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Research Progress, Current Situation Analysis and Development Suggestions of Drilling Fluid Treatment Agents in China
WANG Zhonghua
2025, 42(1): 1-19.   doi: 10.12358/j.issn.1001-5620.2025.01.001
Abstract(125) HTML(32) PDF (2278KB)(46)
Abstract:
To understand the new achievements of drilling fluid additives in China, this article reviews the recent development and application of drilling fluid additives, based on modified biomass materials, synthetic polymers, condensation reaction products, modified industrial by-products, and domestic waste modification products. Modified biomass materials, containing starch, cellulose, lignin, and humic acid, are mainly used for fluid loss reducers, and starch is the most common one; the most studied synthetic polymer materials are water-soluble polymers for fluid loss reducers, viscosity enhancers, encapsulating agents, and viscosity reducers. There are also some studies on water-insoluble materials used for plugging and fluid loss reducers. Monomers with good hydrolytic stability such as NVP as well as DMAM are used to enhance temperature-resistant, salt-resistant, and high valent ion-resistant ability. Condensation reaction products focus on emulsifiers and viscosity enhancers of oil-based drilling fluid, and esterification and amidation reaction of lubricants in water-based drilling fluid as well. Some research has also been conducted on the preparation of drilling fluid treatment agents using industrial by-products and household waste. Although there has already been a large number of research on drilling fluid additives, the research is still not innovative, in-depth, and comprehensive enough. Due to the limitations of molecular design, synthetic means, and evaluation methods, there are relatively few drilling fluid additives that can meet the needs of complex fields on site.There is still a phenomenon of similar or low-level repetitive research. Combining with practice. The research on treatment agents should aim to break through traditional thinking and mechanisms. Around the goals of simplifying drilling fluid components, reducing drilling fluid costs, improving drilling fluid functions, enhancing drilling fluid quality, and promoting green development. Strengthen the development and utilization of biomass resources, innovate synthesis methods and processes, and develop low-cost, high-quality, and long-term multifunctional materials with good comprehensive performance.
Research Progress in Preparation of Nanocellulose and Its Application in Drilling Fluids
ZHAO Xionghu, WANG Can, XIAO Zhe, ZHANG Xi, ZHAO Yueqin
2025, 42(1): 20-29.   doi: 10.12358/j.issn.1001-5620.2025.01.002
Abstract(89) HTML(31) PDF (2409KB)(25)
Abstract:
Celluloses are a common additive used in various water-based drilling fluids to effectively reduce the filtration rate, enhance the drilled solids suspending capacity and improve the rheology of the drilling fluids. Nanocellulose as an innovative drilling fluid additive has, apart from the advantages of the common cellulose, new properties such as high temperature stability and resistance to salt and alkali contamination. The nanocellulose also remarkably improve the stability and rheology, and effectively reduce the filtration rate of the drilling fluids. This paper introduces the methods presently used to produce nanocellulose and the application of nanocellulose in drilling fluids. Prospects are made in the paper of the application of the nanocellulose in drilling fluids, aiming at providing a reference for producing new environmentally-friendly high temperature drilling fluid additives.
DRILLING FLUID
Stress Sensitivity Experiment on Shale Gas Formations in Marine-Continental Transitional Facies in Easten Margin of Ordos Basin
LI Bing, NING Xianyi, ZHU Weiping, CHEN Mingjun, HE Pengbo, KANG Yili, LAI Zhehan
2025, 42(1): 30-40.   doi: 10.12358/j.issn.1001-5620.2025.01.003
Abstract(67) HTML(26) PDF (2417KB)(12)
Abstract:
The shale gas formations in the marine-continental transitional facies of the eastern margin of the Ordos Basin are tight gas formations with complex pore and fracture structures as well as high heterogeneity which result in special stress sensitivity of the formations. To understand the degree of the stress sensitivity of the reservoirs, stress sensitivity experiments were performed on cores taken from the marine-continental transitional facies of the eastern margin of the Ordos Basin. The experimental results, combined with the understanding of the lithology and the physical properties of the reservoirs, help reveal the mechanisms of stress sensitivity of the shale gas reservoirs concerned. The studies performed indicate that when the effective stress is increased from 3 MPa to 35 MPa, the permeability of the artificial fractures, the natural fractures and the base core decreases by 97.1%, 86.8% and 50,5%, respectively. During unloading of the effective stress, the permeability of the artificial fractures, the natural fractures and the base core is recovered by 21.4%, 19.0% and 11.6%, respectively, showing significant stress sensitivity hysteresis effects. The stress sensitivity coefficients of the artificial fractures, the natural fractures and the base core are 0.65, 0.58 and 0.19, respectively, and the degrees of stress sensitivity corresponding to these stress sensitivity coefficients are classified as strong-moderate to strong, strong-moderate to weak and weak. The stress sensitivity coefficients show that the multi-scale pore-fracture structure of the shales under research have significant stress sensitivity. The main control factors of formation damage by stress sensitivity include the mineral components, the development of the fractures as well as the pore structure of the shales in the marine-continental transitional facies. It is thus suggested that a reservoir-protective gas production system be developed, and the production of gas be controlled to ensure high production rate and stable production of the gas wells drilled in the marine-continental transitional facies of the eastern margin of the Ordos Basin.
