Seismic Facies in a Deepwater Area of a Marine Faulted Basin:Deepwater Area of the Paleogene Lingshui Formation in the Qiongdongnan Basin

In recent years, deep water areas have become popular exploration fields because of their abundant hydrocarbon resource potential. There are only relatively poor planar seismic profiles and no wells for deepwater areas of the Lingshui Formation in the Qiongdongnan Basin. A lot of faults developed and strata are fragmented due to high temperatures and high pressure, and this has resulted in dim sequence boundaries. Based on seismic data of the deepwater area and well data of bordering shallow water areas, Lingshui Formation was divided into four third class sequences; namely SI, SII, SIII and SIV, and the three-dimensional isochronous stratigraphic framework of the Lingshui Formation in the studied area was shaped. Based mainly on seismic attributes such as amplitude, continuity, internal structure and external shape, six typical seismic facies were identified, including mat-shaped, filling, wedge-shaped, foreset, moundy-shaped and lenticular-shaped, and a seismic facies distribution map was subsequently drawn. With studies on wells of bordering shallow water areas, regional sedimentary characteristics, and isopach map as references, sedimentary planar distribution features were analyzed. The deepwater area of the Lingshui Formation has mainly developed littoral and shallow sea. Sandstone bodies of fan delta, braided river delta, slope fan, basin floor fan, and turbidite fan are at an interdigitate junction to marine hydrocarbon source rocks and thus are favorable prospecting targets.

Unsupervised seismic facies analysis using sparse representation spectral clustering

Traditional unsupervised seismic facies analysis techniques need to assume that seismic data obey mixed Gaussian distribution.However,fi eld seismic data may not meet this condition,thereby leading to wrong classifi cation in the application of this technology.This paper introduces a spectral clustering technique for unsupervised seismic facies analysis.This algorithm is based on on the idea of a graph to cluster the data.Its kem is that seismic data are regarded as points in space,points can be connected with the edge and construct to graphs.When the graphs are divided,the weights of the edges between the different subgraphs are as low as possible,whereas the weights of the inner edges of the subgraph should be as high as possible.That has high computational complexity and entails large memory consumption for spectral clustering algorithm.To solve the problem this paper introduces the idea of sparse representation into spectral clustering.Through the selection of a small number of local sparse representation points,the spectral clustering matrix of all sample points is approximately represented to reduce the cost of spectral clustering operation.Verifi cation of physical model and fi eld data shows that the proposed approach can obtain more accurate seismic facies classification results without considering the data meet any hypothesis.The computing efficiency of this new method is better than that of the conventional spectral clustering method,thereby meeting the application needs of fi eld seismic data.

Study on the Igneous Rock Seismic Facies in Yingmai 32 Blocks

The western part of north Tarim Uplift underwent multi-stage tectonic movement and multiple stages of magmatism. Igneous rocks are associated with carbonate and buried deep. The seismic response characteristics of igneous rocks are similar in many respects to the seismic response characteristics of karst, making the identification and prediction of igneous rocks more difficult. This study compares the seismic reflection characteristics of igneous rocks. Set up three types of igneous rock seismic facies model penetration type, fracture type and central type. And it concluded that a time-slice, coherence analysis, analysis of the seismic properties of the layers and the method of three-dimensional engraving to identify the igneous rocks. This method has been applied to the identification and prediction of carbonate rock buried and hill igneous rocks in the north Tarim basin YingMaiLi region and has achieved good results.

Study on the Fine Configuration of Reservoir in River Facies Oilfield in Bohai Sea Area

The geological conditions of offshore shallow water delta oil reservoirs were complex, with limited well data and large well spacing. Taking A Oilfield in the Bohai Sea Area, China as an example, the target sand body was formed in a shallow water delta sedimentary environment, with well-developed underwater distributary channels and frequent branching and diversion. The reservoir was strong non-uniformity and uneven plane water cut pressure. To this end, based on the existing work of predecessors, combined with seismic, logging, and production dynamics data, and based on the genesis mechanism of shallow water delta reservoirs, the boundary of composite river channels was identified through seismic facies, and logging facies were used to subdivide them into single river levels within the composite river channels. Then, seismic waveform characteristics were applied to track and characterize the plane distribution of single river channels, guiding the efficient development of offshore shallow water delta oil fields and achieving increased storage and production in Bohai Oilfield, China.

