Drilling Oil Wells Research Articles

Multi-dimensional semi-analytical model for axial stick–slip of a rod sliding on a surface with Coulomb friction

A multi-dimensional lumped element model of a long non-rotating rod that moves on a slick surface with both dynamic and static Coulomb friction is outlined. The rod is accelerated to a constant velocity, and the free end of the rod experiences the effect of stick and slip. This article describes a new modeling approach, where the model is able to switch between different linear semi-analytical sub-models, depending on how much of the rod is moving. Fundamental understanding of the stick–slip effect is revealed, and a potential shortcoming of the model is also discussed. The model is computationally effective and may be suitable for real-time applications in, for instance, oil-well drilling.

Combination of Photoelectrocatalysis and Ozonation as a Good Strategy for Organics Oxidation and Decreased Toxicity in Oil-Produced Water

The oil-produced water generated during drilling of oil wells and gas extraction has been a cause for great concern since it contains a complex mixture of different organic and inorganic compounds, large amount of CO2, grease, salts, minerals, oils, and many hazardous compounds. The present work investigates the efficiency of photocatalysis (PC), photoelectrocatalysis (PEC), ozonation (O3), and photoelectrocatalysis coupled with ozonation (PEC+O3) in the removal of organic and inorganic contaminants in the oil-produced water monitored by Gas Chromatography-Mass Spectrometry (GC-MS) and Ionic Chromatography (IC) techniques. Parameters such as toxicity, which was investigated using Zebrafish embryos, color, turbidity, pH, quantity of dissolved solids, conductivity, chemical oxygen demand (COD), and concentrations of organic and inorganic carbon were also investigated. The best results were obtained by coupling PEC and O3 techniques, which presented superior reduction in color (98%), turbidity (100%), inorganic carbon (99%), COD (73%), and a decrease of 96% in the fluoride and 35% in the chloride detected previously in the real oil-produced water. Among the 12 organic compounds identified in the oil-produced water, the PEC+O3 treatment reached complete oxidation in eight of them and a lower Zebrafish embryo mortality occurred with 12.5% of dilution after 2 h treatment.

Desempenho de controladores IMC aplicados na perfuração de poços de petróleo

O controle de pressão durante a perfuração de poços de petróleo pode ser um dos processos mais complexos e perigosos do estágio da exploração. Este estudo propõe o desenho e a validação do desempenho dos Controladores de Modelo Interno (IMC e SIMC) para controlar a pressão na perfuração de poços de petróleo com base na técnica Manage Pressure Drilling (MPD). O MPD adiciona uma válvula de controle no sistema de perfuração para obter uma outra variável de manipulação na pressão no fundo do poço. Na primeira parte deste trabalho, obteve-se um modelo matemático linear do processo, fundamentado na mecânica dos fluidos. O processo dinâmico apresentou um elemento integrador, além disso, é considerado o acréscimo de um intervalo de tempo entre a ação da válvula e a resposta da variação da pressão no fundo do poço. Na segunda parte, o controlador IMC melhorado foi projetado para compensar o efeito do termo integrado com o atraso de tempo, procurando o melhor desempenho e robustez do sistema. Finalmente, o controlador proposto é testado por problemas comuns durante simulações de perfuração (perda de fluido, influxos, conexão de tubulação e perda de potência da bomba) mostrando sua viabilidade. Além disso, o desempenho do sistema de malha fechada é comparado com um controlador PI clássico.

Dynamic gas kick regulation through control reconfiguration under MPD scenario – Two-phase flow validation

Controlling gas kick is essential to guarantee safe drilling of oil wells. As the gas flows toward the surface, its volume increases due to gas expansion, reducing mud weight. As a result, an uncontrolled gas kick may produce a blowout. A literature review, concerning MPD (Managed Pressure Drilling) technology, unveils that there is a gap regarding experimental validation of gas kick control strategies. Therefore, the main objective of this paper is building an experimental unit, representing the oil well drilling process, for dynamic gas kick control validation. Pressure, flow and level data are employed for real-time monitoring and control purposes. A drift-flux mathematical model (DFM) and a control reconfiguration scheme are validated using two-phase flow data from the experimental facility. The transient nature of the oil well drilling process, exhibiting a variety of operational modes and being nonlinear was successfully regulated by control reconfiguration, which works as an advanced control holistic structure.

