Design of oil wells using analytical friction models

Aadnøy, Bernt S.; Andersen, Ketil

doi:10.1016/s0920-4105(01)00147-4

Cited by 70 publications

(24 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Special attention was paid to analysis of directed bore-holes. Inasmuch as the inclined and horizontal bore-holes permeate the oil-and gas-bearing strata along the stratified structure of the underground reservoirs, they cover larger zones of fuel deposits and are effective expedients to enlarge the extraction efficiency [2][3][4][5]. Analysis of the DS stability in the bore-holes of these types was initiated after the pioneer paper by Dawsen and Pasley [6].…”

Section: Critical Buckling Of Drill Strings In Cylindrical Cavities Omentioning

confidence: 99%

Critical Buckling of Drill Strings in Cylindrical Cavities of Inclined Bore-Holes

Musa¹,

Gulyayev²,

Shlyun³

et al. 2016

JMEA

View full text Add to dashboard Cite

Notwithstanding the fact that the problem of drill string buckling (Eulerian instability) inside the cylindrical cavity of an inclined bore-hole attracts attention of many specialists, it is far from completion. This peculiarity can be explained by the complexity of its mathematic model which is described by singularly perturbed equations. Their solutions (eigen modes) have the shapes of boundary effects or buckles (harmonic wavelets) localized in zones of the bore-hole that are not specified in advance. Therefore, the problem should be stated in the domain of entire length of the drill string or in some separated part including an expected zone of its buckling. In the paper, a mathematic model for computer analysis of incipient buckling of a drill string in cylindrical channel of an inclined bore-hole is elaborated. The constitutive equation is deduced with allowance made for action of gravity, contact, and friction forces. Computer simulation of the drill string buckling is performed for different values of the bore-hole inclination angle, its length, friction coefficient, and clearance. The eigen values (critical loads) are found and modes of stability loss are constructed. The numerical results for the case when the inclination angle equals friction angle coincide with ones obtained analytically.

show abstract

Section: Critical Buckling Of Drill Strings In Cylindrical Cavities Omentioning

confidence: 99%

Critical Buckling of Drill Strings in Cylindrical Cavities of Inclined Bore-Holes

Musa¹,

Gulyayev²,

Shlyun³

et al. 2016

JMEA

View full text Add to dashboard Cite

show abstract

“…In a simple model, drag is the increased/decreased apparent hook-load when tripping plus the observed rotating hook-load at the equivalent depth [2,3].…”

Section: Drag and Friction Forcementioning

confidence: 99%

“…The effect of combined motion is well known, for example when rotating the drill string for running easier into the hole either for tripping in or out or back-reaming; a high rotational speed reduces axial drag considerably so we assume that during tripping operations an over pull may occur due to tight hole conditions. Further, research indicated that under the combined actions of axial load, centrifugal force and torque, the axis of the rotating drill string has a sinusoidal shape with changing wave length, and rotates as a rigid body, with the same speed and direction of the rotary table [2,3].…”

Section: Drag and Friction Forcementioning

confidence: 99%

See 1 more Smart Citation

Tensile and Torsional Loads Stress Distribution Along the Drill String for Deep Wells

Belkacem¹,

Abdelbaki

Gaceb³

et al. 2015

2nd International Congress on Energy Efficiency and Energy Related Materials (ENEFM2014)

View full text Add to dashboard Cite

Common knowledge and rule of thumb tell us that tensile failures will mostly occur in the pipe body, while torsion failures will occur in the tool joints. The total stresses on the drill string should be considered which are induced by combined bending, torsion and tensile stresses. The latter can usually be operating up until 80 % of the pipe body yield stress, a level which is considered as a safe working limit. Moreover, torque and drag are caused by the lateral forces and the friction between the borehole wall and the drill pipe. The lateral forces depend on the weight of the drill string. Torque and drag are sometimes overlooked when drilling simple wells. In deep well this is not acceptable. Proper decision made using correct torque and drag can make all the difference between TD drilling and suspended drilling. Therefore the over pull load plus the torque are the most important points to be considered in deep well drilling, since the resistance of the drill string body to the combined efforts will probably limit its tensional limit. By this I mean, exerting both a tension and torsion load on the drill string of this later will weaken its yield stress consequently applying a high tension effort combined with a significant torque lead to plastifying of the drill pipe body thus reducing its fatigue life. This problem is well observed in back-reaming operation. The results show that fatigue damage from rotation in dogleg during backreaming operation is a significant problem if the severity is greater than the critical value. So the position of drill pipe in the string will influence the amount of fatigue damage it sustains. Furthermore, back reaming can reduce the fatigue life of the drill pipe significantly because of the stress reversal of the drill string under tension in a dogleg.

