Multiple grain-size fraction analysis of heavy minerals and the provenance identification of sediments from the abandoned Huanghe River,eastern China

The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrital grains,provide a reliable provenance-tracing approach.We developed a mineral identification method to analyze the multiple grain-size fraction of sediments,from which the elemental geochemistry of hornblende was used to compare the characteristics of sediments from the Huaihe River and Huanghe(Yellow)River in eastern China.Elements that were statistically identified as being able to discriminate sediment provenance were employed to perform a quantitative analysis of the sources of sediments of the abandoned Huanghe River.Results reveal that the Huaihe River is characterized by a high amphibole content of>60%and that the Huanghe and abandoned Huanghe rivers have greater abundances of limonite and carbonate minerals compared with those of the Huaihe River.The contents of trace elements and rare earth elements in hornblende show that the sediments of the abandoned Huanghe River are similar to those of the Huanghe River but different from those of the Huaihe River.Furthermore,chemical mass balance was used to calculate the relative contributions of different provenances of sediment from the abandoned Huanghe River,and nine trace elements of hornblende were identified as discriminators of provenance.Approximately 2%of the hornblende in the abandoned Huanghe River is derived from the Huaihe River and 98%from the Huanghe River.Considering the proportion of hornblende in the total sediment,it is inferred that the contribution of Huaihe River sediment to the abandoned Huanghe River is approximately 0.5%.This study shows that mineral analysis using multiple grain-size fractions(within the wide range of 1Φto 6Φ)with assessment in elemental geochemistry of hornblende can characterize the provenance of fluvial material in coastal zones.

Integrated classification method of tight sandstone reservoir based on principal component analysise simulated annealing genetic algorithmefuzzy cluster means

In this research,an integrated classification method based on principal component analysis-simulated annealing genetic algorithm-fuzzy cluster means(PCA-SAGA-FCM)was proposed for the unsupervised classification of tight sandstone reservoirs which lack the prior information and core experiments.A variety of evaluation parameters were selected,including lithology characteristic parameters,poro-permeability quality characteristic parameters,engineering quality characteristic parameters,and pore structure characteristic parameters.The PCA was used to reduce the dimension of the evaluation pa-rameters,and the low-dimensional data was used as input.The unsupervised reservoir classification of tight sandstone reservoir was carried out by the SAGA-FCM,the characteristics of reservoir at different categories were analyzed and compared with the lithological profiles.The analysis results of numerical simulation and actual logging data show that:1)compared with FCM algorithm,SAGA-FCM has stronger stability and higher accuracy;2)the proposed method can cluster the reservoir flexibly and effectively according to the degree of membership;3)the results of reservoir integrated classification match well with the lithologic profle,which demonstrates the reliability of the classification method.

Dynamic impact properties of deep sandstone under thermal-hydraulicmechanical coupling loads

The deep rock mass within coal mines situated in a challenging environment are characterized by high ground stress,high geotemperature,high osmotic water pressure,and dynamic disturbances from mechanical excavation.To investigate the impact of this complex mechanical environment on the dynamic characteristics of roof sandstone in self-formed roadways without coal pillars,standard specimens of deep sandstone from the 2611 upper tunnel working face of the Yongmei Company within the Henan Coal Chemical Industry Group in Henan,China were prepared,and an orthogonal test was designed.Using a self-developed geotechnical dynamic impact mechanics test system,triaxial dynamic impact tests under thermal-hydraulicmechanical coupling conditions were conducted on deep sandstone.The results indicate that under high confining pressure,deep sandstone exhibits pronounced brittle failure at low temperatures,with peak strength gradually decreasing as temperature and osmotic water pressure increase.Conversely,under low confining pressure and low temperature,the brittleness of deep sandstone weakens gradually,while ductility increases.Moreover,sandstone demonstrates higher peak strength at low temperatures under high axial pressure conditions,lower peak strength at high temperatures,and greater strain under low axial pressure and high osmotic water pressure.Increases in impact air pressure and osmotic water pressure have proportionally greater effects on peak stress and peak strain.Approximately 50%of the input strain energy is utilized as effective energy driving the sandstone fracture process.Polar analysis identifies the optimal combination of factors affecting the peak stress and peak strain of sandstone.Under the coupling effect,intergranular and transgranular fractures occur within the sandstone.SEM images illustrate that the damage forms range from minor damage with multiple fissures to extensive fractures and severe fragmentation.This study elucidates the varied dynamic impact mechanical properties of deep sandstones under thermal-hydraulic-mechanical coupling,along with multifactor analysis methods and their optimal factor combinations.

