The Experts below are selected from a list of 18 Experts worldwide ranked by ideXlab platform

Marino, Matheus Pareto - One of the best experts on this subject based on the ideXlab platform.

  • Desenvolvimento de um software de código aberto para cálculo hidráulico voltado à engenharia de petróleo
    Niterói, 2017
    Co-Authors: Marino, Matheus Pareto
    Abstract:

    No presente trabalho foi desenvolvido um software, denominado Drilling Fluid Calculator, de código aberto munido de três ferramentas voltado ao cálculo hidráulico de um fluido de perfuração. A primeira, escolhe o modelo reológico que melhor se adequa a um fluido qualquer, dentro dos seis modelos reológicas mais importantes (Newton, Bingham, Power Law, Herschel-Bulkley, Robertson-Cliff e Casson). A segunda, estima a perda de pressão por fricção para os seis modelos reológicos citados e o peso Equivalente da lama em configurações de poços verticais quaisquer. A terceira, determina a pressão de surge ou de swab e estimar o peso Equivalente da lama. A validação do Programa foi feita usando estudos que serviram como base ao software. Todos os Programas obtiveram bons resultados, exceto o cálculo da perda de pressão por fricção do modelo de Casson, que apresentou resultados não satisfatórios. O código fonte do Programa foi estruturado de modo a facilitar as futuras edições e melhorias. O software está disponível para download sem nenhum custo. Portanto, o Programa Drilling Fluid Calculator está disponível e aberto para ser usado ou editado pela comunidade cientifica.This study presents an open source software called Drilling Fluid Calculator. The software provides tree tools that are aim to drilling fluid hydraulics computations. The first tool selects the best Rheological model, within the six relevant models (Newton, Bingham Plastic. Power Law, Herschel-Bulkley, Robertson and Cliff, and Casson model), that most accurately represents the studied drilling fluid behavior. The second calculates the friction loss pressure for each Rheological model cited and the Equivalent Mud Weight for a vertical well configuration. The last one estimates the surge or the swab pressure caused by a drilling operation and the related Equivalent Mud Weight as well. All the Programs were validated by the used of the studs that the software was based. The tree tools achieved goods results, expect the Frictional Pressure Loss calculation for the Casson model that presented results below the minimum acceptable. The software's source code was developed in a way the facility the future improvements and modifications, and it was released to download for free for the operating system Windows and Linux. Therefore, the Drilling Fluid Calculator is available to be used or edited by the scientific community

Ping Chen - One of the best experts on this subject based on the ideXlab platform.

  • a wellbore stability analysis model with chemical mechanical coupling for shale gas reservoirs
    Journal of Natural Gas Science and Engineering, 2015
    Co-Authors: Ping Chen
    Abstract:

    Abstract Chemical and mechanical coupling are the most important factors affecting wellbore instability. The main objective of this research is to propose a wellbore stability analysis model for shale gas reservoirs. A mathematical model was proposed to analyze wellbore stability based on a quantitative solution for stress induced by mechanical, hydraulic and chemical effects, and the effective stress tensor around the borehole in a cylindrical coordinate system was also obtained. Anisotropic mechanical properties and changes in the strength of shale rocks were collected from tri-axial compression experiments, direct shear tests and the literature. To examine for shear failure along the weak plane and across the weak plane, the effective stress tensor in a cylindrical coordinate system was transformed into the weak plane's local coordinate system and integrated into the strength criteria of the weak plane. In addition, the failure regions around a horizontal well were simulated at different drilling times and for different drilling directions, and the real causes of wellbore instability for well X201-H1 in the Sichuan basin were analyzed. The results indicate that the nonlinear evolution equation for the strength parameters obeyed the logistic model; the strength parameters decreased drastically as the soaking time increased over the first five days, after which the strength parameters decreased slowly. In addition, pore pressure increased and solute concentration decreased under the condition C m C 0 , while pore pressure decreased and solute concentration increased under the condition C m  >  C 0 . The decrease in strength and the increase in pore pressure have significant impacts on the stability of wellbores within shale gas reservoirs. Pore pressure propagation changes the effective normal stress on the weak plane of the wellbore and results in the stress concentration exceeding the strength envelope. In traditional models, failure regions occur only on the surface of a borehole; however, in the new model, failure regions can also occur in the interior of a formation, and they can occur within four zones around a wellbore's circumference. The decrease of shale strength and the increase of pore pressure under the condition of water-based Mud (WBM) has a greater impact than in oil-based Mud (OBM), which help define the critical Equivalent Mud Weight (CEMW) requirements at which the rate of collapse increases rapidly. To maintain borehole stability, a series of approaches must be adopted, including reasonable Mud Weight (MW), Mud system, well path, physical plugging, etc. This model can be used to analyze the failure regions around boreholes and calculate the CEMW needed to maintain wellbore stability at different times. This model is different from, and more practical than, the traditional model.

