Sedimentary Microfacies Model Research Articles

Prediction of Sedimentary Microfacies Distribution by Coupling Stochastic Modeling Method in Oil and Gas Energy Resource Exploitation

In view of the problem that a single modeling method cannot predict the distribution of microfacies, a new idea of coupling modeling method to comprehensively predict the distribution of sedimentary microfacies was proposed, breaking the tradition that different sedimentary microfacies used the same modeling method in the past. Because different sedimentary microfacies have different distribution characteristics and geometric shapes, it is more accurate to select different simulation methods for prediction. In this paper, the coupling modeling method was to establish the distribution of sedimentary microfacies with simple geometry through the point indicating process simulation, and then predict the microfacies with complex spatial distribution through the sequential indicator simulation method. Taking the DC block of Bohai basin as an example, a high-precision reservoir sedimentary microfacies model was established by the above coupling modeling method, and the model verification results showed that the sedimentary microfacies model had a high consistency with the underground. The coupling microfacies modeling method had higher accuracy and reliability than the traditional modeling method, which provided a new idea for the prediction of sedimentary microfacies.

Reservoir Modeling of Braided River Reservoirs Based on Geological Knowledge Database: A Case Study of P1x Formation of the Daniudi Gas Field, Ordos Basin, China

Abstract The sandy braided river depositional system developed in the Lower Shihezi Formation of the Daniudi gas field, Ordos Basin. It has the characteristics of frequent migration and oscillation of braided channels and large well spacing, making it challenging to portray the braided river sand body in this area, bringing uncertainty to the 3D geological modeling of the reservoir. This study takes the primary gas reservoir H1 member as an example. It establishes a quantitative geological knowledge database for the reservoir by statistically fitting the correlation equations between the braided channel and channel bar in the planes and profiles to reduce the uncertainty of reservoir modeling. This study combines the multisource and multiscale information from modern sedimentation, field outcrops, and tank simulation experiments of the braided river. From the data, the distribution intervals for the thickness and width of the braided channel sand body in the H1 member are 1–22 m and 7–320 m, respectively, and the thickness, width, and length distribution intervals of the sand body in the channel bar are 3–30 m, 80–1500 m, and 240–4200 m, respectively. A 3D training image is established using the object-based simulation method based on the H1 member’s well data and combining the quantitative parameters of various microfacies in the geological knowledge database. The multiple-point geostatistical modeling method is applied to establish a sedimentary microfacies model. The model’s uncertainty is reduced through multi-information fusion constraint modeling, providing a reliable basis for guiding the prediction of the remaining gas in the Daniudi gas field.

Facies-Controlled Geostatistical Porosity Model for Estimation of the Groundwater Potential Area in Hongliu Coalmine, Ordos Basin, China.

Accurate and reliable evaluations of potential groundwater areas are of significance in the hydrogeological assessments of coalfields because water inrush disasters may be caused by unclear groundwater potential. A three-dimensional geological model of porosity based on deterministic modeling and a facies-controlled method are used to determine the groundwater potential of the coal measure aquifer. The modeling processes are as follows: based on the interlayer and discontinuity (faults) data extracted from boreholes and geological maps, an integrated sequence framework model is developed. Using the results of sedimentary microfacies identification and the method of deterministic modeling, a sedimentary microfacies model is successfully established. Finally, based on facies-controlled and sequential Gaussian methods, an effective porosity model is established that can predict the groundwater potential. The predicted results show that sandstones sedimented in channel, point bar, and batture environments possess high effective porosity and strong groundwater potential; however, the sandstones sedimented in interdistributary bays, flood plains, and sand sheets possess low effective porosity. Model validation was performed based on the hydrological pumping test data collected from observation boreholes, drainage water inflow data from dewatered boreholes in the tunnel around workface, and the mine water inflow in tunnels and the workfaces. The validation analysis results show that the effective porosity and sedimentary facies were correlated with the actual flux. The predicted results are consistent with the actual flux data, validating the predicted model.

Modeling of dense well block point bar architecture based on geological vector information: A case study of the third member of Quantou Formation in Songliao Basin

Abstract Although stochastic modeling methods can achieve multiple implementations of sedimentary microfacies model in dense well blocks, it is difficult to realize continuous convergence of well spacing. Taking the small high-sinuosity meandering river sediments of the third member of Quantou Formation in Songliao Basin as an example, a deterministic modeling method based on geological vector information was explored in this article. Quantitative geological characteristics of point bar sediments were analyzed by field outcrops, modern sediments, and dense well block anatomy. The lateral extension distance, length, and spacing parameters of the point bar were used to quantitatively characterize the thickness, dip angle, and frequency of the lateral layer. In addition, the three-dimensional architecture modeling of the point bar was carried out in the study. The established three-dimensional architecture model of well X24-1 had continuous convergence near all wells, which conformed to the geological knowledge of small high-sinuosity meandering river, and verified the reliability of this method in the process of geological modeling in dense well blocks.

