沙特MTLH-1井全过程欠平衡钻井技术

Whole Process Under-Balanced Drilling Technology in Well MTLH-1 in Saudi Arabia

MTLH-1井是沙特B区块的一口重点探井,为了能及时发现油气层、保护油气层、随钻评价油气产量,该井在钻进Sarah组地层时,采用了全过程欠平衡钻井技术。由于Sarah组地层存在易坍塌段,因此,在进行欠平衡钻进时,要严格控制井底压力,既要能保证井壁稳定,又要能实现边溢流边钻进。详细介绍了该井钻进、接立柱、起下钻、井下套管阀关闭、测井以及测试时控制井底始终处于欠平衡状态的方法和措施。该井在欠平衡钻井的各个环节以及测井和测试过程中,井底始终处于欠平衡状态,测试结果显示该井表皮系数为-3.44,表明在全过程欠平衡作业过程中很好地保护了油气层,达到了实施全过程欠平衡钻井的目的。

Well MTLH-1 is a key exploration well in Block B of Saudi Arabia.In order to discover oil and gas,to protect formation,and to evaluate oil and gas production while drilling,the whole process underbalanced drilling technology was used during drilling Sarah formation.Since part of section is easy to collapse,therefore,the bottomhole pressure has to be strictly controlled to ensure wellbore stability and to achieve overflow while drilling during the underbalanced drilling.This paper details drilling,tripping,downhole valve closing,well logging and methods and measures to maintain the under balanced condition during testing.This well is under-balanced during well logging and well testing,the test results show that the skin is-3.44 which implies that the formation was protected during drilling.The objective of under balanced drilling was achieved.