Tight hydrocarbon reservoirs are a major unconventional reserve. To profitably develop such reserves, horizontal wells and multistage hydraulic fracturing techniques are applied to maximize the reservoir drainage areas and increase reservoir conductivity to the wellbores by creating flow channels in the tight reservoirs. Without in-depth studies that include reservoir characterization, field modeling, well test and production data analysis by a multidisciplinary team, reservoir properties cannot be reproduced and well performance cannot be represented to accurately forecast production. Overestimating or underestimating production rates creates tremendous loss for oil companies or operators. Integrated workflow combines multiple disciplines and professionals for specific projects. The target reservoir is in the central Jungger basin, northern China, which is a green field for tight oil reservoirs with an anticline structure, fault system and unconformity and stratigraphic traps. The paper presents the thorough reservoir characterization, systematic process and reference for a tight oil development plan. The high heterogeneity, low porosity, low permeability and production uncertainty in unconventional reservoirs sped up progress and investment in integrated workflow for reservoir development through risk quantification. This paper presents a systematic study of unconventional resource characteristics, and describes an integrated workflow for reservoir characterization and development of tight oil reservoirs in northwest China which combines geology, seismic, geostatistics, well logging and core data. The process and methodology comprises a geological study, a field geological model with reservoir characterization, petrophysical modeling, numerical well testing, hydraulic fracture modeling based on a geomechanical study and a field reservoir simulation study. Reservoir grid is refined to capture the effect of hydraulic fracture on well performance, calibrate model using well testing and history matching for examining model accuracy, and then finally production of post-fracturing is estimated. This paper also includes the details of sensitivity analysis proposed to address the critical uncertainties and strategy to enhance well deliverability such as well placement, half-fracture lengths, hydraulic fracturing stages and fracture conductivity. The workflow enables the feasibility of coupling multiple disciplines including geology, geophysics, geostatistics, petrophysics and reservoir engineering into an integrated platform for information sharing, project management and strategy using static and dynamic data while simultaneously checking and updating reservoir data.

Unconventional resources play significant role with the increasing demand of hydrocarbon. Horizontal well drilling and multiple-stage hydraulic fracturing are the dominant technology required to achieve economical gas flow rates and improve gas recovery. The accurate prediction of well performance is a major challenge, which involves exploration and evaluation of gas reservoir, proper gas reservoir management, well spacing and hydraulic fractured well design, reservoir simulation and completion process, and reservoir specific issue. The identification and evaluation of tight gas reserves and proper production calculation is the priority. Integration of multi-discipline and multi-scale data is important for field development of unconventional reservoir as compared to the conventional reservoirs.

Characterizing hydrocarbon distribution is one of the most critical and challenging steps, because the initial hydrocarbon saturation determines the original hydrocarbons in place and also subsequent reservoir numerical simulation during the field development stage including history match, production forecast, sensitivity analysis, etc. Accurate hydrocarbon distribution knowledge is vital for optimum reservoir characterization, hydrocarbon exploration and production.For an unconventional reservoir, the distribution of hydrocarbon and water is abnormal and complex compared with a conventional reservoir. The characterization and representation of the reservoir requires a multi-discipline team incorporating geology, geophysics, petrophysics, core analysis, reservoir engineering, etc. to enhance the understanding of reservoir heterogeneity and the target area selected for new development wells during the development phase.

Horizontal wells can increase a reservoir's drainage area and hydrocarbon recovery, but they pose challenges such as early water breakthrough, high water cut and low oil recovery. Water production continues to increase until the economic limit of the well is reached. In a thin-layer water drive reservoir, in particular, the key factors are controlling water coning, extending the water-free production period and controlling water production post breakthrough.This paper details the challenges faced working in horizontal wells, an optimized reservoir Passive Inflow Control Devices (PICDs, called ICD in this paper) mechanism to address such challenges and reservoir simulation analysis in the application of ICDs in China South Sea.Two dynamic reservoir models were built with the same reservoir property inputs but with two well completion types: standalone screen (SAS) completion and ICDs completion. Through the daily oil and water production, cumulative oil and water production, 3D water movement, the performance of an ICD completion were evaluated. The simulation results demonstrate the added value of the ICD completion system compared to a standalone screen completion production and increased oil in a thin-layer bottom water driver reservoir. IntroductionIn a well producing from a bottom water drive reservoir, oil production is promoted by water production. As a primary reservoir drive mechanism, water moves into the pores spaces originally occupied by oil, displacing it to the producing well. Oil withdrawn from the reservoir is replaced volume for volume by encroaching water. In such a scenario, the reservoir pressure remains stable or gradually declines during production. In addition to providing drive energy and displacing oil, an active aquifer poses severe coning issue, typically for vertical wells.A horizontal well is generally more productive than a vertical well and drilling horizontal wells has become an established method of improving recovery of oil and gas. More contact yields a larger reservoir drainage area and less drawdown required to produce the same amount of fluid. Reducing drawdown is a typical technique for a thin-layered water drive reservoir and maximum production rates are limited as a result of coning problems. Although, factors such as heel-to-toe effect, formation heterogeneity, unfavorable oil/water mobility ratio, high reservoir pressure contrast and fractures accelerate early water production, they result in unbalanced oil contributions from the well and low oil recovery.The reservoir formation mentioned in this paper is sandstone with an anticline structure, and immature faults overriding a large aquifer. The production layer is approximately 30ft, which poses difficulties for controlling water breakthrough and high water cut. Furthermore, this thin pay zone is highly heterogeneous and unforable mobility ratio under the reservoir condition. All factors pose challenges for oil recovery.Data from offset wells in this block experienced early water breakthrough and rapid growth of water cu...