Research On Fine Dynamic Appraisal Of Natural Reservoir In Southern Yulin Gas Field

In order to maintain the stable production and realize the highly effective development of southern Yulin natural gas field, the dynamic state of natural gas field must be researched. In this paper, the dynamic analysis clue "’pressure is the soul, reserves is the foundation, deliverability is the core" is used to evaluate the southern Yulin natural gas field and put forward the concept of development block, then the numerical simulation technique is used to forecast the development situation of the southern gas reservoir of Yulin natural gas field.The reservoir pressure is obtained with the reduced pressure method, pressure drop curve method and the mathematical model of pseudosteady state flow method. On the premise of satisfy the calculation accuracy, the contradiction between the shut in pressure test and the production demand is solved which lays a solid foundation for the evaluation of reservoir pressure.In this paper, the dynamic data of gas reservoir production is fully used to establish reserve evaluation methods controlled by gas wells including the dynamic material balance method and function influent method, etc, through re-organize pressure and flow rate to exchange the variable pressure/flow rate production data to equivalent constant pressure/flow rate data basing on conventional pressure drop evaluation method and the adaptability of each method is clearly defined. Thus the dynamic evaluation methods of reserve controlled by gas wells adapt for the Yulin natural gas field are formed.The parameter a of the gas reservoir of southern Yulin natural gas field is calculated according to the modified isochronal test data of60gas wells which lays foundation for the capacity evaluation with single-point method for the Yulin natural gas field. The index method,"AB" coefficient changing method and productivity comparing method are used to evaluate the present productivity of gas wells.The gas reservoir of southern Yulin natural gas field is divided into12development blocks, and the dynamic indicators of the12blocks are evaluated. The division result is applied to the geological model, and the numerical model is set up, and historical matching of172wells is carried on and12blocks is separately forecasted and adjusted accordingly. Under the turbo-charged mining condition, the wellhead pressure reduces from6.4MPa to2.0MPa which makes the period of stabilized production extension and the anticipated recovery ratio increase.