Application of Real-Time Wellbore Stability Monitoring on a Deepwater ERD Well

Abstract

Good geomechanical modeling can provide valuable information for the efficient design and drilling of wellbores. Incorporating real-time wellbore stability monitoring during drilling can reduce the associated risks, especially for deepwater extended-reach wells. This paper presents the preparation, delivery, and outcome of the field trial for a real-time wellbore stability monitoring service delivered at Shell Exploration and Production Company's office in New Orleans. Three key objectives were set for the field trial:to develop the processes to incorporate real-time wellbore stability into the current operations center monitoring provision,to provide frequent updates of the wellbore stability model using a geomechanical modeling technique that was independent of the operator's own methods, andto monitor and verify the geomechanical model based upon the drilling experience enabling proactive decision making during drilling. For the operator's asset team, the main objective was to reduce trouble time and make execution of the well successful. Ram Powell VK 913 A-9 well was chosen as a candidate for the field trial. The Ram Powell tension-leg platform is located in 3200 feet of water in the Eastern Gulf of Mexico. A-9 was planned as an extended-reach exploration and would have the highest angle at the shallowest depth in the field. A geomechanical model for the prospect had already been created using the operator's own well-established methodology. This pre-drill model was transferred into the service company's software, and the real-time model was calibrated to generate as close to the same output as possible. After verifying the real-time model using the drilling experience on the closest offset wells, the 24 hr realtime stability monitoring commenced. The real-time geomechanical monitoring encompassed pore pressure prediction, rock property calculations from formation evaluation tools, wellbore trajectory updates, and the use of surface and downhole drilling data to verify the geomechanical model. Integration of the real-time wellbore stability monitoring contributed to the successful drilling and casing of this deepwater extended-reach well. The trial resulted in a greater understanding of the geomechanics of the field. The trial also resulted in a better understanding of procedures for maximizing the value of real-time data and of associated monitoring services, services that will be incorporated in future Shell E&P wells. Introduction Shell Exploration and Production Company, in co-operation with Halliburton Sperry-Sun, established a real-time Operations Center (OC) within the operator's office in New Orleans.1 The operations center is regarded as enabling a multidisciplinary workspace that seamlessly integrates all aspects of the company's well construction activities. Halliburton Sperry-Sun and GeoMechanics International (GMI) had cooperatively developed a real-time enabled version of new geomechanical analysis software, and approached the operations center with a proposal to complement and enhance the existing well construction process. The proposal was accepted, and a trial was initiated to establish the feasibility of real-time wellbore stability monitoring within the operations center environment. An extended-reach (ERD) well design was chosen that would become the shallowest ERD well attempted on the prospect. Field Trial Outline The ultimate goal of the trial was to enable the real-time update of the geomechanical model output using measurements from the actual conditions encountered during drilling and, crucially, to provide the updates within a time frame and in a format that allowed proactive decision-making while drilling. To meet this goal, the trial had three central objectives. The first was to develop the processes that would allow the incorporation of real-time wellbore stability monitoring into the existing operations center well-construction structure. The second was to provide frequent updates of the wellbore stability model, which in this instance would use techniques that were independent of the operator's own methods. The third was to monitor and verify the geomechanical model based upon the drilling experience to enable proactive decision-making during drilling.

Wellbore Stability Problems in Deepwater Gas Wells

“…Other preventive measures include but not limited to the following [41] The use of drilling mud weight to balance the stress and pressure concentration around the wellbore is not sufficient for effective wellbore stability. The properties of the drilling mud also play a vital role in successful drilling operation [44] [45]. Water-based drilling fluid creates more problems than oil based drilling fluid because of rock-fluid interactions.…”

“…It is almost impossible and unrealistic to have total prevention of wellbore instability because the physical and chemical in-situ properties of the rock cannot be restored to its original state. However, the wellbore stability problem scan be mitigated by adhering to good operational practices are, but not limited to [44] …”

Automated Alarms for Managing Drilling Pressure and Maintaining Wellbore Stability—New Concepts in While-Drilling Decision Making

“…Real-time pressure management is not new to the petroleum industry as the literature contains numerous publications related to real-time pressure management and wellbore stability (Gallant, et al 2007) (Greenwood, et al 2005) (Meng, Fuh and Spencer 2010). Typically, the mud weight window is created in the pre-drill stage (using all available offset well data) and rigsite personnel would "listen" to the well by monitoring secondary parameters (fluid gains and losses, gas trends, cuttings/cavings, etc.).…”