An amount of highly evolved bitumen has been discovered in carbonate reservoirs during ultra-deep oil and gas exploration. This bitumen damages the pore structure and is difficult to dissolve using chemical reagents. To address the gap in studying highly evolved bitumen's impact on carbonate reservoirs. This study utilized samples from the second member of the Dengying Formation (referred to as Deng 2) in Sichuan Basin. Using thin-section observation, and full-diameter CT scanning, were employed to establish two digital models: with bitumen and without. The study aims to observe bitumen distribution characteristics, compare physical properties and pore structures of two digital cores, clarify bitumen content and its impact on the reservoir, and establish a regression equation. The results indicate: (1) Bitumen in Deng 2 exhibits three states: semi-filled, fully filled, and combined cementation; (2) Properties of the bitumen-containing model decline, with significant reductions in pore and throat numbers. Bitumen primarily occupies large-pore spaces with high coordination numbers and blocks large-radius, long-throat spaces; (3) A bitumen calculation model was established using digital core analysis and well logging parameters, demonstrating good applicability. In conclusion, this approach offers guidance for studying the impact of bitumen on ultra-deep reservoirs and quantitative well logging analysis.

The Sinian Dengying Fm in the Sichuan Basin is a set of fractured-vuggy reservoirs mainly dominated by sedimentation and karstification, and characterized by small fractures and vugs, complex stratigraphy and lithology, and strong vertical and lateral reservoir heterogeneity. As a result, the drilling rates are lower and single-well gas productivity varies greatly there. And the reservoir identification results based on seismic data in this area are ambiguous. In view of this, the Deng 4 Member in the Gaoshiti buried structure on the southern flank of the Leshan–Longnüsi palaeohigh was precisely divided in stratigraphy. Then, the types of reservoir assemblages were determined based on gas well logging and test data, and the seismic response characteristics of typical wells with different types of reservoir assemblages and the seismic modes of high productivity wells were studied by using high-resolution seismic data. It is indicated that the Deng 4 Member in this area is divided into three types of reservoir assemblages, which correspond to three seismic modes. Seismic mode I: It presents the seismic response characteristics of “wide wave troughs + double highlights” or “wide wave troughs + complex waves”, indicating that fractures and vugs are developed. It is the preferred seismic mode of high productivity wells in the stage of development. In this mode, the technology of highly deviated wells or horizontal wells can be implemented. Seismic mode II: It presents the seismic response characteristics of “wide wave troughs”, indicating that fractures and vugs are relatively developed. It is the mode of moderate productivity wells. In this mode, the technology of highly deviated wells can be implemented. Seismic mode III: It presents the seismic response characteristics of “wide wave troughs + highlights”, indicating that fractures and vugs are underdeveloped. It is mode of low productivity wells, in which the technology of horizontal wells can be implemented. The new understandings on seismic modes were applied on site. It is shown that the reservoir drilling rate is over 60% and the average gas production rate during the production test of 8 wells is up to 75.34 × 104 m3/d. It is concluded that the seismic mode of high productivity wells based on seismic facies, fracture and vug prediction and integrated target design provides a support for the well arrangement and drilling trajectory adjustment in natural gas exploration and development in the Gaoshiti area and good results have been achieved.

The petrophysical and logging response characteristics of asphaltene carbonate reservoirs were examined based on the measurement of porosity and permeability, density, compressional and shear wave slowness, resistivity and Nuclear Magnetic Resonance transverse relaxation time (T-2) of cores before and after the bitumen dissolving. The results show that (1) the asphalt can damage the pore structure of the reservoir and cause reduction of effective reservoir space and permeability; (2) with the increase of asphalt content, the compression and shear wave slowness generally decrease while the density and resistivity increase; (3) with the increase of asphalt content, the compressional wave slowness and density change less, while the shear wave slowness and resistivity change larger; and (4) the T2 values of asphalt are generally less than 3 ms, and the higher the maturity of the asphalt, the lower the T2 value. Based on these experiments, a method based on conventional and special logging methods was presented to evaluate asphalt content, effective porosity and water saturation in asphaltene carbonate reservoirs. The method has already been applied to 80 wells in the Longwangmiao Formation of the Anyue gas field in the Sichuan Basin to pick out zones rich in asphalt on the plane, which has effectively guided the selection of well location in the gas reservoir development.

