Muruk 2: Drill Stem Test Design and Application

Abstract

Muruk is a recently-discovered gas field located in the Papua New Guinea Highlands, approximately 50 km north-west of the Hides Gas Conditioning Plant. The Muruk 1 well and associated sidetracks, define two separate gas accumulations in the Toro Formation (Muruk A and Muruk B). Both accumulations are sub-hydrostatic with Muruk A being higher pressure than the sub-thrust Muruk B compartment. The Muruk 2 DST was designed to meet the appraisal objectives of producing enough hydrocarbons to measure the pressure transient build up to enable accurate interpretation/evaluation of Original Gas In Place (OGIP). Typically a long term build up test requires the drill rig to stay connected to the DST string to avoid interrupting the main build up, however for a gas well the time required for pressure stabilisation can take weeks, months and even years and therefore can be an expensive operation. To improve accuracy in quantifying the OGIP, the Muruk 2 well adopted a relatively new DST string design that housed the short term (acoustic) pressure gauge system with the long term (Electro-magnetic) telemetry pressure gauges system within the same lower completion body. This meant that the pressure data was a continuous data set from the start of the operation, avoiding the operation of killing the well to implement a long term pressure gauges system and therefore also avoiding interrupting the long term build up data. This paper will discuss the planning, design and execution elements of the Muruk 2 DST, such as determining the appropriate quantity of gas production required to assist with OGIP evaluation, the duration of main build up with the drill rig connected and longevity/reliability of long-term pressure gauge system. A review on the execution of the well test will be covered with particular focus on what was learnt during this operation that can be applied to future DST operations.

AAPG Datapages/Search and Discovery Article #90371 © 2020 AAPG Asia Pacific Region, The 1st AAPG/EAGE PNG Geosciences Conference, PNG’s Oil and Gas Industry: Maturing Through Exploration and Production, Port Moresby, Papua New Guinea, February 25-27, 2020