利用乳酸和双氧水对天然大豆卵磷脂进行了羟基化改性,改性大豆卵磷脂环保无毒,EC50大于30 000 mg/L,同时改性后大豆卵磷脂在清水、淡水基浆及水基钻井液体系中润滑性能良好.在清水中,加入改性大豆卵磷脂的极压膜强度是国产对比润滑剂PF-Lube和CX-300H的2倍以上,在30 min四球摩擦实验中,0.5％改性大豆卵磷脂摩擦系数在0.1以下,优于国外DFL润滑剂.在4％淡水基浆中,120℃老化前后,加入1％改性大豆卵磷脂淡水基浆EP极压润滑系数降低率达90％,润滑性能优于对比的DFL和PF-Lube润滑剂.在密度为2.0 g/cm3的水基环保钻井液体系中,加入1％改性大豆乱磷脂的体系120℃老化后黏度更低,高温高压滤失量降低50％左右,滤饼黏附系数和极压润滑系数均降低60％以上.最后,利用扫描电镜对极压划痕进行了分析,并利用XPS元素分析揭示了改性大豆卵磷脂润滑机理.整体而言,改性大豆卵磷脂环保无毒,并具有良好的极压润滑性能,在大位移水平井水基钻井液中具有一定应用前景.

针对目前中石油集团公司特别强调在钻井生产中节能降耗，减少碳排放，降低生产成本等要求，提出供气设备配套电驱动技术方案。气体钻井供气设备电驱动方案采用全场供电方式，利用网电和井场变压器，配套VFD控制房、集中远程监控系统、电驱动空压机和电驱动增压机。论证了在柴油驱动设备基础上改为电驱动可行性小，需要重新设计配套软启动功能的电驱动空压机和变频控制系统的电驱动增压机。通过配套电驱动技术，气体钻井能达到节能减排的要求，促进气体钻井技术的应用和发展。

气体钻井结束后,在替入钻井液初期,钻井液中的水相会大量快速地进入地层,引起地层中的黏土矿物吸水膨胀而导致井壁失稳或形成厚滤饼,造成起下钻遇阻复杂,解决井眼通畅问题需要花费更多的处理时间.为此,提出了气体介质转换成钻井液介质的钻井初期有效控制井壁失稳新的技术思路——成膜防塌技术.在实验室内研制了一种由高分子有机物和无机物组成的混合液体,称之为“成膜液”,并进行了人造岩心浸泡、泥球浸泡、防清水渗透的室内实验,分别对比考察了岩样的分散、岩心表面成膜及其防水膜的渗水性能.实验结果表明:该成膜液能在短时间(10～30 s)内在实验岩心上形成一层光滑致密的防水渗膜,能有效阻止钻井液中的水相进入实验岩心的内部,起到了防止黏土水化分散、稳定井壁和有效防止厚泥饼形成的作用.最后分别推荐了气体钻井和雾化钻井的成膜液现场应用浓度范围及其操作性强的防渗膜“涂抹”工艺方法.

针对NY1井非储层段的气体钻井过程中钻遇的井下复杂问题,具体分析了产生复杂问题的原因并提出了解决问题的措施.如空气钻井过程中钻遇地层出水,可采取每根单根完划眼、增大注气量、采用充气钻进措施;钻遇地层漏失层,可采取增大注气量、打水泥封堵、连续循环钻井措施;遇到井壁失稳问题,可采取增大注气量疏通或转为常规钻井.经过现场的具体实施,总结形成了一套针对NY1井区块气体钻井处理井下复杂问题的方法.该套方法能够指导现场的气体钻井作业,为此区块的气体钻井提供技术支持.

目前关于气体钻水平井的理论研究大都集中在最小注气量的选择上;而对气体钻水平井水平段井筒内的多相流动的机理缺乏深入的理论研究.在研究水平井段多相流动机理的基础上,应用气固两相流动力学理论,结合扩散理论,建立了适合气体钻水平井水平井段两层流动的理论模型,即上层悬浮层、下层为滑动床流动.根据现场某井数据进行了实例计算结果表明:气体钻水平井井筒携岩的最优速度应大于岩屑的沉降速度;岩屑稳定输送的条件为水平井井筒环空内为分层稳定流动;沿程阻力在低速主要来自于底层滑动床中岩屑颗粒与井壁之间的摩擦阻力,高速区来自于悬浮层内岩屑与井壁之间的摩擦阻力.最后结合计算结果,对比前人在水平气固流动中的实验结果,对气体钻水平井的最优注气量、井筒压降计算等给出了合理的建议.

