塔里木盆地D气藏硫化氢分布特征及成因探讨

Distribution and Origin of H2 S in D Gas Reservoir, Tarim Basin

D气藏正处于开发阶段,自投产以来,由于硫化氢存在多次造成地面管线刺漏,已经严重影响到气藏的正常开发。通过对各井监测到的硫化氢含量数据进行统计分析,结合单井的生产层位、储层物性和气藏温度来研究D气藏硫化氢的分布特征和成因。研究结果表明,D气藏为微(贫)硫化氢气藏;纵向上,硫化氢主要分布在气藏下部;平面上,硫化氢主要分布在气藏西北部,断层对硫化氢有一定的控制作用,离断层近的区域硫化氢含量较高。通过对硫化氢不同成因机理和特征分析发现,D气藏石炭系不具备产生硫化氢的条件,气藏中的硫化氢很可能为下部奥陶系硫酸盐热化学还原反应(TSR)产生,侧向运移到气藏中。

During the development of D gas reservoir, the surfacepipeline leakage caused by H2 S happens sometimes. Consequently, it has seriously impacted the normal development. Through analyzing the data of H2 S content from each well, integrating the producing layer, reservoir's physical property and temperature of single well, the distribution and origin of H2 S were studied. Result shows that(1)D is a gas reservoir with trace amounts of(or poor)H2 S;(2) H2 S is mainly distributed in the lower reservoir longitudinally whereas in the northwestern part in a plane; and(3)some faults may have some controls on H2 S, so a higher H2 S content appears in an area near faults. In addition, according to the analysis on the genetic mechanism and distribution characteristics of H2 S, it is deemed that H2 S can't be generated in the Carboniferous of D gas reservoir. The existing H2 S is possibly from Ordovician generated by thermochemical sulfate reduction(TSR), and then laterally migrated into this reservoir.