Study On Horizontal Well Productivity Prediction Methods Of Volcanic Gas Reservoir

With the growing global consumption of oil and gas resources, declining conventional oil and gas reservoirs.With difficulty of exploration and development increasing, volcanic reservoir of oil and gas resource development to guarantee the supply of global oil and gas resources play a very important role. Volcanic reservoirs are heterogeneity; matrix’s porosity and permeability are low, fractures develop well; conventional vertical well development effect is not very satisfactory. Take Petro China Daqing Oilfield Company’s project "Xu Shen gas reservoir block 21th’sDemonstration of gas reservoir engineering" as the basis, the feasibility evaluation of Xu gas field’s horizontal wells Exploit and analysis of the volcanic gas reservoir in horizontal well productivity evaluation is of great significance.In this paper, I analyze the Geology adaptation of Xu gas field volcanic gas Reservoir’s Horizontal wells.Then I make further analysis of the horizontal well pilot test and finally analysied the feasibility of volcanic horizontal wells,which shows that Xu Shen gas field volcanic gas Reservoir is great to exploited by Horizontal wells.However, conventional horizontal well productivity calculations rarely take into account the starting pressure and rock deformation. Dense volcanic rock matrix and low permeability Determined that fluid’s flow in volcanic gas reservoir mainly depend on crack, when the pressure difference between inside and outside joints become larger, the crack will be gradually closed, thereby it reducing the permeability and reduce the production of gas wells.To solve the above problems, on the base of the conventional horizontal well productivity formula, i take into account the reservoir pressure gradient and the impact of stress sensitivity. Establish appropriate levels of volcanic gas reservoirs Xu well productivity prediction model .At the same time,I use the Horizontal wells data of Xu Shen gas field to calculate their productivity.As the dense reservoir, it need to be fractured. At the same time, the horizontal well productivity requires further account. General fractured horizontal wells could be calculated over a reservoir formula, according to similar principles of oil and gas, to improve it, and take the stress sensitivity and the threshold pressure gradient into accunt.I write VB program on the base of the established model and analysis the factor Affecting productivity of conventional horizontal wells and fractured horizontal well. And then I use the production of existing pilot horizontal wells to verify the accuracy of the model. Finally, Xu Shen gas reservoir newly designed wells’ productivity has been predicted to provide the exploitation of these wells some scientific advice.