利用岩心薄片、岩屑薄片、测井和地震资料对四川盆地须家河组砂岩类型开展研究,明确了川西至川中地区须一、须三、须五段内大面积发育灰屑砂岩,属于三角洲前缘水下分流河道沉积,具有成熟度低、灰质胶结重、粒间孔少、物性差等特征,局部发育相对高孔“甜点”砂体.电性上表现为“三低两高”特征,即低自然伽玛、低声波时差、低补偿中子、高电阻、高密度;地震上表现为高阻抗特征.以灰屑砂岩作为典型标志层,提出在剑阁—蓬莱地区发育大型三角洲体.该三角洲体具有继承性发育特征,在须一、须三、须五段沉积时期,与优质泥质烃源岩共生,生储盖组合好,具备形成大规模致密气的成藏条件.图6参4

The 2nd member of the Upper Triassic Xujiahe Fm in the Sichuan Basin is the major pay zone in the Anyue Gas Field.The reservoirs in this member are characterized by strong heterogeneity,complex pore structure,low porosity,low to ultra-low permeability,and high irreducible water saturation.In addition,these reservoirs are strongly influenced by tectonic structures and lithological facies,the degree of differentiation of gas and water is rather low,the differences in the logging responses of gas layers,intermediate gas-water layers and water layers are ambiguous.Therefore,the identification of fluid types is challenging and the success ratio of formation test is low.In this paper,logging data and formation test data in combination with the characteristics of the Xujiahe Fm reservoirs are used to systematically analyze the logging responses of the gas and water in the reservoirs.Various methods,such as the saturation superposition method,the resistivity-porosity cross-plotting method,the lateral-induction resistivity ratio method,and the compressional-shear wave velocity ratio method are used to identify reservoir properties and reveal the differences between gas,water and dry layers,so as to comprehensively determine the properties of reservoirs in the 2nd member of Xujiahe Fm in the Anyue field.Through tracking and analyzing the new wells drilled during 2011-2012,the saturation superimposition and resistivity-porosity cross-plotting methods were finally selected as the major technologies for the discrimination of fluid types.They were applied to identify fluid types of 46 layers.The coincidence rate of logging interpretation was raised from 60% to 83%,and the success ratio of formation test was also improved significantly.These technologies have strong applicability and operability,and can be applied in other blocks in the Middle Sichuan Basin.

Xujiahe Formation in the south of west Sichuan is composed of tight sandstones with unconventional extra-low porosity and permeability.A set of logging identifying methods for special lithology are summarized by the analysis of electronic characteristics of stones.Furthermore,it is considered carbonaceous sandstones perhaps belong to reservoir,and calcareous cement sandstone as well as cutting sandstone is unfavorable to reservoir.Generally reservoir intervals are classified by the lower limit of porosity and the fracture development is an important evidence for reservoir division.

The relationships among reservoir-forming factors such as source conditions,reservoir characteristics,palaeo and present structural properties,fractures features in Xujiahe 4 Member of Chongxi gasfield are studied systematically.By the comprehensive analysis,it is considered that the palaeo and present structural conditions,reservoirs and fractures are the keys of forming the Xujiahe 4 Member gas reservoir.This reservoir is controlled by source rock,reservoirs,faults and fractures development under the conditions of palaeo and present structural background.It is further showed the most favorable region of gas accumulation to from the reservoir is superimposed region which is characterized by developed reservoir and fractures along with favorable palaeo and present structures.