Rheological Properties of Xanthan Gum, Hydroxypropyl Starch, Cashew Gum and Their Binary Mixtures in Aqueous Solutions

Large volumes of drilling fluids are used while drilling oil wells. Water‐based fluids are widely used because they are generally less expensive and more environmentally correct than synthetic fluids. Polymers are used in drilling fluids with different functions. This article reports a study of the rheological behavior of solutions containing xanthan gum (XG), hydroxypropyl starch (HPS) and cashew gum (CG), as well as their binary mixtures, to evaluate the applicability of CG (an abundant product in Brazil's northeastern region) in aqueous fluid formulations. The results show the potential to use CG in mixtures with XG. The thixotropic effect is confirmed by hysteresis loop analysis; the rheological behavior is satisfactorily described by the Ostwald‐de Waele and Casson models; the aqueous solutions containing XG/HPS mixtures present higher consistency indexes than the XG/CG mixtures; and the activation energy values of the XG/CG mixtures are governed by the CG fraction.

Application of adaptive neuro-fuzzy inference system and data mining approach to predict lost circulation using DOE technique (case study: Maroon oilfield)

Lost circulation is the most common problem encountered while drilling oil wells. Occurrence of such a problem can cause a lot of time and cost wastes. In order to drill oil wells, a fast and profitable way is necessary to predict and solve lost circulation problem. Expert system is a method used lately for problems that deal with uncertainty. In this paper, three approaches are carried out for prediction of lost circulation problem. These approaches include design of experiments (DOE), data mining, and adaptive neuro-fuzzy inference system (ANFIS). Data of 61 wells of Maroon oilfield are selected and sorted as the feed of the systems. Seventeen variables are used as inputs of the approaches and one variable is used as the output. First, DOE is conducted to observe the effects of variables. Plackett-Burman method is used to determine the effects of variables on lost circulation. After that, data mining is conducted to predict the amount of lost circulation. The class of regression is used to determine a function to model the data and the error of the model. Then, ANFIS is applied to predict the amount of lost circulation. The chosen data are used in order to train, test, and control the ANFIS. Furthermore, subtractive clustering is used to train the fuzzy inference system (FIS) of the model. The performance of the ANFIS model is assessed through the root mean squared error (RMSE). The results suggest that ANFIS method can be successfully applied to establish lost circulation prediction model. In addition, results of ANFIS and data mining are investigated through their prediction performances. The comparison of both methods reveals that ANFIS error is much lower than data mining.

Improve the Properties of Iraqi Bentonite Using Salts

After the success of experiments using the Iraqi Bentonite in the work of drilling oil wells as an alternative to the importer Bentonite which encouraged its use as an alternative for the work of civil excavation, such as diaphragm walls, drilling, bore pile, barriers, dams and tunnels. By changing the mixing and drilling method followed in the work of oil wells, which requires the conduct of many experimental mixtures to reach the optimal mix. Benefits were getting from the previous experiments conducted on such type of Bentonite were used by the General Company for Geological Survey and Mining and Ramadan Mubarak Company one of the formalization of the Ministry of Housing and Construction; in which the optimum mix was reached, the method of mixing was determined, the components and quantities of the materials included in the preparation of the optimal mix were determined in 1m3 of water for mixing time of 5 min. This study was supported by the results obtained by the Geological Survey and Mining Company, which relied on the use of (NaOH) as an alternative to the active calcium-centric (CMC) of Bentonite, which is considered to be one of the most expensive materials. This paper will be a good index for all concerned with implementation of civil excavations and field works.

