Currently, type curve analysis methods are being commonly used in conjunction with the conventional methods to obtain better interpretation of well test data. Although the majority of published type curves are based on pressure drawdown solutions, they are often applied indiscriminately to analyze both pressure drawdown and buildup data. Moreover, the limitations of drawdown type curves, to ana...

[1] Year-to-year variations in summer drawdown of Northern Hemisphere atmospheric carbon dioxide (CO2) are compared with corresponding year-to-year variations in sealevel pressure (SLP), surface air temperature, and the productivity of land vegetation as inferred from the satellite-derived normalized difference vegetation index (NDVI). Annual values of CO2 drawdown for the years 1980–2000 are e...

The identification of spatial variations in hydraulic conductivity (K) on a scale of relevance for transport investigations has proven to be a considerable challenge. Recently, a new field method for the estimation of interwell variations in K has been proposed. This method, hydraulic tomography, essentially consists of a series of short-term pumping tests performed in a tomographic-like arrang...

[1] Most analytical and numerical models developed to analyze pumping test data focus on saturated flow below the water table. Traditionally the soil above the initial water table prior to pumping has been thought to have little influence on the test results and has usually been ignored. It is hypothesized that, if the unsaturated zone is capped by low-permeability soil, airflow in the unsatura...

One of the main concerns to design earth dam is the stability of the upstream slope of the earth dam in phase of rapid drawdown. Confined pore water pressure reduces the effective stress in this mode, so possibility of the instability and slippage will be increased. The main goal of this research is to investigate changes in the pore water pressure by using horizontal drains in upstream slope o...

Perforated wells in ultra-deep sandstone reservoirs are characterized by high reservoir temperature, formation pressure, and production, sand production will cause severe safety hazards to these wells. Based on Drucker-Prager (DP) rock failure criterion, a practical analytical model for predicting critical drawdown pressure (CDP) of sanding onset perforated is established comprehensively consid...

Accurately predicting the critical differential pressure (CDP) of sand production contributes to improving peak-shaving capacity and ensuring safe operation underground gas storage (UGS). The CDP sanding in target wells UGS was predicted coupling laboratory tests, inversed analysis with well logging data numerical simulations. in-situ mechanical properties rock were estimated by test results we...

We consider the classic Kelly gambling problem with general distribution of outcomes, and an additional risk constraint that limits the probability of a drawdown of wealth to a given undesirable level. We develop a bound on the drawdown probability; using this bound instead of the original risk constraint yields a convex optimization problem that guarantees the drawdown risk constraint holds. N...

Risk management of drawdowns and portfolio optimization with drawdown constraints is becoming increasingly important among practitioners. In this paper, we introduce new types of contracts which depend on the maximum drawdown or on the average drawdown. Trading drawdown contracts would address directly the concerns of portfolio managers who would like to manage them. The maximum or the average ...

Maximum drawdown, the largest cumulative loss from peak to trough, is one of the most widely used indicators of risk in the fund management industry, but one of the least developed in the context of measures of risk. We formalize drawdown risk as Conditional Expected Drawdown (CED), which is the tail mean of maximum drawdown distributions. We show that CED is a degree one positive homogenous ri...