Combining sedimentary forward modeling with sequential Gauss simulation for fine prediction of tight sandstone reservoir

A considerable number of tight sandstone gas fields are observed in the Xihu Depression, East China Sea. The Y gas field is at the stage of development. It is necessary to describe the reservoir shape and permeability characteristics in detail to deploy development wells. The seismic prediction effects of tight sandstone are not good. Sedimentary forward modeling technology can effectively predict the macroscopic characteristics of sedimentary sand bodies, but this technique lacks micro-details. Geostatistical modeling can depict reservoir details, but this technique cannot easily reflect macro-laws. Therefore, taking H1 layer of the Oligocene Huagang Formation in the Y gas field as an example, the combination of sedimentary simulation and geostatistical modeling is proposed. Geostatistical modeling is combined to describe reservoir details by using the sequential Gauss simulation method under the control of sedimentary simulation results as macro-laws. First, based on the test data and the sensitivity test results of the adjacent study area, five parameters (transport capacity of the river, sand ratio, maximum initial water depth, lake level change, and tectonic subsidence) needed for the simulation are determined. A sedimentary forward simulation is carried out, and a sand ratio model reflecting macroscopic sedimentary law is obtained. Second, in the geostatistical modeling stage, the variogram which has a great influence on the results of geological modeling is discussed. The results show that the larger the length and width of the variogram, the larger the simulated reservoir scale. Then, considering the characteristics of fewer wells in the study area, a reliable variogram is obtained by using the sand ratio results of the sedimentary simulation (2538 m in length and 876 m in width) and the main input parameters of geological modeling (data probability distribution characteristics and variogram) are determined. Subsequently, under the trend of the sediment sand ratio simulation, geological modeling research was carried out by using the sequential Gauss simulation method, and a high-precision sand ratio prediction model was established. Finally, the sand ratio model is transformed into a sedimentary microfacies model and the permeability characteristics of different sedimentary microfacies are calculated. Under the control of sedimentary facies, the permeability model is established by the sequential Gauss simulation method. The model prediction results show that the simulation results can reflect the morphology, distribution and permeability of sedimentary microfacies in detail and the macroscopic characteristics of delta sedimentary law. The permeability of channels in the study area is 0.3 md, and the distribution area is much larger than that of other types of sedimentary microfacies. Compared with other types of deposits, the channel around well A area has better development potential in the front of the delta and is the most favorable oil and gas development area in the study area.

Study on Geological Modeling of Heidimiao and Fuyang Oil Layer in Da’an North Area

In this paper, through the study of reservoir geological modeling, the reservoir modeling software is used to establish the reservoir 3D geological model; combined with the sedimentary microfacies research results, the reservoir sedimentary microfacies model is established; using geostatistics and stochastic simulation methods, the small layer performs stochastic modeling of porosity, permeability and oil saturation properties, and establishes a three-dimensional model of the properties under the control of reservoir sedimentary facies.

Study on facies-controlled model of a reservoir in Xijiang 24-3 oilfield in the Northern Pearl River Mouth Basin

To better understand the internal structure of the Xijiang 24-3 Oilfield in the Northern Pearl River Mouth Basin, a reasonable and effective three-dimensional quantitative geological model is needed to characterize the distribution characteristics of the reservoir. Xijiang 24-3 Oilfield is a braided river delta deposition, which contains many sedimentary microfacies in three subfacies zones. The reservoir structure is complex and heterogeneous. The reservoir modeling research was conducted on the Xijiang 24-3 oilfield H3A reservoir. Analysis of the oilfield core, the well-logging, and seismic data, establish a regional structural model. The regional sedimentary microfacies model is simulated by multi-point geostatistics. The reservoir property model is established by using facies-controlled modeling technology with sedimentary microfacies as a constraint condition. A facies-controlled property model and a non-facies-controlled property model are established respectively. The facies-controlled model corresponds well with the sedimentary microfacies of the reservoir, and the variation trend of the model shows a higher coincidence rate with the distribution characteristics of the well. The facies-controlled model reflects the spatial distribution characteristics of the physical properties of the underground reservoir and is in accord with the actual geological understanding of the reservoir. This model also provides a reliable basis for the next stage of reservoir description and a basis for further exploration and development work. Cited as : Zheng, L., Chen, C., Lu, C., Cheng, M. Study on facies-controlled model of a reservoir in Xijiang 24-3 oilfield in the Northern Pearl River Mouth Basin. Advances in Geo-Energy Research, 2018, 2(3): 282-291, doi: 10.26804/ager.2018.03.06.

