深水气井生产过程中的井筒结垢实验规律

Experimental law of well scaling in the production process of deepwater gas well

海上气井具有深度大、除垢操作复杂、作业成本高等特点,深水气井井筒内结垢的预测与防治具有实际意义。采用室内实验和理论计算相结合的方法,对南海气田的4口深水气井生产过程中的井筒结垢风险进行了评价,预测了生产过程中的井筒结垢速率及气井井筒内的结垢位置,并分析了结垢特点及规律。研究结果表明,地层水组成决定了气井的结垢类型,结垢速率主要取决于表面附着期过后较稳定的垢物附着速率;深水气井生产过程中不同井深处的结垢差异性主要取决于井筒沿程的温度分布,井筒中下部和高产气量及高水气比是防垢重点;相比陆上气井,深水气井受井筒结垢的影响更大,采取及时的防垢手段避免垢物生成或将垢物沉积量控制在容许范围内对维持深水气井的高效安全生产意义重大。

Offshore gas wells are characterized by large depth,complex scale removing operation and high operation cost,so it is imperative to predict and control the scaling in the wells of deepwater gas wells.In this paper,laboratory experiment and theoretical calculation were combined to evaluate the scaling risks in the wells during the production of four typical deepwater gas wells in the South China Sea Gasfield,predict scaling velocities and scaling positions in the wells of gas wells in the process of production and analyze the scaling characteristics and laws.It is indicated that the scaling type of gas well is controlled by the compositions of formation water and the scaling velocity in the production process of gas well is mainly dependent on the deposition velocity of stable scale after the surface deposition period.The scaling difference at different well depths in the production process of deepwater gas well is mainly dominated by the temperature distribution along the well,and the scale control shall focus on the middle and lower parts of the well and the conditions of high gas production rate and high water/gas ratio.Compared with onshore gas wells,deepwater gaswells are affected more by the scaling in wells,so to keep the efficient and safe production of deepwater gas wells,it is quite important to take the scale control measures in time to prevent the formation of scale and control the scale deposition in the allowable range.