Depositional Environment, Diagenetic History and Chemostratigraphy of the Mid-Cretaceous Sarvak Carbonates in Southern Iran

This study presents integrated petrography, stable carbon and oxygen and also strontium isotopes and major and trace element data for the Cenomanian-Turonian carbonates of southern Iran. These data provide new insights into the diagenetic history and reservoir characteristics of the prolific Sarvak Formation and chemostratigraphy of Mid-Cretaceous strata in the Tethyan region. The Cenomanian-Turonian Sarvak Formation forms one of the main hydrocarbon reservoirs in southern Iran and the Persian Gulf. The Sarvak carbonates are underlain by Kazhdumi Shales while a regional unconformity marks the top of the formation. These carbonates were deposited in a ramp setting. Detailed investigation using: well-logs, pertrography and geochemistry indicate that facies and diagenetic processes influenced reservoir quality. Chemostratigraphy established from several sections confirms the presence of the regional Turonian and local Cenomanian-Turonian unconformities and reveals the presence of previously unrecognized subaerial exposure surfaces. The paleoexposure surfaces are recognized by their negative δ 13C and δ18O values (as low as -6.4 and -9.40/00 VPDB, respectively) coupled with low Sr concentrations and higher 87Sr/86Sr ratios. These exposure surfaces have dual effects on reservoir quality: a constructive effect, which enhances the porosity through extensive dissolution of allochems and a destructive effect which includes occlusion of some of the porosity by meteoric cement precipitation. Positive δ13C values in the various carbonate phases reflect values of sea water coeval with Oceanic Anoxic Event (OAB) and Mid-Cenomanian Event (MCE). The δ13C excursions identified in Sarvak carbonate have been correlated globally. The interaction of the Sarvak carbonates with meteoric waters charged with atmospheric CO2, caused dissolution, karstification and palaeosol and bauxite formation below the exposure surfaces in some localities. The latter is likely an indicator of a warm and humid climate during that time. Calcite cementation is the predominant contributor to the porosity loss. The δ18O and δ13C values of various generations of calcite cements overlap to a large extent with calcite matrix and rudist shells, indicating their equilibration with fluids of similar isotopic composition (i.e. marine fluids). More negative δ18 O values suggest a significant meteoric component. The progressive decrease in δ18O values of some of the calcite cements (e.g. -12.3‰) and matrix-replacive dolomites could be related to precipitation at higher ambient temperatures. Their occurrence adjacent to stylolites suggests the formation during burial diagenesis. Partial dolomitization in some mud/wackestone intervals with shale interbeds is another factor in enhancement of the secondary porosity and reservoir development

Disruptive impacts of sustainability in project management and emerging sustainable practices in PMBOK 7th edition

Following concerns about climate change sustainable development has become an urgent need that requires institutional and governmental action. It is obvious that our unsustainable present has been built through projects by neglecting wider issues and Grand Challenges. Sustainability in project management has always been easy to understand but hard to implement in practice due to potential difficulties and lack of implicative solutions in PM standards. A structured review of 164 publications by (Silvius and Schipper 2014) indicates that the PM standards fail to seriously address the sustainability agenda. However, previous studies had a brief review on standards, and they were not updated as the PM standards are evolving during the time to adapt with new business needs. This research is the first study to investigate footprints of sustainability in PMBOK 7th edition with a more holistic and a purely theoretical perspective. The study considers sustainability as a crucial but disruptive aspect to be incorporated into the traditional project management functions. It proposes sustainability requires paradigm shifts which evolves current project management practices in a shift from process-based to a principle-based while creating value instead of focusing on deliverables and outputs

A variational model for stress analysis in cracked laminates with arbitrary symmetric lay-up under general in-plane loading

AbstractThe present research work presents a variational approach for stress analysis in a general symmetric laminate, having a uniform distribution of ply cracks in a single orientation, subject to general in-plane loading. Using the principle of minimum complementary energy, an optimal admissible stress field is derived that satisfies equilibrium, boundary and traction continuity conditions. Natural boundary conditions have been derived from the variational principle to overcome the limitations of the existing methodology on the analysis of general symmetric laminates. Thus, a systematic way to formulate boundary value problem for general symmetric laminates containing many cracked and un-cracked plies has been derived, and appropriate mathematical tools can then be employed to solve them. The obtained results are in excellent agreement with the available results in the literature. In the field of matrix cracks analysis for symmetric laminates, the present formulation is the most complete variational model developed so far