Propylene glycol mono and di stearates as water in oil emulsifiers for oil-well drilling fluids

The objective of drilling operation is to drill, evaluate and complete a well that will produce oil and/or gas efficiently. The responsibility for performing these functions is held by using drilling mud.The research will focus on the oil base mud system due to the importance of that kind of drilling fluid which helped to address several drilling problems such as formation clays that react, swell or slough after expose to WBFs, increasing down hole temperatures, contaminants, stuck pipe, torque and drag.The research will rely on an economical-low cost prepared emulsifiers that used as W/O emulsifiers for oil base mud instead of the imported emulsifier. The new prepared emulsifiers provide an excellent options with emulsification power for oil-based mud that formulated from diesel oil and water.The nonionic emulsifiers were prepared through the esterification reaction of propylene glycol (1 mol) and stearic acid (1 mol) and/or (2 mol), the products were two oil soluble nonionic emulsifiers with hydrophilic/lipophilic balance (HLB) of 3.4 and 2.8 respectively. The chemical structure was confirmed using elemental analysis, FTIR and 1H NMR.The new prepared emulsifiers were evaluated as primary emulsifiers for oil – base mud and the results were compared with the currently used primary emulsifier. The obtained results exhibited interesting rheology properties and shear-thinning behavior, yield value, thixotropy, gel strength and filter loss.

Analysis and Calculation of the Effective Length of a Reader Solenoid Coil Coupled to Rapidly Moving Microtag

This study investigated the effective length of the reader solenoid coil used for oil-well drilling, and the time required for the communication between rapidly moving microtags and the reader solenoid coil attached to the equipment pipeline was calculated. The effective length of the solenoid coil was computed for both static and moving microtags. Then, a mathematical model was developed to describe the relationship among the effective length of the reader solenoid coil, baud rate, number of data bits, and microtag speed. Calculations were performed to design two reader solenoid coils, which were tested experimentally with a carrier frequency of 125 ± 10 kHz. The results show that the effective length of the reader solenoid coil is proportional to the microtag speed and number of data bits but inversely proportional to the baud rate. The proposed system provides a continuous energy supply to the microtags, and the moving microtag identification rate by the reader is 100%. The experimental and calculation results were in good agreement. Furthermore, reader solenoid coils of two lengths were used in the downholes of six oil-well drilling systems over two years.

Synthesis of engineering designs of drilling facilities

The article sets forth key principles of engineering of drilling equipment based on successive analysis of the goals of the production method, technologies of its implementation and conditions of mineral mining using a new approach to systematization of drilling methods. Potential advancement in the technologies and equipment of drilling is illustrated in terms of oil-well drilling.

The Extended Kalman Filter for State Estimation of Dynamic UV Flash Processes

We present an extended Kalman filter for state estimation of semi-explicit index-1 differential-algebraic equations. It is natural to model dynamic UV flash processes with such differential-algebraic equations. The UV flash is a mathematical statement of the second law of thermodynamics. It is therefore important to thermodynamically rigorous models of many phase equilibrium processes. State estimation of UV flash processes has applications in control, prediction, monitoring, and fault detection of chemical processes in the oil and gas industry, e.g. separation, distillation, drilling of oil wells, multiphase flow in oil pipes, and oil production. We present a numerical example of a UV flash separation process. It involves soft sensing of vapor-liquid compositions based on temperature and pressure measurements.

A sequential dynamic Bayesian network for pore-pressure estimation with uncertainty quantification

Pore-pressure estimation is an important part of oil-well drilling because drilling into unexpected highly pressured fluids can be costly and dangerous. However, standard estimation methods rarely account for the many sources of uncertainty, or for the multivariate nature of the system. We have developed the pore-pressure sequential dynamic Bayesian network (PP SDBN) as an appropriate solution to both these issues. The PP SDBN models the relationships between quantities in the pore-pressure system, such as pressures, porosity, lithology, and wireline-log data, using conditional probability distributions based on geophysical relationships to capture our uncertainty about these variables and the relationships between them. When wireline log data are given to the PP SDBN, the probability distributions are updated, providing an estimate of pore pressure along with a probabilistic measure of uncertainty that reflects the data acquired and our understanding of the system. This is the advantage of a Bayesian approach. Our model provides a coherent statistical framework for modeling the pore-pressure system. The specific geophysical relationships used can be changed to better suit a particular setting, or reflect geoscientists’ knowledge. We determine the PP SDBN on an offshore well from West Africa. We also perform a sensitivity analysis, demonstrating how this can be used to better understand the working of the model and which parameters are the most influential. The dynamic nature of the model makes it suitable for real-time estimation during logging while drilling. The PP SDBN models the shale pore pressure in shale-rich formations with mechanical compaction as the overriding source of overpressure. The PP SDBN improves on existing methods because it produces a probabilistic estimate that reflects the many sources of uncertainty present.