目前关于气体钻水平井的理论研究大都集中在最小注气量的选择上,而对气体钻水平井水平段井筒内的岩屑床分布规律缺乏深入的理论研究.文章通过对气体钻水平井段气固流动特性的分析,应用气固两相流理论、扩散理论,建立了适合气体钻水平井水平井段三层流动的理论模型,即上层悬浮层、中间滑动床及底层岩屑固定床.根据现场某井数据进行了实例计算,计算结果表明,气体钻水平井在气速大于沉降速度时,水平井筒内的岩屑床为滑动床;滑动床的高度随着机械钻速的增高而增大,随着气速的增加、钻杆尺寸的增加而减小;相同条件下水平井段滑动床面积从趾端到根端逐渐降低.当气体返速小于沉降速度时则水平井筒内的流动为三层流动,滑动床、岩屑固定床的分布规律趋势与两层流动时大体相同.

Current cuttings separation in gas drilling only relied on dust- water separator,its sand discharge pipe outlet was connected to sewage tank,the ignition was impermissible after gas production. If the exhaust pipe was connected to the combustion pool ignition,the cuttings were easy to accumulate.Based on above causes,a new cuttings separation system was studied which could effectively separate cuttings and realize ignition. Based on the analysis of cuttings separation process in gas drilling,the cuttings separation system of gas drilling was divided into separation system and circulating water treatment system.The principle of the cuttings separation system of gas drilling was analyzed and the entry grain diameter and concentration of cuttings were calculated. Through calculating the dust removal effect of the system,results showed that the separated gas could achieve direct discharge standard and blow off directly into the combustion pools. This system further broadened the application field of gas drilling.

Shielding and temporary plugging technology used currently is more suited for the reservoir,of which the pore throat contribution rate is unimodal distribution.Based on sensitivity analysis,the results showed that pore throat contribution rate of Xujiahe reservoir in Anyue area was multimodal distribution.Therefore,two different particles size for temporary plugging technology was formed for the reservoir protection.On-site application in three wells indicated that different particles size temporary plugging material has little impact on the performance of drilling fluid.Percent ratio of core permeability recovery indoor for drilling and completion fluid with different particles size temporary plugging material was over 85%,which showed that the temporary plugging technology has good result.

The current used shielding temporary plugging technology is only for the reservoirs which the pore throat distribution is in single-peak shape.For the reservoir of Xujiahe Formation in Jiulongshan structure,however,the distribution is in multiple-peak shape.So,another reservoir-protection technology of multiple-level bridging temporary plugging,with three-level bridging particle as the soul,is developed in this study.And its application to Long 113 well indicates that (1) this plugging material has little effect on the property of original drilling-fluid; and (2) after an experiment that the developed drilling and completion fluid is adopted,core permeability may recover more than 89 % and a better effect of reservoir protection can be obtained.

In view of the characteristics of the engineering geology in the deep well section of Longgang area, a thermostable water-base drilling fluid characterized by excellent high temperature thermal stability,strong capacity against salt and calcium contamination and good inhibition property was prepared for the purpose of further optimizing thermostable water-base drilling fluid system.The water-base drilling fluid has been applied in Jianmen No.1 oil well,No.001-3 oil well,No.19 oil well and No.29 oil well in Longgang area. Results of laboratory test and field test have shown that this drilling fluid system could withstand the temperature up to 80℃ ,the salt content up to 15% and the calcium content higher than 1 000 mg/L.The overall performance of the drilling fluid is good.The drilling fluid can be used to control the complex conditions underground effectively,and meets the requirement for safe and fast drilling in the deep well section of this area.

In the deep drilling,rheological properties of drilling fluid have been much influenced by temperature.Studying on the influence of drilling fluid rheological properties caused by temperature is of great importance for safety drilling in deep wells.A HTHP rheometer,RS6000,has been used to measure the rheological properties of a kind of high-temperature water based drilling fluid.Through regression analysis of experimental data with Bingham,Power Law,Carson,H-B and R-S model respectively,it can provide a basis for preference the best model to describe rheological properties of drilling fluid under high temperature.And the regressed results showed that the best model suitable for HTHP rheological properties of this drilling fluid is R-S model,Bingham is next-best and the worst one is Power Law.At the same time,the influence of temperature on the apparent viscosity has been studied and the mathematical model for forecasting apparent viscosity of downhole drilling fluid under high temperature has been established,which provided a reference for safe drilling in the deep wells.