Study On Rational Countermeasures Of Development Technology In Fracture-Cavern Gas Reservoir With Bottom Water

With the increase of gas productivity and the number of gas wells containing underground water, more and more attention have been paid to the study of development countermeasure of gas reservoir with bottom water. The Z system gas reservoir of WeiYuan gas field is the representative of fracture-cavern carbonatite gas reservoir with bottom water, whose reservoir was composed of cavern, fissure, and has the characteristics of low porosity, low permeability, strong heterogeneity and gas reservoir with active bottom water. Aimed at the actual problems within the development of Liao Jiawan high Zdn gas reservoir in WeiYuan gas field, the geology data, logging data, and dynamic production data were used to research gas reservoir engineering, of which mainly were to compute and evaluate reserve, productivity evaluation and development project and so on. Through this study, we found the following:①Based on the analysis of dynamic production data and geology of Z system gas reservoir in WeiYuan gas field, the volumetric method was taken to calculate the geological reserve of current Liao Jiawan high in Z system gas reservoir, combined with flowing material balance method and four kinds of typical curve fitting, the reserves was rechecked.②According to the actual development situation of Z system gas reservoir in WeiYuan gas field, integrating the geological research result of drilling and logging, layered data,small layer of structured and net thickness, using the technology of random modeling method and continuum fracture simulation, the geology structure of district, Parameter model of reservoir, distribution model of fracture. We found that the largest of porosity and permeability was in high tectonic spot, while southwest was the second, and become lower in the surrounding gas reservoir; and cavern was developed in Z2dn2 and Z2dn3; fracture was developed in high tectonic spot and anticline, this was consistent with the geological understanding.③Aimed at the characteristics of Z system gas reservoir in WeiYuan field, the rational development scale and prediction of dynamic gas field development were put forward using the method of gas reservoir engineering, combing the dynamic production data and simulation study of gas reservoir. The main countermeasures of development technology were as follows: 1) Upon the stratum energy and extraction situation of gas reservoir, the vertical well and horizontal well were chosen, and the production rate of which was 4×10~4m~3 per day and 6×10~4m~3 per day respectively.2) Based on the form of current well network of Z system gas reservoir, combined with actual geological situation of gas reservoir, the deployment of well network of Liao Jiawan high in Z system gas reservoir should accord to the principle of"San Zhan San Yan", take the uniform pattern of well network, and the rational well space should be between 700m and 800m.3) The development influence of horizontal well on producing degree of gas reservoir, recovery and gas production were analyzed, development project of water drainage and gas production of horizontal well, the horizontal length of horizontal well were determined, the rational horizontal length of horizontal well was between 500m and 600m.4) After comprehensive analysis of the distribution of remaining reserve and geological situation of every layer, the suggested development plan was to add three vertical wells and five horizontal well.