The mainly difficult problem of production inadequate return top of slurry and poor bonding cementing hole reaction are discussed in the paper; the effective factors of cementing quality – poor slurry property, lost circulation, poor displacement in long bare hole, and o8il-gas-water migration in the processes of slurry setting are analyzed; the technical countermeasure of enhancing cementing quality and preventing casing corrosive are presented. The previous troubles are solved satisfactorily and marked economic benefit abstained by using these techniques in low temperature, weak and oil-gas-water active formation.
A jet Pump s performances are characterized by its efficiency, cavitation and submerence from different aspects. This paper gives a detailed analysis of the factors affecting the jet pump performances and the law of their change from the three aspects respectively, so as to present a reference for the application of jet pumps in oil fields.
Systematic correlation between the Puguang and Yuanba Gas Fields can guide the natural gas prospecting in adjacent area and reef-bank oil-gas field in other basin. Using the chemical and isotopic composition of natural gases，thin sections， porosity data，and geophysical data，the systematic contrastive research of the origin and resource of nature gas，the scale and property of reservoir，the trap type and process of migration-accumulation，the tectonic deformation and preservation condition between Puguang and Yuanba gas field are summarized. The gas reservoir characters are reflected in four aspects. The difference in carbon isotopic composition of natural gas is related to the thermal evolution and hydrocarbon precursor types of the source rock. The scale of source rock and hydrocarbon potential of Puguang Gas Field is better than Yuanba. The main reservoir of Puguang Gas Field is the oolitic beach dolomite of Feixianguan Formation. In contrast，the reef and the backreef beach dolomite of Changxing Formation is the primary reservoir type of Yuanba. The gas reservoir type of Puguang is structurallithologic reservoir，however，Yuanba is lithologic gas reservoir，with a relatively weak adjustment and reconstruction in the late stage than Puguang. Because of the superposition of multi-phase tectonic movement，fault-fracture system is relatively developed in both Puguang and Yuanba gas field，but regional giant halite cap rock makes most of the gas reserved. The central position of source rock kitchen and sufficient oil-cracking gas，and unbroken halite cap rock are the key to the formation of the two gas fields.
Abstract：Particles suspended in injection water could damage the formation and decrease the permeability. And it’s of great importance to study the impact of various factors on the formation impairment for its prevention and treatment. In our study here，pore scale network modeling method is applied to the study of the formation damage patterns and the change of the porethroat radius under various conditions. In network models，different microcosmic particle variation mechanisms are taken into consideration. The results indicate that the pore-throat radius will decrease with the process of waterflooding and pore-throats that are closer to the inlet face will have a much higher decrease of their radius. Besides，the lower the flow rate is，the higher the particle concentration in injection water is，the lower the fluid viscosity and bigger particle size，it will be beneficial for the formation damage.
Abstract：Severe erosion against the tool joint always leads to rapid failure of the drill pipe in gas drilling. In order to understand the mechanism of this problem，we established the CFD model of the erosion of gas with cuttings against the drill pipe with 18° slope based on two phase fluid theory. According to this model，systematical studies have been made about the effects of different eccentricity，injection volume of gas，and drill rate on the erosion rate against the tool joint，and on the trajectory and distribution of cuttings and gas velocity. The results show that：at the first，when the drill pipe is in the cylindrical center of borehole，the distribution of erosion rate is symmetrical，the erosion against tool joint is more severe than against the drill pipes’ body and the maximum erosion rate is near the windward slope top. Meanwhile，the quantitative relationship between cuttings’ mass flow rate，gas velocity and the maximum erosion rate has been worked out. And then，the maximum erosion rate against the drill pipe and the erosion rate against the tool joint on one side of the wide flowpath are more severe when the drill pipe is eccentric. The maximum erosion is transferred from the joint to the drill pipes’ body when the drill pipe eccentricity from 30% to 70%. The maximum erosion rate against the tool joint increased with the increase of gas velocity when drill pipe eccentricity was at 0～30%，50%～70% and 80%～90%，respectively. But the maximum erosion rate against the tool joint decreased with the decrease of cutting concentration in wide flowpath when drill pipe eccentricity was at 30%～50% and 70%～80%，respectively. All the results from these studies provide the theoretical support for preventing failure of the tool joint and were applied in some oilfields.
Multiple eliminating is always the difficult stage of oceanic seismic data processing. The oceanic seismic data processing of west Madagascar sea has become difficult because of great changes at sea bottom，abnormal growth of multiples and multiples attenuation. This paper analyzes the method and principle of SRME（Surface Related Multiple Elimination）related to free surface，predictive deconvolution and parabolic Radon transformation. According to the characteristics of methods above， we make a united solution，that is using SRME to eliminate the surface related multiples，using predictive deconvolution to attenuate the multiples generated between layers and using parabolic Radon transformation to eliminate the residual multiples. The processing results after applying above methods show that the progressively united multiple solution can do a good job in oceanic seismic data multiple elimination，especially for those whose sea bottom depth changes in great range.
