Evolution of the Tulufan Basin, NW China, and Its Potential for Hydrocarbon Exploration

Mark B. Allen

Production of oil from the Tulufan (Turfan, or Turpan-Hami) Basin is projected to reach 24.5 million barrels a year by the end of 1995. This represents a doubling of the production rate in two years. Upper Permian source rocks have recently been discovered in the basin, similar to the highly productive lacustrine oil shales known from the Junggar Basin to the northwest. These strata are interpreted to have formed in rifts during a phase of sinistral shearing that affected much of NW China and eastern Kazakhstan at this time. Better-known source rocks occur in the Jurassic succession, particularly in the western half of the basin.

The basement structures and rocks of the basin and surrounding ranges of the Tianshan formed during the Late Palaeozoic accretion of island arcs and associated subduction complexes to the Asian continent (Altaid orogeny). Following the proposed Late Permian extension, the region has been dominated by compressional tectonics, the result of the collision of further arcs and continental blocks with the southern margin of Asia. The Tulufan Basin has acted as an intracontinental foreland basin throughout the Mesozoic and Cenozoic, with the accumulation of thick fluvial deposits that form the main hydrocarbon reservoirs.

Productive fields occur in Late Cenozoic anticlinal traps in the western part of the basin, particularly along the Fire Mountains. This uplift within the interior of the basin is a hangingwall anticline developed over a southward-directed thin-skinned thrust. Structures at the northern margin of the basin have a polyphase deformation history, and are another area for possible hydrocarbon accumulations.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995