温度及外加剂对G级油井水泥强度的影响

EFFECT OF TEMPERATURE AND ADDITIVES ON STRENGTH OF CLASS G OILWELL CEMENT

利用超声波强度测试仪、高温高压养护釜及强度仪等仪器 ,对各种不同条件下G级油井水泥石强度进行了测试 ,得出了在不同温度及外加剂条件作用下的水泥石强度的发育及变化特点 ,确立了水泥石产生高温强度衰退存在 2个临界温度 ,即 1 1 0℃和 1 50℃ ;确定了能够有效抑制高温条件下水泥石强度衰退的合理硅砂加量为30 %～ 40 % ;阐述了在 1 1 0～ 1 50℃及 1 50～ 2 0 0℃ 2种温度范围内 ,加砂水泥的强度分别具有二级台阶及一级台阶等不同的发育规律。分析了外加剂对水泥石强度及发育特点产生的影响规律和外加剂的适用范围 。

Strength properties of Class G oilwell cement are tested under different conditions by using a Static Gel Strength Analyzer, an High Temperature High Pressure Curing Chamber and other instruments. Characteristics of development and change of compressive strength properties are studied under different temperature and additives. Critical temperatures at which the strength begin to decline are determined to be 110℃ and 150℃ respectively. When temperature exceeds 110℃, the strength will reduce after it reaches a certain value with the increase of curing time. The reasonable amounts of silica sand which will be added to cement slurry to enhance the strength of hardening paste are determined to be 30%～40%. The characteristics of development and change of compressive strength for cement slurry with silica sand are revealed, which there are a two stage type and one stage type within the temperature range of 110～150℃ and 150～200℃ respectively. The influence of additives on the strength and the scope of application of additives are analyzed. The nature which temperature etc. affects on strength properties is revealed.