The objective of this case study is to show the value of the NMR real-time log data, acquired while drilling, for reservoir characterization as a lithology independent porosity logging solution and most important for permeability computation. The applied methods are being discussed with much focus on the added value of the transverse relaxation time T2 spectrum analysis in a highly heterogeneous, upper Jurassic carbonate reservoir, to characterize the pore size distribution while geosteering the wellbore to track the better quality pore systems and generate a real-time permeability profile, supporting the later advanced completion run for the first time, in this offshore field. The current field development plans are based on drilling multi-lateral horizontal and highly deviated wellbores along the layers of Reservoir-D to enhance the injection and production efficiency. Running radioactive-based porosity logging tools with such complicated well trajectories poses a high operational risks and collide with environmental regulations, this paper presents a case where nuclear magnetic resonance (NMR) as a source-less porosity logging device, run with the conventional resistivity-gamma ray logging while drilling combination achieved effective real-time formation evaluation and supported efficient well placement to maximize the reservoir contact. The NMR formation evaluation supported the design of the following Inflow Control Device (ICD) well completion operation for water injection, in a timely effective process, later validated with production logging data. The application is focused on maximizing the value of the real-time LWD (NMR) data for the time-critical (ICD) design and deployment in the highly deviated/ horizontal drains drilled, offshore Abu Dhabi.

This paper discusses the first successful coiled-tubing-conveyed production logging operation in a short radius horizontal well in Saudi Arabia. The production logging tool (Polaris[TM]) was modified with knuckle joints to pass through the severe well dogleg of 58 degrees per 100 ft in openhole. Subsequently, the tool was conveyed an additional 1400 ft in the horizontal section. The logging objective was to determine the flow profile for oil and water and identify the water entry points. The major challenge was tool deployment in this short radius well to gain access to the horizontal section. Monitoring of short radius horizontals has been almost nonexistent due to high dogleg severity. Because of the rigid tool length of conventional production logging systems, tool modifications were crucial and extensive job planning preceded the operations. Planning included modeling maximum rigid tool length, tool modifications, simulations for job feasibility with 1.75 in coiled tubing, and tool string bending moment tests. Prior to the main run, a dummy tool was successfully conveyed through the high dogleg to determine the feasibility of the operation. The successful completion of the log allowed the generation of a flow profile and identification of the major fluid entry poiints. These will help determine the most efficient way of sidetracking wells in the Ghawar Field to maximize reservoir sweep efficiency and to aid in planning future short radius horizontal wells. Introduction As fields mature, short radius horizontal (SRH) wells become increasingly more important in maximizing oil recovery and prolong plateau production performance [1]. One of the main challenges for SRH wells is to obtain reliable formation or well evaluation data to analyze well performance. This type of data is crucial for optimization of oil production as it allows diagnosing any further remedial work such as possible water shut off or selective acid stimulation. During or after drilling SRH wells, only slim access openhole tools can be used to aquire formation evaluation data, due to dimension limitations of conventional LWD and wireline tools. Once SRH wells are put in production, teh tool diminsions of the conventional suite of production logging tools do not allow conveyance through the high dogleg interval of such wells. The well discussed in this paper was drilled as a SRH well with a maximum severe dogleg of 58 degrees per 100 ft. To analyze well performance, and existing horizontal production logging system (Polaris) was adjusted and modified with knuckle joints, allowingthe tool to pass through the severe dogleg and succeddfully log the horizontal well section. The conveyance method for this job was on 1.75 in. coiled tubing. This was the first time worlwide that the Polaris production logging system was used to evaluate flow performance and identify fluid entries in a SRH well.

No abstract

No abstract

No abstract