Qikou Depression Subtle Reservoir Research And Prediction

The subtle reservoir is more and more bigger at the abroad and internal specific proportion occupying, especially in nearer years, along with constantly developing of subtle reservoir theory, the fine description technology of container rock constantly raises, and the high-resolution three dimensional seismic is gathered the advance of handling ability, and subtle reservoir has surmounted the structural reservoir, and becomes the central reserves increasing a little, and makes the contribution for the resources to relieve our country are in short supply. The largest seg of Dagang Oil Field, Qikou seg, is regarded the research object of this text, and taking three units theory of reservoir for foundation, starting with from the sequence stratigraphy method, and applies the research means that traditional method combines the new method of physical geography, what the system was gone deep into has been in progress the research, the result it is to gain inspiring. Article was discussed 4 subjects of aspect altogether:1 The basic geology condition of become reservoir of the Qikou seg areas subtlereservoirsAccording to the cause of formation mechanism of three units theory of reservoir, this essay has been in progress thoroughly analyzing to the interior unit, outer unit and environment unit of Qikou seg.1. 1 Environment unit (the condition of trap). 1.1.1 The sand body of pinchout lithological traps that grows in the slope area. It easily forming the pinchout reservoir, it often growing in the gentle slope and steep slope area on slope, and is the transition area of seg and relief (uplift), and also is the unstable area of structural movement and the pivot area that the sediment stratum changes, the denude of stratum with the change of stratum thickness makes trapping complication. 1. 1.2 lithological traps plugging by the fault on the two side of fault. This easily forming the lithological reservoir plugging by the fault in the steep slope in slope area. Faults generally are 3-4 grades, and ask the fault side direction has a good plugging ability. 1.1.3 The lens body lithological traps forms in the deep seg area: there easily forms the lens body lithological reservoir. This kind of type reservoir exists in the deeply seg area more, the sand body surrounded by the non-permeability mudstone can forming traps. 1.1.4 The lithological traps plugged by face of Discontinuity: easily forms the overlap reservoir on stratum. The traps forming this kind of reservoir exists in the gentle slope area of slope area more, the sand body overlap sediment forms above the base plate stratum not permeated traps. 1. 1. 5 The river facies winding banding sand body traps of Neocene: it chiefly growing at the Neocene river facies stratum, the sand body assumes a banding distribution, and connect with the source fault can forming the reservoir at the higher position of sand body.1.2 Interior unit (container rock condition). When the Tertiary was sedimenting, the Huanghua depression was controlled by three sources, the northern Yan Mountain, the western Cangxian uplift and the southern Chengning uplift as well as part thing source of internal relief, and formed three kinds of sedimentary systems and forms three kinds of optimum reservoir bodies.1. 2. 1 Near bank sedimentary system. The basin has been developed to the basic unified big lake during the Shahejie series sediment, and to foundering and expands is the main characteristic of his structural movement, and for the sediment provides jumbo holding space. The ancient land form of periphery is complicated, and mostly for the hills mountainous region, the lake can directly be gone into by the broken bits from land that come from the south side Chengning uplift, and forms the Yangerzhuang near bank fan sedimentary system under water. The broken bits comes from basin incomplete mounds and isolated islands match the lake water front formed beach (bar) sand bodies along the oblique position of Nandagang, Wangxuzhuang, Koucun, Kongdian and Yangsanmu etc ancient uplifts.1.2.2 The sedimentary system of Deep-water lake basin. The delta from northwest land through slippery collapses and rehandling went to the deep lake area and formed turbidity bodies. The influence in the north Yan Mountain thing source, and easy forms the gravity flow channel sand body of the Banqiao oil series along northern east flutes. This area gravity flow channel sand body chiefly distributes at the Qikou seg eastern edge of northern Dagang, 180km~2 is made an appointment with by area, and the place on layer is the Ban 2 and 3 oil series.1.2.3 Alluvial system of river. It indicated the alluvial fan and the channel deposit, and forming alluvial fan sandstone and channel sand bodies. Channel sand bodies chiefly grow at the Neocene, and the structural movement this moment thoroughly changed the sediment landscape of this area, and the lakes environments by the growth over a long period of time change to the alluvial environment in continent.Alluvial facies sediment sand body is extensively grown, and stratum only thickness difference on the plane docs not have hig rock each other to be distinguished.1.3 The outer unit (oil source and the travel condition). The Qikou seg is the largest oil seg in the Huanghua depression. And the Eogcne is half deep lake - deep lake facies's sediment environment. The water body is stable, and the basin in lake widens, and the life living things in lake arc very grown, and forming mixing inclined to one side decay ooze's mould peirologen, the source sequence is many, growing four sets of source sequences (Cs^, i:s2, Ks1, Ed). the genrating rock volume and effective source capacity is big, and the source capacity is measured to 69% of whole Huanghua depression source capacity of 178.99 X l08t.This area oil gas travels including the side direction and vertical and break three kinds of types.2 The exploration technique of subtle reservoir.2. I The