Gas Field Foam Drainage Gas Research And Applications

As the earlist and most widely ultilized dewatering gas production process in the Sebei Gasfield, foam drainage is a major monitoring production treatment and plays an important role in enhanced gas recovery. Althrough foam drainage has many favorable features, a number of limitations still influence the further application of foam drainage, for instance, lack of recognition of actuality and performance of water production in gas well and short action period. The main objective of this paper is researching into performance and characterization of water production, diagnostic method of gas well with accumulated liquid as well as optimization and technological parameters of foaming agent, so as to improve foam-dewatering gas production process level in Sebei Gasfield. This study draws the following conclusions:1. As water production is increasingly more serious in Sebei Gasfield, water breakthrough will be the leading fator for gas well production. Production of Sebei-1Gasfield reduced by41.3%, production of Sebei-2Gasfield reduced by46%, and production of Tainan Gasfield reduced by41.3%.2. According to the condition of wellhead, applying tubing-casing pressure drawdown, calculation of critical carrying fluid flow and pressure gradient curves et.al, we make estimation of liquid loading, establish liquid loading criteria and make calculating programs for critical carrying fluid flow and hydrops height, aiming at predicting gas well liquid loading in advance and establishing foundation for taking effective foam-dewatering gas production measures.3. Foaming agent optimization evaluation shows:foamer UT-11A, XHY-4A, UT-6and new foamer B have good compatibility with formation water. Foam dosage is among3～3.5‰, as oppposed to0.25-0.5%o for foam suppressant dosage. The dilution ratio of foamer and water is1:8, as opposed to1:8and1:10for dilution ratio of foam suppressant and water.4. Based on the diagnostic method of gas well liquid loading and method selection of foam dewatering time, we establish a warning system for liquid loading, make gas well liquid loading program and make liquid loading warning figure and water block warning figure, so as to provide an important theoritical basis for foam-dewatering gas production process, foam-dewatering time and water block time.5. Writing a software to calculate ritical carrying fluid flow and liquid loading, combining height detected test and tubing-casing pressure drawdown, we esblish and make progress the method of judging liquid loading, providing an important theoritical basis for foam-dewatering gas production process.6. In Sebei Gasfield,53gas wells were carried out foam-dewatering test in all and six wells failed, which meaned effective rate was97.6%. Gas well production increased obviously after foam dewatering. Meanwhile tubing-casing pressure drawdown decreased and gas production ratio grew up as well as critical carrying fluid flow. Finally single well production increased and accumulated water was partly carried out.