Field-Scale and Wellbore Modeling of Compaction-Induced Casing Failures

Hilbert, L.B.; Gwinn, R.L.; Moroney, T.A.; Deitrick, G.L.

doi:10.2118/47391-ms

Cited by 4 publications

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“…Undesirable impacts such as casing deformations and wellbore failures (Hilbert et al 1999;Fredrich et al 2000;Sayers et al 2006) must be prevented to reduce significant economical risks and ensure the maximum safety of the drilling operations. Moreover, the forecast of the land subsidence caused by the compaction of the rock formation can be of major importance.…”

Section: Introductionmentioning

confidence: 99%

On the importance of the heterogeneity assumption in the characterization of reservoir geomechanical properties

et al. 2016

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SUMMARYThe geomechanical analysis of a highly compartmentalized reservoir is performed to simulate the seafloor subsidence due to gas production. The available observations over the hydrocarbon reservoir consist of bathymetric surveys carried out before and at the end of a ten-year production life. The main goal is the calibration of the reservoir compressibility c M , i.e., the main geomechanical parameter controlling the surface response. Two conceptual models are considered: in one (a) c M varies only with the depth and the vertical effective stress (heterogeneity due to lithostratigrafic variability); in another (b) c M varies also in the horizontal plane, that is, it is spatially distributed within the reservoir stratigraphic units. The latter hypothesis accounts for a possible partitioning of the reservoir due to the presence of sealing faults and thrusts that suggests the idea of a block heterogeneous system with the number of reservoir blocks equal to the number of uncertain parameters. The method applied here relies on an ensemble-based data assimilation (DA) algorithm (i.e., the Ensemble Smoother, ES), which incorporates the information from the bathymetric measurements into the geomechanical model response to infer and reduce the 2 C. Zoccarato, D. Baù, F. Bottazzi, M. Ferronato, G. Gambolati, S. Mantica, & P. Teatini uncertainty of the parameter c M . The outcome from conceptual model (a) indicates that DA is effective in reducing the c M uncertainty. However, the maximum settlement still remains underestimated, while the areal extent of the subsidence bowl is overestimated.We demonstrate that the selection of the heterogeneous conceptual model (b) allows to reproduce much better the observations thus removing a clear bias of the model structure.DA allows significantly reducing the c M uncertainty in the five blocks (out of the seven) characterized by large volume and large pressure decline. Conversely, land subsidence can constrain only partially the partitions that marginally contributes to the cumulative displacements of the seafloor.

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Section: Introductionmentioning

confidence: 99%

On the importance of the heterogeneity assumption in the characterization of reservoir geomechanical properties

et al. 2016

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Modeling Horizontal Completion Deformations in a Deepwater Unconsolidated Sand Reservoir

