Methodology Evaluates Artificial-Lift Requirements Amid High Uncertainty

Topics: Artificial lift
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When evaluating artificial-lift requirements, sometimes data present uncertainties at the initial planning stage. This is the case for a field that had 10 wells drilled but only four of them producing after 6 years, at which point operations were suspended. The high-level plan was to exploit and abandon the reservoir as soon as possible. This paper presents the integrated and structured methodology that was used to deal with the high-uncertainty conditions.

Introduction

ABC is a small field that has 10 wells, out of which only four produced from 1993 to 1999 while the remaining six were shut in after few months of production. Subsequently, the operations in ABC were suspended and the surface facilities were mothballed. Because of attractive remaining reserves along with high reservoir pressure, and considering that this field is in an urbanized area, a plan was requested that would deplete and abandon the reservoir as quickly as possible. Because of the adjusted time frame for the project, developing and planning this task required a preliminary analysis using the available data acquired during the 6 years of operation and some complementary reservoir studies. Because ABC is a complex reservoir with natural fractures and varying condensate composition, the reservoir-model uncertainties were difficult to minimize with data from only four wells and 6 years of history.

Typically, artificial-lift evaluation comes after the reservoir has a good model and a defined exploitation scheme. In this case, the selection of the artificial-lift method dealt with high data uncertainty associated with reservoir pressure, gas/oil ratio (GOR), and ­water-cut profiles because of the reservoir’s complexity and pressure/volume/temperature (PVT) properties. To overcome the uncertainty and advance the study concurrently with an ongoing reservoir-­simulation study, the following approach was adopted:

  • Understand and demonstrate how uncertainty in ABC affects artificial-lift selection.
  • Perform a preliminary artificial-lift-method screening for a matrix covering a range of reservoir pressures, GORs, water cuts, and wellhead pressures in order to discard some methods and focus on possible solutions.
  • Build a matrix to determine the conditions under which the wells flow naturally and those under which artificial lift is required.
  • Determine the probability of the scenarios in relation to the results of reservoir-simulation work.
This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 177436, “A Systematic, Integrated Approach To Evaluate Artificial-Lift Requirements While Dealing With High Uncertainty,” by S. Caicedo, C. Montoya, J. Abboud, and S. Tiar, Abu Dhabi Company for Onshore Petroleum Operations, prepared for the 2015 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 9–12 November. The paper has not been peer reviewed.
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Methodology Evaluates Artificial-Lift Requirements Amid High Uncertainty

20 June 2016

Volume: 68 | Issue: 7

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