东胜气田致密高含水气藏合采气井层间干扰影响因素

Influential factor of interlayer interference in commingled-producing wells in tight gas reservoirs with rich water,Dongsheng gasfield

为了明确鄂尔多斯盆地北缘致密高含水气藏合采气井层间干扰及其影响因素,指导同类型气藏合采气井高效开发,以该盆地北缘东胜气田致密高含水气藏为研究对象,分析了储集层地质条件、储集层改造对合采井产层段贡献的影响,指出了该类合采气井层间干扰的主控因素。研究结果表明:(1)合采井各产层段贡献率主要受各产层段的孔隙度、渗透率及含气饱和度控制,其产层段孔隙度占主导地位;(2)储层压裂改造对于提高气井产量具有较大的作用,但对合采井各产层段的贡献率却很小;(3)对于致密高含水气藏而言,含气饱和度是合采井产层段贡献率及层间干扰的一个重要影响因子;(4)合采井各产层段之间的孔隙度级差、渗透率级差及含气饱和度级差直接影响着合采井层间干扰程度。结论认为:(1)合采井产层段的孔隙度越大、渗透性越好、含气饱和度越高,则产层段的产量贡献率越大;(2)合采井孔隙度、渗透率及含气饱和度3个参数的级差越大,层间干扰程度越大,当孔隙度级差大于1.248或渗透率级差大于2.69或含气饱和度级差大于1.22时,合采井层间干扰已经非常严重,亟需开展治理。

With rich water,some tight gas reservoirs in Dongsheng gasfield along the northern margin of Ordos Basin were taken as objectives to make clear the interlayer interference in commingled-producing wells and its main influential factors and to guide the efficient development of commingled wells in similar reservoirs.Moreover,controls of reservoirs'geologi⁃cal conditions and stimulation on the contribution of each payzone in commingled wells were analyzed to determine the in⁃fluential factors on this interference in such well type.Results show that(i)the contributing rate is dominated by porosity,permeability and gas saturation in each payzone,among which the porosity is the leading contributor;(ii)reservoir fractur⁃ing plays a great role in production increase,but it exerts a little effect on the contributing rate;(iii)as for the tight gas reservoirs with rich water,the gas saturation is a key element impacting on this rate and interlayer interference;and(iv)di⁃versities of magnitude order in porosity,permeability and gas saturation among different payzone may affect directly the in⁃terference degree.In conclusion,the production contributing rate of each payzone in commingled wells increases with the porosity,permeability and gas saturation.What's more,the interference degree raises with the diversities in these three properties.The interlayer interference is quite severe and should be governed as early as possible if the porosity,permea⁃bility,and gas saturation diversities are larger than 1.248,2.69,and 1.22,respectively.