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Abstract The risk of improper temperature selection for the design and testing of cement slurries can be detrimental to well construction operations and could affect a well's integrity. The methods for temperature selection in API 10B-2 do not consistently reflect the representative bottomhole conditions for high temperature applications. More so, consider 10B-2 guidance valuable for proving benchmarks in the high temperature domain. Therefore, numerical temperature simulators help manage the risk by predicting the anticipated bottomhole cementing temperatures. Currently several temperature simulators are in use to predict, with better accuracy, cementing bottomhole temperatures. The manuscript investigates the strange differences in predictions between the simulators for a range of high temperature applications. The results of the work efforts should help end users understand the outputs allowing better judgement when selecting representative bottomhole cementing temperatures for a given application.
- North America > United States (0.46)
- Asia > Middle East (0.28)
- Well Drilling > Drilling Operations (1.00)
- Well Drilling > Drilling Fluids and Materials (1.00)
- Well Drilling > Casing and Cementing (1.00)
- (2 more...)
Abstract Both minimizing risks and providing adequate barriers are targets during cementing operations. This paper discusses key factors to consider during the design and execution of managed pressure cementing (MPC) operations in deep water. These factors are the result of important best practices identified for dependable results. The key learnings from different applications can provide more reliable MPC applications while minimizing associated risks. Accurate data collection is necessary to understand cementing simulation results. The process discussed used pressure while drilling (PWD) to collect data, such as equivalent circulating density (ECD) and equivalent static density (ESD). This data, in combination with data generated at the surface from the annulus, and a fit-for-purpose temperature profile were then used in a state-of-the-art software to help replicate actual drilling wellbore conditions and enable model calibration for the cement operation. Using a calibrated model, MPC analysis performed during the planning stage was updated to help predict different MPC scenarios. Cementing simulation results should provide the pumping schedule [e.g., volume in, volume out, planned surface backpressure (SBP), contingency SBP, and critical events along the schedule]. During the planning phase, the simulation results helped address misconceptions regarding MPC operations (e.g., rate out equal to rate in) and the SBP interpretation by accounting for surface equipment setup. The design accuracy was confirmed during the MPC application. Two cement operations were completed, with minor deviations that were addressed properly as a result of the analysis and risk assessment previously performed. Variable sensitivity (temperature, mud compressibility properties, fluids rheology, geometries downhole and at surface, MPD choke limitations) was important to maintaining SBP within the operational window to avoid influxes or losses. This paper discusses recommendations to provide guidelines for deepwater MPC design and execution. MPC operations in deepwater environments have a few applications within the oil and gas industry. This paper provides important information that can help improve this method and provide optimal design modeling and analysis. Additionally presented are key factors for zonal isolation in deep water engineering and operative considerations for improvement of this unconventional method.
- Asia (0.68)
- North America > United States > Texas (0.28)
Abstract Cementing conventional production liners is a mature topic with documented success. For wells drilled in a shallow domain, such as 4,000 feet or less, there can be challenges routinely overlooked technically as well as operationally. If not accounting for these challenges during the service delivery, it may prevent achievement of the isolation requirements. The development of the practices resulted from unfavorable cement evaluation logs that led to remedial cementing operations or worse case, premature well abandonment. A reform of the practices used to cement challenging shallow production liners included aspects of the design as well as the on-location (wellsite execution) phase of the service delivery helping to deliver the isolation requirements. The manuscript provides guidance from a position of managing the cementing service delivery while communicating the learning's contributing to successful shallow production liner cementing in the region of the study. It may provide the same success in other areas, as the reform practices are not unique. The practices include improvements to the service delivery such as liner hanger modifications, wellsite mixing practices, cementing fluid designs and placement optimization methods.
- Asia > Middle East (1.00)
- North America > United States > Texas (0.95)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid management & disposal (1.00)
- Well Drilling > Casing and Cementing > Cement formulation (chemistry, properties) (1.00)
- (4 more...)
Development and Validation of a Hydraulics Simulator for Estimating Subsurface Reverse Cementing Placement Pressures
Wreden, C. (Weatherford International Ltd.) | Simpkins, D. (Weatherford International Ltd.) | Sharma, R. (Weatherford International Ltd.) | Deshpande, K. M. (Weatherford International Ltd.) | Patkar, V. (Weatherford International Ltd.) | Fuller, G. A. (Shell International Exploration and Production Inc.) | Jee, B. (Shell International Exploration and Production Inc.) | Mercado, S. (Shell International Exploration and Production Inc.)
Abstract This paper covers the development and validation of a hydraulic simulator for subsurface reverse cementing placement in which fluids are placed down drillpipe and diverted into the annulus through a crossover tool above a liner hanger. Returns are taken up the liner inner diameter and are re-diverted through the crossover tool back to surface. Since commercially available cementing simulators are unable to model cement placement through this flow path with a crossover tool, a simulator was developed and validated using downhole pressure data collected during large-scale flow testing and a reverse cementing field trial. Development of this simulator is a major step forward to implementing a subsurface reverse cementing system in deep water. This custom simulator determines the magnitude of equivalent circulating density (ECD) reductions and identifies opportunities in which subsurface reverse cementing is advantageous with regard to pressure. Traditionally, placement through reverse cementing results in reduced bottomhole ECDs compared to conventional cementing. This pressure reduction is not uniform throughout the annulus, and a placement simulator that takes into account wellbore geometry, a crossover tool, fluid properties, and cementing hydraulics is required to assess viability of reverse cementing for specific deepwater wells. Computational fluid dynamics (CFD) modeling was conducted using specific crossover tool geometry and various fluid properties to develop a lumped-pressure loss model mimicking local pressure drops. This lumped model was incorporated into a hydraulics system-level solver to estimate surface and downhole pressures. The hydraulics solver was initially validated by comparing model output with downhole pressure data collected from large-scale flow testing and a field trial in which a liner was cemented using the crossover tool. The resulting subsurface reverse cementing simulator is able to simulate incompressible, multi-fluid placement through a crossover tool. Current capabilities of the simulator include incorporation of a crossover tool to divert flow into the annulus directly above the liner hanger in a deepwater well; estimation of surface pressures, bottomhole pressures, and downhole ECDs at any specified depth; and estimation of u-tubing effect from free fall of fluids. During a large-scale closed-system flow test, model output matched pressure gauge readings to within 11%. Comparisons of field trial surface and downhole pressures correlated with model output for cement placement. This paper will present comparisons of simulator pressure output and collected downhole data used for validation, along with simulator output for an example subsurface reverse cementing job for a deepwater liner.
Abstract Most cementing simulators do not account for lost circulation events or the compression/expansion behavior of non-aqueous fluids (NAF) during cement placement. As a result, their output can be unreliable, resulting in potentially poor recommendations and operational performance – in potentially critical well-cementing situations. When isolating potential flow zones and/or performing zonal isolation in high-temperature/high-pressure (HT/HP) and/or deepwater environments for example, accounting for lost circulation and compressibility of non-aqueous fluids can make the difference between a successful cementing operation and a very expensive failure. In addition, overall reliability compared to existing simulators is improved operationally and technically assuring the objectives of the cement placement can be met while complying with new regulations as they can apply to zonal isolation. This paper will explain the theory and methods behind the advanced cementing simulator inputs and resultant outputs with case histories demonstrating some of the field validation of the new simulator's reliability. Also, existing technology in the simulator will be highlighted summarizing the robust package available to meet the objectives of cementing job placement in light of recent industry changing events.
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (21 more...)