理想充填保护油气层技术是根据d90(累积粒度分布曲线中累积体积分数为90％的颗粒直径)规则,通过综合考虑整个地层孔喉尺寸,借助于理想充填软件优选出与地层孔喉相匹配的一组完整的暂堵剂粒径分布序列,可实现对孔喉的有效暂堵和保护.根据吐哈油田各重点区块的储层特性,应用理想充填油气层保护技术,对丘陵、温米和鄯善等近十二个重点区块的钻井液暂堵方案进行了优化设计.通过使用自主开发的理想充填暂堵软件,将1000目、600目、100目3种CaCO3暂堵剂按质量比2∶13∶5复配,可使钻井液颗粒的d90(110.92μm)大于储层的最大孔喉尺寸(dmax=80.33 μm),可有效封堵储层中各种尺寸的孔喉.复配暂堵剂加量为3％时,钻井液流变参数变化较小,滤失量降低,储层岩心的渗透率恢复值可从30％左右增至80％以上,储层保护效果较好.该技术在吐哈油田20口井进行了现场应用,实验井日产液量较邻井提高45％以上,平均含水率18％.图2表8参12

因水平井钻井液安全窗口较窄,所以准确预测水平井井筒循环温度对井底压力控制、安全快速钻进有很重要的意义.在常规钻井井筒温度计算理论和模型的基础上,根据传热学的基本原理和能量守恒方法,建立了包括垂直段、造斜段和水平段的水平井井筒循环温度预测模型,并用实测的井筒温度对模型预测结果进行了验证,误差仅为0.6％.通过计算分析得出,在水平段较短时,环空内钻井液最高循环温度位置位于水平段起始处或在造斜段末端处;当水平段较长时,环空内钻井液最高循环温度位置位于水平段,并随着水平段的延伸逐渐接近井底;水平段起始处的ESD将逐渐降低,ECD沿着水平段逐渐升高,在钻头处(即井底)最高.

介绍了国内外常用的油藏岩石润湿性评价方法及各自的优缺点,然后提出了一种定量评价的新方法,即经改进的接触角测定法,该方法分别使用光滑的石英玻片和经抛光的方解石晶片替代典型砂岩和碳酸盐岩的岩石表面,并用各种不同的钻井液对其表面进行处理后,测定蒸馏水水滴的接触角,以评价钻井液引起润湿性改变的程度.测定实例表明,其数据合理,可定量评价钻井液引起润湿性改变的程度 与传统的Amott法和USBM方法相比较,该方法的特点是不需储层岩心样品,更适合在探井中使用,且操作简便、耗时短,为油基钻井液配方优化提供了评价手段.

In view of the disposal of wasted drilling fluid in environmentally sensitive areas ,a wasted drilling fluid innocuous treatment formula has been developed on the basis of determining the dosage of destablizer SD 131 ,coagulation accelerator SD 132 ,and dispersant SD 133 .After innocuous treatment ,the infiltrate fluid of drilling fluid has low chromaticity and low content of suspended materials .Different mate-rials and elements in the infiltrate fluid are indicated by COD :23 56 mg/L ,total Cr :0.86 1.12 mg/L ,Cr6+0.22 0.40 mg/L ,and hydrocarbon :2.67 4.23 mg/L ,w hich meet the requirement of innocuous treatment of wasted drilling fluid .The test of the technology in environmentally sensitive area of Wenmi Oilfield show s the drilling fluid still has certain porosity and is similar to soil 20 30 d of drying after treatment ,and can bear bulldozer to restore well site .Field test shows the technology can effectively transform and solidify pollutants in drilling fluid .

The reservoir of Jurassic Toutunhe Formation in Fudong Slope Area in Junggar Basin has strong water sensitivity which has created challenges in reservoir protection while drilling .To minimize the drilling fluid damage to the reservoir ,the present organic salt drilling fluid system was optimized .Based on the organic salt drilling fluid system whose core components of main agent was a linear polymer -JN 2 with strong inhibitory ,amine inhibitors and “ideal packing” bridging agent were added to improve the inh-ibitive ability and sealing capability of the system ,thus achieving formation damage control during drilling . The drilling fluid was optimized through lab experiments .Experimental results showed that the rheological property of optimized drilling fluid system before and after aging was stable .HTHP filter loss was reduced from the original 12.6 mL to 8.0 mL .Shale expansion ratio was reduced from 20% to 17% .The recovery of shale was increased to 91.8% from 90.14% .Permeability recovery of natural reservoir cores increased to 82.15% from 73.14% .Results showed that the scheme of combination of amine inhibitors and “ideal pac-king” diversion agent could improve the drilling fluid inhibitive ability and sealing capability ,making it a reasonable application and an effective technical means to protect highly water sensitive formation in the drilling process .

