现有的深水油气井完井技术施工中通常会将部分完井液圈闭于套管环形空间内,进而在深水测试作业时圈闭流体受高温高压产层热流体的影响而产生井筒附加应力。为消除附加应力对井筒完整性造成的损害,设计了一种应用隔热管进行深水油气井生产测试的圈闭压力控制技术。依据南海深水高温高压井的典型井身结构,构建了测试过程的深水井筒热传导模型,通过基于典型井的井筒传热数值计算,分别对常规测试管柱结构及隔热油管测试管柱结构进行了圈闭环空温度场的数值模拟、圈闭压力计算。研究表明,深水高温高压油气井测试过程中,应用隔热管的测试管柱复配技术,可有效降低高温高压产层流体对套管圈闭空间的附加应力影响,避免了井下事故的发生。该技术为深水高温高压油气井的安全高效测试作业提供了一种新的有效方法。
When the existing deepwater oil and gas well completion technologies are brought into operation, the completion fluid is partially trapped in the casing annulus. And when the testing is carried out in deep water, the trapped fluid produces addition stress on the wellbore under the effect of hot fluid in high temperature and high pressure (HTHP) pay zones. In order to eliminate the damage on wellbore integrity, a trap pressure control technology based on the insulation tabular was designed for deepwater oil and gas well production testing. Based on the typical casing program of deepwater HTHP wells in South China Sea, a model for the deepwater wellbore heat conduction in the process of testing was established. After the wellbore heat conduction of typical wells was calculated, the predictedtrap annulus temperature fields in the structures of conventional testing strings and insulated-tubing testing strings were numerically simulated and their trap pressure was calculated. It is shown that during the testing of deepwater HTHP oil and gas wells, the combined testing string technology based on insulation tabular can reduce effectively the addition stress effect of fluid in HTHP pay zones on the trapped casing annulus and avoid downhole accidents. This technology provides a new effective method for the safe and efficient testing of deepwater HTHP oil and gas wells.