新型延迟膨胀堵漏剂特性实验研究

Laboratory Study on the Properties of a New Delayed Expansion Lost Circulation Material

裂缝性地层严重井漏难题严重制约复杂地质条件油气高效钻探开发。目前常用桥接堵漏材料可变形性较差,而常见吸水树脂类堵漏材料的膨胀速度过快,导致上述堵漏材料难以在漏失通道中形成致密承压封堵层。为此,研制了一种新型延迟膨胀堵漏剂SDSAP,密度为1.52 g/cm^3,粒径为0.425~3.35 mm,可根据漏失情况进行调节;具有良好的吸水膨胀性能以及抗压性能、抗盐性能;吸水膨胀后具有可变形性,适用漏失通道尺寸范围较宽;具有适度延迟膨胀效应,常温下膨胀速率较低;同时具有一定温度响应特性,在地层高温刺激下可快速膨胀,有利于降低封堵层形成时间,减少漏失量。基于延迟膨胀堵漏剂SDSAP,协同复配刚性、弹性及纤维等类型堵漏材料,实验优化得到了适用1~3 mm开度裂缝的致密承压堵漏工作液体系配方,承压能力达7 MPa以上,且漏失量较低,可用于较好解决复杂裂缝性地层井漏问题。

Severe mud losses into fractured formations seriously restrict the efficient development of oil and gas in formations with complex geological conditions.Bridging agents presently used for mud loss control have poor deformability,the commonly used water-adsorbing resin lost circulation materials(LCMs),on the other hand,have expansion rates that are too fast,therefore,it is difficult for these LCMs to form dense pressure-bearing barriers in the channels through which the mud is lost into the formations.To solve this problem,a new delayed expansion LCM SDSAP was developed.SDSAP has a density of 1.52 g/cm^3 and particle sizes between 0.425 mm and 3.35 mm which are adjustable according to the rate of mud loss.It has excellent water-adsorbing expanding performance,pressure resistance and salt resistance capacity.When water is adsorbed,SDSAP becomes deformable,and is therefore suitable for control mud losses in loss channels with wide range of sizes.SDSAP has a certain delayed expansion effect and low rate of expansion at ambient temperatures.It also has temperature-response property;when excited by high temperatures in downhole condition,it swells quickly,which is beneficial to shorten the time required to seal off the loss channels and thus reduces the amount of mud lost.An LCM slurry formulated with SDSAP and other LCMs such as rigid,elastic LCMs and fibers to stop mud losses into fractures with opening sizes of 1-3 mm.The barrier formed by the LCM slurry had pressure bearing capacity of more than 7 MPa,and the amount of mud lost was greatly reduced.It can be used to solve mud losses into complex fractured formations.