Acquiring subsurface data in a highly unstable and geomechanically complex formation pose unusual challenges to adequately characterize the reservoir from production and completion perspective. The traditional way of acquiring data through LWD or wireline logging might be operationally constrained by severe hole break-out, mud losses and high differential sticking due to pressure depletion across the reservoirs. This condition warrants a specific and critical approach to optimally design the data acquisition plan to minimize subsurface uncertainties to meet the gas production target from the field. This paper will highlight customized techniques to successfully acquire good quality of subsurface logging and pressure data, technical and operational considerations involved and some of the best practice applied to operate within the threshold limit amidst the time-dependent hole instability culprit. Detailed technical plan, rigorous pre-job simulation and sensitivity analysis set the high tone to acquire critical subsurface log and pressure data prior to completion. Customizing LWD drilling dynamic parameters such as mud circulation rate, real time data transfer rate, pressure drawdown and build-up time, controlling the logging speed in ROP and optimizing the mud design are among the approaches taken to obtain fit-for-purpose data in a very narrow operating limit amidst the borehole instability issues. Acquiring real time image from LWD density tool enables fracture and break-out evaluation validating the existing geomechanical model in this field and enhance the understanding of causes for hole instability issues leading to real time well trajectory optimization and updating. Theoretically, open hole log data can be also complemented by cased hole pulsed neutron and production logging acquisition to formulate reservoir properties, gas water contact and estimated shut-in reservoir pressure through prolific log processing methodology and interpretation procedures. Post data acquisition activities along the problematic reservoir interval and incorporating all the interpretation outcomes, the reservoir connectivity and pressure communication are confirmed throughout the field area. Even though the main target reservoirs in the newly drilled well could not be completed and produced due to operational issues, the case presented in this paper will provide valuable lessons learned in designing and operating a well in the highly complex geomechanical area and strategizing data acquisition program to minimize the subsurface uncertainties. Best practices in customizing LWD open hole and wireline cased hole data acquisition to fully characterize the formation including downhole CO2 gas presence set the pioneering guideline in this region and become the critical benchmark for future well operation. In conclusion, securing adequate and reliable subsurface data in a highly unstable and geomechanically complex formation will justify for a strategic approach and customized plan to obtain much needed insights for sustainable gas production and delivery from the field. The first integrated and comprehensive approach combining both open hole and cased hole logging capabilities in Peninsular Malaysia region are presented in this paper setting a commendable runway for fit-for-purpose operation and optimization.

Abandoning a producer or injector well post production decline and pressure depletion after all intervention efforts to revive the well productivity have been exhausted is gaining momentum in recent years by most of major operators. Huge number of candidates to be abandoned fall under legacy wells category with incomplete drilling history and cement integrity records which warrant new logging run to be conducted for cement bond evaluation at the expense of additional cost and rig time. Conventional cement bond logging will demand additional cost due to tubulars cut and pull requirement to obtain conclusive log evaluation of cement integrity behind multiple casing layers. This paper will highlight a novel and first deployment of new cement evaluation logging technology by the company in multi-layer casings environment to obtain cement quality assessment behind each casing within a single logging run. Rigorous technology seeking efforts are conducted to fill in the industry gaps for a reliable and cost effective solution for well abandonment with unknown cement barrier status behind multiple casing layers. Total of four emerging technologies are evaluated including the slim logging tool version considering various technical criteria on job execution, operating principles, log data quality assurance, technical support and ways to improve which lead to the pilot deployment in 2 wells during the well abandonment campaign. The new cement bond logging technology was run inside a 7 inch tubing with the objective to evaluate cement quality behind 9 5/8 inch and 13 3/8 inch casings. Post logging run, the tubing was cut and pulled to expose single casing layer where conventional ultrasonic cement bond logging will be run for comparison with the new tool technology outcomes. Results indicate that the new logging tool deliverables conform to the conventional logging outcomes which highlights the intervals of good, moderate and poor cement bond condition with likelihood for channeling and flow behind casing event. This approach achieves a lower operational cost by eliminating the cut and pull technique for existing tubulars which is a mandatory requirement for any conventional cement bond logging. The first job trial had successfully recorded USD 0.95 million cost saving, eliminating 3 days of rig time and optimizing 6% of total operational cost. Best practices and quick operational guideline imperative for optimizing well abandonment campaign have been developed to set the high tone for cost and operational excellence. In conclusion, the newly introduced cement logging technology capable of evaluating cement quality behind multiple steel layers had shown encouraging results to support a cost effective well integrity assurance. Technology and measurement will keep evolving with time to resolve current business challenges as well as serving a more advanced technical requirement in the future.