致密碳酸盐岩储层孔喉细小,渗透性差,非均质性严重,微孔微裂缝较为发育,储层易发生应力敏感性损害和水锁损害.结合英买2油田致密碳酸盐岩油气藏特征,系统分析了低渗碳酸盐岩储层的损害特征.评价结果表明,该油田储层应力敏感损害率达82.9％、水锁损害率为72.53％～91.22％是该储层的主要损害类型.在该区原用聚磺钻井液基础上,通过优选高性能处理剂和可有效降低油/水界面张力的表面活性剂,应用理想充填技术,优化设计出了保护储层低损害钻井液；通过开展配伍性、动态污染等实验对该钻井液的储层保护特性进行了评价.实验结果表明,该钻井液具有良好的流变性与配伍性,天然岩心和不锈钢缝板岩心污染实验均表明,优化配方的渗透率恢复值均要高于现用配方,其储层保护效果显著.

Formation damage is prone to occur during drilling into the formations with medium/high permeability in Jabung Oilfield, Indonesia. To prevent formation damage and enhance productivity of oil wells, a novel low-damage drilling fluid was developed on the basis of the modification of currently used KCl polymer drilling fluid using a special technology. By virtue of the synergistic effect of ideal packing agents and film-forming agents, a sealing layer with high pressure bearing capability can be formed on the rock surface of borehole, so as to prevent drilling fluids from invading into formations effectively. It is shown from the results of numerous experiments that this drilling fluid has excellent rheological properties, very low filtration rates (API filtration rate<4mL and HTHP filtration rate≤12.5mL), good lubricity, and strongly inhibitive character to shale. Also, it exhibits remarkable effectiveness of formation protection indicated by the returned permeability as high as 88.11% and extremely low dynamic filtration rate lower than 4mL.

The empirical model of density-predicting for oil-base mud in HTHP conditions which was built on the basis of experiments has high simulation precision. However, the coefficients need to be re-regressed when the density of drilling fluid changed. In this paper, the method of predicting the density of enhanced oil-base mud in HTHP conditions is studied, basing on the density-model for oil-base mud of some certain density, while the formulation was invariant. The experiments data show that the weighting materials bring about additional changes in volume, so that the corrected predicting model has higher precision.

During deepwater well completion in AKPO,Nigeria,low temperature,shale instability,formation of gas hydrate and other factors often cause problems.Because of high-rate filter loss,current completion fluids lead to formation damages to different degrees.Based on reservoir characteristics and potential damage factors,this paper selected key treatment agent and optimized three different formation-friendly deep water completion fluids which are prepared for different well completions.The performance evaluation results showed that,the optimized systems had better properties in rheological behavior,filter-loss reduction,clay hydration inhibition and gas hydrate inhibition,compared with current completion fluids.The reservoir core permeability recovery rate reached over 85%.Field application showed that the skin factor of AKPO-302 completed with optimized fluids was only 0.25,while in some intervals of Well AKPO-1 and Well AKPO-2,the skin factor reached 100.The results proved the completion fluids had remarkable reservoir protection results.

在高温高压井中,当钻遇复杂地层时需及时调整钻井液的密度.目前所建立的油基钻井液在高温高压条件下的密度预测模型都是根据实验结果建立的经验模型,尽管这些模型具有较高的拟合精度,但当钻井液密度发生改变时,其模型中的各项回归系数就不再适用 建立了一个新的密度预测模型,其特点是,当油基钻井液配方不变时,可根据某一给定密度油基钻井液的含温度、压力的密度模型,准确地预测其加重后在高温高压条件下的密度.并且,将模型计算值与实验数据进行对比可以发现,加重材料的加入会对钻井液造成一个附加的体积变化,因而经本研究修正后的预测模型具有更高的准确性.