Torsional Vibration Control in Oilwell Drilling

This paper studies wave propagation control in a one-dimensional (1D) wave guide using a single actuator at the boundary, which relates to an important problem of drilling torsional vibration mitigation in oilwell drilling. Using measurements of both time and spatial derivatives of the drillstring rotational angle at the surface, the torsional wave in the drillstring is decomposed into two independent wave components traveling in opposite directions based on the d’Alambert solution. A top drive speed control method is proposed to mitigate torsional vibration in drilling by reacting to each wave component differently. The method was validated by numerical simulation, which demonstrated its capability for preventing and eliminating stick-slip—a form of torsional vibration that is considered the most common and detrimental type of vibration for drilling. A laboratory experimental platform was also designed and constructed to replicate the torsional vibration time response of drilling system. Preliminary experimental results confirmed the effectiveness of proposed method for torsional vibration mitigation.

Exponential Stabilization of Torsional Vibrations in Rotary Drilling Systems

The paper considers oilwell drilling operations and, in particular, the problem of minimizing drilling vibrations. We develop a stabilizing controller for a one dimension wave PDE with damping term that describes the drillstring torsional system. The drillstring system stability is studied via the Lyapunov theory and the control steps are deduced from a PDE backstepping approach. As a result, exponential vibration suppression is obtained in presence of stick-slip friction due to the drill-bit and the soil interactions. The torsional vibration rejection is shown through the developed simulation results.

Experimental results on acoustic communication through drill strings using a strain sensor receiver

Drilling oil wells is a costly, complex and high risk operation, especially for many wells whose depths can be at least several thousand feet. To minimize the cost and risk involved in drilling, typically there are several sensors mounted near the drill bit, to measure important parameters such as temperature and pressure around the drill bit. The collected information needs to be sent to the surface, to assist the driller with controlling and steering the drill bit. Compared to the use of highly expensive and vulnerable cables for wired communication in deep oil wells, or very low rate communication using pulses of mud in wells, transmission of information using acoustic signals thru the drill string is a feasible and promising method. In this paper, we use a drill string acoustic communication testbed, where the receiver is a strain sensor. This sensor measures local fractional displacements due to received vibrations. Using experimental data, we study key characteristics of a drill string channel impulse response, sensed by a strain sensor. We also demonstrate how the strain channel response structure can control the communication system performance. [This work was supported in part by the National Science Foundation (NSF), Grant IIP-1340415.]

EVALUATION OF OCCUPATIONAL RISKS IN ROUNT-TRIP OPERATIONS WHEN DRILLING OIL AND GAS WELLS

The article presents the analysis of occupational risks when performing round-trip operations during drilling oil and gas wells and provides simple and easy-to-understand methods of occupational risk management. It considers the main negative production factors which harm the health of workers when performing operations on lifting and lowering the drill pipes with the description of mechanical injury-risk factors.

Performance analysis of proportional-integral feedback control for the reduction of stick-slip-induced torsional vibrations in oil well drillstrings

