Recently, Petronas Carigali Sdn. Bhd. in Malaysia has successfully drilled two horizontal wells to boost the gas production of the brown field X, offshore Malaysia. The field X has been producing for many years and production started to decrease since early 2013, requiring immediate infill drilling to cover for the production gap. However, the well planning and execution are very challenging. Due to the target location, the Extended Reach Drilling (ERD) well trajectory design was considered. It would need high drilling efficiency to minimize the extended stationary time to reduce the stuck pipe and ensure the accuracy of landing and geo-steering the well. Moreover, the high uncertainty of subsurface data like gas water contact (GWC), the complexity of carbonate reservoir heterogeneities, reservoir rugose geomorphology caused by fractures or karst and the large variation of reservoir resistivity profile added more difficulties for the pre-drill modeling and real-time execution. The planning methodology combined between several planned trajectories and possible reservoir geological models to achieve the best fit of the current reservoir condition and the planned well objectives. Then, the well placement pre-drill modeling would be performed to optimize the geo-steering execution to maximize the reservoir exposure and place the well in the desired position inside the target layer. Eventually, drilling execution was smoothly and successfully performed. The first well was drilled 614m MD horizontally at approximately 21m TVD above the GWC, exceeding the target objective of 12m TVD standoff. The second well, which was the ERD well, drilled 349m MD horizontally, approximately 6.6m TVD below the top of carbonate. Utilizing the ultra-deep reservoir mapping to identify the top of carbonate, carbonate heterogeneity layers and GWC helped precisely optimize the well in the desired position. Combination of definitive dynamic survey (DDS) technology not only provided better trajectory TVD calculation for improving reservoir mapping boundaries, but also helped to speed up the drilling operation by reducing the standard surveying time, ultimately minimizing the risk exposure for stuck pipe. This paper will describe how the combination of well placement technology ultra-deep reservoir mapping tool and latest definitive dynamic surveying technology helped Petronas achieve the objectives and de-risk and optimize the horizontal wells from planning to operation.

Borehole survey is a very crucial element in drilling a well. The data will be utilized during all phases of drilling campaign – planning, execution, and post drilling. During planning, borehole survey data are critical to avoid well collision with nearby well. It is done through correct survey of offset data and correct toolcode assigned to the survey program together with database QAQC. While actual drilling itself, the survey will be closely monitored to ensure that the well is clear from any collision risk. The survey will guide the directional driller to steer to the geological objectives and hit the geological target with high confidence. Finally, once drilling has been completed, the survey data will be tied in to geological and reservoir models and to be used for planning of future campaign. Since the last forty years, measurement while drilling (MWD) surveys have been the backbone for the borehole surveying. MWD surveys are in fact a measurement/surveying while static condition not during online drilling itself. Industry has experienced multiple evolution of MWD surveys, but none of the evolutions lead to the survey in dynamic conditions. Realizing the true potentials of getting the survey data in dynamic condition, it will help the rigsite operation to minimize the risk associated with longer stationary time. With this definitive dynamic survey while drilling can accurately be taken while drilling, moving, rotating and sliding, it had proven to eliminate the survey-related rig time per survey and reduced associated drilling risks, therefore improves the overall drilling efficiency. The service incorporates the new telemetry innovations that enables up to 20bps and the advance drilling dynamics design includes three-axis shock and vibration and turbine power. Additionally, geological accuracy is refined using gamma ray and electromagnetic resistivity in combination with continuous six-axis direction and inclination sensors. The deployment of this dynamic-survey-while drilling service had enable the operator to acquire precise BHA location data at a higher frequency during drilling for improved decision making, eleiminating up to 15 min of survey-related rig time per survey. This also eliminated the need for additional pump cycles along with their associated washouts, stuck pipe risks and other directional drilling difficulties. The ultimate yield is definitive dynamic surveys, delivering real-time borehole conditions that reduce time to TD. This paper also covers the advance procedure of taking definitive non-static survey. The challenge is to ensure the non-static data to be sent continuously and meet survey acceptance criteria. Hence, the continuous survey data can be qualified as definitive survey and assigned a proper toolcode. To validate this continuous survey measurements, the author analyses the survey comparison with conventional static survey and gyroscopic survey results in the field test runs. The author will then present the conclusions, further work recommendations in which this wellbore surveying advancement can transform the well construction process with great impact in drilling efficiency, as well as minimizing the stuck pipe risk and wellbore uncertainty.

