页岩气井泡沫排水采气技术适应性探究

Adaptability of foaming drainage gas recovery in shale gas wells

为充分了解泡沫排水采气技术在不同井况页岩气井中的实施效果,明确其适应性,以四川盆地长宁中深层页岩气区块的泡沫排水采气井为研究对象,分析不同油管与井型条件下的页岩气井泡排生产情况,并以重庆页岩气、四川页岩气等深层页岩气区块的泡排先导性试验为例,进一步明确泡沫排水采气技术对深层页岩气井的适应性。研究结果表明:①使用Ф50.8 mm连油、Ф60.3 mm连油、Ф60.3 mm油管、Ф73 mm油管均不能依靠自身能力实现长期带液稳产,而泡沫排水技术对不同油管尺寸有较强的适应性,典型井实施泡沫排水后,日均增产天然气约为1.18×10^(4)m^(3),泡沫排水采气效果良好;②泡沫排水技术可起到清洁井筒、疏导气流通道的作用,可实现页岩气井的长期连续稳定生产;③泡沫排水技术对垂直井深超过4000 m的深层页岩气井有很好的适应性。结论认为:①不同油管、井型对泡排效果存在差异,但泡排对Ф50.8 mm连油、Ф60.3 mm连油、Ф60.3 mm油管、Ф73 mm油管条件下的长宁页岩气井有较强的适应性;②泡排工艺因其携液能力强、稳产周期长和可清洁井筒等特性,对中深层、深层页岩气均具备很好的适应性,可进一步推广应用。

To fully understand the performance of foaming drainage gas recovery in shale gas wells under different hole conditions and clarify the adaptability of this technique,some wells with foaming drainage gas recovery in Changning middeep shale gas block,Sichuan Basin,were taken as examples to analyze this recovery running in those wells with various tubing size and well types.Moreover,the adaptability in deep shale gas wells was figured out after some pilot tests on foaming drainage gas recovery in deep Chongqing and Sichuan shale gas blocks.Results show that(i)adoptingФ50.8 mm orФ60.3 mm coiled tubing as well asФ60.3 mm orФ73 mm tubing cannot rely solely on their ability to achieve stable liquid-carrying production for a long term.However,this foaming drainage technique is highly adaptable to tubing size.After the drainage,some typical wells gain better ending with the incremental production about 1.18×10^(4)m^(3)/d on average;(ii)this technique makes wellbore clean and smooths gas flow channel to further enable these wells in the long-term,sustainable and stable production;and(iii)it is more suitable for shale gas wells with the vertical depth exceeding 4,000 m.In conclusion,the foaming drainage performance may vary with tubing size and well types,but is greatly adaptable to shale gas wells usingФ50.8 mm orФ60.3 mm coiling tubing as well asФ60.3 mm orФ73 mm tubing in Changning block.Additionally,the foaming drainage gas recovery is more suitable to mid-deep and deep shale gas wells for its high liquid-carrying capacity,long period of stable production,and ability of wellbore cleaning.And it is worth to popularize.