high-resolution seism collects technique.Because the current seism data quality is bad, the signal to noise ratio is low, the resolution is low, wave characteristic is unknown to show, resulting the difficulty to identify the lithology trap and the special lithologic body, canning not satisfy the main target stratum seismic interpret with the demand that synthesize the geology evaluation. Therefore, the demand process the high-resolution seism collects.2.2 The three dimensional seismic data connects technique cind the technique of fine handles with the targetThe three dimensional seismic data connects technique and the technique of fine handles with the target give an impetus to the search of subtle trap. The three dimensional seismic data connects technique resolved some accurate problem because of crossing many three dimensional areas and suffering the data quality difference limit in interpret.2.3 Fine structural interpretation technique in three-dimensional seismic data. At the stage of subtle reservoir exploration, is the stage of structuralinterpretation turns into fine interprets in target and lithologic bodies gradually, accuracy of interprets increases with the technique. The main technique includes: The seismic wave velocity analysis technique, fine horizon calibrate technique, variance technique, many data volume integrated interpretation technique, three dimensional visualization technique etc.2.4 The technique of reservoir predicts.The technique of reservoir predicts was extensive applied in the exploring of the subtle reservoir, according to characteristics and stage in different researches of the Qikou region, made use of primarily the reservoir inversion technique, seismic waveform analysis technique, seismic attribute analysis technique, frequency division interpret technique etc. various techniques. Wave impedance inversion basis the well logging data, regard seismic data as to control, pass the track around well proceed with well logging data the related analysis, finding out the best relation, in order to set out to push gradually and outside from the well, it have the clear and definite physics meaning, is a key technique 1 hat reservoir predicts, reservoir characteristic describe. The Stratimagic seismic stratum interpret the software package is a kind of new seismic to used for stratum rock explanation to describe with the reservoir estimate to explain the system, it make use of the seismic track waveform character, character of an actual seismic data proceeding a contrast, delicacy depicting the horizontal variety of seismic signal. Gets the flat surface distribute regulation of excrescent seismic body; The seismic attribute technique abstracts the information concerning straiigraphic lithology, reservoir physicalcharacters and attributes of the fluid that conceal in seismic data, and these attributes information can transform into reservoir characteristic, passes this method finding the regulation of reservoir distributes. The interpretative technique of frequency division proceed the instant spectrum analyzes according to the wavelet transformation with the seismic data, its amplitude spectrum can describe the variety that reflect the bed thickness, and the phase spectrum expressed the last horizontal discontinuity in geology.3 the dividing of sequence and the advantageous area selecting.The Qikou seg is located the Huanghua depression central section, the Tertiary chiefly grows the Minghuazhen series, Guantao series, Dongying series and Shahejie series etc. Combining the sequence stratigraphy theory, and data such as well logging, well drilling and seismic etc, the Qikou district Eogene to the Dongying series went through the water level change of big two times from the Shahejie series, and being rising from the whole Mesozoic Erathem stratum exposes the earth's surface to the water level, the water body enlarges, and the Shahejie series stratum begins the sediment. Water that occurs the once full area moved back in Shasan section stratum sediment last phase, and accepts eroding until the Shasan section stratum exposes the earth' s surface, and chiefly formed a low system land, lake entering system land and the high position system. Secondly the Sha'er section stratum begins sediment, until in last phase the Dongying series sediment occurs large-scale water moving back, and that the stratum exposes the earth' s surface begins accepting eroding. Therefore the stable mudstone section inside second sections of Dongying series and Shasan section is two the most general faces of big lake.Passing to the synthetical analysis of protruding area, gentle slope area and steep slope area and seg area, Dividing out three advantageous areas:The Qinan district sand body of gentle slope and steep slope: In the course of the water body sense of propriety of many phases. Sand body of sediment many overlaps the basin boundary of lake or the forms pinchout lithological sand body, and can to form mass lithological traps.Slope of Qibei area: Chiefly means the area of Nandagang fault to the slope area of Qibei seg, exploring the layer ties to the Shayi and Shasan section.Neocene' s target beside the Second class fault is an important area to take. Second class fault in Qikou growth, seg edge with internal growth Yangerzhuang fault, Zhaobei fault, Nandagang fault, Yangbei fault, Gangdong fault etc, the growth of second class fault makes its have to become the Neocene secondary hydrocarbon reservoir. The Neocene structure-lithology trap in two side of fault is an important target.4 Subtle reservoir preliminary prospecting target evaluation.This text passes to evaluate with Qibei slope region Shahejie Formation preliminary prospecting target and Neocene preliminary prospecting targets to the Qinan region, discovers totally 35 beneficial traps, passed to synthesize to analyze optimization 10 among those targets proceeding to put into practice, increase to control totally oil-bearing area 10.7 km',and control geology reserve 880X10"t.