Showing papers on "Annulus (oil well) published in 2016"

Numerical Study on Effects of Drilling Mud Rheological Properties on the Transport of Drilling Cuttings

Abstract: Inaccurate prediction of the required pressures can lead to a number of costly drilling problems. In this study, the hydrodynamics of mud-cuttings were numerically studied using the Mixture Model. To this end, an in-house code was developed to calculate the velocity and pressure fields. The mud velocity profile using of Herschel–Bulkley model and solid phase volume fraction were locally calculated; moreover, pressure drop through the annulus was taken into account. The effects of velocity, mud properties, and solid phase volume fraction on pressure drop were discussed and a new correlation was proposed for calculating friction factor based on corresponding parameters.

Phase state variations for supercritical carbon dioxide drilling

Abstract: A phase state prediction model during supercritical carbon dioxide (SC-CO 2 ) drilling is estab- lished, considering the enthalpy changes caused by the fl ow work variations and changes in kinetic energy, as well as the potential energy caused by the fl uid velocity along with physical property varia- tions. The results show that variations in the fl ow work affect the temperature fi eld of the SC-CO 2 fl uid signifi cantly. Phase state transitions of the fl uid in the drill pipes and the annulus exist; in this example, the depth of the phase transition point in the drill pipes is in the range of 600 to 1000 m, while in the annulus, it is in the range of 400 to 700 m. Different results are observed when the phase state predic- tion is conducted by adjusting the discharge capacities, injecting temperature and pressure. When the discharge capacity is increased, the phase transition points in the drill pipes and the annuluses move downward; the pressure of the bit nozzle upstream increases gradually, while the pressure of the bit nozzle downstream changes slightly. When the wellhead back pressure is increased, the depths of the phase transition points in the drill pipes and the annulus decrease. Moreover, the pressure variations of the bit nozzle upstream and downstream can be divided into two stages: the fast growth stage and the slow growth stage. When the injection temperature is increased, the depths of the phase transition points in the drill pipes and the annulus are reduced; the temperature drop and the pressure drop at the nozzle change slightly. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd

Effect of Yield Power Law Fluid Rheological Properties on Cuttings Transport in Eccentric Horizontal Narrow Annulus

Abstract: Narrow annular drilling such as casing-while-drilling technique is gaining popularity due to its ability to mitigate nonproductive time during oil and gas drilling operations. However, very little is known about the flow dynamics in narrow annular drilling. In this study, the Eulerian-Eulerian two-fluid model was used to examine the influence of Yield Power Law fluid rheological properties on cuttings transport in eccentric horizontal narrow annulus. The flow was assumed as fully developed, laminar, and transient state. The present simulation model was validated against experimental data, where a mean percent error of −1.2% was recorded. Results revealed an increase in the radial distribution of cuttings transport velocity in the wide annular region as the consistency index, , and the flow behavior index, , increase. Nonetheless, increasing the yield stress, , had insignificant effect on the cuttings transport velocity. Three-dimensional profiles showed how cuttings preferred to travel in less resistant flow area, whereas cuttings concentration builds up in the narrow annular region. Furthermore, annular frictional pressure losses also increased as , , and increased. This study serves as a guide to properly optimize drilling fluid rheological properties for efficient cuttings transport and equivalent circulating density (ECD) management in narrow annular drilling.

Exploring the hole cleaning parameters of horizontal wellbore using two-phase Eulerian CFD approach:

Abstract: The present investigation deals with the flow through concentric annulus with the inner cylinder in rotation. This work has got its importance in the petroleum industries in relation to the wellbor...

Method for analyzing cement integrity in casing strings using machine learning

Abstract: The present disclosure provides methods and systems for analyzing cement integrity in a depth interval of a wellbore having a multiple string casing with an innermost annulus disposed inside at least one outer annulus. The method includes processing ultrasonic data obtained from ultrasonic measurements on the interval of the wellbore to determine properties of the innermost annulus. The method also includes processing sonic data obtained from sonic measurements on the interval of the wellbore to extract features of the sonic data. The features of the sonic data are input to a machine learning processing to determine properties of both the innermost annulus and the least one outer annulus. Additional processing of ultrasonic and sonic data can also be used to determine properties of both the innermost annulus and the least one outer annulus. These properties can be used to analyze cement integrity in the depth interval of the wellbore.