Exoscopy of Detrital Zircons from Niamey Neoproterozoic Sandstones (Eastern Edge of the West African Craton, Southwestern Niger): Interpretation of Detrital Sediments Provenance

This study focuses on exoscopic analyses of detrital zircon grains of Archean and Paleoproterozoic age, contained in the sediments from the Niamey Neoproterozoic sandstones (Niamey region), with a view to confirming the sediments sources already proposed (Kénéma-Man domain for Archean-age zircons and Baoulé Mossi domain for Paleoproterozoic-age zircons). Exoscopic analysis reveals that Archean zircon grains are more corroded, with rounded to sub-rounded shapes, while Paleoproterozoic zircon grains are less corroded and mostly angular in shape. The strong corrosion of Archean zircon grains, implying long-distance transport, is consistent with the remoteness of the Kenema-Man domain which are the source these sediments. The fact that the Paleoproterozoic zircon grains show little or no wear implies a proximal source of sediments, corresponding to the Baoulé Mossi domain.

Research on Determination of the Main Factors Influencing the Gas Well Post-Frac Productivity Prediction for Tight Sandstone Reservoirs Based on Factors Analysis

With the characteristics such as low porosity, low permeability and low gas saturation, tight sandstone reservoirs almost have no natural capacity and need to be fractured (or fracturing) for productivity. Therefore, fracturing capacity prediction is very necessary. However there were so many factors, and the relations between the factor and the post-frac productivity are complex. In this study, first of all factors are concluded from the gas well stable productivity formula, then I used factor analysis to look for the main factors from the logging parameters and fracturing parameters in SULIGE area. This study could provide basal references for the gas post-frac productivity prediction in tight sandstone reservoirs.

Subsurface Facies Analysis of the Late Cambrian Mt. Simon Sandstone in Western Ohio (Midcontinent North America)

The Cambrian Mt. Simon Sandstone (MSS) is a possible unconventional gas reservoir in the Illinois, Michigan, and Appalachian Basins, but comparatively little is known about the unit. This study used core and well logs from two deep exploratory wells to interpret the depositional environment of the MSS under western Ohio, where the MSS is about 120 m thick and found 1060 m below ground surface. In western Ohio, the MSS unconformably overlies the Precambrian Middle Run Formation, is conformably overlain by the Cambrian Eau Claire Formation, and has a distinctive gamma-ray log-signature. In well DGS-2627, the MSS consists of tan, friable, moderately sorted, rounded, coarse- to very coarse-grained siliceous quartz arenite with minor heterolithic sandstone-mudstone couplets (rhythmites) and quartz granule conglomerate. Features indicative of tidally-influenced, shallow marine settings include tidal rhythmites, lenticular-, flaser-, and wavy-bedding, herringbone cross-bedding, mud-drapes, tidal bundles, reactivation surfaces, intraclasts, and bioturbation. The unit generally coarsens- and thickens-upward, and is interpreted as migration of a tidally-influenced transgressive barrier sequence. A subsurface facies model for the MSS is developed by interpreting geophysical logs and cores from DGS-2627l, and this model is semi-quantitatively tested by first interpreting well BP-4 using geophysical logs alone, then confirming the results using core.

Reservoir quality evaluation using sedimentological and petrophysical characterization of deep-water turbidites:A case study of Tariki Sandstone Member,Taranaki Basin,New Zealand

