Tight Reservoir Development

Extraction of oil from the Lower Cretaceous reservoir

Tight Reservoir Development (TRD)
Technology Readiness Level 0

A new work programme that focuses on extraction of oil from reservoirs with low permeability (Tight Reservoir Development, TRD) has been established. One of the reservoirs with low permeability in the North Sea is the Lower Cretaceous reservoir. The marly Lower Cretaceous reservoir in the Danish and Norwegian sectors of Central Graben forms a widespread, yet poorly understood reservoir with possible large deposits of oil and gas. The Valdemar field is the only field in the Danish sector were production is ongoing, so data from this field creates the basis for the forthcoming research in this work programme.

When the Lower Cretaceous reservoir was deposited there was a larger inflow of clay to the reservoir compared to when the younger chalk packages were deposited. The inflow of clay varied during time, which caused the layers in the reservoir to alternate between chalk, marly chalk, organic rich marlstone and marlstone, illustrated in figure 1 to right. The presence of clay in the chalk lead to changes in the rock properties. Most importantly, the clay reduces the ability of which the oil can flow through the reservoir, illustrated in figure 2 below. The low permeability makes it harder to produce oil from the reservoir.

Small permeability

Figure 2.

TRD includes research across the partnership and include projects within a wide range of disciplines from basic reservoir characterization, fracture analysis to the dynamic effects of gas injection.

DHRTC Hypoteses

The program contains five hypotheses, all of which - in different ways - aim to find ways to increase the oil recovery. Each hypothesis has expected deliveries, which typically will come from several work packages. You can find the hypotheses and work packages below.

Results from both work packages and the individual research activities are often included to help answer several hypotheses.

The five hypotheses are:

  • Water injection can help improve recovery
  • Gas injecton can help improve recovery
  • Compaction/subsidence is an important contributor to drive mechanism
  • Natural fractures contribute to flow
  • Reservoir Quality distribution can improve OIIP estimate

The 12 work packages are:

  • Sedimentological and Stratigraphic controls on reservoir properties and heterogeneity (KU IGN, GEUS, AU)
  • Tectonic evolution, structural modelling and 4D deformation analysis (AU, DTU Civil Engineering, GEUS DHRTC)
  • Reservoir characterization, clay content and mechanical/flow properties (DTU Civil Engineering, GEUS, KU Kemi, AU)
  • Seismic modelling and optimal inversion (KU IGN, KU NBI, GEUS, DTU Civil Engineering)
  • Rock Mechanics and Rock Physics Properties for Lower Cretaceous Formations (DTU Civil Engineering, GEO)
  • Gas injection investigations (DTU Kemi, GEUS, DHRTC)
  • Phase behavior in tight reservoirs (DTU Chemistry)
  • Reservoir drive from secondary gas cap development in low permeability reservoirs (DTU KT, GEUS)
  • Screening of Strongly Adsorbing Organic Acid Distributions by ATR Spectroscopy (DTU Chemistry)
  • Feasibility of Microfluidic Core Model Platforms - Phase 1 (DTU Nanotech)
  • Why do four particular wells in North-Jens perform outstandingly? Investigations using a Data Analytical approach (KU Chemistry)
  • Investigation of methane seeps impact on reservoir properties (KU IGN)

Expected key deliveries

  • Sector model/Field scale fracture model
  • Updated OIIP model
  • Geo-mechanical model in 3D QC against 4D
  • Feasibility through simulation of conceptual models - Phase 1
  • Feasibility on water injection with respect to additional sweep of the reservoir 

Collaboration

Partner institutions

Other partners:

Picture Source: Finn Jakobsen et al. 2003, GEUS

Technology Readiness Level

The Technology Readiness Level (TRL) scale is used to measure the maturity of a project. All technologies are evaluated on the same basis of Comparison, which provides a better overall picture. The first step on the scale is research still in the idea phase while step 7 is where the idea has matured into applicable technology.

Read more about how we use the TRL scale at DHRTC here

Ideas
Do you have an idea or a proposal for a research project that can enhance the oil and gas recovery from the Northsea? Send us your proposal here.
http://www.oilgas.dtu.dk/english/research/demonstration-models-and-projects/trd
24 FEBRUARY 2018