Research On Gas And Water Distribution And Controlling Factors Of Jia-2Gas Reservoir In Moxi Gas Field, Central Sichuan, China

Basing on cores, flakes, properties and well testing data, the paper comprehensivelyresearched on gas and water distribution and controlling factors of Jia-2gas reservoir in Moxigas field. This paper has made the following main achievements:(1)Moxi structure is a short gentle anticline, which has few faults. The structural traps ofJia-2are mainly anticlines, secondly small-scalenasal structures.Moxi buried structure is theprincipal trap structure, which contains two major buried high structures: Dengjiawan andBuchungou buried high structures.The trap type of Jia-2gas reservoir trap is lithology-structural trap. By using balanced cross-section, figures of tectonic evolution of each sectionare made, combined with the previous two-dimensional seismic studies, this paper believethat Moxi structure has undergone tectonic movement of Tong Bay, Caledonian, Soochow,Indo-China, Yanshan, Himalayan and so on.(2)Combined with previous research experience,this paper, systematically summed upthe small layer division scheme and interface features of Jia-2section.Jia-2stratum can bedivided into T3j21, T3j22A, T3j22B, T3j22C and T3j23.(3) By using the data of conventional reservoirs,this paper analysised the characteristicsof Jia-2complex carbonate reservoir: The main reservoir rocks are clay powder dolomite,oolitic limestone, powder dolomite and doloarenite; The most important reservoir space typesare intergranular pore, intergranular pore and intragranular dissolved pore. Jia-2reservoir isporosity reservoir that locally developed cracks,and the main types of reservoir are type Ⅱand type Ⅲ. Overall a low porosity and low permeability reservoir area,but high porosityand permeability reservoir also have a certain proportion. Their porosity and permeabilityrelationship is more complex, T3j21and T3j22A have a similar porosity and permeabilityrelationship and permeability increases slowly with increasing porosity;While T3j22B, T3j22Cand T3j23have a close porosity and permeability relationship and with the increase of porosity,permeability increases rapidly. (4)The wells of Jia-2gas reservoir in Moxi gas field are mainly gas and water producingwells.There is a situation that water producted in high structure and gas producted in lowstructure. But gas and water distribution and differential degree still have some kind ofdivision: In the south wing, the gas reservoir development performance is the gas-based orwater-based, and there is a clearer air-water interface; North wing structure generally exhibithigher water production due to the low intensity of gas filling and the moderate structure;While gas and water distribution in the shaft of structure is mainly related to the reservoirproperties and reservoir development site,and gas gathered to high structure which havebetter properties prior.(5) Integrated structure, trap types, reservoir and gas migration characteristics research,this paper proposed gas and water distribution and controlling factors of Jia-2gas reservoir inMoxi gas field:①Structural characteristics controls the overall of gas and water distributionarea;②Reservoir characteristics controls gas and water distribution and extent ofdifferentiation;③Transport characteristics controls enrichment degree of gas.