The stick-slip phenomenon, in the process of drilling oil wells, can lead to large fluctuations in drill-bit angular velocity, due to the interaction between drill-bit and rock formation, and, thus, cause irreparable damage to the process. In this work, the performance of control laws applied to the rotary table (responsible for moving the drillstring) is analyzed, in order to reduce stick-slip and drill-bit angular velocity oscillations. The control laws implemented are based on a PI (Proportional-Integral) controller, for which the torque applied to the rotating table has components proportional and integral to the table angular velocity with constant or variable WOB (Weight-On-Bit). For the drillstring, a finite element model with a linear interpolation for the torsional motion was proposed. The torque at drill-bit was modeled considering a non-regularized dry friction model, with parameters that were adjusted using empirical data proposed in literature. Several performance criteria were analyzed and it was observed that a minimization of the mean deviation of the drill-bit angular velocity relative to the target one would provide the best operating condition. Parametric analyses of proportional and integral control gains were performed, yielding level curves for the mean deviation of drill-bit angular velocity. From these curves, stability regions were defined in which the deviation is acceptable. These regions were observed to be wider for smaller values of WOB and higher values of target angular velocity and vice-versa. In addition, the inclusion of a controlled dynamic WOB was proposed leading to reduced levels of mean deviation of angular velocity and, thus, improving stability regions for the drilling process.

Stabilization of torsional vibration in oilwell drillstring system

Stick-slip oscillations also known as torsional vibrations appearing in oilwell drilling systems are a source of economic losses, borehole disruption, pipes disconnection, and prolonged drilling time. The torsional dynamics is modeled by a damped wave equation. An important stability issue is to find a control law that reject perturbations due to torsional vibrations. Hence, the primary aim of this paper is to prove the well-posedness of the damped wave equation. In the next step, using the Riemann invariants, the damped wave equation is transformed into 2 × 2 first-order transport equations. The backstepping techniques combined with kernel equations and the Lyapunov theory are used to prove the local exponential stability of the transformed system, consequently the torsional dynamic. Simulation results are presented to illustrate the effectiveness of the control law.

Karakteristik Gelombang Stoneley dalam Menentukan Permeabilitas Reservoir Sumur Pemboran

In-situ permeability is an important factor in determining whether an economical drilling oil wells to be mined. Therefore, the calculation in determining the true value of permeability with an attempt to take a further decision, whether the industry is continued or not. Research through study literature is obtained a mathematical modeling from Matheu and Toksoz's work which contains the components of acoustic wavesattenuation factor and rock permeability factor. Furthermore, by combining some of the concepts and theories, mathematical models are used for acoustic field data logs and other data which are required to get permeability. Data from the acoustic log is analyzed to determine the time delay for P, S and Stoneley waves, then determination of the speed, frequency and attenuation factor, especially for wave Stoneley. In this permeability calculations, it is assumed that the condition of the rock formations in the area of measurement is a permeable rock and contains fractures. The results show that the permeability in measurement area at a depth position indicates suitable with the data of rock state.

The effects of drilling fluids and environment protection from pollutants using some models

Among the problems faced by the oil industry the environmental pollution caused by drilling oil wells is, due to the increasing energy demand, heavy reliance on oil share drilling operations are important and vital. The drilling process uses drilling fluids and generates waste fluids and cuttings. Drilling fluids used in drilling operations are including water based drilling fluids (WBF), oil based fluids (OBF) and synthetic based fluids (SBF). The wastes generated in the largest volumes during drilling oil and gas wells are drilling fluids and cuttings. There are several options to manage drilling wastes: discharge, down-hole injection and onshore disposal. In many regions of the world, some types of drilling fluids and drill cuttings may be discharged to the sea if they meet certain environmental requirements. Drilling fluids have operational properties including: maintaining pressure, removing cuttings from the borehole, cooling and lubricating and etc. One of the most particular activities in the industrial world is oil drilling industry like any other industrial activity in the waste and wast returns to the environmental and a plan for processing, refining, and there not delete it Long-term adverse effects of climate on the environment will be lasting. Some of fluids have negative impacts on workforce skin and environment for example base oils/solvents type OBF. In general, SBF have substantially lower environmental impacts than OBF. For preventing of fluids dangerous effects Health, safety and environmental (HSE) experts must be managed their impacts in drilling projects. Also the use of isotherms and kinetics models when using the sorbent to remove pollutants such as heavy metals contained in the fluid and drilling mud to describe the adsorption process was very efficient and the Langmuir and Freundlich models usually have better performance for removing of pollutants into environment protection.