大牛地气田烃类组分分析及凝液回收思路

Hydrocarbon composition analysis and condensate recovery in Daniudi Gas Field

为了制定鄂尔多斯盆地大牛地气田天然气降本增效的科学高效开发方案,分析了该气田天然气的烃类组分变化特点。研究结果表明:①随着大牛地气田天然气开采持续进行,甲烷的百分含量逐渐减少,而乙烷和丙烷的含量相应地增大,天然气组分由干气变为湿气;②明确了大牛地气田不同时间段天然气C1/(C2+C3)、iC4/nC4等组分特征,为研究天然气运移、判识成因类型提供依据;③从技术角度出发,提出了天然气分离用作乙烯原料及天然气凝液回收的思路。结论认为:①大牛地气田C2以上烃类含量升高,有利于天然气分离及凝液回收;②可通过制冷剂与膨胀机的联合制冷方法对大牛地气田天然气进行深冷分离,从而将C2组分有效分离。

With the production of domestic natural gas fields, the necessity of applying the condensate recovery technology to recover the hydrocarbon compositions above ethane to act as the raw materials of ethane is emerging gradually. To formulate the scheme for the scientific and efficient development of natural gas in Daniudi Gas Field of Ordos Basin to realize cost reduction and efficiency increase, the change characteristics of hydrocarbon composi. tions of the natural gas in Daniudi Gas Field were analyzed and the idea of condensate recovery was proposed. And the following research results were obtained. First, as the production of natural gas continues in Daniudi Gas Field, the percentage content of methane decreases gradually, but the contents of ethane and propane increase, so the natu. ral gas is compositionally transformed into wet gas from dry gas. The increase of the content of the hydrocarbon above C2 is favorable for natural gas separation and condensate recovery. Second, the compositional characteristics of natural gas (e.g. C1/(C2+C3) and iC4/nC4) in different time intervals of Daniudi Gas Field are figured out, so as to provide the basis for studying the migration of natural gas and determining its genetic types. Third, it is proposed to apply the combined refrigeration method based on refrigerant and expansion machine in Daniudi Gas Field for the cryogenic separation of natural gas, so as to implement the condensate recovery idea that C2 composition is separated effectively to be the raw material of ethane.