Multi-parameter logging while drilling apparatus

Abstract: The invention discloses a multi-parameter logging while drilling apparatus which comprises a drill collar. A pressure test bin is formed in the side face of the lower end of the drill collar. Two pressure sensors used for measuring mud pressure of a water hole and an annulus are arranged in the pressure test bin. The pressure test bin is sealed through a pressure bin sealing end cover. A plurality of grooves are formed in the drill collar and sealed through corresponding sealing cover plates. An axial passageway of the drill collar is achieved through the structural style of the cover plate relay. Pressure of the water hole and pressure of the annulus are integrated in one sealed bin, and pressure transmission passageways are formed by designing transverse small holes and small holes perpendicular to the axial direction. The four grooves are evenly distributed in the axial central position of the drill collar by a circle, strain gauges are arranged at the bottoms of the grooves, and the influences of structure nonlinearity on torque and drilling pressure measurement are reduced. Finally, the overall structural design program of the multi-parameter logging while drilling apparatus is solved, and the sensors are reasonably arranged. The multi-parameter logging while drilling apparatus is reasonable in structural layout, high in reliability, easy to machine, convenient to maintain and beneficial to expansion of instruments.

Gas migration monitoring device and monitoring method based on annulus pressure differential measurement while drilling

Abstract: The invention belongs to the technical field of petroleum engineering, and particularly relates to a gas migration monitoring device based on annulus pressure differential measurement while drilling in the drilling process. The gas migration monitoring device based on annulus pressure differential measurement while drilling comprises a nipple for gas migration monitoring while drilling, a central processing unit and a computer terminal; the two ends of the nipple for gas migration monitoring while drilling are connected with a drill collar and a drill pipe, and the two ends of the central processing unit are connected with a gas migration monitoring device body and the computer terminal; the computer terminal sends a measuring signal to the central processing unit through a data connection bus, the measuring signal is transmitted to the nipple for gas migration monitoring while drilling through an armored cable, a sensor group immediately conducts measurement work, the pressure P, the temperature T and the depth H of a corresponding position are obtained, the actual drilling fluid density is obtained through calculation, and if a difference between the actual drilling fluid density and theoretical density is larger than a gas migration discriminant value, well control prevention measures are started. The gas migration monitoring device is high in monitoring accuracy and extremely high in real-time performance, matching with the drill pipe is simple and convenient, the professional requirement on operation is low, the stability is good, and the automation degree is high.

A Semi-analytical Solution for Start-Up Flow in an Annulus Partially Filled with Porous Material

Abstract: This study investigates the start-up flow in a horizontal annulus partially filled with clear fluid and partially with a fluid-saturated porous material (composite channel) as a result of the sudden application of constant pressure gradient in horizontal direction. Momentum transfer in the porous medium is simulated using the Brinkman-extended Darcy model. The fluid and porous regions are linked together by equating their velocities and incorporating the shear stress jump conditions at the interface. With the application of Laplace transform technique, the governing partial differential equations are transformed into ordinary differential equations which are solved in the Laplace domain to obtain exact solutions. Inversion of the exact solution in Laplace domain to time domain is done using the Riemann-sum approximation approach. Validation of the Riemann-sum approximation method is achieved by comparing numerical values obtained with those of exact solution obtained for steady state flow and transient solution obtained by implicit finite difference method. At large values of time, transient solution obtained using Riemann-sum approximation approach and implicit finite difference method coincide with closed form solution obtain exactly for steady state flow showing excellent agreement between these methods. Line graphs are used to discuss the effect of the different flow parameters involved in the flow formation.

Method of forming a subterranean gas storage vessel

Abstract: A method of forming a subterranean gas storage vessel is provided. A wellbore is drilled through the surface of the ground into the ground, and a casing is inserted into the wellbore, the casing having a size such that a wellbore annulus is formed between the outside surface of the casing and the wall of the wellbore. A cement sheath is then formed in the wellbore annulus, and the interior of the casing is sealed to help prevent gas from inadvertently escaping therefrom. The cemented and sealed casing can then be used as a storage vessel to store and dispense gas such as compressed natural gas (CNG).