Hilbert

Saraf

Birbiglia

et al. 2009

SPE Annual Technical Conference and Exhibition

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We present the development and results of geomechanical models and analyses used to assess the risks of compaction-induced deformation and potential failure of horizontal gravel-pack completions in a field located in deepwater, but at shallow depth below the sea floor. The target reservoir consisted of high-porosity, under-consolidated stacked turbidite sandstones, which are comparable to some of the more well-known, problematic compactive reservoir sands. The formations indicated a high level of risk of depletion-induced compaction, which could produce large deformations and potential failure of completion equipment in horizontal wells. Coupled poroelastoplastic geomechanical finite element models were constructed to assess the risks of completion equipment damage due to depletion-induced reservoir compaction. Both open-hole and cased-hole gravel packed completion configurations were analyzed. Details of the pre-packed screen assembly components were included in the models, such as the ribs between the base pipe and inner screen, and deformable epoxied sand between inner and outer screens. Model results presented in this paper include deformations of the completion equipment and stresses in the screen components, as a function of reservoir depletion pressure. The results of the geomechanical modeling indicated that the overall compaction loading should not cause significant deformation of the specified completion equipment. Background The objective of the work presented in this paper was to quantify deformation of completion equipment as a function of reservoir depletion for shallow unconsolidated turbidite formations in deepwater Gulf of Mexico (GOM). Exploration, drilling and production in such fields can be extremely expensive and challenging The demanding technical and economic challenges of such large projects drive the motivation for increasing production and ultimate depletion pressure. In problematic rock reservoirs, such as that documented herein, economic demands have pushed upward the level of technical sophistication necessary to determine and define the operating limits. Advanced nonlinear geomechanical and mechanical modeling have become an integral part of efforts to extend the operating limits of completion equipment, as documented recently by Grueschow et al. (2008) and Hilbert and Bergström (2008). The field under study in this work is located in deepwater, but the target stacked turbidite sand formations are only 1,640 ft to 2,500 ft (500 m to 750 m) below the sea floor. The sands exhibit high porosity and moderate permeability for the region. This type of reservoir is similar to that studied by Schutjens et al. (2008) and is comparable to sands from some of the more well-known, problematic compactive reservoirs. There is a considerable literature addressing the physics and analysis of compaction and subsidence due to hydrocarbon production (Hilbert 2003 and references therein; Schutjens et al. 2008; Schutjens et al. 2004; Hettema et al. 2000; Khalmanova et al. 2008). If reservoir depletion is sufficiently large, compaction-induced deformation, activation of fault slip, and stiffness contrasts between sands and shales can result in significant casing damage and potential completion equipment failure (Segall 1989; Cernocky and Scholibo 1995; Fredrick et al. 1998; Hilbert et al. 1999; Li et al. 2003; Lee et al. 2008).

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Well-Integrity Evaluation for Methane-Hydrate Production in the Deepwater Nankai Trough

Qiu

Yamamoto

Birchwood

et al. 2015

SPE Drilling &Amp; Completion

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Summary Large accumulations of methane hydrates are known to exist in the deepwater Nankai Trough off the southern coast of Japan. Because of its enormous potential as an energy source, there is growing interest in the production of methane gas from these deposits. An offshore production test was scheduled to test the technological viability to produce the methane hydrate with a depressurization method. However, methane-hydrate production may cause large amounts of compaction and subsidence, which can damage well integrity and cause loss of zonal isolation in the overburden. This condition could provide potential leakage pathways for methane gas to the surface and endanger offshore operations. The paper presents a study in which well integrity was evaluated for a methane-hydrate-production test well in the Nankai Trough. In this study, a new work flow was proposed and applied to honor both fieldwide formation heterogeneity and near-wellbore geometry. The geomechanics properties were determined through integration of seismic inversion data, log data, and core data from the Nankai Trough. Interface elements were installed between the casing and cement and the cement and formation to evaluate the impact of cement-bond quality on the well integrity. The numerical simulation was conducted through coupling of the simulation results produced by a methane-hydrate production simulator from a third party with a 3D finite-element geomechanics simulator. The study predicted the occurrence of 2 cm of subsidence on the seafloor generated by approximately 1.5% of reservoir compaction for a production test of 20 days. Over this period, casing would yield with a plastic strain of approximately 1%. Most findings indicated a low risk in the loss of zonal isolation that is consistent with the results of the production test conducted in March 2013. This simulation evaluated potential risks related to well integrity, and provided critical information for the preparation and execution of the pioneering offshore methane-hydrate production test in the Nankai Trough.

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Field-Scale and Wellbore Modeling of Compaction-Induced Casing Failures

Cited by 4 publications

References 0 publications

On the importance of the heterogeneity assumption in the characterization of reservoir geomechanical properties

On the importance of the heterogeneity assumption in the characterization of reservoir geomechanical properties

Modeling Horizontal Completion Deformations in a Deepwater Unconsolidated Sand Reservoir

Well-Integrity Evaluation for Methane-Hydrate Production in the Deepwater Nankai Trough

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