| Popis: |
Gas well deliquification is the process of removing water or condensate loading from producing gas wells. Water can be loaded into producing gas wells as a result of: an intervention where the well had to be loaded with water or completion fluids because of well control issues; stimulation fluids injected into the well; producible water zone below the gas zone; or well producing wet gas. Whereas, condensate banking can happen both in wet gas wells and retrograde gas condensate wells where condensate loads into the well or banks in the near wellbore region respectively, as a result of producing below dew point. A number of techniques employed to deliquify gas wells include deploying an artificial lift system, installation of velocity string and stimulation. Artificial lift systems can include deployment of electrical submersible pumps, progressive cavity pumps, bean pumps, plunger pumps, and gas lift. Coiled tubing (CT) can be used to nitrogren lift the well or used as a velocity string, and stimulation can cover matrix stimulation or hydraulic fracking of the well. Numerical and analytical software modeling can be performed prior to deploying each of the above mentioned techniques. In this case study after performing intensive modeling, different solutions were proposed but the question is which most efficient and cost effective technique to use?. Thus, In-Well Live Performance CT (I-WLPCT) was the selected technique because it is equipped with downhole pressure, temperature, casing collar and gamma ray sensors along with distributed temperature sensing for real time evaluation of the velocity string, determination of fluid level in the well, conducting surveillance under flow/shut-in test conditions and its results used to validate the software modeling. This paper describes a case study of a retrograde gas condensate well and the challenges encountered during the successful implementation of an engineered approach with the aid of I-WLPCT to successfully select and deploy a velocity string for gas well deliquification. |
