Managing Pressure To Mitigate Environmental Impact

Abstract

Managed-pressure drilling (MPD) as the simple but effective principle that by managing downhole pressures, critical performance indicators such as risk, safety, efficiency, and cost are also controlled. As the energy world works to balance supply, demand, and the environment, efficient solutions such as MPD can help drive the promise of a compatible relationship. Globally, MPD is increasingly seen as an option to move drilling toward a “green” future. Beyond putting in place an adaptive drilling process to precisely control the annular-pressure profile throughout the well, MPD has consistently shown it can support green credentials for the wells where the application is utilized. This article discusses real-world examples of the less often considered but valuable environmental benefits delivered via MPD which include the following. Lowering the risk of spillage and blowouts Reducing mud chemicals; increasing use of simpler drilling fluids Optimizing drilling operations by reducing nonproductive time (NPT) from geopressure-related events and enabling a reduction of drilling carbon footprint through earlier achievement of well objectives Consuming fewer materials (casing, etc.) through streamlined well architecture These MPD benefits are well documented in the technical literature of the industry. In fact, a basic search for the exact phrase “managed pressure drilling” in OnePetro, the online library of technical literature for the oil and gas industry, shows 1,775 results. A majority of these papers was written in the past 10 years with each year averaging more than 100 technical papers and the average over the past 5 years increasing to 150 papers per year. The numbers tell the story of the growing technical interest in MPD technology which has been sustained even through the recent economic downturns. A further search of these MPD papers shows that 1,117 (63%) papers mention “safety,” 849 (48%) mention “efficiency,” and 47 (3%) specifically mention “environmental impact.” With the recent interest in green and environmentally friendly technologies, there is a need to highlight that the safety and efficiency benefits MPD applications already provide are also reducing environmental impact. Generally speaking, choosing MPD vs. conventional drilling methods is a step toward carbon neutrality. The following case studies showcase the improvements MPD has provided in land, shallow-water, and deepwater applications as seen from the perspective of environmental-impact mitigation. Mitigating Environmental Impact For land rigs, particularly in the US, where the majority have for decades now constantly deployed rotating control devices (RCD) that enable operations involving MPD and underbalanced drilling (UBD) methods, RCD technologies have consistently proven to reduce the risk of spillage and blowouts. Studies have shown that the use of a fit-for-purpose RCD has been statistically proven to “reduce the risk of a well-control event when drilling with an essentially incompressible fluid and not inviting the well to flow in the process,” underscoring the safety and environmental benefits of MPD in terms of minimizing unintentional hydrocarbon release.