Study Of Reasonable Well Pattern For Daniudi Shan1 Gas Reservoir

According to the exploration and development practice, Daniudi gas field has special geologic condition,most of the reservoirs have low porosity,low permeability,high water saturation,strong aeolotropism,low production and low pressure. Daniudi gas reservoir has great geological reserves,but its special reservoir conditions induce that the individual well producing rate is low,result in the pressure drop quickly and unstable production. This is the problem of exploration and development. These characteristic induce that lots of reservoirs cannot develop on time. At the same time those bring a lot of difficult to determine the rational spacing between wells. In order to enhance the gas recovery ratio , we need a deep recognition of the gas reservoir geologic condition,and then establish rational well patterns。In view of the low permeability oil and gas reservoirs, establishing a reasonable well pattern is the key point to develop the oil and gas reservoirs of low permeability. Daniudi Shan 1 gas reservoir has strong aeolotropism on plane and vertical direction. Symmetrically arranging wells can get high gas production. Some reservoirs have great effective thickness,high permeability, high reserves abundance. But some reservoirs are thin, low permeability and low reserves abundance, such as the side of structure. Furthermore, some reservoirs have low well density and are lack of control in the plane. So we symmetrically arrange wells at the beginning of the development. After many years of development of Daniudi gas field, it goes to the end of stable production at present. In order to better tap the potential of gas field development, we must to adjust the development well patterns.Base on the geologic reserves of Daniudi gas field Shan 1 reservoir, this paper evaluate the current development well patterns. According to the evaluating of the geologic reserve,conclude that the plane control grade of Shan 1 geological reserve is only 59.06%,that is very low. There is large gas geological reserves of Shan 1 gas reservoir, but reserve property is poor, individual well producing rate is low. Beside,the well patterns are not perfect now. These factors induce the low of the gas production rate and the degree of reserve recovery. Analyses well distance of current production well, we can see the places which sand body combine have good reserve property, and have reasonable well distance, but at the edge of the sand body, the well patterns is not perfect.Begin with the geologic property of Daniudi gas field Shan 1 gas reservoir, it analyses some factors that influence arrangement of well patterns. The factors have five aspects. Those factors are precipitation facie,flowing unit, reserve styles, development layer series combination and fracturing scale. In the end, this paper studys the distribution of remaining gas through the numerical reservoir simulation. On this basis, we get the scheme of adjusting the well patterns, then optimize and choose a perfect scheme. The perfect scheme increases 19 new wells , mainly increase the well networks at the edge of the sand body. Through this scheme,the gas reservoir enhances the average control degree of the reserves. We prognosticate that it will increase output gas production 4.33 million cubic meters,and the degree of reserve recovery will get to 14.61% on Dec,2015.