The final stage of development and operation oil fields is accompanied by many problems, one which the most characteristic, complications due to intensive flow sand from reservoir bottom hole. As liquid seeps through rocks poor collector properties, its skeleton collapses in hole zone grains begin into Sand particles accumulate formation plugs reduces productivity well cases completely stops op...

The productivity equation of a gas well is, in the final analysis, an expression that describes relationship between production and its bottom-hole flowing pressure. There are two kinds equations common use at present: binomial exponential equation. Combined with modified isochronal test, test data interpreted, it is found open flow rates calculated by basically same when pressure difference po...

There are lots of cleats, fractures and many other structure weak planes in coal seams, which make the bullet holes and cleats intersecting. During the hydraulic fracturing process in coal seams, fractures will initiate at coal rock body of borehole wall, and cleats or fractures are different from conventional reservoirs. Thus a new model for initiation pressure calculation during coal seams fr...

The mass of a black hole is interpreted, in terms of thermodynamic potentials, as being the enthalpy, with the pressure given by the cosmological constant. The volume is then defined as being the Legendre transform of the pressure and the resulting relation between volume and pressure is explored in the case of positive pressure. A virial expansion is developed and a van der Waals like critical...

[1] We use a coupled climate model to evaluate ocean bottom pressure changes in the IPCC-A1B climate scenario. Ocean warming in the 21st and 22nd centuries causes secular oceanic bottom pressure anomalies. The essential feature is a net mass transfer onto shallow shelf areas from the deeper ocean areas, which exhibit negative bottom pressure anomalies. We develop a simple mass redistribution mo...

We present a simplified drift-flux model (DFM) describing a multiphase (gas-liquid) flow during drilling. The DFM uses a specific slip law, without flow-regime predictions, which allows for transition between single and two phase flows. With this model, we design an Unscented Kalman Filter (UKF) for estimation of unmeasured states, production parameters and slip parameters using real time measu...

We create air bubbles at the tip of a "bathtub vortex" which reaches to a finite depth. The bathtub vortex is formed by letting water drain through a small hole at the bottom of a rotating cylindrical container. The tip of the needlelike surface dip is unstable at high rotation rates and releases bubbles which are carried down by the flow. Using high-speed imaging we find that the minimal neck ...

A parallel reservoir simulator has been developed, which is designed for large-scale black oil simulations. It handles three phases, including water, oil and gas, and three components, including water, oil and gas. This simulator can calculate traditional reservoir models and naturally fractured models. Various well operations are supported, such as water flooding, gas flooding and polymer floo...