Visual Experimental Study on Evolution and Particle’s Characteristic Behavior of Plugging Layers inside Fractured Loss Zones
PU Lei, XIE Lingzhi, XU Peng, CHEN Huan, XU Mingbiao, WANG Bangzhe
2025, 42(1): 41-50.   doi: 10.12358/j.issn.1001-5620.2025.01.004
Abstract(59) HTML(28) PDF (7521KB)(15)
Abstract:
Mud losses into fractures is one of the most difficult problems encountered in drilling unstable formations. Particle bridging is the most effective method of controlling mud losses into fractures. In traditional fracture experimental apparatus how the plugging layers are formed inside the fractures by the flow of particles is still not clearly understood, and this restricts the scientific build-up of a lost circulation slurry. To investigate the characteristic behavior of particles and the dynamic evolution of plugging layers inside fractures, a wellbore-fracture visualization experimental device is set up, and is used to systematically study the behavioral characteristics of the particles, the pattern in which the plugging layers are formed as well as the influencing mechanisms of the formation of the plugging layers under the effects of key factors such as particle size, particle concentration, flowrate of the particle slurry pumped into the fractures and the viscosity of the carrying fluid etc. The experimental results show that the plugging process taking place inside the fractures can be divided into four stages in each of which co-exist the mixing of the particles and the change of the characteristic behavior of the particles. The position at which a plugging layer is set up is highly sensitive to the size distribution of the particles, the concentration of the particles affects the time required for the fractures to be plugged, the structure of the plugging layers is easily altered by the viscosity of the carrying fluid, and too high a pump rate may damage the plugging structure previously formed.
Wellbore Stability Technology of Fractured Carbonate Formation Drilling Fluid in Shunbei Region
LIU Xiongwei, FAN Sheng, GUAN Jintian, HE Yinbo
2025, 42(1): 51-57.   doi: 10.12358/j.issn.1001-5620.2025.01.005
Abstract(65) HTML(23) PDF (2762KB)(18)
Abstract:
Based on the geological analysis of the carbonate rock formation in Shunbei oil and gas field, the reasons for the formation's easy wellbore instability are clarified: first, the rock is easy to be broken and the fracture develops, which is easy to have secondary fracture development, malignant leakage and even well collapse; Second, the bottom hole temperature is high, and the drilling fluid treatment agent is easy to fail at high temperature; Third, the plugging capacity of the currently used polysulfonate drilling fluid is insufficient, which can’t effectively plug formation cracks and reduce pressure transfer; Fourth, the cementation ability of the current drilling fluid is insufficient, which can’t effectively improve the compressive strength of the near-wellbore rock. To solve the above difficulties, a high temperature resistant cementing sealer AD-1 was synthesized from acrylamide, dimethyldiallyl ammonium chloride, 2-acrylamide-2-methylpropanesulfonate sodium and dopamine hydrochloride. The cementation and plugging properties of the cementing agent were evaluated. The experimental results show that the axial compressive strength of the cemented dry carbonate sand beds is up to 2.5-5.0 MPa at 180℃, and the compressive strength is increased by more than 4 times. The compressive strength of the unconsolidated wet sand beds is 0 MPa, and the compressive strength of the consolidated wet carbonate sand beds is increased to 0.2-0.5 MPa. After adding the cementing sealer, the plugging ability of the polysulfonate drilling fluid was significantly improved, and the drilling fluid could effectively plug the sand beds composed of 40-60 and 60-80 mesh carbonate debris, with the maximum pressure ≥6 MPa, and the cumulative loss in 30 minutes was about 10 mL. In addition, the viscosity of the drilling fluid will increase dramatically when the additive amount exceeds 1.0%, and the additive amount should be controlled as appropriate. Therefore, the polysulfonate drilling fluid system with AD-1 as the core has good temperature resistance, cementation and plugging properties, which can provide strong technical support for borehole stability technology in Shunbei region.
Mechanisms of Borehole Wall Destabilization in Drilling Shale Formations in the Central Part of Block Jinzhou-25-1 in Bohai Basin and Drilling Fluid Countermeasures
GENG Lijun, LIU Feng, GANG peng, DONG Xinrou, LIU Wei, LI Bojia
2025, 42(1): 58-65.   doi: 10.12358/j.issn.1001-5620.2025.01.006
Abstract(54) HTML(20) PDF (2916KB)(14)
Abstract:
Well drilling in the central part of the block Jinzhou-25-1 in Bohai basin has frequently encountered borehole wall destabilization when drilling the Dongying formation shales. Based on the analyses of the components and structure of the shales as well as the measurement of their mechanical properties, it was found that the borehole wall destabilizes mainly in two mechanisms, first is the weakening of the shales caused by hydration and swelling, second is the shearing slip of the formations along the bedding planes. Based on this understanding, a water based drilling fluid PEM and a synthetic based drilling fluid BIODRILL S were compared for their performance from several aspects such as basic properties, plugging capacity, inhibitive capacity and the ability to maintain mechanical strength of a formation etc. It was found that the BIODRILL S drilling fluid has several advantages over the PEM drilling fluid, such as high percentage of shale cuttings recovery in hot rolling test, lower linear expansion rate, lower high temperature high pressure filtration rate as well as better performance in maintaining the mechanical strength of the shale formations. A nano-latex plugging agent PF-NSEAL was added into the BIODRILL S drilling fluid at concentrations between 2% and 2.5%, rendering it better microfracture plugging performance. In field operation, the optimized BIODRILL S drilling fluid was used to drill two extended reach wells, the number of downhole problems was greatly reduced, and the drilling rate was increased by 43.7%. The use of the optimized BIODRILL S synthetic based drilling fluid has provided a technical support for solving the borehole wall destabilization problem encountered in block Jinzhou-25-1.