Kinn, Andreas Andersen - One of the best experts on this subject based on the ideXlab platform.

  • Improving Cementing Practices for Top Hole Casing Strings at the Valhall Field.
    Institutt for petroleumsteknologi og anvendt geofysikk, 2014
    Co-Authors: Kinn, Andreas Andersen
    Abstract:

    The main goal of a primary cement job is to provide zonal isolation in the well. Obtaining zonal isolation according to regulations at the Valhall field have been challenging. The complex overburden at Valhall contains several permeable zones that need to be isolated from each other and the surface. A new set of strict internal regulations for cementing operations has lead to a change in the basic casing design. This was done in an effort to increase the chances of obtaining an approved job according to the new regulations. This has, however, proven to be challenging as the cement jobs have suffered severe problems with lowside channeling and general bonding problems.This thesis investigates the recent cementing operations at Valhall for the top hole casing strings (18 5/8" and 13 5/8"). A total of eight case histories are investigated, where important aspects of the operations are presented. An evaluation of the case histories are performed, where the effect of important factors are discussed. This includes spacer volume, displacement rate, centralization, and fluid properties. The effect of the factors are discussed both from a theoretical perspective and with the basis in the case histories and results.One of the most significant improvement was seen when displacing the drilling fluid to a low rheology Mud prior to performing the cement operation. The low rheology WARP OBM from M-I SWACO was found to give the best results. This is also consistent with the theory, as the WARP OBM had the lowest rheological properties of all the investigated drilling fluids.A big potential improvement was found to be the increase in displacement rate up towards turbulent flow for the spacer. This is not realistic to be achieved using todays cementing technique. Managed Pressure Drilling (MPD) equipment during cementing was found to reduce the Equivalent Circulating Density (ECD) by 0,9 ppg Equivalent Mud Weight at target depth. This reduction in pressure can be used for a significant increase in displacement rate, possibly up towards turbulent flow.

Wang Yanfang - One of the best experts on this subject based on the ideXlab platform.

  • An Improved Foam Modeling Technique and Its Application to Petroleum Drilling and Production Practice
    LSU Digital Commons, 2020
    Co-Authors: Wang Yanfang
    Abstract:

