Research On Wellbore Trajectory Predict Technology Based On CPR-LWD In Jianghan Oilfield

Based on the real-time geographical information and directional data provided by LWD equipment, Geosteering drilling is a technology that can identify the geographical environment the drill is dealing with and predict what kind of geographical environment the drill will meet. In this way, we can lead drill dig into oil layer and make sure that well can extend along oil layer. This tech needs to measure multiple kinds of underground information as premise. The underground information is divided into two categories:one is geographical parameters including resistivity, natural gamma litho-density, neutron porosity, sonic, dipmeter and other. The other one is industrial parameters including engineering parameters, including inclination, azimuth, tool face angle, and bottom hole pressure. At present, in China geographical directional equipment is used to measure four geological parameters, resistivity, natural gamma litho-density, neutron porosity, these two geographical parameters can satisfy geographical-guided demands. Among these parameters, CPR is Compact Propagation Resistivity. The technology claimed above is a combination of drilling technology,well detecting tech and oil conservation industrial tech.Also, controllability of trajectory’s track is enhanced while drill is working in the reservoir. The application of this tech plays an important role in improving the accuracy of drilled stratigraphic geological structure and the reservoir characteristics, which brings huge economic profit in increasing productivity and reducing costs.In Jianghan oilfield,there are plenty of naturally formed complicated hidden reservoir, thin reservoir,the remaining edge and bottom water reservoir remained in long-term developed old oilfield. As technology backup, geographical-guidedl tool provides us a powerful technological guarantee when developing these kinds of reservoirs. In2009, CPR-LWD equipment was brought in from Britain’s Geolink, while research of techniques supporting geographical guide were also carried out.This thesis was written under the background of Jianghan Oilfield’s highly focused project "The Promotion And Application of CPR-LWD Geosteering Inclinometer" to study the prediction while drilling about the geosteering drilling well trajectory. First, the method of longitudinal and transverse was applied to compute mechanic of drilling tool sets, which is used to be combined with practical data statistic in order to analyze generally used drilling tools’effect to build-up rate of BHA in Jianghan oilfield. Then, prediction model of generally used drilling sets’build-up rate of BHA was founded using multiple regression methods to generate a more precise forecast of drilling sets’build-up rate of BHA. Base on those work above, the prediction models about geosteering drilling borehole trajectory were set and each different drilling method was corresponded to a certain suitable prediction model, also, application system of well trajectory prediction and its control was developed. Using these models and systematic software, computation of Jianghan oilfield region’s actual drilling data, analysis of predicted results can be done to instruct geographical guided drilling and realize the prediction and control of well track.Based on the research of the borehole trajectory control on the geosteering drilling, this thesis claims a set of CPR-LWD optimized and fast geographical guided drilling supporting technology, which is suitable for Jianghan oilfield and show promotion and application of CPR-LWD geosteering inclinometer of Jianghan oilfield a practical and applicable technical method.Main contributions of this thesis are listed as followed:1. Combining actual drilling data and theoretical computation of tool’s build-up rate, multiple regression model is founded to increase precision of tool’s build-up rate, which can precisely predict the build-up rate of generally used BHA in Guanghua and Haokou two regions of Jianghan oilfield and keep the result difference within5%.2. Through the research of tool’s build-up rate and well trajectory prediction model, well trajectory prediction and control software was complied.It can be combined with the geological real-time information to predict and control well trajectory through the graphical by the two-dimensional map to display and monitoring the status and future direction of the trajectory real-time,which was successfully applied in several wells,such as Guang2Ping7.