Investigation of High-Temperature Resistant Ionic Liquid Inhibitors for Xinjiang ShapaiGroup 9 and Their Inhibition Mechanism
GAO Shifeng, QU Yuanzhi, HUANG Hongjun, REN Han, JIA Haidong, LIU jingping, JIA Han
2025, 42(1): 66-73.   doi: 10.12358/j.issn.1001-5620.2025.01.007
Abstract(62) HTML(25) PDF (3543KB)(13)
Abstract:
The effect of reservoir lithology on the stability of the wellbore in Xinjiang Shapai Group 9 was investigated from multiple perspectives via X-ray diffraction, infrared spectroscopy, scanning electron microscopy, and water contact angle. The inhibition performance, inhibition mechanism, and application of three typical ionic liquids (MOA, CP-DES, MM6) were evaluated.The rocks in this group have a high content of clay minerals and contain a large number of hydroxyl groups on their surfaces, which are highly susceptible to swelling with water. Among the samples treated by three ionic liquid inhibitors, the lowest linear swelling rate (21.2%), the highest hot-rolling recovery (63.1%, 180℃), and the excellent application results of drilling fluid system indicate that deep eutectic solvent ionic liquid (CP-DES) is the most suitable inhibitor for the Xinjiang Shapai Group 9.Further studies revealed that CP-DES could form strong interactions with the clay surface through hydrogen bonding and enter the clay interlayer to hinder the intrusion of water. Meanwhile, the cationic groups could compress the electric double layer on the clay surfaces and weaken the electrostatic repulsion between the particles, which consequently inhibited the hydration swelling of the clay.
Development of a Biodegradable Polymer Temporary Plugging Agent for Drilling Fluid
TIAN Zhiyuan, QI Duo, WANG Haibo, ZHANG Xinpeng, GUO Baohua, XU Jun
2025, 42(1): 74-81.   doi: 10.12358/j.issn.1001-5620.2025.01.008
Abstract(68) HTML(28) PDF (2868KB)(18)
Abstract:
Biodegradable polyester temporary plugging agents (TPAs) have good degradability and low damage to reservoirs, but the disadvantages, which include low thermal stability, low strength of the plugging layers formed and high production cost etc., make it difficult for them to be widely used. To satisfy the requirements for TPAs to work at elevated temperatures, a new biodegradable TPA is developed. This new TPA is prepared by melt blending polybutylene terephthalate (PBT), which has slower hydrolysis rate, and polyamide 6 (PA6), and an epoxy chain extender ADR is added to improve the compatibility of the melt blending materials. The new TPA has better thermal stability and forms plugging layers of higher strength. Experimental results show that the new TPA has better degradability, in a NaOH solution (pH=10) at 120-150℃, percent weight loss of the new TPA after 20-60 d is greater than 80%. When the ratio of PBT and PA6 in the melt blending system is 70% PBT/30% PA6, and into the melt blending system add 1.5% ADR, the compressive strength of the new TPA can be 91 MPa, after degrading at 150℃ for 16 h the compressive strength is still greater than 70 MPa. This new TPA has good compatibility with drilling fluids and excellent plugging performance, and after degrading at 120℃ for 14 d, the residual compressive strength of the plugging layer is 2 MPa.
High Density and High Performance Drilling Fluid System Research and Application at Pakistan North Region ADHI Block
LI Ling, ZHOU Chuxiang, JI Yongzhong, ZHANG Guangjin, WU Gang
2025, 42(1): 82-89.   doi: 10.12358/j.issn.1001-5620.2025.01.009
Abstract(72) HTML(25) PDF (3282KB)(17)
Abstract:
The mid-upper Early Miocene Murree formation in the ADHI block, northern Pakistan, is a long red mudstone located in the Φ311.15 mm interval with a length of 1400-1600 m, which is a major difficulty and extremely challenging drilling operation in the block. The red mudstone section has the characteristics of strong dispersion and high slurry production, and the rheological property of drilling fluid is often out of control. Easy to expand and shrink, bit balling, return a large ball of cuttings, blocking the horn; The formation pressure coefficient is high, the density is as high as 1.80-2.00 g/cm3, and the accidents such as differential pressure sticking and broken drilling tools often occur. Formation water, high pressure and low permeability, 1-3 m3/h; The high density further increases the difficulty of controlling rheology and poor solid content of drilling fluid. In order to solve the above Drilling problems in the AHDI block, show Chuanqing's image as a pioneer in complex oil and gas drilling in the open oil and gas service market overseas, and establish the brand of "CCDC Drilling Fluid", the author conducted analysis and research on the mineral components and hydration characteristics of mudstone in the Murree formation. A high-density high-performance water-based drilling fluid system with a density of 2.20 g/cm3, yield point less than 20 Pa, temperature resistance of 100℃ and resistance to 5% mudstone pollution suitable for ADHI block in northern Pakistan was developed based on "efficient mudstone inhibitor, clay accretion inhibitor and ROP Enhancer, nano-microne plugging agent and application technology of macromolecule encapsulation inhibitor under high density conditions". Successfully applied 4 Wells in Pakistan.
A Thermodynamic Model for Predicting 3D Phase Equilibrium Surface of Natural Gas Hydrates Considering Salt Concentration
ZHANG Geng, LI Wentuo, HUANG Honglin, LUO Ming, MA Chuanhua, WU Yanhui, LI Jun
2025, 42(1): 90-101.   doi: 10.12358/j.issn.1001-5620.2025.01.010
Abstract(58) HTML(18) PDF (4899KB)(14)
Abstract:
Accurate prediction of the thermodynamic stability of gas hydrates in salt-bearing systems is of great significance for predicting the accumulation range and determining the decomposition domain of hydrate. Therefore, considering the non-spherical characteristics of hydrate crystal cavity and the electrolyte interaction in the salt-containing system, a thermodynamic model of gas hydrate phase equilibrium considering salt concentration was established, and compared with the experimental data. The results show that the established three-dimensional phase equilibrium surface can effectively predict the thermodynamic stability of NGH, and the absolute mean relative deviation of temperature is only 0.08 in pure water, and no more than 0.15 in salt. When the molar fraction of chloride is greater than 0.02 and the pressure is higher than 20 MPa, the chemical factors cause the p-T curve to shift. When the pressure is small, the equilibrium temperature changes dramatically along the gradient of salt concentration, and the p-T curve no longer has translation characteristics. At the same time, AlCl3 has stronger inhibitory effect on CH4 hydrate than other chlorine salts when the molar fraction is the same. The lnp-X-1/T three-dimensional surface of CH4 hydrate exhibits better Clausius-Clapeyron linear behavior locally, and the surface as a whole has certain nonlinear characteristics. Moreover, the better the inhibition effect of chloride electrolyte on CH4 hydrate, the stronger the nonlinear characteristics.
