Tight carbonate gas well deliverability evaluation and reasonable production proration analysis

Jiang Li,Ping Gao,Jingchao Zhou,Xianchao Chen

doi:10.1007/s13202-021-01222-1

Abstract

It is very important to accurately predict the gas well productivity and reasonably allocate the gas production at the early development stage of gas reservoirs. However, both the non-Darcy and stress sensitivity effects have not been investigated in dual-porosity model of tight carbonate gas reservoirs. This paper proposed a new dual-porosity binomial deliverability model and single-well production proration numerical model, which consider the effects of non-Darcy and stress sensitivity. The field gas well deliverability tests data validated the accuracy of the new analytical model, which is a very helpful deliverability method when lacking deliverability test. A geological model was built on the results of the well log, well testing, and well production analysis. Then, a reasonable production proration analysis was conducted based on history matched single-well numerical model. The gas productivity index curve and production–prediction of MX22 several simulation cases were adopted to analyze the reasonable production proration. The results indicate that 1/6 may be suitable for high productivity gas well proration. In addition, the absolute open flow rate from the numerical simulation is higher than that from the new deliverability equation, which also shows that the pressure transient analysis sometimes has some deviation in formation property prediction. It is suggested comprehensively utilizing the analytical binomial model and the single-well numerical model in tight carbonate gas well deliverability evaluation.

Highlights

The development of tight carbonate gas reservoirs usually goes through three stages: early production building, middle stable yield, and late production decline
Gas well deliverability evaluation and reasonable production proration analysis play an important role in reservoir production management (Jia, 2017)
The new dual-porosity gas well deliverability model can make a reasonable prediction based on the well build-up test interpretation result, which is a very helpful deliverability method when lacking the deliverability test data

Summary

Introduction

The development of tight carbonate gas reservoirs usually goes through three stages: early production building, middle stable yield, and late production decline. The reservoir characteristics make it difficult to accurately Both the non-Darcy and stress sensitivity effects are key in evaluating tight carbonate gas well productivity. A new dual-porosity binomial deliverability model was proposed to consider the effects of non-Darcy and stress sensitivity. Based on the above motion equation, a binominal deliverability equation was proposed for vertical gas well productivity evaluation considering the inertial effects around the wellbore (Houpeurt, 1959) This conventional binomial deliverability equation was widely used for conventional gas reservoir well productivity calculation. A matched fracture dynamic permeability equation was used to describe this effect (Shusheng et al 2015) They proposed a stress-sensitive relationship against crack-type carbonate reservoirs. Deliverability testing is the most accurate method for well productivity evaluation It can be calculated by directly taking the pressure transient analysis results into the deliverability equation.

Findings

Kf 2i rw2 Km1i

Discussion