The current study aims to ascertain the reservoir characteristics of the Tariki Sandstone Member of the Otaraoa Formation,Taranaki Basin,New Zealand.This study was carried out by integrating the comprehensive petrophysical evaluation,sedimentological and petrographic studies,as well as well log analysis by using data from six wells.The porosity-permeability relationship is used to divide the samples of the Tariki Sandstone Member into reservoir and non-reservoir facies.A thorough petrophysical analysis shows that the maximum porosity values fluctuate between 16.6%and 22.1%,while permeability ranges from 102 mD to 574 mD,which indicates fair to good reservoir quality.Moreover,the Tariki sandstone represents six hydraulic flow units with a high reservoir quality index and flow zone indicator representing good reservoir characteristics.The pore size varies between nano and megapores with dominant macropores.Based on the sedimentological and petrographic analysis,the Tariki Sandstone Member is classified as a combination of subarkose,arkose,and lithic arkose with fine to medium and moderately to moderately well-sorted grains.The main diagenetic factor affecting the reservoir quality is cementation,which occupied all the pores with calcite.On the bright side,the secondary pores are developed due to the dissolution of calcite cement and few grains.The well log analysis demonstrates the presence of low clay volume ranging from 0.3%to 3.1%,fair to good effective porosity values between 13.6%and 15.9%,net pay thickness from 18.29 m to 91.44 m,and hydrocarbon saturation from 56%to 77.9%.The findings from this study revealed that the Tariki Sandstone Member possesses fair to good reservoir quality and hydrocarbon potential,which indicate submarine fans as appealing hydrocarbon reservoirs.This study can be used in similar depositional environments elsewhere in the world.

Petrophysical and capillary pressure properties of the upper Triassic Xujiahe Formation tight gas sandstones in western Sichuan,China

The tight sandstones of the Upper Triassic Xujiahe Formation（T_3x） constitute important gas reservoirs in western Sichuan.The Xujiahe sandstones are characterized by low to very low porosity （av.5.22%and 3.62%） for the T_3x^4 and T_3x^2 sandstones,respectively）,extremely low permeability（av. 0.060 mD and 0.058 mD for the T_3x^4 and T_3x^2 sandstones,respectively）,strong heterogeneity,micronano pore throat,and poor pore throat sorting.As a result of complex pore structure and the occurrence of fractures,weak correlations exist between petrophysical properties and pore throat size,demonstrating that porosity or pore throat size alone does not serve as a good permeability predictor.Much improved correlations can be obtained between permeability and porosity when pore throat radii are incorporated. Correlations between porosity,permeability,and pore throat radii corresponding to different saturations of mercury were established,showing that the pore throat radius at 20%mercury saturation（R_（20）） is the best permeability predictor.Multivariate regression analysis and artificial neural network（ANN） methods were used to establish permeability prediction models and the unique characteristics of neural networks enable them to be more successful in predicting permeability than the multivariate regression model.In addition, four petrophysical rock types can be identified based on the distributions of R_（20）,each exhibiting distinct petrophysical properties and corresponding to different flow units.

Sediment transport in the Luanhe River delta:grain size trend analysis

Sediment grain size in the deltaic environment of the Luanhe River(LR),Liaoning,China,contains sediment transport pathway information useful in elucidating the shoreline change and fluvialmarine interaction.In this study,we utilized numerical partitioning of the sedimentary components and geostatistical grain size trend analysis(GSTA)to define the sediment transport pattern in the Luanhe River delta(LRD)and interpolated the sediment transport pattern using content changes of end numbers(EM).EM1(the mean grain size 7.12Ф,fine silt),EM2(2.37Ф,fine sand),and EM3(1.27Ф,medium sand)components were identified by the numerical partitioning by GSTA.Kriging interpolation method was used to interpolate the parameters of the grain size for the regular grid,and the interpolation radius was 0.015 decimal degree.We chose 0.09 decimal degree as the characteristic distance for GSTA in the semivariogram model using the geostatistical method.The FB(-)case(finer,better sorted and more negatively skewed)was adopted in GSTA for its satisfaction in the Global Moran’s I test.The result of the GSTA shows that the sediments in the south barriers(SBs)were transported to the southwest of the study area.The sediments in the north,in the SE direction of sediment transport trend from the river mouth,indicated that the sediments in the north of the study area were transported from the LR to the northern beaches,and to the south and east of the study area.The sediment transport trend that simplified by GSTA as the FB(-)case was approved by the content changes of sedimentary components(i.e.EM1,EM2,and EM3).In addition,the turbulent jet diffusion pattern indicated that the coarse sediments(EM3)were delivered by LR during the flood season,and the EM2 and EM1 were from wave and tide,respectively.