Through research on the flowing state of free water in drilling fluids, a special complexing agent was developed. This additive can increase the capillary force for free water to invade reservoirs and thus control filtrate invasion by effectively complexing the free water in drilling fluids. The invasion quantity and invasion depth of water into reservoirs can be reduced. In addition, the complexed free water can form a kind of special micelle and low-pemeability membrane so that it can effectively plug pore throats and microfractures, increase the bearing pressure of formations and decrease the required density of drilling fluids. Based on the results of CST tests, spontaneous water imbibition test of cores and measurement of free water content, it is concluded that the newly formulated drilling fluid with less free water can effectively complex free water in drilling fluids and reduce liquid invasion to formations. Field application shows that the less free water drilling fluid has good behaviors of rheology, lubricity and inhibition. It can increase the bearing capability of the formation, decrease the required density of drilling fluid, and shorten the drilling time.

针对目前西非深水钻井现场产生大量含油钻屑的情况,选取表面活性剂清洗法清除钻屑表面的油污,使其达到环境保护的要求.通过室内实验,清洗剂选用ABS或ABSN,清洗搅拌时间为15 min；使用油基钻井液的岩屑处理方案为:淡水+0.5%ABS或海水+0.5%ABS+0.1%三聚磷酸钠,可将钻屑含油量降至2%以下,达到西非海域就地排放钻屑的要求.结合现场情况,确定采用振动式钻屑清洗机与LWTU污水处理系统,并制定了海上钻屑处理工艺流程.

If the drilling fluid can form the mud cake with no permeability on the borehole wall,the drilling fluidwill have better reservoir protection effectiveness.We need to find a more reasonable method,based on the optimummatching relationship between particle size of temporary blocking agent and pore size of reservoir.According totheIdeal Packing Theoryand thed90 Rule,a new beneficial optimum method for reservoir protection is putforward.We can find out the optimum matching relationship more rapidly and accurately,among different kinds oftemporary blocking agent products with a variety of particle size.Compared to traditional methods,the new methodis of a higher recovery value of core permeability,and it can stop the solid particle and filtrate from invading intohydrocarbon reservoir more effectively.Therefore it is good for reservoir protection.Field test also confirmes thatapplication of this new method can achieve the ideal effects of reservoir protection.

Surfactants are chosen to remove the oil on the surface of oily cuttings which are produced during the deepwater drilling in the West Africa. It is shown from experimental results that the two surfactants, ABSN and ABS, are suitable as the cleaning agents. The period of cleaning time is determined as 15 minutes. Based on the evaluation results, the formulations of cleaning agents are determined as follows: water +0.5% of ABS (sea-water +0.5% of ABS + 0.1% of STPP). By using this cleaning method, the oil content on the surfaces of cuttings can be reduced to below 2% which can meet the requirement of disposal to the sea. The vibrating washing machine and the LWTU wastewater treatment system are selected, and a treatment process for offshore drilled cuttings is proposed.

Conventional hot rolling furnace has some disadvantages,such as small radius of rotation of aging tank and low collision probability of the cuttings in the tank during experiments.As a result,HFZO-1 upturned hot rolling furnace has been developed to overcome these disadvantages.By using HFZO-1 upturned hot rolling furnace,many experiments have been performed in lab to study the factors affecting formation of gumbo balls during fast drilling.A new kind of surfactant that can be fast absorbed on the surface of cuttings has been developed.Combined with the measures,such as controlling solids,applying bentonite clay-free drilling fluid and reducing viscosity of drilling fluid,this new surfactant can effectively prevent the formation of gumbo balls during fast drilling.The application of this surfactant in Dongfang 1-1 gas field showed the good effect.

