Papers by Keyword: Tight Reservoir

Abstract: Because of the obvious non-Darcy characteristic of fluid flowing in tight reservoirs, there is a virtual moving boundary at the flow edge, and these percolation models of fractured wells with Darcy formula are no longer applicable. Based on the threshold pressure gradient effect, the unsteady seepage flow model of vertical fractured well was established in the drain area by means of Source and Green's Functions. With the flow characteristics at the boundary of tight reservoir, the motion equation of axes of moving boundary was obtained. By Example analysis, its proved that the moving boundary is approximate circular in the far-field, and it will move slower with the increase of the threshold pressure gradient.

Abstract: Petrophysical property cutoff effective reservoir properties can be affected by reservoir properties, crude property, depth, formation temperature, formation pressure and other factors, among which reservoir properties, burial depth and formation temperature are the main factors in effective reservoir development degree of deep tight sandstone, formation pressure has a great impact on the effective reservoir development, while fluid properties have a relatively small impact. The development of oil production technology would reduce petrophysical property cutoff, which will lead to the transformation of non-effective reservoir earlier reckoned into effective reservoir in the future. Therefore, it is necessary in oil and gas exploration to continuously analyze lower limit of effective reservoir physical properties.

Abstract: In general, the scale of production, exploitation period and the economic benefits of oil and gas field are, to a large extent, depended on the selection, deployment and adjustment of well patterns, especially for tight reservoir. So far, some problems exist in Changqing low permeability oil field, such as the effective displacement system is not easy to be established, a low utilization efficiency of injection water, low oil production and so on. Therefore, five kinds of different well pattern schemes are designed. Then, the well pattern schemes are optimized through numerical simulation method based on the exploitation index including the daily oil output per well, moisture content and oil recovery. Results show that the well patterns of horizontal-vertical wells have better development efficiency than the well patterns of vertical wells. For the optimized well pattern, when the horizontal segment length of horizontal well is 300m, the optimalizing well spacing is 400m and the optimalizing row spacing is 100~150m.

Abstract: Reservoir plane heterogeneity means the geometry，the scale，the continuity and the plan variation of physical properties of reservoirs, which is one of the main factors influencing the injection-production in oil reservoirs. Therefore, the study of the reservoir plane heterogeneity play a great role in guiding development wells deployment，gas reservoir well nets adjustment and residual oil & gas development. The reservoir heterogeneity of the sandstone size of gas and the border, and unbalanced formation pressure because of the degree of the development of each well is uneven prevent ChangBei gas field to develoment. They cause difficulty of evaluating the gas field comprehensive，level development wells deployment and well trajectory adjustment，and lead to certain geology risk. It is necessary to study the reservoir heterogeneity of the number 2 of shanxi Formation in this block for concerning the unfavourable extraction condition. The composite index of reservoir plane heterogeneity of the number 2 of shanxi Formation in ChangBei gas field have calculated by adopting entropy method considering influcing reservoir plane heterogeneity which is porosity, tight sandstone, mutation coefficient and variation coefficient of permeability, range of permeability and interlayer frequency. The distributive maps of reservoir's plane heterogeneity under the restriction of sedimentary facies have also been drawed. The entropy method can full use of the reduction and strengthen of entropy method,which means the characteristic of removing the similarities and depositing differences. The study indicate that reservoir plane heterogeneity of the number 2 of shanxi Formation in study area presents the medium to slightly strong characteristics in general.