Successful Implementation and Effective Hydraulic Fracturing of Jurassic, HPHT and Tight Carbonate Reservoir in the State of Kuwait: A Case Study of an Exploration Well

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202636, “Fishbone Stimulation: A Game Changer for Tight Carbonate Productivity Enhancement—Case Study of First Successful Implementation at ADNOC Onshore Fields,” by R.V. Rachapudi, SPE, S.S. Al-Jaberi, SPE, and M. Al Hashemi, SPE, ADNOC, et al., prepared for the 2020 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, held virtually 9–12 November. The paper has not been peer reviewed. The operator’s first successful installation of fishbone stimulation technology was aimed at establishing vertical communication between layers in a tight carbonate reservoir and maximizing the reservoir contact. Furthermore, the advanced stimulation technology connects natural fractures within the reservoir, bypasses near-wellbore damage, and allows the thin sublayers to produce. This technology requires running standard lower-completion tubing with fishbone subs preloaded with 40-ft needles and stimulation with the rig on site. Introduction The operator plans to develop tight carbonate reservoirs as part of its production growth strategy. Field Q is a 35×15-km field under development with a phased approach. Phase 1 was planned and production began in 2014. Phase 2 is being developed by drilling wells using the pad concept. Reservoir A, a tight carbonate formation with low permeability ranging from 1 to 3 md and porosity from 15 to 25%, is part of Phase 2 development. The aver-age thickness of Reservoir A is approximately 90 ft across the field, with seven sublayers. The major challenge of Reservoir A development is poor vertical communication and low permeability. Based on appraisal-well data, the average production rate per well is approximately 200 to 400 BOPD with a wellhead pressure of 200 psi. Therefore, appraisal-well testing confirmed the poor productivity of the wells. In addition, the wells are required to produce to the central facilities located in a Phase 1 area 18 km away from Phase 2. In summary, each Phase 2 well is required to be produced against a back-pressure of 500 to 600 psi. Fishbone Stimulation Technology Fishbone stimulation technology is an uncemented-liner rig-deployed completion stimulation system. The liner includes fishbone subs at fixed intervals, and each sub consists of four needles that will connect the sublayers by penetrating into the formation. The typical fishbone completion after installation and jetting the needles in formation is shown in Fig. 1.

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Comprehensive Fracture Characterization in Tight Carbonate Reservoir Using LWD High-Resolution Image and Multi-Pole Sonic Measurement; A Case Study from Offshore North West Java, Indonesia

10.2118/206244-ms ◽

2021 ◽

Author(s):

Debby Irawan ◽

Icuk Dwi Wibowo ◽

Bertha Martinauly ◽

Linda Fransiska ◽

Leonora Ludwina Lilasari ◽

...

Keyword(s):

High Resolution ◽

Open Fracture ◽

Carbonate Reservoir ◽

Fracture Zones ◽

Closed Fracture ◽

Fracture Characterization ◽

North West ◽

Tight Carbonate ◽

Resistivity Log

Abstract Tapping into an unconventional reservoir such as naturally fractured tight carbonate or basement has become more common in the industry. Open natural fractures, when present are the major contributor to production flow in such formation. Therefore, a comprehensive understanding of fracture properties including aperture, intensity, and permeability is required to identify the productive fractures and optimize production. In this paper, we discuss the first application of the latest Logging-While Drilling (LWD) high-resolution laterolog resistivity image in combination with LWD multi-pole sonic to provide comprehensive fracture characterization in Pre-Talang Akar Formation tight carbonate reservoir, in the offshore North West Java Basin, Indonesia. The methodology involved identification of borehole breakouts, natural or drilling-induced fractures, faults and vugs from the high-resolution LWD image data, which were then interpreted further to provide the fracture attributes and the secondary porosity distributions from each of the identified features. The Stoneley measurement from LWD multi-pole sonic log enabled the analysis of the fracture system producibility using the sonic fracture technique. The characterization of fractures and faults (open/closed) from the integration of these two independent methods were complemented by the triple combo measurements, caliper, and drilling loss data, as well as sonic compressional and shear data. This methodology has successfully managed to differentiate open fracture zones and closed fracture zones along with their computed fracture properties. The open fracture zones were characterized by a cluster of conductive fractures with large fracture aperture and fracture porosity value. These fractures were also associated with positive fracture indication from the sonic data, decrease in density logs, shallow - deep resistivity log separation and drilling loss occurrence. Whereas, closed fracture zones were characterized with minor fracture dip development. It also showed negative open fracture indication from sonic data, flat density log response and overlaying resistivity log response with no drilling loss occurrence. The case study in this paper shows excellent LWD data quality and fracture characterization result, on par with wireline conveyed data that were commonly used to quantify fracture attributes. The results provide invaluable information for volumetric calculation, well completion and production planning in this area.

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