Thought Suppression

The idea that suppressing an unwanted thought results in an ironic increase in its frequency is accepted as psychological fact. Wegner’s ironic processes model has been applied to understanding the development and persistence of mood, anxiety, and other difficulties. However, results are highly inconsistent and heavily influenced by experimental artifact. There are a substantial number of methodological considerations and issues that may underlie the inconsistent findings in the literature. These include the internal and external validity of the paradigms used to study thought suppression, conceptual issues such as what constitutes a thought, and consideration of participants’ history with and motivation to suppress the target thought. Paradigms that study the products of failed suppression, such as facilitated recall and attentional deployment to thought relevant stimuli may have greater validity. It is argued that a shift from conceptualizing the persistence of unwanted thoughts as products of failed suppression and instead as internal threat stimuli may have merit.

Water Blocks in Tight Formations: The Role of Matrix/Fracture Interaction in Hydrocarbon-Permeability Reduction and Its Implications in the Use of Enhanced Oil Recovery Techniques

Summary Hydraulic fracturing is used to obtain economical rates from tight and unconventional formations by increasing the surface area of the reservoir within the flowing distance to a high-conductivity pathway. However, a significant fraction of the fracturing fluid is never recovered, and thus may reduce the hydrocarbon permeability near the fracture. Here, we experimentally mimic the water-invasion process during fracturing, and measure the effective permeability changes in a low-permeability core. Measurements of water flowback and effective permeability as a function of interfacial tension (IFT), flow rate, and shut-in time suggest that water is being held at the fracture face because of the capillary discontinuity (i.e., when the water leaves the matrix and enters a space with minimal capillary pressure). This effect arises from the capillary interaction between the matrix and the fracture, and is akin to the capillary end effect in coreflood experiments. The results show that this effect, although only a laboratory experimental artifact for conventional reservoirs, can be a significant source of effective hydrocarbon-permeability reduction by fracturing-fluid invasion into the formation in unconventional and tight reservoirs.