Reservoir characteristics and three-dimensional architectural structure of a complex fault-block reservoir, beach area, China

The objective area in this paper is a complex fault-block reservoir, which is provided by China Petroleum Engineering Design Competition. Reservoir characteristics which comprise of stratigraphic features, vertical changes, and section properties (thickness, percentage sand, and percentage amalgamation) are documented. Through comprehensive analysis on structural architecture and reservoir characteristics, a three-dimensional quantitative reservoir modeling is taken at a regional scale of 69 × 97 × 37 m3 with the application of geostatistics as theoretical guidance. Then, a high-resolution hierarchical reservoir model of this field has been generated with a combination of hierarchical, structural, physical, and well trajectory data. The established three-dimensional geological model integrates all well and structural information, which can provide a basic model for subsequent sedimentary microfacies modeling and property modeling as well. Finally, a series of profiles are built successively, they are three-dimensional fence diagrams, connecting well sections and well group profiles, which can be a valuable tool for reflecting geologic body with great reality and thus achieve reservoir characterization of the complex fault-block reservoir.

Reservoir Characteristics and Three-dimensional Architectural Structure of a Complex Fault-block Reservoir, Beach Area, China

The objective area is a complex fault-block reservoir, and is provided by China Petroleum Engineering Design Competition(CPEDC). Reservoir characteristics, including stratigraphic features, vertical changes and section properties (thickness, percentage sand and percentage amalgamation) are documented. Based on comprehensive analysis on structural architecture and reservoir characteristics, a three-dimensional quantitative reservoir modeling is taken at a regional-scale of 69×97×37 m3 with the application of geostatistics as theoretical guidance, and thus high-resolution hierarchical reservoir model is generated with a combination of hierarchical data, structural data, physical data and well trajectory data. Therefore, the established three-dimensional geological model integrates all well-point information and structural information, and provides a basic model for subsequent sedimentary microfacies modeling and property modeling as well. Finally, three-dimensional fence diagrams, connecting-well sections and well group profiles are built successively.

A three-dimensional high-resolution reservoir model of the Eocene Shahejie Formation in Bohai Bay Basin, integrating stratigraphic forward modeling and geostatistics

Reservoir characterization based on geostatistics method requires well constraints (e.g. seismic data with high quality) to predict inter-well reservoir quality that is conformed to geological laws. Nevertheless, the resolution of seismic data in multiple basins or reservoirs is not high enough to recognize the distribution of different types of sand bodies. In this paper, we propose a new method to improve the precision of reservoir characterization: reservoir modeling with the constrains of sedimentary process model and sedimentary microfacies. We employed stratigraphic forward modeling, a process-based method, to constrain the reservoir modeling in one oil-bearing interval of the third member of Eocene Shahejie Formation in J-Oilfield of Liaoxi Sag, Bohai Bay Basin.We divide reservoir modeling into two orders using different types of constrains. In the first order, we use the simulated shale model from stratigraphic forward model that is corrected by wells data as a 3D trend volume to constrain the reservoir sand-shale modeling. In the second order, different types of sedimentary microfacies in the sandy part of the model are further recognized and simulated within the constrains of sedimentary microfacies maps. Consequently, the porosity, permeability and oil saturation are modeled under the control of precise sedimentary microfacies model. The high-resolution reservoir model shows that the porosity, permeability and oil saturation of distributary channel is generally above 20%, 10md and 50%, respectively, which are much higher than that of other types of sedimentary microfacies. It can be concluded that comparing to other types of sedimentary facies, distributary channel has better physical properties and more oil accumulation in the fan-delta front and therefore is the most favorable zones for petroleum development in the research area.

