西南石油大学学报(自然科学版) ›› 2020, Vol. 42 ›› Issue (4): 121-126.DOI: 10.11885/j.issn.1674-5086.2019.03.21.02

• OIL AND GAS ENGINEERING • Previous Articles     Next Articles

Improvement and Solution Binomial Production Equation of High Pressure and Low Permeability Gas Wells

MA Shuai, ZHANG Fengbo, WANG Wenjuan, ZHA Yuqiang, WANG Yanli   

  1. CNOOC China Limited, Zhanjiang Branch, Zhanjiang, Guangdong 524057, China
  • Received:2019-03-21 Online:2020-08-10 Published:2020-08-10

Abstract: The gas reservoir pressure in Ledong X Area of the western South China Sea is up to 100 MPa and permeability is as low as 0.1 mD. The binomial productivity equation slope obtained from the productivity test regression of such high pressure and low permeability gas wells is often negative, and the real productivity cannot be obtained. The production binomial's slope of high pressure and low permeability is always negative which results in failure to get real capacity. The gas well testing process is analyzed and the material balance model within the effective supply range is established and solved. It is considered that except the first level system, the formation pressure changes with the output and time, and the lower the permeability of the formation, the greater the pressure change. The traditional binomial method does not consider the formation pressure change is the main reason for the negative slope of regression. Taking into account the formation pressure drop in the effective supply range during the test, the new binomial equation of deliverability and the expression of unobstructed flow are obtained by regression. It is considered that the unobstructed flow in the gas well is related to the original formation pressure, test conditions and formation physical properties. The correction of the binomial production equation of six high pressure and low permeability wells, such as LDX-5-A, has successfully solved the production capacity anomalies in this type of wells, provided a basis for rational development of gas fields in the next step and a solution to the abnormal capacity correction of such high pressure and low permeability gas wells.

Key words: high pressure, low permeability, gas well, binomial production equation, material balance

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