Productivity Evaluation And Recovery Calibration Of Gas Wells In QK Deep Gas Condensate Reservoirs

QK gas reservoir is a condensate gas reservoir with high temperature,high pressure,low permeability and medium condensate.It has complex geological characteristics such as deep burial,poor physical property,low surface pressure and great variation of condensate oil content.In the development process,gas wells generally exist such problems as low productivity of single well,rapid production decline,easy accumulation of gas wells and difficult production of stable gas wells.This paper is based on a large number of domestic and foreign literature research of condensate gas reservoir,using modern reservoir engineering theory,the integrated use of gas reservoir engineering,test analysis and other disciplines theory and methods,combined with QK gas condensate reservoir static and dynamic characteristics of exploitation,mainly carried out the productivity evaluation and recovery calibration.Firstly,using the conventional binomial productivity equation,quasi single fluid binomial productivity equation,a method combining the gas well deliverability equation,the initial test data,the production of QK 15 wells calculated results for gas well early open flow capacity range(2.0?22.0)×104m3/d,the average is 10×104m3/d.the capacity difference between wells and well.at the beginning of the actual gas production range(0.6?4.0)×104m3/d.Using quasi single fluid binomial productivity equation in early testing data curve will encounter abnormal situation,need to introduce the pressure loss coefficient of C modified 7 wells abnormal test data,using gas reservoir engineering method is modified by 7 wells capacity range is(2.4?31.9)×104m3/d,with an average of 16.4×104m3/d.Then combined with the gas wells currently well test data,using the quasi single fluid binomial deliverability equation and one point method for deliverability equation capacity calculation of QK block of 15 wells,the results showed that the gas flow current range(0.09?4.4)× 104m3/d,the average is 1.57x 104m3/d.the gas production capacity range(0.11?1.68)×104m3/d.The unimpeded flow rate of each gas well is lower than that of the initial open flow,and the average decrease is 88.32%,which indicates that the retrograde condensation phenomenon has great influence on the productivity of the condensate reservoir.It is considered that the unhindered flow calculated by the quasi single phase flow method is reliable and can be used as the basis for the later distribution.Using the experience method,gas production curve method,the critical liquid carrying flow method.node analysis method of reasonable production calculation of bridge 69-5 wells,the yield is(0.44?0.55)×104m3/d,0.59×104m3/d,0.76×104m3/d,0.65×104m3/d,to determine the reasonable yield of 0.76×104m3/d.At the same time,using the experience method,the current distribution range of 21 wells is(0.02-1.02)×104m3/d.Secondly,the condensate gas and condensate oil recovery of QK condensate gas reservoir Q14,Q69 andQ58 are calculated by using 3 methods of analogy,empirical formula and analytic method.The empirical formula method is used as the recovery rate of the 3 fault blocks.The condensate gas recovery rate of Q14,Q69 and Q58 is 60.52%,61.33%and 64.73%respectively,and the recovery factor of condensate is 40.09%,42.96%and 47.01%,respectively.Using material balance method hungter recovery calculation of the whole gas reservoir,condensate gas by mining and condensate oil recovery were 72.91%and 42.59%.The decrement formula is used to predict the annual gas production of the block,which is consistent with the hyperbolic decline rule.The calculated recoverable reserves of the condensate gas in the block are 3.4×108m3,and the recovery is 64.18%.The annual oil production decline accords with the law of harmonic decline.The recoverable reserves of the block condensate oil are 4.9163×104t and the recovery rate is 27.89%.The use of HCZ,Hubbert,HC,Logistic a total of 4 kinds of model fitting the whole month gas reservoir gas production and the monthly production rate changing with time,choose the best fitting results of HC model to prediction of condensate gas and condensate production,get the recoverable reserves of 2.599×108m3 gas condensate,1he recovery rate was 46.42%;the condensate oil recoverable reserves of 4.72×104t,the recovery rate was 26.77%.