深水油气井环空带压预防弹性隔离液体系

深水油气开发过程中，套管圈闭环空内流体温度升高会引起环空带压的现象，严重时会挤毁或胀裂套管，给生产作业带来严重的安全隐患。为解决这一问题，室内研究了一套预防环空带压的弹性隔离液体系，并采用自制的"高温高压弹性流体评价仪"和"弹性材料往复压缩试验仪"对隔离液的性能进行评价。研发的弹性隔离液体系配方为:海水+0.4%悬浮剂HX+6%弹性剂+超细铁矿粉，密度在1.10~1.90 g/cm3内可调。评价结果表明:①该弹性隔离液体系具有高弹性、抗压缩性强的特点，弹性恢复率为100%；②在不同温度条件下能够稳定地保持弹性，缓解压力效果稳定；③与钻井液和水泥浆配伍性较好，不影响弹性隔离液和固井水泥浆施工作业。研发的弹性隔离液体系应用在深水油气井可以缓解和控制环空带压现象。 

An Elastic Spacer for Preventing Trapped Pressure in Annulus of Deepwater Oil and GAs Wells

In deepwater oil and gas development, temperature rise in fluid trapped in the annulus between casing string and drill pipe causes an increase in the pressure trapped in the annulus, resulting in collapse or bursting of casing string which brings serious hidden risk to oil and gas production. To resolve this problem, an elastic spacer for preventing trapped pressure in annulus was developed and evaluated with a self-made "HTHP elastic fluid evaluation tester" and a "reciprocating compression tester for elastic materials". The composition of the elastic spacer is:sea water + 0.4% suspending agent + 6% elastic agent + ultra-fine iron ore powder. The density of the spacer is adjustable between 1.10 g/cm3 and 1.90 g/cm3. Laboratory evaluation of the spacer shows that:1) the elastic spacer has high elasticity and high compressive strength, and shows 100% elasticity. 2) the spacer retains its elasticity at different temperatures, effectively relieve accumulation of pressures. 3) the spacer has good compatibility with drilling fluids and cement slurries, and does not affect the use of the spacer and well cementing job. The spacer developed can be used to mitigate and control trapped pressure in annulus in deepwater drilling.