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A new method of objectively quantifying formation tester data quality has recently been developed with the aim of optimizing the generation of fluid gradients and contacts. This paper demonstrates how this new method of processing formation test data and integration with the open hole log data can be applied to improve job planning for sampling. By using data that have been quality controlled, sampling operations can be improved by using the optimal sampling tool configuration which can result in higher operational efficiencies with reduced rig time for complex logging and sampling operations. In this case study, formation tester objectives included establishing gradients and fluid contact points, determination of formation fluids and capturing representative samples over multiple horizons in a single 6 ⅛" wellbore. An additional factor which increased the complexity of this operation was the length and deviation of the wellbore, raising concerns about differential sticking due to the lengthy stationary sampling times required. The formation tester evaluation process was divided into two runs: wireline deployed pressure testing and drill pipe conveyed sampling. This culminated in successfully completing 22 pumpouts with 4 samples captured over 6 days without any incidents. The straddle packer was used 17 times in varying permeability formations and is considered to be the most number of inflations in the Middle East region. The real-time formation tester data acquired were compared to the quality controlled data used for post processing analysis. The results were then used to identify the optimum procedures to be followed and future best practices. The lessons learned from the case study presented are used to demonstrate a quality control process with recently developed realtime methods for evaluating test quality. This allowed the data to be analyzed quickly and with confidence, enabling improved pumpout and sampling operation planning.

It is more effective to capture clean reservoir fluids as early as possible during drilling operations, and with the realization of formation-sampling-while-drilling (FSWD), this goal is fast becoming a reality. This paper summarizes one example from Saudi Aramco and shows the benefits of this evaluation procedure. Our experience in sampling oil bearing formations drilled with water-based mud, has seen that the data from these instruments, which are now able to withstand the rigors of the drilling environment, can be used in real-time to control the sampling process, capture high quality samples, and also place the well where required. In this case study, a tight carbonate reservoir was the objective with the oil column being near saturation pressure. Under these circumstances, the challenges presented to us while sampling, included maintaining low flow rates and potential three-phase conditions, due to unavoidable drawdown while minimizing the time on the wall. During sampling, pump efficiency was consistent with low-mobility formations, even with the various multiphase flow regimes encountered. Hydrocarbon breakthrough was significantly faster than historical wireline sampling performed in the same reservoir. FSWD greatly improves our costs by saving rig time. Also, FSWD was utilized to evaluate low-resistivity-pay zones and observe if they hold a movable water fraction. We see this as crucial for geosteering wells to prevent drilling through the zones with movable water, which will enhance the productivity index of the wells. As a first time experience of FSWD in tight zones, a valuable lesson came to light where additional real-time monitoring improvements can be made, including the need to improve real time data quality, to accurately determine clean-up fractions while sampling. Based on this experience, we have formulated operational guidelines for improving real-time data analysis and determining the most opportune time to sample during the drilling process.