Research And Application Of Chemical Water Plugging Technology For Offshore Gas Wells

Water production of gas wells affects normal production of gas wells.Water shutoff is an effective method to control water production.At present,the commonly used water shutoff technologies at home and abroad include mechanical water shutoff,chemical water shutoff and chemical and mechanical water shutoff.On the basis of a large number of investigations on common water shutoff technologies at home and abroad,the advantages and disadvantages of mechanical water shutoff and chemical water shutoff are summarized and analyzed.Aiming at the development mode of water drive gas reservoir in offshore gas field,the water production law and main control factors are studied and analyzed.On this basis,the drainage and water control measures used in a offshore gas field in recent years are systematically summarized,and the basic understanding of drainage and water control measures for gas wells is obtained.Optimum selection of chemical water shutoff technology for offshore gas fields is also made.In view of the limitations of water plugging operation on offshore platforms,a low-cost and high-precision water plugging technology is urgently needed,taking into account the factors such as construction cost and successful plugging rate.Through the research of this paper,a chemical plugging system suitable for coiled tubing operation is obtained,which meets the requirements of "injection,plugging,environmental friendliness,easy configuration" and so on.At the same time,combined with the matching plugging system,the layer selection and plugging can be implemented in multi-layer combined production wells,and the application scope of the technology is improved.By optimizing the construction process,a set of fine chemical water plugging construction mode can be formed,which can effectively control the plugging error and improve the success rate of plugging.At present,the plugging system and water plugging technology have completed two wells of field practice,and have achieved success.The cost of single well water plugging operation is reduced by more than 5 million yuan compared with the conventional mechanical water plugging method used in offshore gas fields before.