Stiffness reduction of cracked general symmetric laminates using a variational approach

AbstractIn this paper, stiffness reduction of general symmetric laminates containing a uniform distribution of matrix cracks in a single orientation is analyzed. An admissible stress field is considered, which satisfies equilibrium and all the boundary and continuity conditions. This stress field has been used in conjunction with the principle of minimum complementary energy to get the effective stiffness matrix of a cracked general symmetric laminate. Natural boundary conditions have been derived from the variational principle to overcome the limitations of the existing variational methods on the analysis of general symmetric laminates. Therefore, the capability of analyzing cracked symmetric laminates using the variational approach has been enhanced significantly. It has been shown that the method provides a rigorous lower bound for the stiffness matrix of a cracked laminate, which is very important for practical applications. Results derived from the developed method for the properties of the cracked laminates showed an excellent agreement with experimental data and with those obtained from McCartney’s stress transfer model. The differences of the developed model with McCartney’s model are discussed in detail. It can be emphasized that the current approach is simpler than McCartney’s model, which needs an averaging procedure to obtain the governing equations. Moreover, it has been shown that the existing variational models are special cases of the current formulation

Variational analysis of free-edge stress and displacement fields in general un-symmetric and thin-ply laminates under in-plane, bending and thermal loading

A variational approach based on the minimization of complementary energy is developed to determine accurately a complete solution for both free-edge stress and displacement distributions of a laminate with arbitrary lay-ups (possibly un-symmetric and made of thin plies) under combined in-plane, bending and thermal loading. The key idea is partitioning the total stresses/displacements in a laminate with free edges into unperturbed (without free edges) and unknown perturbation stresses/displacements caused by the presence of free edges. It enables the theory of variational stress-transfer to deal easily with both applied traction and displacement boundary conditions. A methodology is introduced to obtain displacement fields for a stress-based variational approach. The resulting stress and displacement fields exactly satisfy local equilibrium equations, strain-displacement relations together with all traction/displacement boundary and continuity conditions. By comparing the results with those obtained from the finite element method, the accuracy and computational efficiency of the developed model, is confirmed

A variational model for free-edge interlaminar stress analysis in general symmetric and thin-ply composite laminates

A variational model is developed to exactly determine both stress and displacement fields at free edges of general symmetric composite laminate strips under thermomechanical loads. By partitioning the total stresses in a composite with free edges into unperturbed (without free edge) and perturbation stresses and using the minimum complementary energy principle, the optimal stress and displacement fields are derived that exactly satisfy equilibrium, compatibility, boundary and continuity conditions. The paper extends the theory of stress-based variational stress transfer so that the effects of both applied traction and displacement loads can be considered. It has been also shown how the displacement field can be determined for a stress-based variational approach. The results are compared to refined finite element results. The superiority of the developed method over finite element method, both in terms of accuracy and computational efficiency, is discussed. The method is also applicable to thin-ply laminates and is computationally efficient

Disruptive impact of sustainability in project management and emerging sustainable practices in PMBOK 7th edition

Following concerns about exponential growth of world population, pollution, resource scarcity and its consequences sustainable development has become an urgent need that requires institutional and governmental action. It is obvious that our unsustainable present has been built through projects by neglecting wider issues and Grand Challenges. Sustainability in project management has always been easy to understand but hard to implement in practice due to potential difficulties and lack of implicative solutions in PM standards. This paper explores paradigmatic impacts of sustainability in project management practices and sustainability footprints in PMBOK 7th edition. In the first phase, the research follows an integrative literature review and thematically structure the review to synthesis the concepts to come up with a specific conclusion. In the second phase, researches will conduct interviews to strengthen the initial findings and generate new ideas about sustainable project practices. The study considers sustainability in project management as a crucial but disruptive aspect to be incorporated into the traditional management functions. It proposes sustainability as a key factor which evolves current project management practices in a shift from process-based to a principle-based while creating value instead of focusing on deliverables and outputs