    Foam is one of the most common used multiphase fluid in Underbalanced Drilling (UBD) and Managed Pressure Drilling (MPD). Because of its low density, high capacity of lifting and carrying cuttings, low cost and compatibility with formations, foam has become more superior than the conventional drilling Mud when depleted reservoir pressure, severe lost circulation, or unstable borehole are encountered. In general, the success of foam applications rely on the understanding of the fundamentals of foam rheology in downhole conditions. Foam rheology has been studied for decades. Conventional foam rheological models such as Power Law, Bingham Plastic, Herschel-Bulkley to explain foam behavior usually fail to interpret the monitored circulating pressure changes in operation, not to mention foam behaviors in downhole. Understanding bubble size and foam texture impacts at different foam quality ranges in the foam model development become very significant. A new foam rheological model based on Low-Quality Regime (LQR) and High-Quality Regime (HQR) behaviors is developed. This new model, which originally came from comprehensive foam flow experiments, together with the visualization of foam texture and bubble distribution, is proved to be easily and conveniently implemented for industry use in this study. The model requires nine model parameters – three (uwRef, ugRef,DPRef) to define the transition region, four to capture Power-Law rheology in both HQR and LQR (KH, nH, KL, nL), and two to describe the sensitivity of steady-state pressure drops as a function of gas and liquid velocities in both regimes (mH, mL). With the newly developed foam model, we apply it in the following two foam applications in petroleum industry, in which the foam rheology and foam handling are the main concerns for successes. First of all, a foam drilling and wellbore clean-up application with foam is investigated. These scenarios consider foam circulation into 10000 ft long wells at different inclination angles with a long vertical, inclined, or horizontal trajectory. The results are compared with two existing foam modeling techniques, so-called Chen et al.’s model (based on the correlations for wet foams only) and Edrisi and Kam’s model (based on wet- and dry-foam rheological properties with five model parameters). The conclusions show that, with or without formation fluid influx, the new foam model demonstrates the robustness of the new modeling technique in all scenarios capturing foam flow characteristics better, whenever the situation forms stable fine-textured foams or unstable coarse-textured foams. Second, foam-assisted Mud cap drilling for gas migration situation, which simulatesthe process with accurate foam characteristics when foams are used to suppress gas kicks under certain well and fluid conditions, is presented. The new foam model with Two Flow Regimes is used throughout the simulation process. The results show how Mud-cap drilling parameters (such as pressure, foam density (or Equivalent Mud Weight), foam velocity, and foam quality) change at different operating conditions and scenarios. Moreover, a set of field data from a wellbore clean-up with foam operation is demonstrated and the circulating pressure changes provide the evidence of Two Flow Regimes

Fu Yao - One of the best experts on this subject based on the ideXlab platform.

  • Leak-off test (LOT) models
    2014
    Co-Authors: Fu Yao
    Abstract:

    textA leak-off test is one of the most common procedures to test the fracture pressure of the exposed formations. After cementing and drilling out of the casing shoe, the LOT is run to verify that the casing, cement, and formation can withstand the pressure needed to safely drill the next section of the well. The Equivalent Mud Weight obtained from the test is recorded and reported to government agencies as the strength of the casing shoe. Drilling engineers also rely on the reading from the LOT and use it as the maximum pressure that may be imposed on the formation to avoid fracturing. Exceeding the maximum pressure may result in serious consequences such as lost circulation, one of the most costly events in drilling operations. Therefore, accurate determination of formation fracture gradient is critical and can avoid a variety of well control problems. Considerable efforts to model LOT and leak-off behaviors have been done in the past. Altun (2001) and Paknejad (2007) each presented a unique method to estimate leak-off volume by dividing the pressurized system into four sub-systems: Mud compression, casing expansion, fluid leakage, and borehole expansion. The volume response from each sub-system is then combined to represent the total volume pumped during a LOT. However, neither model included the expansion volumes of cement sheath and formation rock outside of the casing; these volumes are not trivial and should not be neglected. In addition, both models use only pump pressure to calculate volumes generated during a LOT. The actual downhole pressure and the pressure acting from the outside are ignored. In this study, the volume contributions from cement sheath expansion and formation rock expansion are calculated using single cylinder Lame’s equation. The results are added with Altun’s borehole expansion volume, Mud compression volume, and fluid leakage volume to represent the total volume for the enhanced Altun model. Secondly, a Wider Windows mechanical expansion model is developed based on the concentric cylinder theory. This model simulates the compounded effect of casing, cement, and formation expansion along the cased hole based on pressures inside the wellbore and out in the far-field stress region. The volume generated from concentric cylinder expansion is then combined with Altun’s Mud compression volume and fluid leakage volume to simulate the total volume pumped during a LOT. The developed models were verified using three sets of field LOT data obtained from literature and compared with the original Altun model. The results confirmed that leak-off volume along the cased hole should be analyzed as a compounded effect of casing, cement, and formation expansion. Overall, the WW models accurately simulate both leak-off volume and leak-off behaviors.Petroleum and Geosystems Engineerin