Characteristics and Main Controlling Factors of Tenggeer Formation Reservoir in Sanghe Area, Baiyinchagan Sag

Key words: 
• Baiyinchagan Sag /
• Sanghe area /
• characteristics of reservoir /
• main controlling factors

Abstract: Reservoir rocks of Tenggeer Formation in Shanghe area of Baiyinchagan Sag, mainly consists of arkose , lithic arkose and feldspathic litharenite. The main interstitial matter is carbonate, basically comprised by calcite and dolomite. Cementation type is pore cementation. The primary intergranular pores are the main reservoir spaces.The pore structure is characterized by small pore throat radius,poor connection and poor sorting.The reservoir porosity and permeability has a good positive correlation and the reservoir permeability is mainly controlled by the pore abundance.
  The primary controlling factors of reservoirs in this area are sedimentary environment,burial depth and diagenesis.Sedimentary facies, clastic particle's physical property and differences of diagenetic minerals significantly controlled the physical properties of reservoirs. The component of diagenetic minerals are influenced by the sedimentary facies and the lithology at provenance. The 1 6001 900 m well section shows abnormal lower value of physical properties with the plastic minerals such as debris and feldspar significantly increased. Burial depth in this area also have some control effect on physical properties. Generally, reservoir physical properties becomes poor with the increasing of burial depth. In addition, diagenesis have exerted great effects on the proporties of reservoir rocks. The most destructive diagenesis is compaction,  it is one of major affecting factors for poor reservoir physical properties in the study area. Compaction and cementation are the main pore destroyers,  which reduce the pore space and block pore throat. Dissolution play a constructive role in forming secondary solution pores,  it obviously improved the reservoir properties. In 2 0002 200 m range, it developed a dissolution zone. In this zone, the reservoir physical properties become better.
 Transitional area of fan delta plain and fan delta front is the favorable zone in the study area. The transitional zone is a balance area with the joint influence of depositional facies, burial depth and diagenesis. This balance area tends to have the features of proximal  provenance and multiple origins with rapidly deposited sediments, where compaction is the dominate diagenesis. The reservoir physical properties in this balance area is controlled by many factors,  and its favorable physical properties is the contribution of their comprehensive effects.