Jerzy Stopa

A Simplified Semi-Analytical Model for Water-Coning Control in Oil Wells With Dual Completions System

In this paper, a mathematical model and numerical investigations on dynamic water/oil contact (WOC) in a reservoir with active bottom waters are addressed. An original analytical solution describing the theoretical shape of the dynamic oil-water contact in the reservoir is presented and compared with some results of numerical simulations made by a commercial flow-simulator. It is shown that both water and oil may be produced simultaneously but selectively from their respective zones. This allows a theoretical control of the dynamic WOC by the water flow rate. Consequently, an increased amount of oil can be produced along with water, depending on the well completion interval in relation to the oil/water contact in the reservoir. This shows the possibility of an in situ separation concept. The advantage of such a separate production of water and oil is to prevent the mixing oil with water within the pump and tubing.

Foams Stabilized with Nanoparticles for Gas Well Deliquification

Abstract This study examined the interaction of solid nanoparticles and anionic and non-ionic surfactant at an air–water interface. Aqueous foams stabilized by silica nanoparticles in water with different levels of salinity were studied in detail. The stability of solid/surfactant dispersion was evaluated visually. Nanoparticles content impact and concentration of surfactant on the foamability, deliquification of foams and structure of wet foams were studied. It was found that the foamability of dispersion depends either on the surfactant concentration or on the nanoparticles concentration. The adsorption of hydrophobically modified silica particles and surfactants reduces the air/water interface tension. The results of the examinations showed that the use of nanoparticles allows to increase the efficiency of brine unloading even up to 20%. Surfactant particle and nanosilica present synergistic action, use of 4 wt% of nanoparticles allows to reduce surfactant consumption up to half. The cost of the preparation of the proposed dispersion is slightly higher, about 5%, compared to the sole surfactant.

Computer Modeling of Coal Bed Methane Recovery in Coal Mines

This paper presents an improved reservoir simulation approach to methane production in a longwall mining environment. The coal beds are naturally fractured systems with the gas adsorbed into the coal matrix. Fractures penetrating the coal matrix have limited storage capacity, but they play the role of a gas transportation system. The proposed simulation technique is based on the assumption that a mass of coal removed by mining transfers its gas to adjacent fractures. By using an ECLIPSE coal bed methane simulator, the pore volume of the matrix represents the coal volume of the simulation cell. Consequently, the exploitation of coal can be simulated by modifying the matrix pore volume over time. This paper presents theoretical backgrounds of this approach and investigates numerical effects. A case study of the Moszczenica coal mine in Poland, including computer simulations of methane production, is also reported to show that a long history of the methane and coal recovery can be reproduced using the proposed technique.