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Results
Abstract When constructing deepwater wells, incompatibility between synthetic-based mud (SBM) and Portland cements can lead to poor cementation and loss of cement integrity, which in turn may compromise zonal isolation. An alternative cementitious material based on geopolymers has been developed with improved SBM compatibility for primary and remedial cementing purposes as well as lost circulation control. Geopolymer benefits go beyond mere SBM compatibility: it is in fact possible to solidify non-aqueous fluids such as SBM and oil-based mud (OBM) using geopolymer formulations. This also means that non-aqueous fluids (SBM, OBM) can be disposed of in a cost-effective way, which presents a viable option for environmentally acceptable on-site or off-site disposal of drilling muds and cuttings. Geopolymer is a type of alkali activated material that forms when an aluminosilicate precursor powder (such as fly ash) is mixed with an alkaline activating solution (such as sodium hydroxide). A novel SBM solidification method was developed by blending varied amounts of geopolymer and SBM. This solidification method was tested with various sources of precursor powders, SBMs and OBMs. The rheology and strength of the geopolymer/SBM blends were measured under downhole conditions. Strength testing results showed that geopolymer cement lost only 30% of its strength when blended with 10% SBM, while a neat Portland slurry lost 70% strength. Geopolymer/SBM blends containing up to 40% SBM were found to have measurable strength when cured under downhole conditions. By changing the amount of geopolymer and SBM in the slurry, the geopolymer/SBM system can be developed into a lost circulation treatment with low compressive strength, or into a primary cementation material with higher compressive strength. The geopolymer/SBM blends at different mixing ratios have shown great improvement in rheology of the geopolymer cement, allowing for pumpability of the slurry for well cementation. For instance, 30% SBM blends have downhole rheology profiles that approach those of neat Portland slurries.
Abstract Synthetic based mud (SBM) contamination of portland cement slurries negatively affects the integrity of cementations in oil and gas wells, particularly drilled in deepwater environments. Few systematic studies to assess the effects of SBM contamination on portland cements have been reported in the literature, despite the industry understanding that such detrimental contamination occurs. In addition, solutions to reduce or eliminate the effects of SBM contamination of slurries have not been developed. A multi-phase project has been initiated to study the effects of SBM contamination on slurries, particularly those employed in deepwater wells (where long displacements, restricted circulation rates in tight annular clearances etc. can exacerbate the impact of mud contamination), and to assess which chemical interactions are causing the unfavorable behavior. The first phase of the project was to quantify the effects of contamination on typical portland slurries and to explore formulation changes that would make such slurries more tolerant to contamination. The control in the study was Class H portland cement, which has been the long-standing "workhorse" of the oil and gas industry for primary cementations. Two class H cements and other API cement types were investigated in the work. Alternative cements were also contaminated with the SBM for comparison with the Portland slurries. Results from the first phase of our work clarify the detailed contamination behavior of portland cements, showing the susceptibility of portland slurries to such contaminations. Results for alternative cementing formulations indicate distinctly lower sensitivity to SBM contamination. These results then provide a first set of guidelines on how to minimize and possibly avoid SBM cement contamination, which is expected to greatly help guarantee primary cementing success and proper zonal isolation in deepwater wells.
