TA is an over-pressurized well in the field development project located Offshore Peninsular Malaysia. Although the well was drilled as a development well, it also had an exploration objective as it was the first to penetrate the over pressured zones across a fault in the TA field. An initial attempt to drill conventionally resulted in severe gain and loss scenarios across the first of three sands 80 m below the 7" casing shoe, primarily due to weak coal formations. After many attempts to control losses, it was decided to plug-abandon the 6" open hole and to temporarily suspend the well due to insufficient operating window to drill ahead. After a year of suspension, a new drilling approach using a statically underbalanced mud weight (MW) in combination with an Automated Managed Pressure Drilling (MPD) system was introduced as the best solution for drilling into the well objectives. During the planning stage, different scenarios were analyzed based on the formation fracture gradient (FG) and pore pressure (PP) estimations. MPD plans were designed based on statically underbalanced mud while drilling, running the liner, and during the cementing job. During drilling, Dynamic Flow Checks (DFC) and Dynamic Formation Integrity Tests (DFIT) were performed using the MPD system to identify and confirm operating window. The target total depth was successfully reached with mud weighted within the narrow 0.35 ppg drilling window (17.8–18.1 ppg). Decision was then made to top kill the well at 1200 m-MDDF with 18.30 ppg mud, providing an overbalanced condition of 85 psi. Open hole logging operations were then successfully executed. The well was then displaced to a 16.30 ppg mud prior to performing Managed Pressure Cementing (MPC). This technical paper aims to discuss all of the MPD - MPC challenges faced and best practices developed during both the planning and execution stages of the program.

Field BY Coiled Tubing (CTU) Operation comprised of 2 wells to be cleaned out and perforated that are A1 and A4. These two wells target reservoir was untapped and has good potential of increasing gas production rate from BY Field. Well A1 is an infill well while A4 is a workover well, which both operations were commenced in October 2009 using a jack up drilling rig. Problem started when these wells experienced held up as there was solid restriction inside the liner, which prevented further movement of the wireline tool and as such, perforation can't take place. After considering the escalating daily spread cost, in February 2010, decision was made to release the rig and temporarily suspend the wells for future well intervention. Few options were available for the intervention job. After assessing all risks, the drilling team has decided to deploy CTU operation with Catenary system. This operation was considered unique and the first for Drilling Departrment. The challenge was high for the inexperienced team in handling the CTU Catenary operation. With shear determination and commitment, the drilling team managed to deliver the operation, where both wells were successfully cleaned out, perforated and flowed exceeding the minimum target. This paper discusses the challenges faced by the drilling team in carrying out the CTU operation and lessons learnt throughout the operation. Introduction Upon suspension of well A1 and A4, the drilling team has started to look for solution to carry out the intervention job. Factors like cost, rig availability, effectiveness and offshore/weather condition played important roles in making the decision. Based on detail technical discussion, the team had decided to use Rig-less CTU Catenary system. Instead of rig, a workboat was required to support the operation. It allowed Catenary system equipments (Coiled tubing Reel, Catenary System Power Pack, and Coil Feeder) to be positioned on a workboat and at the same time provided space for temporary storage of other major equipment such as tank and silos for clean-up fluids storage. Other major equipment were CTU Power Pack, Control Cabin, Injector Head stack up and flying Gooseneck were positioned on platform deck. Besides that, the platform was loaded with Well Testing equipment to control the flow by choke manifold and disposal of return from the wells by flaring through Burner Boom. On the other hand, a Slick line and Wire line equipments were placed on the platform deck for the purpose of tubing clearance check and perforation operation respectively. Using a workboat essentially saved the overall project cost because the daily charter rate for a workboat package including one support vessel is a quarter of a standard jack up rig daily cost.

Casing-while-drilling (CWD) operations have become a well-known technology used to minimise drilling time and reduce AFE budget. PETRONAS has drilled several wells in Malaysia by using this technology, and it has proven to be a cost efficient strategy particularly in batch drilling process. Past CWD operational experiences have demonstrated stark differences when compared to conventional drilling in terms of wellbore surveying and formation evaluation. Weak and noisy signals from mud pulse telemetry were primary issues that required a significant amount of rig time when acquiring measurement-while-drilling (MWD) and logging-while-drilling (LWD) data. In fact, several significant challenges were encountered. First, the mud pulse signal which traverses from downhole (MWD) to the surface somehow dampened out. Although various types of mud pulse telemetry have been used, significant problems remain. In addition, the signal transmission worsened when seawater was used as the drilling fluid, resulting in nonproductive time due to provisioning ofchange out tools with different configurations for mitigation and trial-and-error purposes. Finally, overall drilling efficiency was reduced as a result of poor signal detection and capturing. EM-MWD used in combination with gyro-while-drilling (GWD) was identified for implementation when drilling four wells using Tesco CWD technology in the Erb West field. The mud pulse and electromagnetic telemetry systems were executed asa pair to compare captured signal strengths in the same environment, i.e., directional CWD with seawater drilling fluid. After drilling ceased, the generated results proved that EM-MWD is a viable technology that can be used to overcome signal attenuation issues in a CWD operation. It also minimise health, safety, and environment (HSE) risks as well as established a working model of EM-MWD-CWD. Most importantly, such application reduced rig time by 3.9 days which contributed to 26% of cost saving for the surface section drilling by having trouble free MWD signal detection and faster drilling operation.

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.