(Sponsored by Yangtze University JOURNAL OF OIL AND GAS TECHNOLOGY (JOURNAL OF JIANGHAN PETROLEUM INSTITUTE-J JPl Vol 27 No. 1 Feb 2005 MAIN ABSTRACTS 137 Law of Reservoir Formulation and Exploration Techniques of Natural Gas Lithologic Reservoir in Ordos Xin-shan, HUANG Duo-jun ( Changging Oil field Branch ComPany, CNPC, Xi'an 710021) Abstract: Ordos basin is rich in natural gas resources, which is a large coal-bearing basin. Four giant gas fields, such as Yulin, Sulige, Wushenqi, Mizhi Fields are found out in the basin. Only out, potential for gas exploration is relatively high. In upper Palaeozoic system, the strata including coal bed main con- tain hydrocarbon source rocks. From late j to early Cretaceous, the hydrocarbon source rocks are mature at large scale, and showing the character of" widely-covered"gas-generation. The relatively high-porosity a: d inigh-permeability sandstone of delta distributary channel are mainly reservoir rock, on the background c lo.pon caity and low-permeabil The large-sized lithologic traps made up of many lithologic traps arc in the majority. The gas migration is mainly close quarters, so the forming and distributing of gas field arc controle i by the inter siry of hydrocarbon generation. To he exploration of upper Palaeozoic strata, a series of tec hniques suit of Changqing Oilfield are established. With the ad ent of exploration theory and rechaiq es, a set cf method suitable for low permeability lithologic gas reservoirs ablished in Chengqi: g (ilfiaid Key words: gas reservoir: rule of hyolrocarbon accumulation; Palaeozoic: coal-bearing basin; Ordos Basin 142 Physical Modeling on the Inversion Structures in the West Sag of Liaohe Depression MA Bao-jun, Ql Jia-fu, YU Fu-sheng (Key Laboratory for Hydrocarbon Accumulation Mechanism, (Ministry of Education), China University of petroleum, Beijing 102249 ract: According to the structure characteristics of the west sag fracture in Liaohe Depression two groups of sand box experiments are designed to make full study of the deformation characteristics of the inversion structures in rigid conditions. The experiments show that there is usually a larger scale of inversion under the drive of free-boundary basement and the inversion occurs at the rigid boundary along the original fault. at the free end, no inversion occurs however low-angle thrust fault could be developed. @iNversion develops under miner lateral force, but the scale of inver- sion is usually small. with the increase of angle of the original faults, inversion tends occurs along the single side to both sides at the rigid boundaries. The experiments are approved that the inversion structures in the west sag of the liaohe Depression are developed under the wrench- compressive depressing deformation forces on the downside of the rigid faul Key words: Liaohe Depression: physical model; forcing mechanism; half-graben; inversion structure 153 Control of Gypsum-salt Zone in Structural Formation of Qiulitage Structural Belt and Its Hydrocarbon Accumul FAN Ouhai, LU Xiu-xiang, YANG Ming-hui (China University of Petroleum, Beijing 102249: Key Lab for Mechanism of Hydrocarbon Accu ministry af ON, Beiy ing 102249) Abstract Qiulitage structural belt is divided into east and west sections by Kangcun sliding fault, when the gypsium-salt cone of Palaeozoic in the east and Cenozoic in the west are grown, which have obvious control action on the formation of tructural belt and hydrocarbon accumulation Sliding of the gypsum- salt zone causes the combined structural force turn ing to south from north, the analysis on linear force applied on plain structure indicates that pressing force is the highest in the middle of the structural belt, which describes the great resources pressed to the south of the structural belt. The difference between the east and west gypsum horizons determines that the west is oil enriched, the east is condensate and gas enriched, and the main hydrocarbon accumulation horizons are located under the Palaeozoic system in and its accumulation is mainly located bellows the Cenozoic system in the east. the saltbed as exploration area 201994-2007ChinaAcademicJournalElectronicPublishingHouse.Allrightsreservedhttp://www.cnki.net