Classification of tight sandstone reservoirs based on NMR logging

The traditional reservoir classification methods based on conventional well logging are inefficient for determining the properties,such as the porosity,shale volume,J function,and flow zone index,of the tight sandstone reservoirs because of their complex pore structure and large heterogeneity.Specifically,the method that is commonly used to characterize the reservoir pore structure is dependent on the nuclear magnetic resonance(NMR)transverse relaxation time(T2)distribution,which is closely related to the pore size distribution.Further,the pore structure parameters(displacement pressure,maximum pore-throat radius,and median pore-throat radius)can be determined and applied to reservoir classification based on the empirical linear or power function obtained from the NMR T2 distributions and the mercury intrusion capillary pressure ourves.However,the effective generalization of these empirical functions is difficult because they differ according to the region and are limited by the representative samples of different regions.A lognormal distribution is commonly used to describe the pore size and particle size distributions of the rock and quantitatively characterize the reservoir pore structure based on the volume,mean radius,and standard deviation of the small and large pores.In this study,we obtain six parameters(the volume,mean radius,and standard deviation of the small and large pores)that represent the characteristics of pore distribution and rock heterogeneity,calculate the total porosity via NMR logging,and classify the reservoirs via cluster analysis by adopting a bimodal lognormal distribution to fit the NMR T2 spectrum.Finally,based on the data obtained from the core tests and the NMR logs,the proposed method,which is readily applicable,can effectively classify the tight sandstone reservoirs.

Grain-size distribution characteristics of red sandy sediments in Dongjiang River valley,southern Nanling Mountains,during the MIS2 stage

Layer LJ3 of Linjiang stratigraphic section in Dongjiang River valley in the south of the Nanling Mountains is a set of red sandy sediments.Measured by thermoluminescence(TL) dating,it was found to be formed in MIS2-9,500 ± 800 yr to 19,600 ± 1,800 yr B.P.After analy-sis of the grain sizes of the 16 samples(LJ3-100 to LJ3-85) in this layer,it was discovered that(1) The contents of each grain group in dif-ferent samples are similar.(2) The values of Md,Mz,,Sk,and Kg vary from LJ3-100 to LJ3-85 in a narrow range.(3) The segments of each sample in the accumulative curves extend parallel with similar slopes.All the three aspects reveal the Aeolian characteristics of Layer LJ3.Therefore,it is thought that Layer LJ3 consists of red sandy sediments formed in MIS2 in the south of Nanling Mountain,which reflects the arid climate at that time.

Textural Characteristics and Depositional Environment of Ngrayong Sandstone (Middle Miocene) from Rembang Area, Northeast Java, Indonesia

Granulometric analysis of Ngrayong sandstone samples from Rembang area of NE Java (Indonesia) has been carried out to examine the textural characteristics and elucidate depositional environment. The result data from the grain size analysis indicates that the Ngrayong sediments are classified as sand or muddy sands. They are very fine- to medium-grained (phi values: 1.67 to 3.35), moderately- to well-sorted (standard deviation: 0.19 to 0.57), strongly fine-skewed to strongly coarse-skewed (skewness values: 4.82 to −5.97), and very platykurtic to very leptokurtic (kurtosis values: 0.36 to 2.41). Sandstone samples show unimodal grain size distribution. The sediments are interpreted to be transported in all three modes-traction, saltation and suspension, however, suspension and rolling are the major processes during transportation. Discriminant functions indicate diversity in the depositional environment for the sandstones. However, shallow marine is regarded as the dominant depositional environment. The preponderance of fine-grained sediments and lack of coarse sands suggest low to moderate energy conditions during deposition of Ngrayong sediments.

库车坳陷日达里克地区铀成矿控矿要素与成因分析

塔里木盆地日达里克地区上新统库车组存在较大的砂岩型铀矿成矿潜力。笔者按照水成铀矿基本理论,充分运用和研究野外地质调查、钻孔资料和微观地球化学等第一手资料,系统总结了区内基本地质条件和铀矿化特征,重点分析了与铀成矿相关的岩性岩相、构造、还原介质以及层间氧化带含矿性等控矿要素,并对铀矿成因和成矿类型进行尝试性探讨,初步分析认为日达里克地区上新统库车组铀矿化与层间氧化带密切相关。

基于主成分自组织神经网络法的测井曲线分层技术

在砂岩型铀矿找矿工作中,提高测井岩性分层效率和精度至关重要。为提高砂岩型铀矿岩性分层效果,本文采用主成分分析法对多个测井曲线进行降维处理,将主成分分析法的第一主成分、第二主成分、第三主成分作为自组织神经网络的样本数据,进行自组织神经网络训练,将训练好的网络模型用于砂岩型铀矿岩性的自动化分层。实验结果显示:主成分自组织神经网络法岩性分层精度可达到85%以上,高于传统自组织神经网络算法78%的分层精度,具有更好的测井岩性分层效果。因此,主成分自组织神经网算法的岩性分层方法有效减少了输入样本的种类,简化了自组织神经网络结构,其自动化分层效果要优于传统的自组织神经网络算法。本文的研究结果表明,主成分自组织神经网算法在砂岩型铀矿领域岩性识别工作中具有较好的应用效果。

