the well completion design, planning and execution stages in the "Well-B" located on the "Field-A" offshore Malaysia. In addition, it highlights the modifications and techniques incorporated in the completion design to ensure that the well was delivered flawlessly in terms of HSE and quality. At the initial planning stage, the proposal on this well was to complete two oil producer sands with active sand control methods, the upper zone with Cased Hole Gravel Pack (CHGP) and the lower zone with Open Hole Standalone Screens (OHSAS), this concept changed after the analysis of the logging while drilling (LWD) output, when the subsurface team decided to complete an additional zone (midzone) with a stacked Cased Hole Gravel Pack. The well completion operation effectiveness on this well could have been affected by the following challenges: High deviationMultiple sand control techniques in one wellOperation and logistic challengesAdditional zone expected to be completed with the available inventoryLimited resources and time The team incorporated several techniques into the original completion design to enable the effective execution of these three zones and achieving the overall well objective. After the well was successfully completed, it became the first highly deviated well in the field with an open hole standalone screens in the lower zone and two cased hole gravel pack in the upper zones with a dual upper completion string. This well completion will become the benchmark for planning, designing and deploying future wells with similar characteristics and reservoir conditions.
Completing well in a carbonate formation is often a big challenge due to occurrence of severe losses in highly fractured limestone formations. In some cases, total losses might lead to prolonged operation time and/or well abandonment with attendant cost implications. Traditionally, Loss Circulation Materials (LCMs) are used to combat losses before completion operation commences. However, there have been limited success with this approach especially in this case where Karst was encountered.Originated under Managed Pressure Drilling (MPD) system, Pressurized Mud Cap Drilling (PMCD) with continuous seawater injection was introduced in XT Carbonate Oil Development Project. Due to the subnormal formation pressure, seawater was injected continuously down the annulus to maintain the hydrostatic pressure of the hole while ensuring that no formation fluid or gas entered the well bore. By injecting at a rate higher than the loss rate, an artificially induced surface pressure allows for wellbore monitoring while completion assemblies are being deployed.Prior to running in Lower Completion, a composite bridge plug was set at deepest possible location in production casing instead of the conventional Downhole Deployment Valve (DDV) resulting in the savings of about USD 1 Million. Some modifications were made on initial completion string whereby a sacrificial motor and a bit were included in Lower Completion string design. With the well in static mode, this modified lower completion string which consists of mud motor, drill bit and pre-drilled liner was used to drill out the bridge plug effortlessly. PMCD mode with continuous sea water injection was activated once the plug has been drilled out and while Lower Completion string was run to Total Depth (TD). After setting the Liner Hanger Packer and closing Fluid Isolation Valve, the well was back to static mode and ready for wellbore cleanup and upper completion runs.Five (5) high temperature wells have been designed employing the above technique which resulted in significant savings in rig time and cost as well as formation damage reduction and increased operating efficiency. This paper summarizes the practical experiences gained during the planning and deployment of lower completion string with perforated liners in a total losses condition with PMCD .
Conventionally, a well completion would involve perforating the reservoir followed by a separate run to clean up the wellbore from perforating debris and burrs on the casing and liner to prevent damage to the completion packer when passing through the perforated interval. This is especially prevelant in dual completion and single selective completion wells where the lower packer will have to be run past the upper set of perforations. The wellbore clean up bottomhole assembly typically consists of a drill bit scraper and magnets run between the perforating and well completion phases.As a result of the increasing emphasis on reducing operating costs and increasing operating efficiency, a new system was designed for perforating wells in underballanced condition and performing post perforation wellbore clean up in the same run by using standard equipment and techniques. The concept was developed after identifying the opportunity to optimize operations in wells where the perforating and wellbore clean up equipment operations are required.Five jobs have been performed employing this combined underballanced perforating and wellbore clean up technique which have resulted in significant savings in rig time and increased operating efficiency. This paper summarizes the practical experiences gained during the development and deployment of this integrated perforating and wellbore clean up technique.
Gas wells in X-Field Malaysia often produce sour gas (H 2 S) along with significant quantities of CO 2 . When it is suspected that these conditions will be encountered, corrosion-resistant alloys (CRAs) must be used in completions. This paper discusses an unique development strategy for an offshore gas cluster off Peninsular Malaysia. The planning for the project had to consider that the environment contained approximately 57% mol CO 2 in addition to maximum H 2 S content of up to 11 ppm. To meet the needs of this project, a dedicated team from the operator and service/engineering company developed a completion strategy incorporating several firsts for this area. This paper will discuss the unique completion strategies selected, the reasons they were used, and the resulting success of the well completions. This was the first use of 25Cr completion equipment and 22Cr tubing by this operator in Malaysia. Some of the changes included the following: Alloy 25Cr was used for all 3½-in. and 4½-in. completion equipment. 22Cr tubing for 3½-in. and 4½-in. completions was used. The equipment was rated for 5,000 psi and 7,500 psi.The wells were completed without any issues relating to the use of new strategies; these strategies have become the standard reference for all future monobore/dual completion wells with high CO 2 content and low H 2 S content for both upper and lower completions. The wells have been in operation for more than one year, and production has been as anticipated.This case history covers the early stage planning (including the materials recommendation stage), technical design review, equipment design, CRA handling and equipment preparation onshore, CRA handling offshore, completion execution throughout the campaign, and lessons learned from the campaign. Results of the operation from a mechanical perspective will also be presented.
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