Novel well bore structure and well completion method for geothermal well

Abstract: The invention aims to provide a well completion method to overcome existing technical defects. According to the well completion method, a casing string is put into a drilled borehole according to design standards, and cement is poured into the well wall annulus of a well so that the well bore design quality can be ensured. The well completion method mainly depends on the grading well cementation technique and the water stopping technology of a geothermal well, cement is poured into an annulus between a second-opening borehole water taking section and a casing through an outer casing packer, a classification hoop and other components, and the effect of permanent separation and water stopping is achieved. The invention further provides a novel well bore structure for the geothermal well. The well bore structure is a perpendicular drilling well structure. A surface casing, a well fixing section and a production casing are sequentially arranged from the ground to the well bottom. The surface casing is arranged from the ground to the well fixing section, and one section of the upper end of the well fixing section is wrapped with the surface casing in the circumferential direction. The well fixing section is composed of a wellhead well fixing section body and a well bore well fixing section body. The adopted structure has the following advantages that permanent water stopping of the geothermal well can be achieved, surface water can be protected permanently, heat losses of a production well can be reduced, and the heat preservation effect is achieved.

Method of sealing wells by squeezing sealant

Abstract: A method for sealing a well includes: placing an obstruction in a bore of an inner tubular string disposed in a wellbore; forming an opening through a wall of the inner tubular string above the obstruction; mixing a resin and a hardener to form a sealant; and squeezing the sealant into the bore, through the opening, and into an annulus formed between the inner tubular string and an outer tubular string, thereby repairing a cement sheath present in the annulus.

Theoretical treatment of disc cutters subjected to general cutting forces

Abstract: This paper constructs a theoretical framework to investigate the stress and deformation state within the body of a roller disc cutter from the cutter characteristics (radii of the shaft and disc and the length of the shaft), the characteristics of the cut (depth of cut), the mechanical properties of the constructive material (Poisson’s ratio and Young modulus) and the boundary conditions involved during the disc cutting process. To pursue the objectives, mathematical formulations and calculations required for the analysis of elastic variables induced in the disc and shaft parts of a roller disc cutter subjected to general cutting forces are investigated. Assuming elastic material behaviour, the disc cutter in contact with its shaft is considered as a partially loaded annulus, and the shaft inside the disc as a laterally loaded cylinder subjected to stresses corresponding to different cutting configurations. The Airy stress function, Michell’s method and Papkovich–Neuber solutions are employed in two- and three-dimensional elastic domains using a double Fourier series technique.

Decomposing full-waveform borehole acoustic data with application to data from a North Sea well

Abstract: The objective of this study is to establish whether sonic data acquired in a cased hole can be used to estimate the material behind a second casing when the annulus between the two sets of casings is fluid filled. We have analyzed full-waveform data acquired using the Schlumberger tool Sonic Scanner for a double casing with a fluid between them, and where the outer annulus, outside the outer casing, might be cement filled or fluid filled. The sonic tool uses a cylindrical array of 104 omnidirectional receivers. The cylindrical array — approximately 4 in. in diameter and 1.8 m (6 ft) long — allows a formal decomposition of the acquired data into quasi-plane waves. Analyzing these plane waves, we have identified subtle but distinct changes in the waveforms. These changes appear to be dependent on the material filling the outer annulus, allowing for the determination of the fill material. The most significant changes relate to the propagating Stoneley waves. The identifications made are confirmed by ...

Computational Study of the Effect of Draft Plates on the Solid Behavior in a Spout-Fluid Bed

Abstract: Using computational fluid dynamics coupled with the discrete element method (CFD-DEM), the gas–solid flow in the spout-fluid bed with or without draft plates is numerically simulated to quantify the effect of draft plates and plate length on the behavior of the solid phase. The mixing behavior, force, velocity, and dispersion of the solid phase in all three regions of the system are explored. The results demonstrate that the insertion of draft plates slows the mixing of the solid phase. Increasing the draft plate length leads to a lower fraction of particles in the spout and fountain regions, increases the solid cycle time, and the solid residence time in the annulus and fountain regions. Also, the collision force between particles is one order-of-magnitude larger than the fluid force. Moreover, increasing the draft plate length enhances the translational and rotational solid velocity, and the vertical solid dispersion in both the spout and fountain regions.