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The mature Greater Burgan field has the largest clastic oil reservoir in the world producing from multiple units for more than 70 years. Wara and Burgan are the two main sandstone reservoirs in the field with several sub-units of varying mineralogical and mechanical properties. Continuous oil production from some low strength reservoir units has resulted in pressure depletion and the associated water encroachment has led to the initiation of sand production in few wells. This paper presents an approach to analyze rock mechanics, reservoir and production data to predict the sanding tendency in a heterogeneous rock of the world's largest clastic oil reservoir. Analytical poro-elastic geomechanical sanding evaluation approach was used to study rock failure and sand production. A number of wells (both with sand production and without sand production) were selected for geomechanical analysis based on the data availability and their respective location across the field. Various types of rock mechanical tests were performed with stringent quality control criteria to determine the mechanical characteristics of the rocks. Field calibrated geomechanical model along with reservoir and production data were used to build a calibrated sanding model for the Wara reservoir. The sanding model was then utilized to create sanding evaluation logs; perforation optimization and safe operating envelop plots for existing and future wells. As per the calibrated geomechanical model, the reservoir units comprise intervals of variable rock strengths. The sanding model calibrated from offset wells suggested that drawdown and rock strength are the most sensitive parameters in failing the rock and sand production. The wells with and without sanding had mixed response to water breakthrough and there does not seem to be any obvious pattern of sanding observed with respect to the onset of water production in the wells. It was also noticed that few offset wells did not exhibit sand production despite strength and stress conditions in these wells were favorable for early sand production. Potential explanation was found for those cases. These models helped to identify selective intervals to optimize sand-free production with limited drawdowns. However, for wells with very high drawdowns (installed with artificial lift pumps and 1000 psi drawdown pressure), none of the prolific sand interval could be stable and downhole sand control measures may be required. The combination of measured and modelled parameters have helped to understand the sanding tendency and behaviors of a highly heterogeneous reservoir. This analysis has produced guidelines on the best and worst well trajectories and optimum perforation orientations to mitigate well-life sanding risks with a rock strength sensitivity. Furthermore, data priorities have been identified in order to come up with holistic sand management strategy.

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A geomechanical evaluation and monitoring programs was conducted in order to reduce non-productive time and drilling complications while drilling in a tectonically stressed area of Kuwait. Offset wells had experienced problems related to the tectonic stresses and associated faults, fractures, complex structures, and anomalous pore pressure. Additional challenges were faced due to complicated and highly deviated well designs where planes of weakness in the formation being drilled and their relative angle with respect to the well path become crucial factors in assessing stability of the borehole. Multiple failure mechanisms such as stress induced wellbore instability, invasion of drilling fluids into weak bedding / micro-fractures and osmotic sensitivity, are found to be the root cause of wellbore instability across reactive shale and other problematic formations especially during drilling of highly deviated wells. To successfully achieve the above objective, it was prudent to be armed with proper assessment and understanding of wellbore stability along with optimizing the most appropriate drilling strategy. Five offset wells were assessed from Geo mechanical point of view in the area in order to simulate the back analysis of the borehole collapse in the unstable zones. The previous wells experience showed a high risk to drill the shales and depleted reservoir formation in one section, causing a high ECD in depleted reservoir which dramatically led to severe losses. The planned well was monitored in real time through the control of the ECD and drilling parameters. Since shales in that section are unstable and tend to be plastically deformed, high mud weights were typically used. Based on the geomechanical inputs of the wellbore stability while drilling, new casing strategy was formulated taking into-account the wellbore stability input, drilling parameters and the mud rheology. The shale section was isolated with separate casing and well was successfully drilled to TD without any drilling complications and minimum Non Productive time. Geomechanical modeling and real-time monitoring allowed the well operator to overcome serious drilling hazards and optimize the drilling practices. This application promises to open the prospect of drilling similar wells without complications and reduced NPT in Kuwait.

With increasing complexity to tap oil in clastic reservoirs due to stratigraphy, structure and facies variation optimization of placement of horizontal well has become a key to success. To augment this aspect Kuwait Oil Company (KOC) has established Geosteering Centre which has become the hub for decision making while the well is getting drilled for landing at top of reservoir or lateral is being drilled. The Great Burgan field located in South East Kuwait asset of KOC major Horizontal drilling campaign started in 2005 mostly in clastic reservoirs.. This field been on the production since 70 years, most of its development wells were drilled and completed as vertical or deviated. It was decided to utilize horizontal well technology to drill thin productive layers. This paper illustrates an integrated approach using 3D-Model along with seismic analysis, knowledge sharing and most advanced Geosteering technology to successfully transfer, edit, and interpret the dynamic data in real time to monitor the drilling progress specially the lateral section. This state-of-the-art computing and visualization technology enables geologists to take corrective measures keeping the well in sweet zone as much as possible, through direct satellite communication with the rig's Geosteering unit and planned well course VS actual trajectory was continually updated and well path corrected based on information received. The Geosteer center moved Field Development South-East Kuwait to a whole new level of collaboration that is equipped with latest in visualization, communication and computer technology in order to properly place and geologically navigate one of the world's largest siliciclastic reservoirs. Today the interactive process of geosteering, using real-time data and making real-time decision has resulted in mitigating inherent geological risk in order to optimize the best drilling results for each horizontal well and to ensure an effective implementation of all new ongoing field development plans and made it possible to tackle thin reservoirs which now can be drilled economically. Introduction Kuwait oil Company initiated horizontal drilling approach since early 1990's, and to place the wells successfully in the desired reservoir, an integrated approach using static model and subsurface analysis, knowledge sharing, effective communications and state of the art geosteering technology have all been utilized in order to have a successful well placement.