基于序关系分析—独立性权系数法的含水层富水性研究

为评价冯家塔煤矿4煤顶板山西组砂岩含水层富水性,选取了山西组富水砂岩厚度、岩心采取率、砂泥岩互层层数、脆塑性岩厚度比、砂岩岩性系数5个影响因素,利用序关系分析法求出影响山西组砂岩含水层富水性的主观权重,利用独立性权系数法求出客观权重,采用乘法合成法得出综合权重,构建了富水性评价模型。结果表明,冯家塔4煤顶板山西组砂岩含水层富水性较强和强富水区域主要分布在井田南部和西部,弱富水区域主要在井田北部及中部小部分区域。通过对比矿井物探、井下积水区及抽水试验的结果,预测模型准确率较高,与实际情况相符。

秋里塔格地区库车组下段砂岩岩石地球化学特征及物源分析

秋里塔格地区位于新疆塔里木盆地库车坳陷南缘,上新统库车组下段为其重要的赋矿层位,然而对其物源分析的研究仍较为薄弱。文章自西向东选取区内已发现较好矿化线索不同地段的库车组下段砂岩样品,进行岩石岩相学及岩石地球化学分析,结合现有地质资料,探讨该区域物源补给特征及规律。研究结果表明,该地层主要由砾岩、砂砾岩、含砾砂岩、粗砂岩、粉砂岩以及泥岩等组成,磨圆以次棱角-次圆状为主,具有近源沉积特征,西起喀拉玉儿滚东至盐水沟,岩屑含量逐渐增多,石英及长石组分减少,粒度逐渐变细。岩石地球化学分析结果显示,砂岩自西向东具有SiO_(2)、Al_(2)O_(3)、K_(2)O、Na_(2)O以及FeO等含量逐渐降低,轻稀土相对富集、重稀土相对亏损以及具有明显的Eu负异常等特征。综上所述,秋里塔格库车组下段砂岩的碎屑组分在横向上变化较为明显,总体而言具有“西粗东细”的特征,物源主要为中酸性花岗岩,沉积岩及火山岩次之,且对各地段的物源贡献自西向东逐渐减小;原岩主要形成于被动大陆边缘构造背景;南天山为研究区北西侧主要蚀源区,提供物源、铀源及有利地球化学环境。

鄂尔多斯盆地西北部下白垩统物源定量分析研究

下白垩统是鄂尔多斯盆地晚中生代的一个重要构造层,同时也是近年来新发现砂岩型铀矿的重要层位。恢复该时期的源汇系统对认识燕山运动晚期在华北克拉通西部的构造沉积响应、古气候转变和盆地内砂岩铀矿的富集规律均有较大的帮助。本文通过对鄂尔多斯盆地西北部下白垩统进行古流向测量、不同层位碎屑锆石U-Pb测年,优化周缘潜在物源区锆石U-Pb年龄数据集的汇编方案,定量计算出各物源区对盆内的碎屑贡献比例,恢复了鄂尔多斯盆地西北部早白垩世的源汇系统。研究结果表明,鄂尔多斯盆地西北部下白垩统中碎屑锆石具有1.79~1.64 Ga、2.02~1.82 Ga和2.58~2.45 Ga 3个稳定的前寒武纪年龄峰值,以及336~257 Ma和476~425 Ma两个稳定的显生宙年龄峰值。定量的物源分析结果表明,阴山、狼山、桌子山贺兰山和阿拉善地区以不同的贡献比例为研究区提供物源,具多物源同时供给的特征。阴山在整个早白垩世一直是主要的物源供给区,与狼山共同向盆地内部提供河流相沉积。阿拉善地区则通过原地风蚀将物质从桌子山北部和贺兰山顶以风沙搬运的方式带入鄂尔多斯盆地,在洛河罗汉洞沉积期共同构成了研究区风成与水成交替的沉积特征。