Sedimentary Microfacies and Porosity Modeling of Deep‐Water Sandy Debris Flows by Combining Sedimentary Patterns with Seismic Data: An Example from Unit I of Gas Field A, South China Sea

AbstractSandy debris flow deposits are present in Unit I during Miocene of Gas Field A in the Baiyun Depression of the South China Sea. The paucity of well data and the great variability of the sedimentary microfacies make it difficult to identify and predict the distribution patterns of the main gas reservoir, and have seriously hindered further exploration and development of the gas field. Therefore, making full use of the available seismic data is extremely important for predicting the spatial distribution of sedimentary microfacies when constructing three‐dimensional reservoir models. A suitable reservoir modeling strategy or workflow controlled by sedimentary microfacies and seismic data has been developed. Five types of seismic attributes were selected to correlate with the sand percentage, and the root mean square (RMS) amplitude performed the best The relation between the RMS amplitude and the sand percentage was used to construct a reservoir sand distribution map. Three types of main sedimentary microfacies were identified: debris channels, fan lobes, and natural levees. Using constraints from the sedimentary microfacies boundaries, a sedimentary microfacies model was constructed using the sequential indicator and assigned value simulation methods. Finally, reservoir models of physical properties for sandy debris flow deposits controlled by sedimentary microfacies and seismic inversion data were established. Property cutoff values were adopted because the sedimentary microfacies and the reservoir properties from well‐logging interpretation are intrinsically different. Selection of appropriate reservoir property cutoffs is a key step in reservoir modeling when using simulation methods based on sedimentary microfacies control. When the abnormal data are truncated and the reservoir properties probability distribution fits a normal distribution, microfacies‐controlled reservoir property models are more reliable than those obtained from the sequence Gauss simulation method. The cutoffs for effective porosity of the debris channel, fan lobe, and natural levee facies were 0.2, 0.09, and 0.12, respectively; the corresponding average effective porosities were 0.24, 0.13, and 0.15. The proposed modeling method makes full use of seismic attributes and seismic inversion data, and also makes the property data of single‐well depositional microfacies more conformable to a normal distribution with geological significance. Thus, the method allows use of more reliable input data when we construct a model of a sandy debris flow.

Geostatistical modeling for fine reservoir description of Wei2 block of Weicheng oilfield, Dongpu depression, China

The Wei2 block of Weicheng oilfield is characterized by complicated structure mainly caused by high degree of fault development. Multiple reservoir types are found in this block and the reservoir heterogeneity is severe. The oil and gas reservoirs have already stepped into the stagnant stage of a great water-cut degree together with a rapid production decline rate. Thereby, both stabilizing the oil and gas production and optimizing adjustment for further exploitation make it urgent for geomodelers to build a useful model to predict the inter-well parameters and the distribution of the remaining oil and gas. A three-dimensional geological model established with the help of stochastic modeling technique may provide a perfect window and carrier for fine structure interpretation and reservoir heterogeneity description, compared with a traditional two-dimensional model. Hence, based on stratigraphical layering points, significant surfaces and fault points as well seismic interpretation, an integrated structure model is developed. Using the truncated Gaussian simulation and taking the existing geological maps as references, the sedimentary microfacies model was successfully constructed. Through the use of sequential Gaussian simulation method and the facies-controlled modeling method, the reservoir physical properties are populated. Meanwhile, the comparison between facies-controlled and non-facies-controlled property models indicates that the former is more loyal to previous researching and the representation of heterogeneity is ideal. Finally, the ideas of sample density and reserves fitting are proposed to evaluate the practicability and accuracy of the property models.

3-D geological modeling for tight sand gas reservoir of braided river facies

Abstract Considering the poor applicability of conventional geological modeling to tight sand gas reservoir in braided river facies, a modeling method of “multi-stage constraints, hierarchical facies control and multi-step modeling” was put forward taking Sulige gas field in Ordos Basin as the study object. The method obtains the GR field by seismic inversion constrained by logging data, and GR model is built under the control of the prior geological knowledge; the relation regression is realized between the GR model and the sandstone probability, sandstone probability model is built, and rock facies model is obtained by multi-point geostatistics theory; sedimentary microfacies model controlled by rock facies and braided-river-system is made; and eventually an effective sand body model is built by integrating sedimentary microfacies, effective sand body scale and reservoir properties distribution. The research method discussed in this paper has put geological constraints into the model as far as possible, enhanced the inter-well sand body predictability and improved the precision rate, thus it can provide a more reliable geological basis for gas reservoir development.

