Study On Development And Adjustment Scheme Of DK13 Low Permeability Gas Reservoir

The design of development plan and its adjustment scheme is so crucial for gas field development that reasonably designing a set of field development project or development adjustment scheme can effectively reduce the investment cost, maximize the overall development efficiency of gas field and increase economic benefits.Since2005, DK13gas reservoir has been put into production for over7years. It has entered decline stage at present, which makes it difficult to maintain stable production. With the continuous development and further geological research, we gradually realized that there are uncontrolled geological reserves between wells. Moreover, there are untapped reserves between layers, because of the predomination of single layer mining in H3, S1with large thickness and fine reservoir physical properties. So that the current main target of development adjustment is how to improve the reserves produced degree and maximize the ultimate recovery.For DK13gas reservoir, on the basis of analyzing production data, this paper analyzed the law of gas production, water production and pressure changes, and evaluated development indexes like rational gas production rate and production pressure, and single well controlled reserves. And then the reasonable adjustment thinking was presented on the basis of grasping dynamic characteristics and reserves produced degree of gas reservoir. Moreover, a numerical simulation model was built to clarify the remaining gas distribution, and to make simulation and prediction by using different adjustment plans. And then the most optimal solution can be selected by comparing the predicted results, which can provide technical support to further increase of the ultimate recovery.According to the analysis results of gas reservoir engineering methods, the idea for adjustment was concluded:for the produced reserves, pressurization stimulation will be used to improve gas well recovery; for the untapped reserves, the producing degree can be increased by drilling infill wells, reperforating, and supplemented by fracturing and pressurization and other measures. On the basis of this adjustment idea,15sets of adjustment programs containing reperforation, pressurization, infill wells were designed. By comparing the results predicted by numerical simulation, the optimal adjustment program including encryption horizontal wells, encryption vertical wells, reperforation and pressurization was ultimately recommended. In this program,204×104m3of daily gas production can maintain for2years, the final recovery degree is56.25%. The daily gas production is improved by45×104m3compared with gas-based schemes and the stable period is extended for another two years, and the final recovery degree is increased by17.42%.