鄂尔多斯盆地伊和乌素地区环河组砂岩地球化学特征及对物源区、构造背景的指示

为了探讨下白垩统环河组砂岩的构造背景和物质来源,主要通过镜下鉴定和岩矿测试,分析了鄂尔多斯盆地伊和乌素地区环河组砂岩岩石学及地球化学特征。伊和乌素地区环河组砂岩主要成分为石英、长石和云母等矿物,含有少量黄铁矿和炭屑等暗色物质。颗粒磨圆呈次棱角状,分选较差,具有近源沉积的特征。砂岩元素地球化学分析具有SiO2含量较高(平均为71.69%),Al2O3含量中等(平均为12.39%),其他元素含量较低的特点。化学蚀变指数(CIA)平均为60.92,化学风化指数(CIW)平均为68.47,表明源区源岩经历了中等强度的风化作用。微量元素地球化学结果显示:研究区环河组砂岩富集Ba、Th、La和U等元素,亏损Nb、Zr、Ho和Er等元素。稀土元素配分图反映研究区环河组砂岩Eu显示负异常,轻稀土元素富集,重稀土元素亏损,LREE/HREE平均为10.23,La/Yb平均为16.27,LaN/YbN平均为11.65。伊和乌素地区环河组砂岩的母岩沉积构造背景为活动大陆边缘,主要物源区为长英质火成物源区。综合研究认为:伊和乌素地区环河组砂岩母岩物源区主要来自狼山和乌拉山地区。

致密砂岩储层压裂效果地质—工程影响因素评价

我国致密砂岩储层具有巨大的油气储量和开发潜力,水平井水力压裂改造技术是致密砂岩储层开发的关键增产措施。川中—川西过渡带J气田侏罗系沙溪庙组致密砂岩储层受其岩石力学性质及地质力学特征差异影响,相近压裂工艺下各井压裂改造效果差距较大。为提高压裂改造的有效性及针对性,研究了表征岩石力学性质的脆性指数及表征地质力学特征的最小水平主应力、水平两向主应力差3个地质因素对压裂效果的影响。以水平两向主应力差为分类条件,将研究区地质条件由好到差分为Ⅰ类和Ⅱ类;分析两类地质条件下各类工程因素对压裂效果的影响,并给出了不同地质条件下的工程参数优选范围。采用层次分析法和灰色关联法计算了上述地质及工程参数对压裂改造效果的影响权重,建立了压裂改造效果定量评价模型。基于所建模型与压裂改造效果的相关程度,优选层次分析法所建模型用于评价研究区压裂改造效果,并验证上述研究给出的工程参数建议范围的合理性及压裂改造效果综合评价模型的适用性。不同地质条件下水平井压裂工程参数建议范围存在较大差别,地质条件较好的水平井工程参数建议范围明显比地质条件较差的范围更大。优选层次分析法建立了用于评价研究区压裂改造效果的地质—工程综合评价模型。

胜北洼陷致密砂岩气储层分类方法

针对吐哈盆地胜北洼陷中侏罗统三间房组储层岩性致密、孔隙度和渗透率低、孔隙结构复杂、纵向非均质性强、油气水同产、储层分类困难等问题,需要明确储层分类方法,为水平井甜点段优选提供技术支撑。通过以岩石物理实验为基础开展储层“四性关系”研究,优选孔隙度、渗透率、粒度中值、排驱压力、核磁T2几何均值、电阻率和声波时差等资料,利用K-means聚类分析方法进行储层分类。研究结果表明:(1)胜北三间房组岩性成熟度中等,黏土和碳酸盐岩矿物填充孔隙空间,强压实作用导致储层致密,孔隙结构变差;(2)三间房组致密砂岩气藏含油气性受储层岩性、物性、孔隙结构和储层非均质性等因素控制,以粒度中值、孔隙度、渗透率、最大孔喉半径、排驱压力、中值压力和电阻率为参数进行聚类分析,将储层划分为Ⅰ、Ⅱ、Ⅲ类;(3)Ⅰ类优质储层岩性为中粗砂岩、分选好、排驱压力和中值压力低,声波时差和核磁T2几何均值大,孔隙结构好;(4)三间房组储层横向连片发育,纵向非均质强,整体以Ⅱ类储层为主,局部Ⅰ类储层发育,Ⅰ类优质储层富集区的水平井体积压裂能获得较高效益。