| Cold Heavy Oil Production (CHOP) is a non-thermal process in which sand is aggressively produced to stimulate a heavy oil production process for a higher oil production rate. Wormholes are primarily responsible for the enhanced production rates and unusual fluid production profiles because wormholes provide the main conduits for fluid flow in reservoirs. Foamy oil flow is crucial in making this production technology work because oil and gas mixtures mostly flow in the form of a continuous foam with a relatively high compressibility.; In this thesis, comprehensive models were developed to simulate CHOP well performance, including transient pressure behavior and production rate behavior. Firstly, the material balance principle was applied to the sand production data to obtain the possible wormhole geometries in unconsolidated formations. Secondly, the reservoir flow model was developed, with the consideration of static wormhole geometries and highly compressible foamy oil, to simulate transient pressure behavior of CHOP wells. In order to simulate production rate behavior of CHOP wells, dynamic wormhole growth and pressure-dependent viscosity was incorporated into the developed reservoir flow model. The wormhole flow was then coupled with the reservoir flow. Finally, solution methods were provided to numerically solve the proposed flow models by means of programming codes developed in Visual C++. The solution methods and numerical calculations were validated by comparing the results with those obtained from analytical solutions and commercial software.; Based on the proposed models and the developed programming codes, the transient pressure behavior and production rate behavior of CHOP wells were extensively analyzed. Transient pressure behavior analyses were conducted to understand the effects of growth pattern, pressure drop along wormholes, cumulative sand production, etc. on transient pressure and derivative responses. In addition, production rate behavior analyses were carried out to understand the effects of dynamic wormhole growth, outer boundary, drainage area, and well location on production rate profiles. Finally, the proposed models were applied to analyze field production data of two CHOP wells from the Edam Waseca Sand Pool, Saskatchewan, Canada.; It is shown that the proposed models not only provide reliable transient pressure behavior and production rate behavior of CHOP wells, but also are able to estimate static wormhole geometries, to understand dynamic wormhole growth processes, to calibrate reservoir and fluid parameters, to predict CHOP well performance, and to help the optimization of production system designs. Moreover, the results obtained from this research are essential for the applications of post-cold production technologies, as well as for pool development and management. |