This paper will describe a new method for using a computer workflow to automatically choose the safest and lowest cost option wellbore trajectories with minimum input needed from the user. It allows oil and gas industry operators' drilling, subsurface and service provider users to plan, risk assess and lower the cost of drilling wellbores by better understanding earlier in the planning and design phase to better invest in time and money for the best wellbore trajectory options. Wellbore placement challenges include but are not limited to choosing an optimal surface location, intersection of geologic target volume, avoiding faults and geohazards, and an assessment of the wellbore commercial and engineering risks to drill successful oil and gas production wellbores. This method involves a targeted approach focusing on drilling operational parameters such as Drilling Difficulty Index (DDI) and a financial index such as Measure Depth (MD) and additional engineering limiting factors or constraints such as Dog Leg severity (DLS), Maximum Inclination (MI) and kick of depth (KOD). Utilising this technique improves the efficiency of the risk assessment and optimisation aspects for a wellbore in the design phase. One of the most important aspects of efficiency improvement is the ability for multi discipline teams to work on the same wellbore design challenges in collaboration. High risk wellbore trajectory options are highlighted early on in the design phase and removed from the viable surface to target wellbore options list.Interactive model and wellbore data 3D visualisation helps the user choose wellbores which naturally avoid geological faults, nearby wellbores, and provide improved wellbore designs to intersect hard geologic targets. Geologic targets which represent the largest wellbore risk and cost are identified, allowing for a major manual iteration of the surface location followed by the wellbore trajectory design. In this practice, parameters are defined to separate all the possible wellbore trajectories and they are arranged individually and finally, they are merged and tested for ultimate ranking to choose the best fit. The ranking method described in this paper is non-weighted.As part of a new operator Operational Excellence and Drilling the Limit initiative, the viability of the trajectory optimiser has been reviewed for incorporation in upcoming drilling projects. During the design and execution process for wells drilled offshore Malaysia, asset management, subsurface, geoscience and drilling teams utilise data from a large number of models and data sources to perform the numerous and time

From an operator's perspective, many operational instructions are written implicitly that are not sufficiently detailed to optimize drilling efficiency. Upon a review of several partner operators’ drilling performance, it was noticed that there was a significant focus on the following aspects of technical limit drilling: ROP, tripping speeds, offline activities and connection times. One operator specifically reviewed Gulf-of-Thailand best practices and implemented them in Malaysia. One of the significant areas of improvement includes drilling connections. In the previous version, PETRONAS Malaysia Drilling Operations follows a conservative ERD connection method requiring to ream a single/stand, take a good survey a minimum 10m off bottom prior to making a connection and applied to all wells regardless of inclination or complexity. This was in response to risk of stuck pipe incidents happening during these critical static periods. A comparison of the connection times after their change in practice compared to PCSB practices given the same tools and well complexity indicated massive potential time savings with no additional costs. A change in the drilling connection practices could easily save almost half of this particular "flat time" with no significant risk, amounting to a possible saving of almost 26 hours in a well of around 3000m MDDF. This also led to a better understanding of the impacts of certain "rule-of-thumb" practices that needed to be questioned from time to time. This comparison coupled with many existing literatures available allowed a data-driven approach to improving well times. Some of this information is easily glossed over considering the only time-based data most wells refer to would be the Daily Drilling Report. This paper also emphasizes the importance of data collection and usage of historical databases to search for more opportunities in terms of safety, cost and time.