Condensate gas reservoirs with low-permeability are characterized by a tiny size of pore throats,poor permeability,high content of clay minerals and severe heterogeneity.Therefore,this type of reservoirs is susceptible to the damage of water sensitivity,water blocking,etc.caused by invasion fluids,and frequently to the damage of specific retrograde condensation.We analyzed mechanisms of formation damage systematically based on reservoir characteristics of the Baka condensate gas reservoir with low-permeability,the results showed that water blocking was the major damage to this reservoir and the damage ratio induced by water blocking ranged from 65.23% to 91.01%.On the basis of the sulphonic polymer drilling fluid previously used in this area,surfactants capable of effectively reducing the interfacial tension of oil/water contact were optimized,a new protection method characteristic of synergetic effectiveness by combining film forming with ideal packing was adopted,and consequently a drilling fluid with low damage was developed.The protection effect of this fluid on reservoirs was verified in compatibility tests and dynamic damage tests.The results showed that this fluid was of excellent rheological performance and compatibility,being capable of increasing the returned value of core permeability from 63.2% to 84.7% and of distinct protection of reservoirs.

There are continuous high concerns on formation protection technology in international petroleum engineering field. The reservoir drill-in fluid (RDF) is the first non-native fluid to contact formation, and which influences directly the ultimate capacity of oil and gas well. The paper discusses the smart RDF design method based on conventional drilling fluid. The designed RDF system is characterized as good formation damage control, as well as the performance easily adjusted for field application. The technology combines ideal packing technology with active calcium carbonate to obtain low permeability filter cake, high return permeability and low initial flowing pressure. The sized calcium carbonates contribute to develop sealing zone for preventing filtrate and solids from invading into formation, and the organophilic passageway in filter cake (the active calcium carbonate) is favorable to open automatically passageway for oil and gas during production. Different modifiers used to ground calciumcarbonate surface modification are evaluated in laboratory. And the laboratory results show modified calcium carbonates are comfortable with conventional drilling fluids additives such as XC(Xanthan ), potassium polyacrylate(K-PAM), sodium carboxymethyl cellulose(Na-CMC).

通过研究温度、压力、pH值等因素对CO2、CaCO3垢溶解度的影响,分析高含CO2天然气藏储集层的结垢机理.CO2的溶解度随温度升高而降低,随压力升高而升高,随地层水矿化度的升高而降低；CaCO3在水中的溶解度随温度升高而降低,随压力的升高而升高,溶液pH值升高会促进CaCO3的生成.结合吉林油田典型含CO2天然气藏储集层特征进行了结垢预测,认为钻井液滤液侵入储集层后,储集层近井地带存在结CaCO3垢的可能.针对气藏储集层埋藏深、井底温度高、地层压力系数低、裂缝发育等特点,优选了水包油及甲酸盐无固相两种欠平衡钻井液体系,CO2侵入、动态污染实验评价表明,两种钻井液均具有很好的抗CO2污染能力,储集层保护效果显著.两种欠平衡钻井液体系已分别在龙深2井和龙深3井进行了现场应用,效果良好,现场钻井液的岩心渗透率恢复值均在85％以上,满足欠平衡钻井的要求.

Downhole accidents such as borehole instability,hole enlargement,hole shrinkage,low coring efficiency and tripping problem are often seen during drilling process in the Block 6 of Sudan. Based on "ideal packing theory" and membrane-forming technology,a new low damage anti-sloughing drilling fluid system has been developed and applied in the Block 6 of Sudan by blending temporary plugging agents of different grain sizes in certain proportion according to reservoir lithology,aperture,pore throat and permeability. Experiment result shows that the original drilling fluid has severely damaged the core; the new drilling fluid uses treatment agents uncontaminated to environment and without fluorescence,and the cuttings are better representative and easy to clean. The new drilling fluid can significantly improve the return permeability of core sample,reduce the dynamic filtration rate,effectively prevent solid particles and filtrate from entering reservoir,and meet the requirements of safe,fast and economic drilling in the Block 6,Sudan. This new drilling fluid system has been successfully used in drilling the Aradeiba shale formation and achieved very satisfactory effect of reservoir protection.

Wellbore sloughing and reservoir damage are prone to occur during drilling formations with high porosity and high permeability in block 6,Sudan.A low damage anti-sloughing drilling fluid was developed based on original KCl polymer drilling fluid using ideal bridging agents along with film forming agent.Lab tests indicate that this drilling fluid performs good inhibition compared with original one,and can reduce fluid loss remarkably and improve core recover ratio up to 88.32%,and behaves remarkable reservoir protection effectiveness.This drilling fluid was tested in two wells during drilling the third hole sections and achieved better wellbore stability and reservoir protection,and resolved technical challenges of both wellbore caving and formation damages.