In present,it is difficult to measure the downhole pressure of gas wells with throttler using pressure gauge,and the liquid level measured using echometer is also not accurate.The downhole pressure calculating formula with throttling effect is derived.The liquid depth is calculated from the relationship between the liquid pressure above the throttler and casing pressure,and then the downhole pressure is obtained by well depth iteration in the annular space between oil tubing and casing.The application cases show that the average relative errors between the downhole static pressure and flowing pressure calculated using this method and those obtained using acoustic pressure testing are less than 2% and 6% separately,and the average relative errors between the downhole static pressure and flowing pressure calculated using this method and those obtained using pressure gauge are less than 9% and 4% separately.The proposed method can conveniently and accurately gain downhole pressure for gas wells,and it is a reliable gasfield dynamic monitoring way.

Coreing from many wells in the region of interest in Liandaowan exploration area have been observed,data from Lian 2 Well,Lian 18 Well,Hua 103 Well and data from logging.Detail study on depositional microfacies of chang 6 of Yanchang formation in Liandaowan exploration area.In Liandaowan exploration area,delta depositional system was mainly developed,especially delta front,in Chang 6 oil-bearing formation triassic.In the north part of the region of interest,delta plain had an advantage.In the region of interest,delta front deposit was in the main place,and could be further classified into subaqueous distributary channel,subaqueous natural levee,mouth bar and interdistributory bay.Delta plain deposit could be further classified into distributary channel,crevasse splay,alluvial flat and so on.

气井的产能是气藏工程中的重要参数，是指导气井调配产和编制方案的主要依据。气井产能通常是通过气井试井来完成的，气井试井周期长、成本相对较高。影响气井产能最主要的因素是储层物性及地层压力，储层物性和地层压力的求取相对容易，前人也做过一些利用测井解释的储层物性、地层压力等静态资料预测气井产能的一些研究。预测产能肯定没有试井产能准确，但是预测产能在井网不完善井区，来预测加密产建能力；新井刚测井后预测产能指导后续的产建工作方面具有积极作用，2009年靖边气田产能建设加大了上古气井建产力度，主要利用丛式井来开上古气藏，一个丛式井场有两到四口井组成，井网密度大大增加，井数增多，试气工作量增大。若能利用静态资料来预测气井产能，一方面节省了大量费用、另一方面缩短了建产周期，因此，本文试图研究靖边气田上古气井产能快速预测方法研究，希望能够解决现场问题。

Based on the analysis of the geo-chemical characteristics of the oil samples collected from Chang 10 member of G52 well in Ansai oilfield,the distribution characteristic of the biomarkers and the oil source of the samples are systematically studied.The results show that n-alkane of the oil samples is characterized by unimodal distribution without even or odd n-alkanes predominance,and main carbon peak is at nC21.The distribution C27∶C28∶C29 ααα20R steranes presents L shaped,and ββ-steranes has high abundance.The abundance of tricyclic terpane is medium,and Ts,C29Ts and 18a(H)-rearranged hopanes have higher abundance and lower gammacerane index.The lower abundance of C31-C35 homohopanes indicates that the oil has high maturity.The compositions and parameters of the biomarkers indicate that the mature crude oil is generated from the lacustrine source rock mainly enclusing lower hydrobionts and lacustrine algaes under the environments of fresh-brackish lacustrine.According to the comparison of the distribution and related parameters of the biomarkers in Chang 10 crude oil with those in the hydrocarbon source rock of Chang 6-Chang 9,it is shown that the characteristics of the biomarkers in Chang 10 crude oil is similar to those in Chang 9 hydrocarbon source rock,so it is held that the Chang 10 crude oil is mainly from the Chang 9 hydrocarbon source rock.

Aim Reservoir modeling technology controlled by sedimentary facies is a practical new technology which can improve the accuracy of geological modeling greatly.The key point is to establish an accurate digital model for spatial distribution of reservoir depositional micro-facies.Furthermore,to simulate the spatial distribution patterns of reservoir parameters,laying a solid foundation for reservoir simulation and remaining oil prediction.Methods modeling for fluvial facies reservoir of the Chang 2 group,Yanchang Formation of the upper triassic in Ordos basin constrained by the temporal and spatial distribution of depositional facies is studied in this paper.On the basis of the depositional facies model constructed by toughly consideration of the facies formation and origin,based upon application of multi-parameter coordination and on different level constraint approach.Results show that reservoir model controlled by depositional facies can truly reflect heterogeneity of the reservoir characteristics and connectivity of the sand bodies.Furthermore,depositional facies controlled reservoir model can simulate underground distribution of hydrocarbon-bearing reservoir properties more accurately and precisely,at the same time,it can provide a reliable basis for oil-pool digital simulation,residual oil prediction,adjustment and exploitation.

