一种新型绕煤层固井井下装置的研制

A new bypass coalbed cementing downhole device for coalbed methane well

针对煤层气井常规套管完井时水泥浆污染煤层的问题,提出一套绕煤层固井技术方案,设计研制一种新型结构的绕煤层固井井下装置;测试整套装置的耐压性,计算水泥浆通过该装置时的局部流体压耗。测试及计算结果表明:该装置可承受28 MPa的管内压力,额外增加的循环压耗约为2.2 MPa,可以满足施工需要;下入套管时,把多组装置连接在套管串上对应煤层的位置,即可实现水泥浆仅封固非煤层段,避免水泥浆和煤层的接触,从而避免水泥浆对煤层的污染,为煤层气井及油气井低压层段提供一种新的完井手段。

To avoid the cementing damage to the coal bed in casing completion, a new bypass coalbed cementing downhole device for coalbed methane well was presented. The pressure resistance was measured and local pressure drop of the cementing slurry flowing along the device was calculated. The results show that the device can bear inner pressure of 28 MPa, and the extra circulate pressure drop is about 2.2 MPa, which can satisfy the field requirement. In casing completion operations, multiple tools should be connected to the casing string at the corresponding coal intervals, which can realize cementing slurry bypassing such target sections and avoid damage to combed. This technology provides a new completion method in coal methane wells or oil wells with lower pore pressure intervals.