Study On Reservoir Characteristics Of Niuxintuo Buried Hill Reservoir

Buried hill reservoir is widely distributed in the Liaohe basin, Liaohe Oilfield, after decades of exploration and development, has found a lot of carbonate rocks, igneous, metamorphic complex lithologic reservoirs, and has achieved a high-yield industrial oil flow in these complex lithology reservoirs, which gained significant economic benefits. With increasing demand for oil and gas resources around the world, complex lithologic reservoirs have gradually become an important area of exploration and development.This paper studies Niuxintuo buried hill reservoir from Western Depression of Liaohe rift. Niuxintuo oilfield is located in Huandong Country of Taian County in Liaoning Province; the tectonic position is in Niuxintuo fracture anticline belt which lies in the northern part of western depression in Liaohe Basin. The reservoir thickness is remarkable, containing various types of lithology and complex structure in buried hill, not only developing the Mesozoic volcanic and magmatic rocks, but also developing the Archean regional metamorphic and mixed rocks. An angular unconformity contacts with Archean is erosion of Mesozoic sedimentary rocks and volcanic rocks of residue cover on top of Archean. Inside area of Niuxintuo buried hill reservoir has characteristics of multi-stage fracture cut and vantage reservoir identification difficultly of reservoir.Buried hill fracture development controls by multiple factors, such as the structure and lithology,with The lack of system analysis of interbeds reservoir distribution, which is unclear about the horizontal distribution and vertical distribution. Facing constantly in-depth of development research in buried Hill reservoir, it is more important to carry out full detailed of research on this district reservoir geological content, and today parts of the geological situation is lack awareness, thus can’t meet needs of efficient development, coupled with high cost level and big risk of well implementation,, so it is essential to carry out continues research analysis of reservoir geological content, to reach purpose of keeping reservoir’s high stable yield and improving reservoir development effect.Through the study of Niuxintuo buried hill reservoir, the following findings are mainly made:Firstly. Petrological characteristics in the study area of buried hill, at this area based on cores, cuttings, observation and identification, using log data analysis, guided by identified rocks in Niuxintuo buried hill reservoir which have main types of metamorphic rocks and igneous rocks, including Archean metamorphic rocks and Mesozoic volcanic igneous rock. Those types are Gneiss class (plagioclase gneiss, corner black cloud Flash-plagioclase gneiss),Amphibolite class (plagioclase amphibolite, and amphibolite), also contains a mix of gneiss and migmatitic granite migmatite, dynamic metamorphic rock (cataclastic breccia and rocks), mafic rocks (andesite and diabase).It has diverse types of rocks and the distribution is more complex with various sizes.The second.through the study and extraction of buried hill metamorphic rock logging data, we gain logging curve characteristics of different rock types, using natural gamma logging curve, neutron porosity logging and density logging curve, logging data to buried hill migmatite, granite, gneiss, amphibolite and basicintrusive rocks are distinguished recognition, and establishes the identification standard of different rocks.The third. Through study of drilling cores and flakes observation in buried hill, we determine the developmental characteristics of buried hill cracks. Studies have shown that buried hill reservoir space includes dual media pores and cracks, but the main body is crack, with different crack types, including high-angle fractures, oblique slit, horizontal seams and mesh cracks which split with oblique slit oriented. Rock type joints most developed mixed granite, followed by mixing rock, amphibolite and diabase least developed cracks.Fourthly.The major determinant factors of fractured reservoir space are rock types, physical properties and pore structure characteristics, on this basis the metamorphic reservoir is divided into three categories:Class I crack porosity reservoirs are well developed to reflect. Class II reservoir reflects a certain physical properties, but was poor. Class III non-reservoir fractures are not developed.In summary, by studying the papers, we have further understanding of Niuxintuo buried hill reservoir, combined with regional geology, through reservoir characteristics of core research, lithology, logging data, comprehensively identified hill petrography, buried hill reservoir space characteristics and developmental characteristics hill cracks. According to petrography, measured physical characteristics and pore structure characteristics, the Archean metamorphic reservoir is divided into three categories. Therefore, this study is not only deepen the understanding of the geological foundation of Niuxintuo buried hill reservoir, but also provides a good study idea for the exploration and development of similar buried hill reservoirs.