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Synthesis and Evaluation of A Primary Emulsifier for High Temperature Oil Base Drilling Fluid
QIN Yong, JIANG Guancheng, DENG Zhengqiang, GE Lian
2016, 33(1): 6-10.   doi: 10.3969/j.issn.1001-5620.2016.01.002
[Abstract](2632) [PDF 4926KB](672)
摘要:
以妥尔油脂肪酸和马来酸酐为主要原料合成了一种油基钻井液抗高温主乳化剂HT-MUL,并确定了妥尔油脂肪酸单体的最佳酸值及马来酸酐单体的最优加量。对HT-MUL进行了单剂评价,结果表明HT-MUL的乳化能力良好,配制的油水比为60:40的油包水乳液的破乳电压最高可达490 V,90:10的乳液破乳电压最高可达1000 V。从抗温性、滤失性、乳化率方面对HT-MUL和国内外同类产品进行了对比,结果表明HT-MUL配制的乳液破乳电压更大、滤失量更小、乳化率更高,整体性能优于国内外同类产品。应用主乳化剂HT-MUL配制了高密度的油基钻井液,其性能评价表明体系的基本性能良好,在220℃高温热滚后、破乳电压高达800 V,滤失量低于5 mL。HT-MUL配制的油基钻井液具有良好的抗高温性和乳化稳定性。
Status Quo of Water Base Drilling Fluid Technology for Shale Gas Drilling in China and Abroad and Its Developing Trend in China
SUN Jinsheng, LIU Jingping, YAN Lili
2016, 33(5): 1-8.   doi: 10.3969/j.issn.1001-5620.2016.05.001
[Abstract](2155) [PDF 1051KB](1180)
摘要:
综述了国内外页岩气井井壁失稳机理、稳定井壁主要方法及水基钻井液技术研究与应用现状,讨论了当前中国页岩气井钻井液技术面临的主要技术难题,分析了美国页岩气井与中国主要页岩气产区井壁失稳机理的差异,指出了中国页岩气井水基钻井液技术研究存在的误区与不足,提出了中国页岩气井水基钻井液技术发展方向。
Preparation and Characteristics of Nano Polymer Microspheres Used as Plugging Agent in Drilling Fluid
WANG Weiji, QIU Zhengsong, HUANG Wei'an, ZHONG Hanyi, BAO Dan
2016, 33(1): 33-36.   doi: 10.3969/j.issn.1001-5620.2016.01.007
[Abstract](1403) [PDF 2843KB](271)
摘要:
页岩具有极低的渗透率和极小的孔喉尺寸,传统封堵剂难以在页岩表面形成有效的泥饼,只有纳米级颗粒才能封堵页岩的孔喉,阻止液相侵入地层,维持井壁稳定,保护储层。以苯乙烯(St)、甲基丙烯酸甲酯(MMA)为单体,过硫酸钾(KPS)为引发剂,采用乳液聚合法制备了纳米聚合物微球封堵剂SD-seal。通过红外光谱、透射电镜、热重分析和激光粒度分析对产物进行了表征,通过龙马溪组岩样的压力传递实验研究了其封堵性能。结果表明,SD-seal纳米粒子分散性好,形状规则(基本为球形),粒度较均匀(20 nm左右),分解温度高达402.5℃,热稳定性好,阻缓压力传递效果显著,使龙马溪组页岩岩心渗透率降低95%。
Progress Made and Trend of Development in Studying on Temporarily Type Plugging Reservoir Protection Drilling Fluids
JIANG Guancheng, MAO Yuncai, ZHOU Baoyi, SONG Ranran
2018, 35(2): 1-16.   doi: 10.3969/j.issn.1001-5620.2018.02.001
[Abstract](1545) [PDF 4562KB](469)
摘要:
通常在勘探开发油气过程中会发生不同程度的油气层损害,导致产量下降、甚至"枪毙"油气层等,钻井液是第一个与油气层相接触的外来流体,引起的油气层损害程度往往较大。为减轻或避免钻井液导致的油气层损害、提高单井产量,国内外学者们进行了长达半个世纪以上的研究工作,先后建立了"屏蔽暂堵、精细暂堵、物理化学膜暂堵"三代暂堵型保护油气层钻井液技术,使保护油气层效果逐步提高,经济效益明显。但是,与石油工程师们追求的"超低"损害目标仍存在一定差距,特别是随着非常规、复杂、超深层、超深水等类型油气层勘探开发力度的加大,以前的保护技术难以满足要求。为此,将仿生学引入保护油气层钻井液理论中,发展了适合不同油气层渗透率大小的"超双疏、生物膜、协同增效"仿生技术,并在各大油田得到推广应用,达到了"超低"损害目标,标志着第四代暂堵型保护油气层钻井液技术的建立。对上述4代暂堵型保护油气层技术的理论基础、实施方案、室内评价、现场应用效果与优缺点等进行了论述,并通过梳理阐明了将来的研究方向与发展趋势,对现场技术人员和科技工作者具有较大指导意义。
Experimental Study on Airtightness of Cement Sheath Under Alternating Stress
LIU Rengguang, ZHANG Linhai, TAO Qian, ZHOU Shiming, DING Shidong
2016, 33(4): 74-78.   doi: 10.3969/j.issn.1001-5620.2016.04.015
[Abstract](1041) [PDF 2049KB](199)
摘要:
利用自主研发的水泥环密封性实验装置研究了套管内加卸压循环作用下水泥环的密封性,根据实验结果得出了循环应力作用下水泥环密封性失效的机理。实验结果显示,在较低套管内压循环作用下,水泥环保持密封性所能承受的应力循环次数较多;在较高循环应力作用下,水泥环密封性失效时循环次数较少。表明在套管内较低压力作用下,水泥环所受的应力较低,应力水平处于弹性状态,在加卸载的循环作用下,水泥环可随之弹性变形和弹性恢复;在较高应力作用下,水泥环内部固有的微裂纹和缺陷逐渐扩展和连通,除了发生弹性变形还产生了塑性变形;随着应力循环次数的增加,塑性变形也不断地累积。循环压力卸载时,套管弹性回缩而水泥环塑性变形不可完全恢复,2者在界面处的变形不协调而引起拉应力。当拉应力超过界面处的胶结强度时出现微环隙,导致水泥环密封性失效,水泥环发生循环应力作用的低周期密封性疲劳破坏。套管内压力越大,水泥环中产生的应力水平越高,产生的塑性变形越大,每次卸载时产生的残余应变和界面处拉应力也越大,因此引起密封性失效的应力循环次数越少。
Progresses in Studying Drilling Fluid Nano Material Plugging Agents
MA Chengyun, SONG Bitao, XU Tongtai, PENG Fangfang, SONG Taotao, LIU Zuoming
2017, 34(1): 1-8.   doi: 10.3969/j.issn.1001-5620.2017.01.001
[Abstract](2347) [PDF 2528KB](789)
摘要:
分析了硬脆性泥页岩井壁失稳的原因,介绍了纳米材料特点及其应用,并概述了国内外钻井液用纳米封堵剂的研究进展,包括有机纳米封堵剂、无机纳米封堵剂、有机/无机纳米封堵剂,以及纳米封堵剂现场应用案例。笔者认为:利用无机纳米材料刚性特征以及有机聚合物可任意变形、支化成膜等特性,形成的一种核壳结构的无机/聚合物类纳米封堵剂,能够很好地分散到钻井液中,且对钻井液黏度和切力影响较小,这种类型的纳米封堵剂能够在低浓度下封堵泥页岩孔喉,建立一种疏水型且具有一定强度的泥页岩人工井壁,这不仅能够阻止钻井液侵入,而且还能提高地层承压能力,无机纳米材料与有机聚合物的结合是未来钻井液防塌剂的发展方向。
