Abstract The Nagra/PSI Chemical Thermodynamic Data Base is a critical selection of thermodynamic data used to support performance assessments for planned radioactive waste repositories in Switzerland. For this purpose, the data base is focused on actinides and fission products, but also includes additional data for major elements occurring in common groundwaters. Recently, a peer-reviewed update was carried out (from data base version 05/92 to 01/01) involving major revisions for most actinides and fission products. Altogether, more than 70% of the data base contents have been revised. Most of the thermodynamic data for U, Np, Pu, Am, and Tc were adopted from the reviews by the NEA TDB project. In contrast, data for Th, Sn, Eu, Pd, Al, as well as the solubility and metal complexation of sulphides and silicates, were extensively reviewed. Less effort was put into the review of data for Zr, Ni, and Se as these elements are currently being reviewed in Phase II of the NEA TDB project. The data for metal complexation with organic ligands from data base version 05/92 were not included in this update. They will be reconsidered in a future update, after completion of the NEA TDB Phase II review of organic ligands. The chemical consistency of the selected data was checked with empirical rules related to the periodic properties of the elements and with correlations based on charge/size relations. As a result of the update, major gaps in the data base could be identified, especially with respect to missing carbonate complexes. In some systems, for example, Th(IV)-H 2 O and U(IV)-H 2 O, conflicting experimental data cannot be described by a unique set of thermodynamic constants and a pragmatic approach closely reproducing measured solubility data was chosen for application to performance assessment. The electronic version of the Nagra/PSI Chemical Thermodynamic Data Base 01/01 and information concerning its full documentation is available on the PSI web site.

Abstract Drilling horizontal wells is the common mode of operation for field development in low-permeability unconventional reservoirs such as the Eagle Ford Shale. Assumptions are made regarding the homogeneity of the reservoir as wells are drilled away from the vertical pilot well. It is assumed that the reservoir characteristics remain uniform and also that the structure is constant based on the dip of the beds in the pilot hole wellbore. Making such assumptions can lead to wells being placed out of zone and in rocks with much different reservoir quality and stress magnitude than those in the pilot hole, which can adversely affect the production potential of the well. With the high cost of drilling and completing these wells, it is generally economically beneficial to do some evaluation of the lateral to ensure proper placement of the well and also the optimal placement of completion zones along the lateral. Lateral measurements and petrophysical interpretations can be used to define variations in reservoir quality (RQ) and completion quality (CQ) along the wellbore, which can then be used to optimize the completion design, for example, placing perforation clusters in similar rocks to increase production when compared to peer wells completed with a geometric design. The next step in integration is correlating pilot and lateral wellbore measurements with the structural component. This process is defined as geology quality (GQ). After taking together, RQ, CQ, and GQ, a comprehensive design of a wellbore-specific completion treatment can be achieved. This methodology of integrating data from many sources provides a better understanding of the variability and structural challenges of these complex reservoirs.