History, Evolution, and Future of Casing Design Theory and Practice

Howard, John A.; Trevisan, Ruggero; McSpadden, Albert R.; Glover, Simon

doi:10.2118/206183-ms

Cited by 5 publications

(1 citation statement)

References 50 publications

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“…On this basis, the fracture mechanism of the stabilizer connecting thread was revealed. Amir et al [13,14] described the composite string design method, which can serve as a guide for selecting suitable candidates for this design and an operational guide for complex well section design. Yu et al [15][16][17] explored the mechanical properties of hanger casings through corrosion and tensile tests and optimized different thread connection methods.…”

Section: Introductionmentioning

confidence: 99%

Research on Thread Seal Failure Mechanism of Casing Hanger in Shale Gas Wells and Prevention Measures

Mou,

Xie,

Wei

et al. 2024

Processes

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The strength and sealing failure of the connecting thread of the casing head mandrel hanger causes huge economic losses. One of the major challenges is the thread seal failure mechanism of the casing hanger in the wellhead during pressure testing in shale gas wells. In order to analyze the failure causes of connecting threads and put forward improvement measures, a typical case of a well accompanied by a hanger seal failure is analyzed in this paper, and a series of material tests are carried out. The microstructure and mechanical properties of casing materials and hanger materials could meet the field requirements. It is concluded that both the hanger material and casing material are characterized with significant ductile fracture. A three-dimensional model of the hanger and casing system is established, and the mechanical behavior is calculated for the connecting thread under different working conditions. The results showed that the connection degree of the hanger–casing is insufficient at the torque recommended by the manufacturer because of the difference in wall thickness between the box thread of the hanger and the box thread of the joint according to the connection degree of the coupling casing. It is seen that the high contact pressure ring of zone three on the sealing surface plays an effective sealing role under the manufacturer’s recommended torque (20,465 N·m). Finally, when the torque is increased by 25%, the maximum contact pressure between the pin thread of the casing and the box thread of the hanger can fully meet the internal pressure from the wellbore pressure test and the internal pressure strength required for subsequent operations.

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Section: Introductionmentioning

confidence: 99%

Research on Thread Seal Failure Mechanism of Casing Hanger in Shale Gas Wells and Prevention Measures

Mou,

Xie,

Wei

et al. 2024

Processes

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Closed-Loop Geothermal Well Design with Optimization of Intermittent Circulation and Thermal Soak Times

McSpadden¹,

Coker²,

Bohlander

2022

Day 3 Wed, October 05, 2022

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A closed-loop geothermal well design is presented which incorporates both wellbore configuration and completions components as well as a strategy for well operations which together achieve meaningful production of thermal energy. Planning and optimization of intermittent circulation enable "thermal soak" periods to thermally charge the working fluid while mitigating thermal depletion in the reservoir. Technical challenges of a viable closed-loop downhole heat exchanger scheme are discussed. Advantages of Closed-loop Geothermal Systems (CLGS) compared to Enhanced Geothermal System (EGS) designs are also considered. Fully transient and closely coupled thermal-hydraulic simulations using an industry standard software model were performed on a representative well design and schedule of well circulation operations. The simulation model accounts for detailed conduction, forced and natural convection and radiative heat transfer modes in both the wellbore and the formation as appropriate. Detailed thermophysical characteristics are incorporated into the model for all wellbore completion components which include industry available OCTG grades and sizes, specialized variations such as Vacuum-Insulated-Tubing (VIT), insulating fluids including nitrogen, conventional and foamed cements and syntactic foam as well as the variation in the earth formation. Water is used as a demonstration working fluid and the full spectrum of fluid behavior for all potential phase and quality regimes are accounted for throughout the circulation flow path and at the surface wellhead. Resultant transient temperatures over an extended sequence of flow and shut-in periods are reported inclusive of near-by earth formation temperatures out to the far-field boundary. Comparisons with analytical reference models are also considered. Well simulations presented herein achieve repeatable and extended return fluid temperatures in the range of 200°F to over 400°F. In combination with a pad well concept, this allows for long-term steady energy generation. Clearly the generation of useful temperatures and ultimately justifiable enthalpy delivery with closed-loop configurations is a challenge. Further work on innovative design concepts, refinements such as integration with surface plant processes to optimize surface pressures and pump requirements as well as the recycling of heated water, and identification of optimal locations for deployment will progress this work. Advantages of fully closed-loop well systems include avoidance of potential problems associated with traditional geothermal and EGS wells such as induced seismicity and bedding plane slippage, formation interface skin quality, reservoir degradation over time and introduction of corrosive formation species into the wellbore, and disposal thereof. Combined optimization of both wellbore configuration components and staged circulation and thermal soak periods is shown here to provide a realistic option for significant steady heat generation. Impact of various completion components on operational efficiency can be quantified. In particular, the optimal staging of intermittent circulation operations and their associated thermal soak periods is a featured design option which has not received wide consideration in the literature.

