Research on the flow law of shale gas in horizontal wellbore: Taking C01 well area as an example

Objective In the middle and late stages of shale gas well development in C01 well area, natural energy is insufficient and wellbore fluid accumulation is common. As a result, the implementation effect of drainage gas recovery technology is not good, it is necessary to study the wellbore fluid flow.

Methods Based on the current situation of fluid accumulation in C01 well area, the Beggs fluid holdup model is revised by using production data and wellbore flow patterns. It is compared with the measured data of the production logging profile, the accuracy of the modified model is verified. Besides, based on the actual shale gas wellbore data, a geometric model of the entire shale gas well was established that realized the simulation of gas-liquid two-phase flow and analyzed the influence of well type on the location of fluid accumulation.

Results When the modified liquid holdup model is applied in shale gas wells, the average relative error is 6.66%, which can provide a more accurate identification of the location of fluid accumulation on site. Numerical simulation results show that down-dip and up-dip shale gas horizontal wells tend to form fluid accumulation in the deflection section.

Conclusions The application of the modified liquid holdup model to calculate the liquid accumulation position shows that the shale gas horizontal well is prone to liquid accumulation in the deflection section. The results of numerical simulation are consistent with the calculated results of the modified liquid holdup model. And the location of wellbore fluid accumulation can be predicted by using the predicted production data.