show abstract

“…At the same time, prolific offshore hydrocarbon fields were located at depths of 7 km and more in the Black and Azov seas. Since directional deep-well drilling technologies are of relevance for the energy sector of Ukraine, it may be concluded that the mathematical simulation of the mechanical behavior of drillstrings for deep wells of various configurations is of theoretical and practical importance.The bending stability of vertical deep-well drillstrings was studied in [8, 10]; their bending and torsional vibrations were analyzed in [7]; the mechanical behavior of drillstrings in curved boreholes was studied in [5,6,[11][12][13][14] by modeling them by perfectly flexible cables and in [9] by formulating direct and inverse problems of bending of a curved elastic rod. Relevant reviews can be found in [2,3].…”

mentioning

confidence: 99%

Mechanical behavior of drillstrings in curved boreholes with local geometrical imperfections

2011

View full text Add to dashboard Cite

The problem of elastic bending of drillstrings in deep curved boreholes with geometrically imperfect axial lines is stated based on the theory of curved flexible bars. The dependence of the force resisting the motion of the drillstring on the amplitude, spacing, and location of geometric imperfections is analyzed numerically. The numerical results are discussed Introduction. Three well drilling methods are most widely used in developing offshore oil and gas fields. One of the methods weakly depends on the seabed depth over the producing field and the offshore distance. The method employs special ocean vessels and was used to drill a 4000 m well through hard rock under the ocean bottom (3050 m) in the Gulf of Mexico [12]. Using fixed offshore platforms for well drilling at relatively shallow depths is another method. It is less labor-intensive and more popular. It is obvious that on-land drilling is the simplest method. The last two methods drill curved boreholes that reach the field at some distance from the surface location. There are extended-reach wells with a horizontal departure of more than 12,000 m, and even 15,000 m was planned [6].It is significant that curved extended-reach wells make it possible not only to target remote underground oil and gas reservoirs, but also to considerably increase the well productivity and oil/gas recovery factor. For example, the maximum recovery factor is 37% for vertical wells and 55% for curved wells. However, the directional well drilling technologies are accident-prone, and since the fraction of trouble-free wells drilled all over the world is only 67% [11], the implementation of deep-well drilling technologies necessitates theoretical simulation of the mechanical phenomena accompanying drilling operations to prevent accidents.The majority of easily accessible fields of oil, gas, and gas condensate in Ukraine are at the final stage of development. At the same time, prolific offshore hydrocarbon fields were located at depths of 7 km and more in the Black and Azov seas. Since directional deep-well drilling technologies are of relevance for the energy sector of Ukraine, it may be concluded that the mathematical simulation of the mechanical behavior of drillstrings for deep wells of various configurations is of theoretical and practical importance.The bending stability of vertical deep-well drillstrings was studied in [8, 10]; their bending and torsional vibrations were analyzed in [7]; the mechanical behavior of drillstrings in curved boreholes was studied in [5,6,[11][12][13][14] by modeling them by perfectly flexible cables and in [9] by formulating direct and inverse problems of bending of a curved elastic rod. Relevant reviews can be found in [2,3].Here we set out to determine the forces resisting the motion of a drillstring in a curved borehole with local geometrical imperfections of its axial line. We will analyze cases where these imperfections considerably reduce the mobility of the drillstring (DS) and cause its sticking (freezing).1. Elastic Bending of a Drillstri...

show abstract

Design of oil wells using analytical friction models

Cited by 70 publications

References 13 publications

Critical Buckling of Drill Strings in Cylindrical Cavities of Inclined Bore-Holes

Critical Buckling of Drill Strings in Cylindrical Cavities of Inclined Bore-Holes

Tensile and Torsional Loads Stress Distribution Along the Drill String for Deep Wells

Mechanical behavior of drillstrings in curved boreholes with local geometrical imperfections

Contact Info

Product

Resources

About