Effect of Retained Fracturing Fluid on the Imbibition Oil Displacement Effciency of Tight Oil Reservoir
GUO Gang, XUE Xiaojia, LI Kai, FAN Huabo, LIU Jin, WU Jiang
2016, 33(6): 121-126.   doi: 10.3969/j.issn.1001-5620.2016.06.022
[Abstract](1226) [PDF 11047KB](227)
摘要:
统计长庆油田罗*区块2015年存地液量与油井一年累积产量的关系发现,存地液量越大,一年累积产量越高,与常规的返排率越高产量越高概念恰恰相反,可能与存地液的自发渗吸替油有关。核磁实验结果表明,渗吸替油不同于驱替作用,渗吸过程中小孔隙对采出程度贡献大,而驱替过程中大孔隙对采出程度贡献大,但从现场致密储层岩心孔隙度来看,储层驱替效果明显弱于渗吸效果。通过实验研究了影响自发渗吸效率因素,探索影响压裂液油水置换的关键影响因素,得出了最佳渗吸采出率及最大渗吸速度现场参数。结果表明,各参数对渗吸速度的影响顺序为:界面张力 > 渗透率 > 原油黏度 > 矿化度,岩心渗透率越大,渗吸采收率越大,但是增幅逐渐减小;原油黏度越小,渗吸采收率越大;渗吸液矿化度越大,渗吸采收率越大;当渗吸液中助排剂浓度在0.005%~5%,即界面张力在0.316~10.815 mN/m范围内时,浓度为0.5%(界面张力为0.869 mN/m)的渗吸液可以使渗吸采收率达到最大。静态渗吸结果表明:并不是界面张力越低,采收率越高,而是存在某一最佳界面张力,使地层中被绕流油的数量减少,渗吸采收率达到最高,为油田提高致密储层采收率提供实验指导。
High Performance Water Base Drilling Fluid for Shale Gas Drilling
LONG Daqing, FAN Xiangsheng, WANG Kun, FAN Jianguo, LUO Renwen
2016, 33(1): 17-21.   doi: 10.3969/j.issn.1001-5620.2016.01.004
[Abstract](1620) [PDF 540KB](330)
摘要:
目前中国页岩气水平井定向段及水平段钻井均使用油基钻井液,但油基岩屑处理费用昂贵,急需开发和应用一种具有环境保护特性的高性能水基钻井液体系。介绍了2种高性能水基钻井液体系的室内实验和现场试验效果。在长宁H9-4井水平段、长宁H9-3和长宁H9-5井定向至完井段试验了GOF高性能水基钻井液体系,该体系采用的是聚合物封堵抑制方案,完全采用水基润滑方式;在昭通区块YS108H4-2井水平段试验了高润强抑制性水基钻井液体系,该体系采用的是有机、无机盐复合防膨方案以及润滑剂与柴油复合润滑方式。现场应用表明,定向段机械钻速提高50%~75%,水平段机械钻速提高75%~100%。通过实验数据及现场使用情况,对比分析了2种体系的优劣,找出了他们各自存在的问题,并提出了改进的思路,为高性能水基钻井液的进一步完善提供一些经验。
Progress in the Study of Environmentally Friendly Drilling Fluid Filtration Reducer
WU Xinlei, YAN Lili, WANG Lihui, WANG Fayun
2018, 35(3): 8-16.   doi: 10.3969/j.issn.1001-5620.2018.03.002
[Abstract](1216) [PDF 851KB](277)
摘要:
解决环境污染问题是改善钻井液的关键,开发环保型抗高温降滤失剂是当前研究的重要领域之一。概述了国内外环保型降滤失剂的研究进展,对国内外在环保型降滤失剂研制中所使用的原材料及产品性能,以及中国抗温改性天然高分子降滤失剂的发展近况进行了介绍。天然高分子降滤失剂是通过对淀粉、纤维素及木质素等天然高分子材料进行改性以提高其抗温、抗盐能力,使其可以应用于井温更高的深井钻探中。目前,中国环保型降滤失剂普遍可以应用到150℃的高温中,部分抗温能力可达到180℃却未能推广使用。通过对现有降滤失剂的研究,分析其抗高温的作用机理,探寻能有效提高抗温能力的单体分子结构及发挥作用的功能基团,例如磺酸基团、内酰胺基团等,以期对环保型抗高温降滤失剂的研制起到一定的指导和参考作用,加快环保型抗高温降滤失剂的发展。
Borehole Wall Collapse and Control in Shale Gas Well Drilling
LIU Jingping, SUN Jinsheng
2016, 33(3): 25-29.   doi: 10.3969/j.issn.1001-5620.2016.03.005
[Abstract](987) [PDF 7874KB](250)
摘要:
页岩气井水平井段井壁失稳是目前中国页岩气资源勘探开发的关键技术难题。通过云南昭通108区块龙马溪组页岩的X-射线衍射分析、扫描电镜(SEM)观察、力学特性分析、润湿性、膨胀率及回收率等实验,研究了其矿物组成、微观组构特征、表面性能、膨胀和分散特性,揭示了云南昭通108区块龙马溪组页岩地层井壁水化失稳机理。该地层黏土矿物以伊利石为主要组分,不含蒙脱石及伊蒙混层,表面水化是引起页岩地层井壁失稳的主要原因。基于热力学第二定律,利用降低页岩表面自由能以抑制页岩表面水化的原理,建立了通过多碳醇吸附作用改变页岩润湿性,有效降低其表面自由能、抑制表面水化,进而显著抑制页岩水化膨胀和分散的稳定井壁方法。
Dissolution of Barite Filter Cake Using Chelating Agents: A review of Mechanisms, Diagnosis and Removal Strategies
WEI Zhongjin, ZHOU Fengshan, XU Tongtai
2020, 37(6): 685-693.   doi: 10.3969/j.issn.1001-5620.2020.06.002
[Abstract](6670) [PDF 5710KB](466)
Abstract:
As a weighting agent of drilling fluid, barite is easy to migrate, transform and precipitate in the reservoir to form acid insoluble barite mud cake, which causes serious damage to oil and gas reservoir. Therefore, it is necessary to remove the blockage of barite safely and reliably. However, many reasons, such as put too little emphasis on barite blocking, unclear mechanism of barite blocking and removal, improper design of removal methods, large investment but poor output, confidentiality of business, et al, have restricted the progress of remove barite blockage technology in China. The chelating agent with amino polycarboxylate as the main component is the most promising process choice for removing the barite blockage, while the chelating agent structure (amino group type, carboxyl number, ring chain size, chemical stability, et al), the properties of metal ions (charge, ion