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LONG-TERM GOALS My goal within the EuroSTRATAFORM program is to understand the creation of the preserved stratigraphic record on continental shelves and slopes as the product of physical processes acting with spatial and temporal heterogeneities. I have been using numerical models to provide insight into the formation and preservation of stratigraphic sequences at margins. My goal has been to obtain a quantitative understanding of the interactions of environmental parameters and their influence on stratal architecture and facies distribution. I wish to be able decipher the stratigraphy on margins to read the geologic record of the past and predict future stratigraphy. OBJECTIVES EuroSTRATAFORM is an opportunity to extend stratigraphic model applicability to new margins and to expand the capabilities of our products. The Rhône and Adriatic margins are similar to the earlier field areas in that they are mid-latitude clastic margins, but the stratigraphy is highly affected by the 3D geometry of the basins. The forcing provided by these boundary conditions provide a challenge, but are also necessary for modeling realistic systems. My aim is to quantitatively determine the system response of margins to different forcing functions sufficiently to be able to both predict stratigraphy and invert observed sequence architecture for geologic history. APPROACH I have used numerical models as a tool to provide insight into the formation and preservation of stratigraphic sequences at continental margins. To study these margins I will apply a multi-pronged approach. Together with Italian and French colleagues, I have been modifying and apply our existing 2D stratigraphic models to serial sections of the two EuroSTRATAFORM margins. This will test the portability of the models. It will also aid in evaluating the relative along-and across-strike transport and tectonics, and their influences on sequence architecture. John Swenson, with assistance from Chris Paola, Juan Fedele, I and others are jointly developing a 3-D sequence stratigraphic model. Together, we will extend our time-averaged, moving-boundary model for continental-margin sedimentation with its coupling of multiple transport regimes from 2-D to 3-D. The advantage of this modeling approach is that it allows for a systematic exploration of the margin's response to variations in sea level, sediment supply, tectonic subsidence, and wave climate over longer timescales. I am providing flexural component and parameterizations for the field areas. I will also make use of 3D flexural modeling and backstripping being done for a separate project on the Gulf of Lion to recover 1

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Ocean Drilling Program (ODP) Leg 174A drilled a total of 12 holes at three sites on the New Jersey shelf and slope, recovering almost 1 km of core ranging in age from late Eocene through the Pleistocene. Determining the timing, amplitudes, and causal mechanisms of sea-level variations, as well as their relation to the resulting stratigraphic record, continues to be a fundamental goal of ODP. The major goal of Leg 174A was to investigate the OligoceneHolocene history of sea-level change as part of a transect of holes from the slope (ODP Leg 150) to the coastal plain (150X and 174AX), which constitutes the Mid-Atlantic Sea-level Transect.

For more than 15 years, foamed cementing has been deployed on wells drilled in the Fahud and Natih fields of North Oman. The production section targets the Natih formation, a fractured Mesozoic hydrocarbon-bearing carbonate sealed by the Fiqa above and the Nahr Umr shale below. The Natih carbonate characteristically requires a cementing design to cure losses while providing zonal isolation. Foamed cement is the standardized cement design used to meet this objective. Previous attempts to mitigate lost circulation during cement placement using conventional lost-circulation materials were attempted with little success. Since 2006, the advent of foamed cementing has been prescribed as the standard design for cement placement across the 8 1/2-in. production section. These wells have experienced an evolution of stage tools as well as liner packers to aid isolation. The cementing operation consists of a decision tree design approach based on the tools used on the 9 5/8-in. section as well as the quality of wellbore returns observed during cement delivery. The initial stage consists of nitrified water with a foaming agent intended to reduce the hydrostatic burden observed on the fractured formations. This is followed by a four-stage "filler" of foam cement, each with a specific nitrogen rate necessary to maintain the designed density at the final placement depth. If wellbore returns are stable throughout the "filler" phase, the nitrogen rate is reduced to target an ideal final cement density to help ensure the cement sheath has optimized sealant capabilities across the section objective. If wellbore returns are unstable, the final nitrogen stages are maintained, and emphasis is placed on finalizing displacement and choking the backside, as necessary, to maintain foam expansion. Approximately 270 foamed cement applications were executed in the field using this approach. The acceptance criteria target for this section is for returns to be observed at the surface during cement displacement before packer installation. Continuous lessons learned on design parameters necessary to achieve the objective were captured in the 15-year period discussed. The value added using stage tools versus liner packers was measured and the base slurry designed used for the foam has been modified over time to deliver the highest probability of success for these wells. Designed cement properties were evaluated and optimized over the 15-year period of foamed cement delivery. Improvement to cement hydration analysis (CHA), permeability, transition time, and expansion slurry properties are discussed. Additionally discussed, as losses continue to be challenging across these sections, a variation of 11-kPa/m ultra-lightweight foamed slurry designed for wells in the Fahud and Natih production sections are an alternative option for extreme losses observed at > 5 m3/hr before cementing.