- North America > United States > Gulf of Mexico > Norphlet Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.94)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Sargelu Formation (0.94)
Abstract As shown by the Macondo blowout, an uncontrolled deepwater well control event can result in loss of life, damage to the environment, and significant damage to company and industry reputation. Consistent adherence to safety regulations is a recurring issue in deepwater well construction. The two federal entities responsible for offshore U.S. safety regulation are the Department of the Interior's Bureau of Safety and Environmental Enforcement (BSEE) and the U.S. Coast Guard (USCG). The regulatory authority of these two bodies spans well planning, drilling, completions, emergency evacuation, environmental response, etc. The wide range of rules these agencies are responsible for cannot be comprehensively verified with the current infrequency of on-site inspections. Offshore regulation and operational safety could be greatly improved through continuous remote real-time data monitoring. Many government agencies have adopted monitoring regimes dependent on real-time data for improved oversight (e.g. NASA Mission Control, USGS Earthquake Early Warning System, USCG Vessel Traffic Services, etc.). Appropriately, real-time data monitoring was either re-developed or introduced in the wake of catastrophic events within those sectors (e.g. Challenger, tsunamis, Exxon Valdez, etc.). Over recent decades, oil and gas operators have developed Real-Time Operations Centers (RTOCs) for continuous, pro-active operations oversight and remote interaction with on-site personnel. Commonly seen as collaborative hubs, RTOCs provide a central conduit for shared knowledge, experience, and improved decision-making, thus optimizing performance, reducing operational risk, and improving safety. In particular, RTOC's have been useful in identifying and mitigating potential well construction incidents that could have resulted in significant non-productive time and trouble cost. In this paper, a comprehensive set of recommendations is made to BSEE and USCG to expand and improve their regulatory oversight activities through remote real-time data monitoring and application of emerging real-time technologies that aid in data acquisition and performance optimization for improved safety. Data sets and tools necessary for regulators to effectively monitor and regulate deepwater operations (Gulf of Mexico, Arctic, etc.) on a continuous basis are identified. Data from actual GOM field cases are used to support the recommendations. In addition, the case is made for the regulator to build a collaborative foundation with deepwater operators, academia and other stakeholders, through the employment of state-of-the-art knowledge management tools and techniques. This will allow the regulator to do "more with less", in order to address the fast pace of activity expansion and technology adoption in deepwater well construction, while maximizing corporate knowledge and retention. Knowledge management provides a connection that can foster a truly collaborative relationship between regulators, industry, and non-governmental organizations with a common goal of safety assurance and without confusing lines of authority or responsibility. This solves several key issues for regulators with respect to having access to experience and technical know-how, by leveraging industry experts who would not normally have been inaccessible. On implementation of the proposed real-time and knowledge management technologies and workflows, a phased approach is advocated to be carried out under the auspices of the Center for Offshore Safety (COS) and/or the Offshore Energy Safety Institute (OESI). Academia can play an important role, particularly in early phases of the program, as a neutral playing ground where tools, techniques and workflows can be tried and tested before wider adoption takes place.
- North America > United States > Texas (0.45)
- North America > United States > California (0.28)
- North America > United States > Gulf of Mexico (0.28)
- North America > United States > Oklahoma (0.27)
- Overview (0.92)
- Research Report (0.67)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Structural Geology > Tectonics > Plate Tectonics > Earthquake (0.86)
- Government > Regional Government > North America Government > United States Government (1.00)
- Government > Military (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Gulf of Mexico > Central GOM > East Gulf Coast Tertiary Basin > Mississippi Canyon > Block 252 > Macondo Field > Macondo 252 Well (0.99)
- North America > United States > Gulf of Mexico > Norphlet Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.94)
- (5 more...)
- Well Drilling > Pressure Management > Well control (1.00)
- Health, Safety, Environment & Sustainability > Safety > Operational safety (1.00)
- Health, Safety, Environment & Sustainability > HSSE & Social Responsibility Management > Contingency planning and emergency response (1.00)
- Data Science & Engineering Analytics > Information Management and Systems > Knowledge management (1.00)
Abstract Blow-out prevention and formation gas/fluid influx control is a major concern in any drilling operation. In conventional drilling, the only widely accepted response to a gas influx is to shut the well in on the BOPs. New Managed Pressure Drilling (MPD) technology using the constant bottom-hole pressure (CBHP) technique allows for circulating small and medium-sized influxes out without the need to shut in the well, either by increasing casing back-pressure and/or adjusting pump flow rate. Evident benefits include a faster response to the influx (with clear safety benefits) and a considerable time and cost savings compared to the conventional approach. Unfortunately, there is currently no method available to decide upon the best MPD-CBHP response during an influx, because such a response depends on many parameters, such as Maximum Allowable Surface Pressure (MASP), wellbore geometry, fracture pressure of any weak zones exposed in open hole, type of drilling fluid, influx size, etc. To remedy this situation, we present a fast and accurate decision-making method that overcomes the traditional difficulties and automatically selects a best well control response. The method incorporates a transient multi-phase model based on mass, energy and momentum conservation. A sophisticated numerical simulator was developed for this purpose. Comparing the actual well response with simulated results during an influx event and following the proposed algorithm allows the best response to be taken in a quick, convenient, and accurate manner. Moreover, the approach lends itself well to fully automated control. Here, we describe the new method and its validation using available two-phase experimental data for annular air-mud flow for a wide range of flow rates and flow regimes. We believe that the method provides a powerful new decision-making and design tool in MPD operations that ensures delivery of safer wells with lower non-productive time and associated trouble cost spent on well control operations.