Application of Facies-Controlled Physical Property Modeling in Oubei Block, Jinhu Depression

Three dimensional (3D) models provide insights into the distribution, external and internal geometry of the reservoirs. The core description shows that the fourth segment of Funing Formation (E1f4), Oubei Block, Jinhu Depression mainly develop delta front subfacies which included underwater distributary channel, mouth bar, sand sheet and so on. Well data and structural maps were integrated to build 3D structure model and sedimentary microfacies model of Oubei reservoirs using stochastic simulations with geometry data. The result of facies-controlled property model can reasonably reflect reservoir characteristics in detail, providing a reliable geological model for late reservoir adjustment and valuable reference for numerical reservoir simulation as well.

Application of Reservoir Geological Modeling in the Wang Longzhuang Block

Wang Longzhuang Block has entered the middle or later stage of high water cut and high recovery, quantity of remaining oil still remain in the reservoirs. The paper establishes the fine three-dimensional geological modeling on the basis of reservoir description of Wang Longzhuang Block, including the structure modeling, sedimentary microfacies modeling, reservoir parameter modeling and liquid distribution modeling, which forming the fine reservoir description of three dimensional visualization, and those provide evidences for the studies of the distribution of remaining oil in Wang Longzhuang Block.

Fine description of structure and sedimentary microfacies of Li32 block of Lijin oilfield, Dongying depression, China

Considering that available data in Li32 block is limited, log phase method and core analysis were used to divide sedimentary facies and sequence, the former is principal, and two short-term cycles, five middle term cycles, and fifteen short-term cycles were divided. Combined seismic interpretation with fault point and fault rod, the instantaneous phase profile explained small fault more clearly and accurately. The sever faults were analyzed, and integrated structure was constructed. Lithofacies in cored wells were observed; the grain-size probability curves mainly are suspension and jumping transport; grain size is mainly for the siltstone and fine sandstone; the color of mud in the second segment of Shahejie formation (ES2) is mainly gray–green, gray to dark gray, these reflect that sediment environment is delta front, which included underwater distributary channel, mouth bar, distal bar, and so on. Well data and structural maps were integrated to build 3D structure model and sedimentary microfacies model of Li32 reservoirs using stochastic simulations with geometry data. The integrated 3D geological model is a valuable tool of reflecting geologic body with great reality and can accurately represent and describe the complex reservoir heterogeneity.

储层建模技术在羊二庄油田明馆储层油藏描述中的应用<br>Application of Reservoir Modeling in Description of Minghua and Guantao Reservoir in Yangerzhuang Oil Field

羊二庄油田明馆储层均为河流相沉积，由于曲流河的侧向迁移和辫状河河道的多期叠加造成储层非均质性严重。目前进入高含水、高开发后期，剩余油分布比较复杂，第一次油藏描述中应用传统的确定性建模方法已经不能满足剩余油挖潜描述的需要。为了解决上述问题，采用了RMS相控建模软件，通过构造建模、沉积微相建模、储层物性建模建立羊二庄油田三维可视化相控地质模型，并实现了与数模软件的无缝接口。 The Minghua and Guantao reservoir in Yangerzhuang oil field pertain to fluvial facies, so the lateral migra- tion of Meander River and the multi-period superposition of braided channel lead to the serious reservoir heterogeneity. It is the time of last period of high cut and high development at present, residual oil distribute more complicated. Tradi- tional deterministic modeling adopted in the first description of reservoir can’t meet the excavation of residual oil. In order to solve the problems mentioned above, RMS phase-control modeling software is adopted to establish the three- dimensional visible phase-control geographical model in Yangerzhuang oil field by setting up structural modelling, sedimentary microfacies modeling and reservoir property modeling, which has realized the seamless interface with nu- merical simulation software.

Application of facies-controlled modeling technology to the fault-block A11 in A'Nan Oilfield

Abstract The fault-block A11 in the A'Nan Oilfield of the Erlian basin is now at a high water-cut period, and its reservoir heterogeneity has severely affected development results. To accurately describe the reservoir and its through-going characteristics, this article establishes a structural model, a sedimentary microfacies model, and a microfacies-controlled petrophysical model, step by step, using facies-controlled modeling technology with multiple stochastic modeling methods and on the basis of study results on seism, logging, geology, and development performance. The correlation of analogy results between facies-controlled petrophysical parameters and direct petrophysical parameters reveals that the facies-controlled attribute model is more reliable in describing reservoir heterogeneity. The successful application in the A'Nan Oilfield shows that facies-controlled modeling technology can satisfactorily realize the petrophysical parameter analogy of reservoirs with quick-change sedimentary microfacies and severe heterogeneity, providing a dependable geological basis for the later development and adjustment of oil and gas fields.