页岩气井精细控压生产技术可行性研究与现场试验

Feasibility Study and Field Trail of Precise Managed Pressure Production Technology for Shale Gas Wells

页岩气压裂水平井控压生产能够延缓裂缝闭合,提高单井最终可采储量EUR。北美页岩气开发已进入精细控压生产成熟阶段,而川渝页岩气控压生产还处于起步阶段,亟需加强控压生产工艺的研究。文章从控压生产发展进程、产层特征、单井最终可采储量和单井产量等方面对比北美页岩气和川渝页岩气,并在国内首次进行井筒内控压并配合可调式油嘴精细控压生产试验(4口不同生产方式的试验井),验证精细控压现场实施的有效性。研究表明川渝页岩气实施可调式油嘴精细控压生产工艺潜力较大,目前川渝页岩气开采情况同北美早期页岩气开采情况较为接近,产量递减快,增产空间较大。通过现场精细控压试验,并结合预测单井最终可采储量的对比分析,结果表明初期下油管配合可调式油嘴的精细控压生产工艺能有效降低压力衰减速率并平稳生产,在保护储层的前提下能够有效提高单井最终可采储量。该技术有助于推进国内页岩气井精细控压生产工艺的发展。

Managed pressure production(MPP)in fracturing horizontal wells for shale gas is used to delay fracture closure and improve ultimate recoverable reserves of single well.Shale gas development in North American has entered the mature stage of precise MPP,while that in shale gas of Sichuan-Chongqing is still in its infancy,so it is urgent to strengthen the research on managed pressure production technology.This paper compares shale gas in North American and Sichuan-Chongqing from the aspects of MPP development process,reservoir characteristics,single well ultimate recoverable reserves and production,and carries out the precise MPP test with adjustable choke in the wellbore for the first time in 4 wells with different production modes in China to verify the effectiveness of on-site implementation of MPP.The research shows that there is great potential for shale gas in Sichuan-Chongqing to implement the precise MPP process with adjustable choke.At present,the exploitation of shale gas in Sichuan-Chongqing is quite close to that of early exploitation in North America,with rapid production decline and large space for stimulation.Through the field precise managed pressure test,combined with the calculation of single well final recoverable reserves comparative analysis,it shows that the initial tubing running combined with precise MPP process with adjustable choke can effectively reduce the pressure decline rate,stabilize production as well,and effectively improve the ultimate recoverable reserves of single well on the premise of reservoir protection.The conclusion shows that this technology can promote the development of MPP process for domestic shale gas wells.