radius, ionization potential or alkalinity, co-associated metal ions, et al), medium environment (pH, temperature, pressure, et al) and so on, have a profound influence on the dissolution of barite. The economic and efficient design of chelating barite blocking remover and its removal process must take removal characteristics of different chelators, concentration, catalyst, converting agent, polymer breaker, bottom temperature, environment friendly, corrosiveness, formation rock matrix, secondary reservoir damage caused by removal process and other factors into account. With the help of modern experimental technique evaluation, such as filtrate cake dissolution, dissolution product composition and morphology, core flow, et al., and carefully design the details of chelating removal process, such as injection volume, injection pressure, soaking time, flow-back fluid treatment, et al, so as to fully understand the mechanism of barite blocking, the design of chelating removal agent and its application in oil and gas fields. In this paper, the systematic work of removing the blockage of barite filter cake is reviewed, which done by the previous researchers in recent years. Hoping to provide a new perspective for the readers, so as to improve the technical innovation level of drilling fluid and completion fluid in China.
Status Quo of Water Base Drilling Fluid Technology for Shale Gas Drilling in China and Abroad and Its Developing Trend in China
SUN Jinsheng, LIU Jingping, YAN Lili
2016, 33(5): 1-8.   doi: 10.3969/j.issn.1001-5620.2016.05.001
[Abstract](2155) [PDF 1051KB](452)
Abstract:
This paper summarizes the studies and applications of the mechanism of borehole collapse, the main methods used for stabilizing instable borehol, and the status quo of water base drilling fluid technology, discusses the major difficulties presently faced in shale gas drilling in China, analyzes the differences between the mechanisms of borehole collapse both in China and in the America, illustrates the misconceptions and deficiencies existed in the studies on water base drilling fluids for shale gas drilling in China, and points out the technical direction for the development of water base drilling fluids for shale gas drilling in China.
Status Quo of Methods for Evaluating Filtration Performance and Mud Cake Quality of Drilling Fluid
YAO Rugang, ZHANG Zhenhua, PENG Chunyao, FENG Yanyun, DING Guangbo
2016, 33(6): 1-9.   doi: 10.3969/j.issn.1001-5620.2016.06.001
[Abstract](1518) [PDF 2116KB](363)
Abstract:
This paper discusses the instruments and procedures available presently for evaluating fltration property, sizes of pore throats, thickness and compressibility of mud cake. Analyzed in this paper are the status quo of using SEM and energy spectrum in studying the microstructure of mud cake and the distribution of mud cake constituents. Studies presently conducted were focused on the observation of surface topography, while knowledge about the interior microstructure of mud cake is still in demand when optimizing the quality of mud cake. The spatial distribution of the microstructure of mud cake needs to be extensively studied in the future to further understand the mechanism of fltration control and the way of reducing fltration rate. These studies are of help to the development and perfection of the basic theory of controlling drilling fluid fltration and ability of building mud cake, and will provide guide and technical support to the development of new high performancemud additives and to the improvement of drilling fluid technology.