Aim To study controlling factors of sedimentation,diagenesis,and diagenetic facies on reservoir quality of the Chang 8 and Chang 6 members of Yanchang formation in Xifeng-Heshui area semi-quantitatively or quantitatively.Methods Based upon detailed description and observation of drilling cores,various modern analytical and measurement techniques including identification of blue epoxy resin-impregnated thin sections,grain size analytical data,electron san microscope(ESM) and capillary pressure for integrative studying of reservoirs.Results Compaction and cementation are the main diagenetic factor which caused the loss of porosity both for the Chang 6 and Chang 8 sandstones.Recrystallization and dissolution are two important approaches to improve physical properties for the sandstones.Five diagenetic facies can be recognized and they are obviously controlled by the depositional microfacies.Conclusion There are obvious differences between the Chang 8 and Chang 6 sandstone of petrological characteristics,physical properties and pore structure features.The fine grain size and high content of argillaceous in the Chang 6 sandstones are internal causes resulted in low-porosity and very low-permeability.

The reservoir of Ansai oilfield was low porosity and low permeability reservoir. The characteristic of the reservoir and microfacies of Chang6 reservoir in H area of Ansai oilfield was analyzed, and the characteristic of the six microfacies include underwater channel, riverside, interfluve, debouch bar, underwater lateral levee, and sheet sand in the area were analyzed in detail. The facies model and reservoir model of the study area were built up by using lots of indicators. The results of the modeling show that ,under the control of facies model, the reservoir model can show the facts underground better, and the model is fit for the work for developing the remaining oil.

Houshi district is one of the important oil field in Ansai oil fields whose regional tectonics are westdipping monoclinal layers,and the Chang-6_1 oil reservoirs are the chief production zones.The analyses on core,grain size,thin section,shape of the log curves show that pre-delta deposition is the main sedimentary system of Chang6_1 in Honshi district,Ansai oilfield.The main sedimentary microfacies including submerged distributary channel,debouch bar,distal bar,front sand sheet and interdistributary deposits were divided.According to the core analysis and well-test results,the submerged distributary channel was believed to be the main reservoir microfacies,debouch bar was the poor reservoir,and front sand sheet was worse reservoir relatively in this area.

候市地区是安塞油田的一个主力区块,区域构造是平缓的西倾单斜,长61油层为其主力产层.根据岩心、粒度、薄片及测井曲线等资料,运用沉积学理论将研究区长61油层确定为三角洲前缘亚相沉积环境,进一步识别出水下分流河道、河口砂坝、远砂坝、前缘席状砂以及水下分流河道间等五种微相.在此基础上结合物性以及试油成果,确定物性及含油性最好是水下分流河道,河口砂坝次之,前缘席状砂相对较差.

Light and heavy mineral combination characteristic,directions of palaeo-flow,sandstone petrography,space distribution of sand bodies of subaquatic distributary channels and sedimentary structure feature were used to analyze source rock,source direction and depositional system of Chang 8-6 oil-beds of Yanchang Formation of the Upper Triassic in Longdong area of Ordos Basin.The palaeo-flow parameters show that the sediments are carried from department by the basin to the center in the depositional period of Yanchang Formation.Three main source directions can be divided according to the light and heavy mineral combination characteristics,as west,southwest and northeastern directions.In addition,there is the secondary source in the south according to ancient flow direction.The quartzite,neutral-basic and neutral-acid volcanic rock,metamorphic rock of Precambrian and shallow metamorphic rock,carbonate rock,gravel rock of Palaeozoic group from basin outer edge are the source rocks.The depositional system of Chang86 oil-beds of Yanchang Formation of the Upper Triassic in Longdong area can be divided into four systems.One of them is Wuqi-Huachi delta depositional system from northeast;others are Huanxian fan delta depositional system from west,Zhenyuan-Jingchuan braided delta depositional system from southwest and Heshui-Guchengchuan turbidite fan depositional system from south.On the basis of the depositional systems,petrographic characteristics,sand body pattern,sedimentary structure of different depositional systems and the evolution process of the depositional systems are elaborated in detail.