To reach many of the world's petroleum-rich formations, drilling must first penetrate challenging shale formations where wellbore instability frequently results in costly stuck pipe, lost circulation, non-productive time, and expensive sidetracks. One technology gaining traction through successful field usage is a wellbore stabilizing agent (WSA) to limit the invasion of drilling fluid and wellbore pressure into the formation. Using a WSA can assist in stabilizing shales, delivering trouble-free drilling, and reduce losses and non-productive time. The drilling team was assigned a challenging well involving the Mutriba Formation, a shale-limestone formation notorious for stuck pipe and lost circulation. Focusing on wellbore stability and minimizing of the destabilizing nature of invasive drilling fluid and wellbore pressure, the team utilized a wellbore stabilizing agent to stop fluid invasion at the borehole wall. This barrier, or "shield", minimizes formation damage and mitigates fracture growth which can lead to destabilization of the wellbore Constant monitoring and additions of the wellbore stabilizing agent resulted in a thin, tight, flexible HTHP filtercake and wellbore stability while drilling this challenging formation. The entire section through the Mutriba Formation was drilled with 100% returns and later casing was run without problems. No adverse wellbore conditions were encountered while tripping or drilling, and no non-productive time was lost in stuck pipe or lost circulation events. When compared to the offset well, the successful well using the wellbore stabilizing agent came in 7 days ahead of schedule and with a cost savings of more than 21% for the Mutriba section. Controlling wellbore instability, especially in shale and shale-composite formations, is a key element of successful drilling in many fields across the globe. Information on field-proven technologies, such as this wellbore stabilizing agent, are important to the continual improvement of drilling fluid to safely drill similar fields around the world.

Wellbore instability while drilling mechanically weak, unstable or vugular formations has been a problem for decades. The cost of wellbore instability is a major challenge in achieving safe and economical drilling operations. As drilling operations moved into challenging formations in Kuwait, the operator sought to drill the Burgan shale and Shuaiba limestone formations in one section as opposed to the traditional two sections required to isolate each formation separately. This paper focuses on a class of technology additives used to mitigate the challenges of drilling weak and unstable formations. One approach for drilling micro-fractured shale and weak sands with vugular limestone is to mitigate the invasion of drilling fluids into the formation. Other approaches include: stabilizing the reactive shale by preventing hydration and swelling, improving the filtercake texture and strength, and sealing natural micro-fractures. Drilling fluid invasion can change the pore pressure, which may trigger wellbore instability problems. Thus, using ultra-low invasion drilling fluids, sealing micro-fractures and maximizing shale inhibition are key components for mitigating wellbore instability. Field data for the wells using the ultra-low invasion additives and shale stabilizers is presented and compared with previous wells drilled across Burgan and Shuaiba formations in Kuwait. The field data demonstrates the successful application of these additives to meet challenging key performance indicators (KPI) when drilling the Burgan shale and the vugular Shuaiba limestone in the same hole section. Using the ultra-low invasion additives along with shale inhibitors and borehole stabilizers, resulted in successful drilling operations with no differential sticking, torque-and-drag issues, sloughing, or tight hole problems as compared with usual incidences of differential sticking, pack-offs, and tight hole in other wells within the area. Using those additives also eliminated the need for a higher density fluid to control micro-fractured and tectonically stressed shales. The addition of the additive combination did not affect the rheological profile of the drilling fluid. Meeting these goals through the use of chemical additives in the drilling fluid reduced both non-productive time and formation damage in a cost-effective manner. Data from this paper specifically addresses a chemical solution for drilling the Burgan shale formation together with vugular Shuaiba limestone in a major Middle East producing field. However, the technique of mitigating wellbore instability by using this combination of chemical additives is fundamental to safe and economical drilling operations for any depleted, weak or micro-fractured formations globally.

The Automated Drilling Director, a software application for drilling automation, integrates a physics-based model of the drilling system with machine learning and optimization algorithms to project the well path, monitor collision risk, manage vibrations, and control steering in real time automatically. With "intelligent" rotary steerable systems (RSSs), these steering decisions can be downlinked directly to the tool, thus, fully closing the loop around steering decision-making. Implementation of the Automated Drilling Director within a remote drilling center (RDC) enables the drilling operations to be conducted remotely and effectively with less rig site personnel. The resulting decisions are consistent and reliable, while a team of subject matter experts (SMEs) monitor the operations to optimize well assets, ensuring that the pre-job design of service (DoS) is executed properly. The validation of this innovative technology and approach in Kuwait, amongst others, opens the door to a new way of doing business, where resources, experience, and data are combined in the most efficient manner to improve consistency, as well as to maximize the value of the operators’ assets.

In one of the prolific fields in Kuwait, achieving zonal isolation posed a big challenge mainly due to setting the production liner shoe close to the oil-water-contact zone. Cement bond logs from the primary cementing jobs were not acceptable due to contamination from intruding water leading to a high water-cut in the produced oil. We review the first implementation of a self-sealing Cementing System in Kuwait to improve zonal isolation and cutting the water production. A comprehensive pre-job study was executed to engineer a suitable cementing system containing a swellable elastomer for oil-water-cuts with proper test in Lab. A novel HPHT multi-function test cell apparatus and procedure were utilized to measure in-situ ability of fractured cement specimens to seal oil-water-flows under the given simulated downhole conditions. Shrinkage or expansion of the set cement was also verified under pressure and temperature with a continuous test method run over several days. Thorough lab tests and Computational Fluid Dynamics simulations were run to enable a fit-for-purpose and robust cement slurry design ensuring proper placement of the cementing system in the well. This paper will describe how this cement was designed and engineered in laboratory. It will also describe how the set up was made simulating a crack in cement specimen and injecting water cut oil reacts and provides desired results. A calculated cement engineering approach was adopted to ensure better cement slurry placement and reduce the chances of slurry contamination. The test conditions were staged to replicate the most appropriate downhole conditions of pressure, temperature and simulated micro channel in the cement sheath. After the successful implementation of the self-sealing cementing system along the 7-in production liner in 2 wells, the corresponding cement bond log images showed hydraulic isolation and the production data from the wells indicated a reduction of nearly 50% in the water cut thus allowing a favorable oil production. This technology is applied in other wells of this field and other fields also with good results. This is being continued to use in critical wells.