Progresses in Studying Drilling Fluid Nano Material Plugging Agents
MA Chengyun, SONG Bitao, XU Tongtai, PENG Fangfang, SONG Taotao, LIU Zuoming
2017, 34(1): 1-8.   doi: 10.3969/j.issn.1001-5620.2017.01.001
[Abstract](2347) [PDF 2528KB](454)
Abstract:
This paper analyzes the mechanisms under which the hard and brittle shale formations destabilize, introduces the characteristics and application of nano materials, and summarizes the progresses made in the studies of drilling fluid nano material plugging agents, including organic and inorganic nano plugging agents. Also discussed in this paper are several case histories of the application of nano plugging agents. The authors believe that plugging agents having core-shell structures, which take advantage of the rigidity of inorganic nano materials and the deformability and filming ability of organic polymers, do not heavily affect the viscosity and gel strength of the drilling fluids in which the plugging agents can well dispersed. This kind of nano plugging agents can plug the pore throats of shales at low concentrations, thereby produce a pseudo hydrophobic "borehole wall" with some strength. This pseudo "borehole wall" not only hinders the invasion of drilling fluids, it also increases the pressure bearing of formation. The authors thus believe that the combination of inorganic nano materials and organic polymers indicates the direction for the development of anti-collapse additives in the future.
Drilling Fluid Technology for “Three High” Wells in Qaidam Basin in Qinghai
WANG Xin, ZHANG Minli, WANG Qiang, ZHUANG Wei, ZHANG Weijun, WANG Zhibin, LI Yifeng
2016, 33(6): 45-50.   doi: 10.3969/j.issn.1001-5620.2016.06.008
[Abstract](1316) [PDF 729KB](360)
Abstract:
Four blocks in the Qaidam Basin, Niudong, Lenghu, Zahaquan and Yingxi, have formation rocks with complex lithology, such as salt, gypsum, mirabilite, and hard and brittle shales etc. Downhole troubles have been frequently encountered in previous drilling operations. The Niudong nasal structure in the piedmont of the Altun Mountain in the basin, affected by the orogenesis, has overall formation dipping angles between 60° and 70°. High formation stress, high pressure saltwater and varied coeffcients of pressure have resulted in frequent borehole wall instability in open hole section. A BH-WEI drilling fluid for the so-called "three high" (high pressure, high sulfde, and high risk area) wells, has been used in drilling 20 wells since 2013. To perform well in drilling fluid technical service, relevant data were investigated prior to drilling. Based on laboratory experiment and feld practice, it was concluded that drilling fluid with low activity, strong plugging and inhibitive capacity was benefcial to borehole wall stability. Four key exploratory wells, the frst multi-lateral horizontal well and the frst horizontal well in Zahaquan have been completed, the maximum mud density used was 2.35 g/cm3, the average percentage of hole enlargement was 4.67%, and the ratio of successful wireline logging was 100%. The well Zaping-1 is the frst horizontal well targeted with tight oil reservoir in Zahaquan. In the block Dongping, a four-interval horizontal well was drilled in 2013 with Weatherford's MEG drilling fluid. This well was not be able to drill to the designed depth because of severe mud losses and other downhole troubles. Using the BH-WEI drilling fluid, six horizontal wells were completed successfully in 2013-2014 in the same block, and no downhole trouble has been encountered throughout the drilling operations. Two horizontal wells, Ping-1H-2-1 and Ping-1H-2-2, put into production in 2014, were both high production rate wells in the same block; the average daily gas production rate was 50×104 m3/d. Field application has shown that the BH-WEI drilling fluid had simple formulation, and the mud properties were thus easy to maintain. The BH-WEI drilling fluid had good shear thinning property, high YP/PV ratio, low plastic viscosity, low pressure loss in annular space, good hole cleaning performance and good lubricity and inhibitive capacity. Using this drilling fluid, borehole collapse in drilling the dark gray Jurassic mudstone, inability to exert WOB in horizontal drilling and differential pipe sticking were avoided. To concluded, the BH-WEI drilling fluid is a unique drilling fluid suitable for use in drilling exploratory well and horizontal well in the troublesome drilling areas in Qinghai oilfeld.
Synthesis and Evaluation of A Primary Emulsifier for High Temperature Oil Base Drilling Fluid
QIN Yong, JIANG Guancheng, DENG Zhengqiang, GE Lian
2016, 33(1): 6-10.   doi: 10.3969/j.issn.1001-5620.2016.01.002
[Abstract](2632) [PDF 4926KB](709)
Abstract:
A primary emulsifier, HT-MUL, for high temperature oil base drilling fluid was developed using tall oil fatty acids and maleic anhydride, and the optimum acid value of tall oil fatty acids and optimum concentration of maleic anhydride for the reaction were determined. Evaluation of HT-MUL shows that HT-MUL performs very well as an emulsifier. Using HT-MUL, a water-in-oil emulsion (O/W ratio=60:40) was formulated, having electrical stability of 490 V, and another water-in-oil emulsion (O/W ratio=90:10), having electrical stability of 1,000 V. Comparison of HT-MUL with other primary emulsifiers demonstrates that emulsions formulated with HT-MUL have higher electrical stability voltage, lower filter loss and higher rate of emulsion, proving that HT-MUL has better general performance than other emulsifiers. A high performance high density oil base drilling fluid was formulated using HT-MUL, retaining electrical stability of 800 V and filter loss less than 5 mL after hot rolling at 220℃. Oil base drilling fluids formulated with HT-MUL have good high temperature performance and emulsion stability.