Integrative method in lithofacies characteristics and 3D velocity volume of the Permian igneous rocks in H area, Tarim Basin

This paper introduces horizon control, seismic control, logging control and facies control methods through the application of the least squares fitting of logging curves, seismic inversion and facies-controlled techniques. Based on the microgeology and thin section analyses, the lithology, lithofacies and periods of the Permian igneous rocks are described in detail. The seismic inversion and facies-controlled techniques were used to find the distribution characteristics of the igneous rocks and the 3D velocity volume. The least squares fitting of the logging curves overcome the problem that the work area is short of density logging data. Through analysis of thin sections, the lithofacies can be classified into eruption airfall subfacies, eruption pyroclastic flow subfacies and eruption facies.

Seismic Reflection,Distribution,and Potential Trap of Permian Volcanic Rocks in the Tahe Field

Permian Kaipaileicike （开派雷兹克） volcanic rocks approximately 0-200 m thick are drilled in the Tahe （塔河） field. The distribution of volcanic rocks and their potential to form hydrocarbon reservoirs are discussed based on the integrated interpretation of log and 3D seismic data. The volcanic rocks, mainly consisting of dacites and basalts, are sandwiched between the Lower Triassic and Lower Carboniferous and bounded by top and bottom unconformities. The dacites accumulated in a mound shape around volcanic craters, whereas the basalts are deposited in tabular or trough-fill ge- ometries. Permian volcanic craters mainly located at the northwest corner of the Tahe field are identi- fied from volcanic rock thickening, occurrence of volcanic breccias, structural arch of the top Permian, seismic attribute anomalies, and fault （piercing conduit） reflections. Along the northwest wing of a Carboniferous salt dome, a stratigraphic trap is formed by a northeast updip pinch-out of Permian volcanic rock. Oil indications within the trap are found in numerous wells. The reservoir volcanic rocks are mainly of the fracture-pore pattern and covered by the caprock of a Lower Triassic mudstone. The hydrocarbon reservoir, which can potentially be a medium-sized oil pool, is connected to Camhrian-Ordovician source rocks through normal faults along the salt dome boundary.

Study on sedimentation distribution based on cooperative analysis of geologic-geophysical in less well area: A case study of Suweiyi sandstone in the DB area, Kuqa Depression in Tarim Basin

The Kuqa Depression in Tarim Basin develops fan deltaic,braided river deltaic,and lacustrine sedi-mentation,espeially extensive braided river deltaic sedimentation,in the Cretaceous-Paleogene Sys-tems.However,fine sedimentary pattern of the Kuqa Depression and North Tarim Uplift belt since the Middle Cenozoic still needs to be studied.As a combination zone of the Kuqa Depression and North Tarim Uplift,the sedimentary characteristics of the DB area in the southern margin of the east of the Kuqa depression have been paid more attention.To better understand the sedimentary framework in the Kuqa Depression and North Tarim Uplift in the Mesozoic and Cenozoic,through joint geologic-geophysical study,sedime ntation of sandstone at the bottom of the Paleogene Suweiyi Formation in the DB area and its peripheral area is investigated.Sedimentary facies and sandstone distribution in the area are identified through core observation,component analysis,logging interpretation and seismic inversion.Based on seismic facies analysis,sedimentary facies distribution in the area is delineated.Results show that sandstone at the bottom of the Paleogene Suweiyi Fommation in the DB area and its peripheral area is developed in shore shallow lacustrine beach-bar facies.The beach-bar arenaceous sediments are mainly distnibuted in the southern DB area and the shallow lacustrine mudstone is developed in northern DB area,showing obvious north south di ferentiation charactenistics.