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Casing Design Load Case for Shut-In After Worst Case Discharge Using a Progressive Depth Analysis Approach

Howard,

Grant,

D'Amico

et al. 2023

Day 3 Wed, October 18, 2023

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The US Bureau of Ocean Energy Management (BOEM) defines Worst Case Discharge (WCD) as the maximum foreseeable daily flow of oil from a well, commonly referred to as a "well blowout." When casing design engineers refer to "WCD", they focus on the impact of shutting in a maximum flow case on casing stresses as opposed to "volume" of discharge. This is sometimes referred to as Worst Case Discharge Pressure (WCDP) or Maximum Discharge Casing Pressure (MDCP) or Worst Case Discharge Load (WCDL). The US Bureau of Safety and Environmental Enforcement (BSEE) may refer to this pressure as Pressure Gradient (PG). Some international operators refer to "WCD" only as a load case and not a discharge volume so the term "WCD" may mean different things to different people. A new approach is presented to augment casing design load methodology associated with shut-in of an openhole flow event and where multiple hydrocarbon zones are exposed in an openhole section. The proposed methodology determines the casing design loads for the highest potential flowing temperature and highest shut-in at capping pressure case establishes stresses on the existing casing and verification of casing hanger lift-off. Uniform understanding and resolution of volume-based assessment and well survivability considerations in current practice are discussed. The Progressive Depth Approach focuses on determination of the highest stress by considering the progressive contribution of multiple reservoirs flowing during an uncontrol flow event and subsequently shut-in. The load case is conceptually structured in two events: 1) uncontrolled hydrocarbon flow through exposed casing strings with related discharge to ambient conditions (seabed in subsea wells) and 2) shut-in of the well with capping installed at wellhead. From a casing design and well integrity viewpoint, the load case enables quantification of stress changes along existing casing strings and at the casing hanger to assess well survivability. Thermal effects typically generate compressive forces (hot cases) and induce annular fluid expansion in casing annuli (if sealed) potentially leading to hot casing collapse scenarios in combination with severe draw-down pressures in the inner wellbore. Axial forces generated at the casing hanger need careful evaluation relative to lockdown mechanism ratings in a subsea wellhead. Operators may incorrectly assume that shut-in of the deepest reservoir in an open-hole section generates the highest stress casing load. Rather it could occur from a shallower reservoir depending on formation pressures, fluid composition and contribution of the remaining reservoir exposed (commingled fluid and flow conditions). An advanced load methodology to apply flow conditions and shut-in of an open-hole flow event given multiple reservoir zones for the determination of maximum thermal effect and shut-in pressure at capping wellhead condition is presented herein.

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History, Evolution, and Future of Casing Design Theory and Practice

Cited by 5 publications

References 50 publications

Research on Thread Seal Failure Mechanism of Casing Hanger in Shale Gas Wells and Prevention Measures

Research on Thread Seal Failure Mechanism of Casing Hanger in Shale Gas Wells and Prevention Measures

Closed-Loop Geothermal Well Design with Optimization of Intermittent Circulation and Thermal Soak Times

Casing Design Load Case for Shut-In After Worst Case Discharge Using a Progressive Depth Analysis Approach

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