A New Fracturing Fluid with Temperature Resistance of 230℃
YANG Zhenzhou, LIU Fuchen, SONG Lulu, LIN Lijun
2018, 35(1): 101-104.   doi: 10.3969/j.issn.1001-5620.2018.01.019
[Abstract](1658) [PDF 604KB](416)
Abstract:
The natural vegetable gum fracturing fluid presently in use works effectively at temperatures up to 177℃. To fracture formations with higher temperatures, a fracturing fluid with temperature resistance of 200-230℃ has been developed with ultrahigh temperature thickening agent, high temperature resistant zirconium crosslinking agent, high temperature stabilizer and efficient gel breaker through large quantity of laboratory experiments. The experimental results showed that, under the synergetic effect of these additives, the fracturing fluid is suitable for use in fracturing formations whose temperatures are higher than the temperature limit of conventional gels. The fracturing fluid has good shear-resistance property at high temperatures up to 230℃, and the polymer consumption for formulating the fracturing fluid is obviously reduced. Complete gel breaking can be realized with the fracturing fluid, and damage to the fluid conducting formations with proppants is low.
Development of Extreme Pressure Anti-wear Lubricant MPA for Water Base Drilling Fluids
QU Yuanzhi, HUANG Hongjun, WANG Bo, FENG Xiaohua, SUN Siwei
2018, 35(1): 34-37.   doi: 10.3969/j.issn.1001-5620.2018.01.006
[Abstract](1457) [PDF 963KB](383)
Abstract:
An extreme pressure organic sulfur anti-wear additive has been developed for use in water base drilling fluids. Structural characteristics and extreme pressure anti-wear performance evaluation showed that the organic sulfur compound is a saturated alkane, with sulfur content as high as 35.49%, and has good extreme pressure anti-wear property. An extreme pressure anti-wear additive, MPA, was developed with a modified vegetable oil as the base oil, the extreme pressure organic sulfur anti-wear additive and surfactants. The components of MPA are all environmentally friendly. Performance evaluation showed that MPA has good compatibility with other additives, and is completely dispersible in fresh water or drilling fluids. It helps optimize the properties of drilling fluids and has excellent lubricity.
Plugging Micro-fractures to Prevent Gas-cut in Fractured Gas Reservoir Drilling
HAN Zixuan, LIN Yongxue, CHAI Long, LI Daqi
2017, 34(1): 16-22.   doi: 10.3969/j.issn.1001-5620.2017.01.003
[Abstract](1461) [PDF 2831KB](331)
Abstract:
The Ordovician carbonate rock reservoirs drilled in Tazhong area (Tarim Basin) have complex geology and developed fractures, 50% of which with widths between 20 μm and 400 μm. These fractures have led to frequent lost circulation, well kick and severe gas cut, which in turn resulted in well control risks. Complex distribution of fractures and high formation temperatures (180℃) make bridging with sized particles less effective in controlling mud losses. In laboratory experiment, commonly used testing methods for evaluating the performance of plugging drilling fluids are unable to effectively simulate the real fractures, and hence there is a big discrepancy between the laboratory evaluation and practical performanceof the plugging agents. To solve this problem, a new method has been presented based on the idea of plugging micro-fractures to prevent gas-cut. In this method, natural/artificial cores are used to make test cores with fractures of 20 μm-400 μm in width and roughness that is closely simulating the fractures encountered in the reservoirs drilled. Included in the new method are a device used to evaluate the performance of a drilling fluid in plugging micron fractures, and an evaluation procedure. With this method, particle, fiber and deformable LCMs sized in microns and nanometers were selected and an LCM formulation compatible with polymer sulfonate drilling fluid and ENVIROTHERM NT drilling fluid developed. This plugging PCM formulation, having acid solubility of greater than 70%,does not render contamination to reservoir.
A Temperature Sensitive Expanding Microcapsule Anti-Gas-Channeling Cement Slurry
ZHANG Xingguo, YU Xuewei, GUO Xiaoyang, YANG Jixiang, YAN Rui, LI Zaoyuan
2018, 35(1): 71-76.   doi: 10.3969/j.issn.1001-5620.2018.01.014
[Abstract](1432) [PDF 4092KB](392)
Abstract:
A temperature sensitive expanding microcapsule anti-gas-channeling agent has been synthesized with acrylonitrile (AN), methylmethacrylate (MMA) and methyl acrylate (MA) as the wall material, and iso-butane as the core material. The effects of the amount of iso-butane used in the synthesis on the performance of the anti-gas-channeling were studied, and the performance of the temperature sensitive expanding microcapsule anti-gas-channeling cement slurry in controlling gas channeling was evaluated. The studies and the evaluation results showed that the temperature sensitive expanding microcapsule anti-gas-channeling agent can be obtained under the following conditions:in 100 g of deionized water add AN, MMA and MA in a ratio of 3:0.4:2, 30% iso-butane, 1% lauroyl peroxide (LPO, as initiator), 0.1% 1, 4-butanediol dimethacrylate (BDDMA, as crosslinking agent), 20% nano silicon dioxide (as dispersant), and react these substances at 65℃ with the protection of nitrogen. The anti-gas-channeling agent has initial expansion temperature of 65℃, optimal expansion temperature of 83℃, and is resistant to temperature as high as 120℃. Rate of expansion of the anti-gas-channeling agent is 50. Stimulation of water-channeling/gas-channeling in oil well cement and test of cement slurry condensation and contraction indicated that volumetric contraction of cement slurry can be made up for with less than 2% of the synthesized anti-gas-channeling agent, meaning that this anti-gas-channeling agent has good gas-channeling prevention ability.
Governed by:
China National Petroleum Corporation Ltd
Sponsored by:
CNPC Bohai Drilling Engineering Co. LtdPetroChina Huabei Oilfield Company
Editor-in-Chief:Shi-chun Chen(Engineer Technology Research Institute,BHDC)
Deputy Editor-in-chief:
Gui-juan Wang(Engineer Technology Research Institute,BHDC)Qiang Ren(Engineer Technology Research Institute,BHDC)
Address:
Editorial Office of Drilling Fluid and Completion Fluid, Bohai Drilling Engineering Institute, Yanshan South Road, Renqiu City, Hebei Province
Postcode: 062552
Tel:(0317)2725487 2722354
E-mail: zjyywjy@126.com
   CN   12-1486/TE
ISSN   1001-5620