常规方法解释裂缝具有分辨率较低、多解性较强、直观性较差等缺陷,而成像测井的应用目前较为有限.在基岩电阻率较高的硬地层中,在去除了泥质、孔隙、高矿化度地层水和其他矿物等影响因素后,地层电阻率与致密围岩电阻率的差异就被认为是裂缝因素引起的.将常规测井资料与成像测井、岩心、录井、试油等资料相结合,在对电阻率进行各种附加导电校正的基础上,利用双侧向电阻的差异计算裂缝张开度,根据简化的双侧向解释公式计算裂缝孔隙度,根据裂缝宽度与裂缝渗透率实验关系求解裂缝渗透率.采用这套方法对某地区奥陶系碳酸盐岩储层计算裂缝参数,与取心井段岩心裂缝孔隙度、成像测井资料、地层动态渗透率及试油(气)结果吻合较好,说明该套估算裂缝参数的方法是可行且有效的.

公山庙构造位于四川省南部、仪陇、蓬安、南充县境内,东邻营山油田,南与莲池油田相望,西邻八角场油气田,钻探控制面积约500km2.其侏罗系沙一段油藏为湖泊相～河流相交互沉积的砂岩油藏,目前已有十多口井试获油气流.本次研究通过对公山庙沙一段地质、测井综合研究,充分考虑到该地层复杂的泥质、残余油气、井眼等影响因素,建立了一套合理的孔、渗、饱储层参数计算模型.并通过对测井、试油、压汞等资料的分析研究,利用各种交会图,确定了有效厚度下限,与地质方面的研究吻合较好,为该区储量升级打下了坚实的基础.

川东北地区飞仙关组鲕滩气藏是西南油气田分公司近几年来油气勘探的重要发现之一.位于开江～梁平海槽东侧的温泉井西、渡口河、罗家寨、铁山坡、五宝场等构造钻探了近20口井,钻获大、中、小各类气藏4个,那么同属于开江～梁平海槽沉积体系的铁山、双家坝构造是不是也具有和东侧一样好的储层呢?因此有必要对铁山、双家坝构造进行储层预测研究,搞清楚其储层特征及储层分布情况.本文利用Strata反演技术和Jason反演技术对铁山、双家坝构造进行了预测并绘制了其储能系数分布图.

砂体能否最终成为有效储集体，其经历的成岩作用则是关键。成岩研究表明，区内沙一段储层成岩作用类型主要有压实作用、胶结作用、交代作用和溶蚀作用。成岩作用是影响储层物性好坏的主控因素之一，其中压实作用和胶结作用是主要的破坏性成岩作用，而溶蚀作用和交代作用是主要的建设性成岩作用，其增加新的储集空间进而使储层的孔隙性得到改善。沙一段储层经过一系列成岩作用改造后，基质孔隙度降至0.1～8.94％，孔隙类型主要由残余粒间孔、粒间溶孔和粒内溶孔组成，见少量铸模孔、胶结物内溶孔和杂基内溶孔。对成岩作用强度定量研究表明，沙一段储层压实作用和胶结作用强度较大，视压实率在50～75％之间，因压实作用使原始孔隙度损失18—25.5％；视胶结率高达12～48％，使原生孔隙度损失3.14～18％，压实作用和胶结作用对储层物性的降低影响最大的成岩作用类型。

利用DCI薄层预测技术、ISIS反演和Stratimagic综合地震分析软件对黑楼门—双合寨地区地震资料的处理、分析,预测了石炭系和泥盆系在该区的分布倩况。根据楼1井的薄片分析,确定了泥盆系的岩性、探讨了泥盆系储层、裂缝发育情况。根据地震反演和成藏条件,对该区石炭系地层—构造复合圈闭进行了综合评价。

论证DCI薄层预测技术在四川盆地东北部石炭系分布预测研究中的可行性和可靠性,以地质、测井等资料为约束条件,对四川盆地东北部地区五宝场、黑楼门等地区的地震资料进行了DCI处理,对五宝场地区进行了石炭系分布预测研究.