Study On Cold Production Mechanisms Of Poorly Consolidated Sandstone Heavy Oil Reservoirs

Heavy oil reservoirs with abundant reserve are widely distributed in our country, and the onshore heavy oil and bitumen reserve is approximately 20% of the total oil reserve. Currently, thermal recovery technologies are applied to the production of heavy oil reservoirs, however, the cost of these technologies is very expensive, and these technologies also have some strict restrictions on the quality of reserve, so, large amount of heavy oil reserve remains undeveloped. Heavy oil cold production technologies nearly have no restrictions, and the production cost is extremely low, these technologies can be intensively applied to the exploitation of heavy oil reservoirs. In recent years, the introduction of cold production technologies gives a promising future to the development of heavy oil reservoirs with low quality reserve, and these reservoir's development will play an important role in the enhancement of the oil production of our country; and the cold production technologies will become the new generation of production technologies in the development of heavy oil reservoirs.Using cold production technologies, there is no need of steam injection, and no need of using sand proof technologies; the only need is the direct application of progressive pumps after perforation. The field tests and applications of cold production technologies have been very successful. However, many questions of production mechanisms still remain unsolved, and need to be investigated profoundly. Besides the laboratory investigation on various kinds of production mechanisms, the inter-relationship of these mechanisms should be considered, the contribution to the production rate and recovery efficiency should be investigated simultaneously, then the production mechanisms will be in their integrity.Concerning about the problems above, according to the complicated geological characteristics and mechanical properties of poorly consolidated sandstone heavy oil reservoirs, and based on the former achievements, laboratory researches and theory studies have been integrated, and rock mechanics, hydrodynamics, oil and gas flow in porous media, and theories of oil-gas field development have been combined, and theoretical researches and field applications have also put together, finally a complete set of cold production mechanisms has been founded. Based on the research on the mechanical properties, the failure criteria conditions, and the sand production criteria conditions of poorly consolidated sandstone heavy oil reservoirs, several laboratory researches have been done, such as wormhole mechanism, the solution gas drive mechanism of foamy oil, and the sedimentation law of sand particles/agglomerates, and...